Optical recording method, optical recording device, master medium exposure device, optical information recording medium, and reproducing method

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an optical recording apparatus for making a master by exposure process (exposure apparatus for making a master), an optical recording medium and information reproducing method which use the decoding by the maximum likelihood scheme such as PRML, an optical recording device. In particular, the present invention relates to a technique of recording the optimum recording conditions of implementation of the adaptive write compensation at least according to the length of the blank for gaps preceding interested mark and following it, in order to reduce the optical intersymbol interference or thermal interference due to the recording or reproducing tags or pits, which is considerably smaller than the spot diameter of the light beam. The present invention also relates to a technique of recording the optimum recording conditions of implementation of the adaptive recording compensation according to the lengths of spaces to spaces preceding interested mark and following it, and further, the lengths of labels to tag spaces preceding and following them.

In this specification, the direction in which the spot of the light beam at a specific position is moved along the optical information recording medium (the optical disc medium) due to rotation of the optical disk medium is called "rear / downstream" and the opposite direction with respect to a certain position is referred to as "front / preceding" .

BACKGROUND

Conventional standards of optical disc media include BD-R, BD-RE, DVD-RAM, DVD-R, DVD-RW, CD-RW, etc. There are techniques to overwrite or sequential recording of data by emitting laser light onto the optical disk storage, that are consistent with these standards.

EXAMPLE optical disc media is an optical disk medium based on the phase transition. Recording information on an optical disc medium on the basis of the phase transition is realized by irradiating an optical disc medium with laser light to locally change the state of a covalent bond material thin film formed on the recording surface of the film under the influence of laser light energy. Irradiation of laser light changes the physical state of the irradiated area and the surrounding area. In particular, the crystalline state and an amorphous state have different reflection coefficients. Since the difference in the physical state leads to a difference in reflectance, information can be read by irradiating the disc with laser light considerably less power than that used in recording and detecting the change amount of reflectivity.

Examples of optical disk media for phase change include recordable media where GeSbTe material is used as the recording material for the recording layer, optical disc write once media. Patent Document 1 discloses a number technique using a material containing Te-OM (wherein M - at least one of metal elements, semimetal elements and semiconductor elements) as an example of the optical recording material is a write-once disc media. Te-OM is a composite material which contains Te, O, and M. Immediately after the film formation, particles Te, Te-M and M dispersed uniformly and randomly throughout the matrix of TeO2. Irradiation of a thin film formed of this recording material by a focused laser light causes the melting of the film, which in turn leads to precipitation of crystals Te or Te-M with a large grain size. The change of the optical state caused by this process, it is possible to detect the signal. This provides a recording mode in which recording can be performed only once in the same area, so-called write-once mode.

In the write-once disc based alloy made of an inorganic material, two thin films made of different materials are combined into a laminate. These materials are heated by laser to melt, causing the materials are mixed with each other to form the alloy, thereby forming the recording mark. In another known optical disc medium of another write-once type, such as the temperature is increased by laser irradiation to thermally decompose organic pigments of an organic pigment material, and the refractive index change unfolded portion decreases, whereby the recorded information. In the optical disc medium once recording this type, the principle of recording information is that the optical path length of the light transmission layer in the recorded portion is less than a blank portion that creates an effect like pits concavity / convexity, e.g., CD read-only feed light.

In the case of recording marks on the edges of this optical disc medium write-once optical disc medium is irradiated with laser light consisting of a plurality of pulse series, called "multiimpulsami", whereby the physical state of marks is changed, whereby information is recorded. The information is read by detecting the change in reflectance.

A possible measure to increase the recording density is, typically, a decrease in the length of marks and spaces which are to be recorded. However, especially when the length of the blank, which is preceded by a recording mark decreases, there is thermal noise, due to which the heat at the trailing end of the recorded mark is passed through a portion of space, resulting in an increase in temperature at the front end of the subsequent label, and on the other side , the heat at the front end of the recorded mark affects the cooling cycle at the rear end of the previous mark. Even when marks and spaces formed on a track have correct lengths, edge positions of short marks and spaces which are detected in reproduction adversely different from their ideal values ​​due to the frequency characteristics of the reproducing optical system which depend on the size of the laser spot. Deviation detected edges from the ideal values ​​are generally referred to as "intersymbol interference". When the sizes of marks and spaces smaller than the laser spot, large intersymbol interference occurs, and accordingly, the jitter in reproduction is increased, because of which the bit error rate increases.

When recording densities typical for DVD and BD, the dimensions of marks to be recorded, and the distance between the marks and spaces are small. As a result, the heat of the laser light used for forming a mark not only reaches the area intended for the label, but also passed through the gaps, reaching the areas for preceding and succeeding marks, so that deformation can sometimes occur interested mark and the preceding and succeeding marks. There are those nicknames to avoid this problem, for example, the technique changes the position of the front pulse multiimpulsa to generate labels varies according to the ratio of the length of the interested mark and the length of a space followed by the label, and technology changes position adjustable pulse multiimpulsa to generate labels varies according to the ratio of the length of the interested mark and the length of a space with the preceding mark. These techniques are techniques of recording marks with preliminary amendments to the thermal noise recording marks. This mode of control of the write pulse position is generally referred to as adaptive recording compensation. Patent Document 2 discloses a number of such a method adaptive recording compensation.

According to the recording method disclosed in Patent document number 2, a recordable optical disc medium contains pre-recorded reference conditions of a recording pulse that allows to set the positional information of write pulses for a respective one of a plurality of possible combinations of length of mark lengths gap followed by a label or the length of a space with the preceding label. The recording apparatus retrieves the write pulse reference conditions from the optical disc medium to modify currently-effective standard recording pulse conditions for optimum recording pulse conditions.

In particular, the positional information is established for all combinations of lengths of marks and the lengths of spaces to a space followed by the label included in the reference conditions of the write pulse, or all combinations of lengths of marks and the lengths of spaces for space with the preceding mark included in the reference conditions of the write pulse, used to perform the first test writing on the target track on the optical disc medium. The information recorded at the first trial recording, playing, and the playback signal is detected first tremor. Changing the first predetermined value is added uniformly to the position information for the respective all combinations of lengths of marks and lengths of spaces included in the write pulse reference conditions. Homogeneous change positional information is used to perform the second test writing on the target track on the optical disc medium. The information recorded in the second test recording, playing, and the playback signal is detected the second tremor. At the last stage of the first jitter and second jitter are compared, and the positional information that is used in the trial record, generating less jitter, selected for the write pulse conditions.

Recording control methods disclosed in patent document number 3, number Patent Document 4 and Patent Document 5 number, a method for decoding by the maximum likelihood scheme, but uses the values ​​of jitter in the reproduced signal for preliminary evaluation signal pattern from a reproduced signal waveform. When comparing the reproduced signal waveform and the estimated signal waveform, the reproduced signal is converted by decoding into decoded data which has a signal path with the maximum likelihood. This method is used to optimize the recording of recording information in order to minimize the likelihood of errors in the decoding process according to the scheme of maximum likelihood.

In recent years, increasing the density of optical disk media leads to the fact that the lengths of recording marks are close to the limit of optical resolution, and therefore is an increase in intersymbol interference and decrease in SNR (signal / noise).

Systemic tolerance can be maintained using the method PRML higher order. For example, Patent Document 1 discloses a number that in the optical system, wherein the laser wavelength is 405 nm and NA (numerical aperture) of the lens is 0.85 and the recording density is such that the disc Blu-ray (BD) 12 cm has a capacity of 25 GB (gigabytes) of data in the recording layer, the admission system may be maintained by use of the method PR (1, 2, 2, 1) ML. This document also discloses that, in a case where the linear density is increased by reducing the length of the label for maintaining a capacity of 25 GB or more (e.g., 30 GB or 33.4 GB) per layer data record by using the same optical system, it is necessary to apply the method PR (1,2,2,2,1) ML.

The patent document number 6, patent document number 7 and Patent Document 8 discloses a number of different optimization recording parameters by adjusting the write pulse waveform based on the quality of composite data in accordance with the method PR (1,2,2,2,1) ML if optical storage media with high recording density of 30 GB to 33.4 GB per data recording layer.

Bibliography

Patent Literature

Patent Document number 1: Japanese Patent Publication № 2004-362748

Patent Document number 2: Japanese Patent Publication № 2000-200418

Patent Document number 3: Japanese Patent Publication № 2004-335079

Patent Document number 4: Japanese Patent Publication № 2004-63024

Patent Document number 5: Japanese Patent Publication № 2008-159231

Patent Document number 6: Japanese Patent Publication № 2007-317334

Patent Document number 7: Japanese Patent Publication № 2008-33981

Patent Document number 8: Description of the published US patent application № 2008/0159104

Non-patent literature

Non-Patent Document number 1: Illustrated Blu-ray Disc Reader, Ohmsha, Ltd.

Disclosure of invention

Technical problem

However, the techniques described in the above mentioned documents are associated with various problems described below.

Firstly, according to the method of determining the level of which is described in the patent document number 2, where "0" and "1" in the reproduced signal are determined relative to the level of the slice, the amplitude of the reproduced signal is very small when playing marks or pits, which is considerably smaller than the spot diameter of the light beam. Therefore, signals reproduced from short marks and short spaces are near the slice level and are therefore subject to noise or intersymbol interference, resulting in frequent determination errors in the level determination.

Secondly, in the case of adjusting the edge positions of recording marks, which is carried out using the method of PRML higher order with high reproducibility as described in Patent document number 3, patent document number 4 and patent document number 5, the recording of high density in recording density of 30 GB to 33.4 GB per data recording layer is not successful under the recording when the ratio SN (SNR) is maximum, resulting in reduction of tolerances in the recording and playback of the entire system of the optical disc.

Third, according to the methods of compensation records described in the Patent Document number 6, patent document number 7 and patent document number 8, the adjustment of the write pulse is only positional information corresponding to the combination of the length of the label interested mark and the length of the blank for a space followed interest Tagged or a combination of the length of the label and mark are interested in space for the length of a space with the preceding interested mark. These methods are not applicable to mark lengths which are beyond the optical resolution that depends on the size and tag size of the laser spot.

As described above, none of the above conventional techniques are not suitable for forming or reading marks with sufficient accuracy in the case of high density recording which is beyond the optical resolution. As a result, it is impossible to realize sufficient data recording layer density and reliability.

One of the objectives of the present invention is to provide an optical recording method and optical recording / reproducing apparatus to accurately compensate for thermal interference and optical intersymbol interference during recording or reproduction of the optical disc media.

Another object of the present invention is to increase the systemic tolerance of the optical disc media. In particular, in the case of high linear density recording where the shortest mark length is approximately 0.124 m to 0.111 m, in the case of disk Blu-ray (BD) of 12 cm diameter and a capacity of 30 GB or 33.4 GB per data recording layer and when an optical system in which the laser wavelength is 405 nm and NA (numerical aperture) of the lens is 0.85, adaptive compensation is made on the write pulse conditions according to the length of the interested mark preceding and / or succeeding space lengths and preceding and / or follow label, based on the playback information that is decoded by the scheme the maximum likelihood using the method of PR (1,2,2,2,1) ML, in order to reduce the optical intersymbol interference or thermal interference that can have a negative impact on record high density, thereby forming recording marks of high quality, and increases the system tolerance of optical disc media.

Solution

According to the method of optical recording according to the present invention, an optical disc medium is irradiated with a modulated series of pulses of recording laser light, changing over a plurality of power levels, whereby the optical disk medium is formed by a plurality of marks, the edge positions of each of the marks and a space between two adjacent marks are used for recording information. The method includes the steps of: encoding record data to generate encoded data which is a combination of marks and spaces; encoded data are classified according to the combination of the length of the label to label gap length for the first space, followed by the tag and the length of the gap to the second gap with the previous mark; generating a series of pulses to form recording marks, wherein at least one of the edge positions of the front end edge and rear end position of the pulse width series of write pulses is changed according to the result of the classification; and irradiating the optical disk medium generated by a series of write pulses to form a plurality of marks on the optical disc medium.

Stage classification can include an act consisting in the fact that the encoded data are classified according to the combination of the length of the label for the shortest mark length of a space for the first space and the length of the gap to the second gap.

Step labeling may include effect consisting in classifying the encoded data according to a combination of the following conditions: the length of the label for the label; is whether the length of the blank space for the first "n" or "n + 1 or longer"; and whether the length of the gap is equal to the second space "n" or "n + 1 or longer", where n - the length of the shortest space.

When a combination of classification is a combination of the length of the label for the label, the length of a space for the first space and the length of the gap to the second gap stage classification can include an act consisting in the fact that carry the first gap to any of the predetermined number of M classes the length of the gap (M - an integer greater than or equal to 1) and the second space to carry any one of a predetermined number N of classes gap length (N - integer greater than or equal to 1, and M ≠ N).

Step labeling may include effect consisting in classifying the encoded length data space into four classes length space for the first space, "n", "n + 1", "n + 2" and "n + 3 or longer ", and two classes of length space for the second space," n "and" n + 1 or longer ", where n - the length of the shortest space, and the step of generating may include the action consists in the fact that changing the boundary position of the front end a series of write pulses according to the result of classification.

Step labeling may include effect consisting in classifying the encoded length data space into two classes, the length of a space to the first space, "n" and "n + 1 or longer", and four classes length space for the second space, " n "," n + 1 "," n + 2 "and" n + 3 or longer ", where n - the length of the shortest space, and the step of generating may include the action consists in the fact that changing the boundary position of the rear end a series of write pulses according to the result of classification.

Step labeling may include effect consisting in classifying the encoded length data space into four classes length space for the first space, "n", "n + 1", "n + 2" and "n + 3 or longer ", and two classes of length space for the second space," n "and" n + 1 or longer ", where n - the length of the shortest space, and the step of generating may include the action consists in the fact that changing the pulse width of the pulse series Recording according to the result of classification.

Step labeling may include effect consisting in the fact that, if the length of the label to mark longer than the shortest mark, classify the encoded data according to at least any one of a combination of the length of the mark and the length of the first space and the combination of the length of the mark and the length of the second gap .

The optical recording method further includes the steps of: generating an analog signal from an optical disc medium and generating a digital signal from an analog signal; changing the waveform of the digital signal; decoding scheme Maximum Likelihood digital signal is a modified form of the method according to the PRML (maximum likelihood of incomplete response); generating a binary signal that represents the result of the decoding by the maximum likelihood scheme; and detecting a shift amount in the waveform of the digital signal based on the reshaped digital signal and a modified form of a binary signal. A step of generating a series of write pulses may include an action which consists in that the change on the basis of the detection result shift value of at least one of the edge positions of the front end edge position the rear end and the pulse width series of write pulses to form a plurality of labels .

Detection step may include the action consisting in detecting a shift amount in the waveform of the digital signal by comparing the encoded data and the binary signal and the step of generating a series of write pulses may include an action consisting in the fact that the change of at least one of the edge positions of the front end edge and rear end position of the pulse width recording pulse series.

A step of generating a series of write pulses may include action consisting in the fact that changing the position of at least one of the fronts of the pulses of the first to third counted from the front end and the front pulse of the first to third counted from the rear end, according to the result classification.

Preferably, the following formula is satisfied:

ML <λ / NA × 0,26

where λ - the wavelength of the laser light, NA - NA lens, and ML - the length of the shortest mark.

The length of the shortest mark ML, preferably equal to or less than 0.128 microns.

The wavelength λ of laser light, preferably in the range of from 400 nm to 410 nm, and NA, preferably in the range of from 0.84 to 0.86.

The optical recording according to the present invention is capable of recording information by irradiating the optical disk medium of the modulated series of pulses of recording laser light, changing over a plurality of power levels, whereby the optical disk medium is formed by a plurality of marks, the edge positions of each of the marks and a space between two adjacent marks used for recording information. The apparatus includes: an encoding section configured to encode record data to generate encoded data which is a combination of marks and spaces; classifying unit configured to classify the encoded data according to the combination of the length of the label to label gap length for the first space, followed by the tag and the length of the gap to the second gap with the previous mark; waveform generating unit records, configured to generate a series of pulses to form recording marks, wherein at least one of the edge positions of the front end edge and rear end position of the pulse width series of write pulses is changed according to the result of the classification; and laser driving unit configured to irradiate the optical disc medium generated by a series of write pulses to form a plurality of marks on the optical disc medium.

The optical recording may further include: a processing unit PRML, configured to receive a digital signal generated from an analog signal reproduced from the optical disk medium, for changing the waveform of the digital signal and for decoding scheme maximum likelihood digital signal reshaped by the procedure PRML (maximum likelihood of incomplete response); shift detecting unit configured to detect a shift amount in the waveform of the digital signal based on a binary signal that represents the result of the decoding by the maximum likelihood scheme and a modified form of a digital signal; and recording compensation unit operable to change, based on the detection result of the shift of at least one of the edge positions of the front end edge and rear end position of the pulse width series of write pulses to form a plurality of labels.

Apparatus exposure for making a master according to the present invention is adapted to record information by irradiating an optical disc medium which is a physical disk coated resist modulated series of pulses of recording laser light, changing over a plurality of power levels, whereby the optical disk medium is formed by a plurality of labels, wherein each of the edge positions of marks and spaces between two adjacent marks used for recording information. The apparatus includes: an encoding section configured to encode record data to generate encoded data which is a combination of marks and spaces; classifying unit configured to classify the encoded data according to the combination of the length of the label to label gap length for the first space, followed by the tag and the length of the gap to the second gap with the previous mark; waveform generating unit records, configured to generate a series of pulses to form recording marks, wherein at least one of the edge positions of the front end edge and rear end position of the pulse width series of write pulses is changed according to the result of the classification; and laser driving unit configured to irradiate the optical disc medium generated by a series of write pulses to form a plurality of marks on the optical disc medium.

Provided an optical disk medium in which information is to be written according to the above optical recording method, the optical disc media contains information about the classification in a predetermined area.

Provided a method of manufacturing an optical disc medium in which information is to be written according to the above optical recording method, the method includes the step of forming a predetermined area in which information on the classification to be written.

Provided a method for reproducing information from an optical disc medium in which marks are to be recorded according to the above optical recording method, the method includes the step of reproducing information by irradiating the optical disc medium with laser light.

Advantageous Effects of the Invention

As described above, according to the optical recording according to the present invention, each label is to be written, is classified according to the length of the label for the label and the length of preceding it and following gaps and / or length of the marks, preceded by a space, and following them. The positions of edges of pulses of the pulse train for recording each label change according to the result of classification that allows you to control the recording pulse signal. This allows you to precisely control the position of the front end or rear end position of the mark, which is to be formed on the track of the optical disc media. In particular, the position of the front end and the position of the rear end of the mark can be strictly controlled in view of the optical intersymbol interference or thermal interference which can adversely affect the recording of high density, when the linear density beyond the OTF (optical transfer function) that depends on the length of the shortest mark and the diameter of the laser spot. This improves the reliability of recording and reproduction, which enables to realize high density recording medium and a high capacity and at the same time reduce the size of the information recording device and record carrier.

In particular, in the case of high linear density recording where the shortest mark length is approximately 0.124 m to 0.111 m, in the case of disk Blu-ray (BD) of 12 cm diameter and a capacity of 30 GB or 33.4 GB per data recording layer and when an optical system in which the laser wavelength is 405 nm and NA (numerical aperture) of the lens is 0.85, the write pulse conditions of recording / reproducing apparatus are determined based on information reproduced using the method of PR (1,2, 2,2,1) ML, to compensate for inter-symbol interference or thermal interference that can have a negative effect on high-density recording. As a result, the recording mark can be formed of high quality and to increase system tolerance of the optical disc media.

Given the impact of heat on the leading and trailing spaces, the leading edge of the pulse of laser radiation, for example dTF1 and dTF2, exposed to the heat of the previous space, which is one of the spaces closer to these pulse edge. In other words, the recording mark is exposed to thermal interference according to the length of the preceding space. According to the method of extended recording compensation according to the present invention, the shortest mark (2T) is recorded with recording compensation, performed according to the lengths of the preceding and succeeding spaces. In case of changing the trailing edges of pulses, e.g. dTF1 and dTF2, pulse width TF2 between dTF1 and dTF2, or pulse width TE2 between dTE2 and dTE3, thermal interference can be reduced more effectively compensates for recording so that the number of classes for write compensation in respect of length previous gap was greater than the number of classes for the recording compensation in relation to the length followed by a space. Furthermore, by reducing the number of subsequent space length classes can reduce the total number of classes in the recording compensation table. Thus, it is possible to avoid complication of LSI can be reduced training efforts in learning record.

Given the impact of heat on the leading and trailing spaces, trailing edge for the laser pulses, for example dTE1 and dTE2, exposed to heat from the subsequent gap, which is one of the spaces closer to these pulse edge. In other words, the recording mark is exposed to thermal interference according to the length followed by a space. According to the method of extended recording compensation according to the present invention, the shortest mark (2T) is recorded with recording compensation, performed according to the lengths of the preceding and succeeding spaces. In case of changing the pulse leading edge, for example dTE1 and dTE2, thermal interference can be decreased more effectively, making the recording compensation in such a way that the number of classes for the recording compensation in respect of the subsequent gap length was greater than the number of classes for the recording compensation in respect of the length of the preceding space. Furthermore, by reducing the number of classes of the length of the preceding space, it is possible to reduce the total number of classes in the recording compensation table. Thus, it is possible to avoid complication of LSI can be reduced training efforts in learning record.

Through the establishment of the classification for the length of a space for a space, followed by interest to the label, and the length of the space to a space with the preceding interested mark by a combination of the two classes, "the length of the shortest gap (n)" and "the length of the space, exceeding the length of the shortest space (n + 1 or longer) ", can be more effectively reduce thermal noise. If a space with the preceding interested mark or with subsequent interest label is a space with a length equal to the length of the shortest gap (n), marker before interest label or following it, is closer, which is why interest to the label is particularly vulnerable to the effects of heat from the previous or subsequent marks. In view of this classification is arranged by the combination of two classes, "the length of the shortest space (n)" and "length of the blank exceeding the length of the shortest blank (n + 1 or longer)", and different adjustment value provided in the case of "the length of the shortest space ( n) "in the case of" space length greater than the shortest space length (n + 1 or longer) ", whereby more precise adjustment is possible in the case of the shortest space length (n). The result can be more effectively reduce thermal noise.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 - a schematic diagram showing an entire configuration of an optical recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 - a diagram showing the configuration of an optical information recording medium according to an embodiment of the present invention.

FIG. 3 - is a timing chart concerning a recording method according to an embodiment of the present invention.

FIG. 4 - is a timing chart showing a relationship between the lengths of marks and the waveforms recording pulse series according to an embodiment of the present invention.

FIG. 5 - is another timing chart showing a relationship between the lengths of marks and the waveforms recording pulse series according to an embodiment of the present invention.

FIG. 6 - a graph showing the relationship between OTF and the spatial frequency in an optical system according to an embodiment of the present invention.

FIG. 7 - a schematic diagram showing the relationship between the laser spot diameter and the recorded marks according to an embodiment of the present invention.

FIG. 8 - a flowchart of an optical recording method according to an embodiment of the present invention.

FIG. 9 - diagram showing a control example of a series of write pulses according to an embodiment of the present invention.

FIG. 10 - examples of values ​​set for the write pulse conditions according to an embodiment of the present invention.

FIG. 11 - a diagram showing another example of a control series of write pulses according to an embodiment of the present invention.

FIG. 12 - examples of values ​​set for the write pulse conditions according to an embodiment of the present invention.

FIG. 13 - examples of values ​​set for the write pulse conditions according to an embodiment of the present invention.

FIG. 14 - a diagram showing the state transition rules, which are set recording code RLL (1,7) and aligning PR (1,2,2,2,1).

FIG. 15 - trellis diagram which corresponds to the state transition rules according to an embodiment of the present invention.

FIG. 16 - a graph showing an exemplary ideal PR equalization waveform, shown in Table 1 according to an embodiment of the present invention.

FIG. 17 - a graph showing an exemplary ideal PR equalization waveform, shown in Table 2 according to an embodiment of the present invention.

FIG. 18 - a graph showing an exemplary ideal PR equalization waveform, shown in Table 3, according to an embodiment of the present invention.

FIG. 19 - examples of values ​​set for the write pulse conditions according to an embodiment of the present invention.

FIG. 20 - a diagram illustrating an exemplary ideal PR equalization waveform, shown in Table 1, and the relationship between the waveform and a recorded mark according to an embodiment of the present invention.

FIG. 21 - a diagram illustrating an exemplary ideal PR equalization waveform, shown in Table 2, and the relationship between the waveform and a recorded mark according to an embodiment of the present invention.

FIG. 22 - a diagram illustrating an exemplary ideal PR equalization waveform, shown in Table 3, and the relationship between the waveform and a recorded mark according to an embodiment of the present invention.

FIG. 23 - a diagram showing an exemplary result of the comparison section to correct the erroneous pattern according to an embodiment of the present invention.

FIG. 24 - is a flowchart showing a procedure of optimizing the write pulse conditions for an optical information recording medium according to an embodiment of the present invention.

FIG. 25 - a diagram showing the complete structure of the exposure apparatus for manufacturing the master according to an embodiment of the present invention.

FIG. 26 - a diagram showing a configuration of layers of a three-layer optical disc media.

THE INVENTION

Embodiments of the present invention are described below with reference to the accompanying drawings. The embodiments are described as an example of an optical disc write once media based on phase transition (especially, BD-R (Blu-ray disc write once)) used as a recording medium. Note that this does not mean that the recording medium is limited to any particular type. Type recording medium is not intended to limit, under the condition that a type in which information is recorded by injecting energy into the recording medium to form marks or pits which differ in their physical properties from unrecorded part. For example, techniques described herein are equally applicable to a rewritable optical disc media (eg, BD-RE (rewritable disc Blu-ray)). Described herein technique is equally applicable to the post in the heating mode on the coating of the inorganic resist, as in the case of the device platen for making a master, referred to as device PTM (mastering by phase transitions), which is used to manufacture read-only disc consisting of a substrate with pits concavity / convexity and formed thereon the reflective film.

Examples of major optical conditions and disc configuration employed in a recording method according to the present invention are:

laser light: in the wavelength range from 400 nm to 410 nm, e.g., 405 nm;

lens: NA in the range of 0.84 to 0.86, e.g., NA = 0.85;

track pitch: 0.32 m; thickness of cover layer on which falls the laser light, from 50 microns to 110 microns; the shortest mark length of optical disc medium (2T): from 0.111 microns to 0.124 microns, e.g., 0.111 microns (this also applies to the shortest space):; and

modulation method for modulating data to be recorded: 17PP modulation.

In the case of recording linear density at which the above-mentioned length of the shortest mark is equal to 0.111 microns, the capacity per data recording layer of the optical disk medium with a diameter of 12 cm is approximately 33.4 GB. With regard to the 3-layer disc, the total capacity of the disk is approximately 100 GB. With regard to 4-layer disc, the total capacity of the disk is approximately 134 GB. The following description is based on the assumption that the shortest mark length is 0.111 m. Strictly speaking, the value is 0.11175 mm, which is 3/4 the length of the shortest mark for BD, 0,1490 mm. Note that the concept of the present invention is not limited to this value.

In the case of recording linear density at which the shortest mark length is 0.116 m, the capacity per data recording layer of the optical disk medium with a diameter of 12 cm is approximately 32 GB. With regard to the 3-layer disc, the full capacity of the disc is about 96 GB. With regard to 4-layer disc, the total capacity of the disk is approximately 128 GB.

Under the same conditions, when the shortest mark length is 0.124 m, the capacity per data recording layer is 30 GB. With regard to the 3-layer disc, the full capacity of the disc is about 90 GB. With regard to 4-layer disc, the total capacity of the disk is approximately 120 GB.

It is assumed that the recording speed, for example, twice in BD with the channel rate of 132 MHz (Tw = 7.58 ns).

FIG. 1 shows an example of the entire configuration of an optical recording / reproducing apparatus according to the present invention. The optical recording / reproducing apparatus includes a light emitting unit 102, the block preamplifier 103, the control unit 105 equalizing the waveform processing unit 108 PRML unit 109 detecting the shift computing unit 110 conditions the write pulse, the control unit 111 generate the recording pattern, the control unit 112 write compensation and section 113 of the laser excitation. Functions of the respective components described in relation to the process of reproduction and recording process of the optical recording / reproducing apparatus, which will be described below.

Note that in FIG. 1 shows an optical disk medium 101, which is an optical information recording medium, although the optical disc medium 101 may not be included in the optical recording / reproducing apparatus.

FIG. 2 shows the data structure of the optical disc medium 101. The optical disk medium 101 includes, from the outer perimeter to the inner perimeter, area data 1001, 1002 learning region for learning recording conditions and recording conditions area 1003 storing the initial value on the inner side of learning recording conditions .

Field Data 1001 - this is an area used by the user for the actual storage of data on an optical disc medium. Area 1002 learning recording conditions - this is an area used for test recording which is carried out before the actual data recording in the user area for correction of errors in recording power and write pulse conditions caused by start-up or a change in temperature. 1003 Storage Area initial values ​​- an area of ​​read-only, which contains information predetermined for each disc, for example, the recommended values ​​of the recording power, the recommended values ​​for the write pulse conditions, the linear velocity of the recording, ID disc, etc. These information items are recorded in the form of a molded structure on the disc substrate using, e.g., areas of the wobble track as a recording unit.

Next, a process for reproducing data from the optical disk medium 101.

The light emitting unit 102 is, for example, an optical head including a laser diode (LD) that is configured to emit a light beam onto the optical disk medium 101.

The optical head emits a light beam outputted from the laser diode onto the surface of the optical disc medium and receives reflected light. The reflected light is converted by the photodetector into an electrical signal which is an analog signal reproducing. The analog reproduction signal is converted into a digital signal pre-amplification unit 103, AGC unit 104, the block 105 waveform equalization block 106 and A / D conversion. The digital signal is sampled at block 107 of the PLL (Phase Locked Loop) clock cycles. The digital signal is supplied to the PRML processing unit 108 (the maximum likelihood from incomplete response). PRML processing unit 108 includes a decoding scheme of maximum likelihood, for example, a Viterbi decoding unit that is configured to decode the digital signal by the maximum likelihood scheme to generate a binary signal that represents the result of the decoding by the maximum likelihood scheme. The binary signal is supplied to the shift detection unit 109.

The following describes the process of recording data on an optical disc medium. In the recording operation unit 111 outputs a recording pattern generating random code sequence in the waveform NRZI (non-return to zero inverted). Condition calculation unit 110 sets the write pulse of the write pulse conditions to the write compensation unit 112 according to the result of calculation. Laser drive unit 113 excites a laser diode provided inside the light emitting unit 102, according to the recording pulse series signal which is converted based on the NRZI signal to record data at desired positions on the optical disc medium by changing the recording power of laser light.

FIG. 3 (a) - (f) are diagrams illustrating a sequence of marks and spaces recording code, and an operation for generating a series of pulses for recording marks and spaces in this optical recording / reproducing apparatus. FIG. 3 (a) shows the waveform of the reference time signal 1201 which serves as the time standard for the write operation. The reference timing signal 1201 is a pulse clock with a period Tw. FIG. 3 (b) shows the signal NRZI (non-return to zero inverted), which is a record code sequence generated by the template generating unit 111 records. There Tw - the width of the detection window, which is the minimum unit of length changes the length of the mark and a space in NRZI 1202.

FIG. 3 (c) shows an image of marks and spaces actually recorded on the optical disc medium. The spot of laser light scans the marks and spaces are shown in Fig. 3 (c) from left to right. For example, the mark 1207 corresponds to "1" in the NRZI signal 1202 on a one-to-one basis, and is formed so that it is proportional to the length of this period.

FIG. 3 (d) shows a count signal 1204. The count signal 1204 counts the time from the front ends of the label 1207 and gap 1208 in units of Tw.

FIG. 3 (e) shows a diagram of the signal classifying unit 1205 for calculating the 110 of the write pulse conditions. In this example, encoded data is classified according to a combination of five values ​​including the mark length of each mark, the lengths of spaces with the spaces for the preceding and succeeding mark lengths and labels with labels for the previous space and the following space. Here, the coded data means recording data encoded by the combination of marks and spaces. With regard to the labeling of, for example, "3-4-5-2-6" in FIG. 3 (e) means that: a label length has series 5Tw preceding 4Tw space; There is a label with a long series of 3Tw preceded by a space 4Tw; mark with a length of the series is followed by a space 5Tw 2Tw; and there is a label with a long series of 6Tw preceded by a space 2Tw. Note that Tw is sometimes briefly denoted "T", e.g., "2T", "3T". The length of the gap is sometimes identified by the suffix "s", for example, "4Ts". The length of the label is sometimes identified by the suffix "m", for example, "2Tm".

FIG. 3 (f) shows a waveform of the recording pulse signal, which corresponds to the NRZI signal 1202 of FIG. 3 (b). This waveform is an example of actually recorded optical waveform. Recording pulse signal 1206 generated based on the count signal 1204 NRZI signal 1202, the classification signal 1205 and the recording compensation table data output from the calculating unit 110 of the write pulse conditions.

Note that, in this embodiment, the classification signal of FIG. 3 (e), classified according to the combination of the five values ​​including the mark length of each mark, the lengths of spaces with the spaces for the preceding and succeeding mark lengths and labels with labels for the previous space and the following space. However, in the example to be described later, the classification can be arranged by a combination of three or four of the five values ​​including the mark length of each mark, the lengths of spaces immediately preceding mark and following it, and the length of the marks to mark with the preceding space and followed by a space.

We now describe the method of compensating for recording the optical recording / reproducing apparatus according to the present embodiment. FIG. 4 (a) - (f) are diagrams generally showing the relation between the mark length and the waveform of the recording pulse signal 1206. FIG. 4 (a) shows the waveform of the reference time signal 1201 which serves as a time standard in the recording operation. As previously described, the period of the reference time signal 1201 is Tw. FIG. 4 (b) shows the count signal 1204 which is generated by a counter. Count signal 1204 counts the time from the leading end of the label in units of reference time Tw. Timing when the count signal goes to 0, correspond to the leading ends of marks or spaces.

FIG. 4 (c) - (f) show examples of the waveform of the pulse signal 1206 during the formation of recording recording marks. The level of the recording pulse signal 1206 is modulated among three values, the peak power (Pw), which is the highest level, a space power (Ps), which is a level for irradiation of non-printing intervals, and the bottom power level (Pb), which is the lowest level. After the trailing end pulse, a cooling pulse is formed at the lower power level.

FIG. 4 (c) - (f), the vertical axis represents the power level during radiation of the laser and the horizontal axis represents time.

Note that although in this example the power level is modulated among three values, the level of cooling power (Pc), which is taken for the cooling pulse, which follows the pulse trailing end, and a lower power level (Pb) for an intermediate pulse may have different levels, whereby the power level can be modulated between all four values. The lower power level may be between the space power level and peak power level although in FIG. 4 lower power level below the power gap. Although in the case of optical disc media, write once the power level for irradiation of non-printing intervals called "power gap", the power level is sometimes referred to as "erase power (Pe)" because erasure of previously-recorded marks on a rewritable optical disc medium by means of spaces is realized by erasing the recorded marks with using the power of white space intervals.

FIG. 4 (c) - (f), the write signal pulse for 4Tw mark includes one intermediate pulse. However, as the mark length (code length) increases in units 1Tw, e.g., 5Tw, 6Tw, and so on, the number of intermediate pulses accordingly incremented.

A pulse which includes N-1 peak power level pulses as shown as an example in FIG. 4 is used for recording a mark with mark length N. Such a pulse is called an impulse type record N-1. However it is possible to use a pulse-type N-2, the pulse type N / 2, the so-called write pulse type walls, which includes an intermediate power level between the two peak power levels, or a so-called write pulse L-type, wherein the second peak power-type fortified wall is an intermediate power level. As expected, presented below description applies to these cases.

We now describe an example of a recording pulse L-type. FIG. 5 (a) - (f) are diagrams generally showing the relation between the mark length and the waveform of the recording pulse signal 1206. FIG. 5 (a) shows the waveform of the reference time signal 1201 which serves as a time standard in the recording operation. The period of the reference time signal 1201 is Tw. FIG. 5 (b) shows the count signal 1204 which is generated by a counter. Count signal 1204 counts the time from the leading end of the label in units of reference time Tw. Timing when the count signal goes to 0, correspond to the leading ends of marks or spaces.

FIG. 5 (c) - (f) show examples of the waveform of the pulse signal 1206 during the formation of recording recording marks. Level pulse of the recording signal 1206 is modulated among four values, the peak power (Pw), which is the highest level, the intermediate power (Pm), which is an intermediate power level output gap (Ps), which is a level for irradiation of non-printing intervals, and power level cooling (Pc), which is the lowest level.

The intermediate power level may be lower than the space power level although it is higher than the power level of a space in FIG. 5. Although in the case of optical disc media, write once the power level for irradiation of non-printing intervals called "space power", the power level is sometimes referred to as "erase power (Pe)" because erasure of previously-recorded marks on a rewritable optical disc medium by means of spaces is realized by erasing the recorded tags using the power of white space intervals.

Adaptive compensation records, according to the present invention uses a recording compensation table in which each mark is classified according to the combination of: the length of the label for a particular label, for which a series of pulses generated by the record; and the lengths of spaces with the preceding interested mark and follow interest tags; and / or the length of the marks immediately following the space and precede them. It generated pulse signal recording, in which the position of the edge of the first or second pulse, measured from the end of the series of pulses for recording each mark is changed according to the result of classification by the movement of the front dTF1, dTF2 and / or dTE1, dTE2. Thus, it is possible to precisely control the leading end position or trailing end position of the mark when forming marks on the optical disc medium for recording information. Thus, the position of the front end or the position of the rear end of the mark can be more precisely controlled, taking into account the optical intersymbol interference and thermal interference as compared with a conventional method of classification, wherein each mark is classified only according to the mark length and the length of the gap followed label against the edges of the front end and according to the length of the mark and the length of a space with the preceding mark in respect of the rear end.

In particular, the classification table of compensation records organized so that, if the interests of the label has a length of 2T (the shortest mark) and the length of a space, followed by interest mark is 2T (the shortest space), the interests of the mark further classified according to the length of the mark, which is directly preceded directly preceded by a space. It generated pulse signal recording, in which the position of the edge of the first, second or third pulse measured from the end of the series of pulses for recording each mark is changed according to the result of classification by the movement of the front dTF1, dTF2, dTF3 and / or dTE1, dTE2, dTE3. It is more effective for precise control of the position of the front end or the rear end position of the mark when forming marks on the optical disc medium for recording information.

Likewise, the classification table of compensation records organized so that, if the interests of the label has a length of 2T (the shortest mark) and the length of a space with the preceding mark is 2T (the shortest space), the interests of the mark further classified according to the length of the label, which immediately follows the space . Generated pulse signal recording, in which the position of the edge of the first, second or third pulse measured from the end of the series of pulses for recording marks varies according to the result of classification by the movement of the front dTF1, dTF2, dTF3 and / or dTE1, dTE2, dTE3. It is more effective for precise control of the position of the front end or the rear end position of the mark when forming marks on the optical disc medium for recording information.

As described above, when successively appear the shortest mark (2T) and the shortest space (2T), the compensation record produced by classifying the lengths of the preceding and succeeding marks into classes "length of the shortest mark (2T)" and "longer than 2T "to reduce the number of classes for the recording compensation. In addition, the optical intersymbol interference and thermal noise can be effectively removed without complicating the configuration of the LSI. Note that when the series having the shortest mark is 2T and the shortest gap 2T, payment records can be made, taking into account at least one of the length of the label for the label that precedes the preceding space and the length of the label for the label, which follows the subsequent space.

The recording / reproducing apparatus according to the present invention uses an optical pickup which includes a semiconductor laser with a laser wavelength of 405 nm and a lens with NA = 0.85, and wherein the laser power for reproduction is set to 1 mW. Disk configuration provides three-layer optical disc medium including three data recording layers measured from the laser emitting side, respective ones of which are made with the possibility of recording and reproducing information. Thus, when the effective diameter of the laser spot during reproduction is the diameter of the area of ​​1 / e ^ 2 of the peak intensity of the Gaussian beam, the effective spot diameter is expressed as 0,82 × (λ / NA), which is approximately 0.39 m . Thus, in such an optical system, the recording marks comprising shortest mark length of 0.111 microns, are beyond the optical resolution limit at which the optical spot is capable of identifying marks.

The amplitude of the reproduction signal of the signal reproduced from a recorded mark using a light beam decreases as the recorded mark lengths and reaches 0 at the optical resolution limit. The reciprocal of the length of the recorded mark is the spatial frequency.

The relationship between the spatial frequency and the signal amplitude is called OTF (optical transfer function). The signal amplitude decreases linearly with increasing spatial frequency. The limit at which the signal amplitude reaches 0, referred to as the cutoff frequency OTF. The relationship between OTF and the spatial frequency in the above-described optical system is illustrated in FIG. 6. In the case of the above optical system, the cutoff cycle of OTF is calculated from wavelength λ and NA lens, namely, λ / NA × 0.5. In particular, when λ = 405 nm and NA = 0.85, the cutoff cycle is 0.237 microns. The length of the shortest mark is equal to half of the cutoff cycle, i.e. 0.1185 microns. When the length of the shortest mark is 0.111 m or 0.116 m, the recorded marks, the spatial frequency is above the cutoff frequency are included, where marks can be optically reproduced up to the cutoff frequency. Therefore, reproduction and recording are difficult. The limit of the cutoff frequency varies due to variations in the optical head, the deformation of the recording mark, and the mark shape, etc. Taking into account other conditions, in addition to specific numerical values ​​of the present embodiment (λ = 405 nm, NA = 0.85), under which the maximum spot size is achieved, for example, laser wavelength of 410 nm, a lens NA = 0.84, and mistakes 5% due to the above variations, 1/2 cycle cutoff OTF is λ / NA × 0,26 = 0,128 m. Thus, when recording or playback mark, for which the shortest mark length is approximately 0.128 m or less, the optical intersymbol interference can not be neglected.

FIG. 7 (a) and (b) are diagrams showing the relationship between the effective spot diameter of the light beam and the physical size of the recorded marks. FIG. 7 (a) and (b) a laser spot 501 - a light spot focused on the disc surface of the optical disk media. The spot has the form of a Gaussian beam with a diameter of 0.39 m. FIG. 7 (a) and (b) also show recorded marks 502, 503, 504, 505, 506 and 507 which have different lengths. FIG. 7 (a) shows the relationship between recorded marks whose shortest mark length most (2T) is 0.111 m and spaces. FIG. 7 (b) shows the relationship between recorded marks whose shortest mark length most (2T) is 0.149 m and spaces. With respect to BD with a diameter of 12 cm, the example shown in FIG. 7 (a), equivalent to a capacity of 33.4 GB, and the example shown in FIG. 7 (b), equivalent to the capacity of 25 GB.

When the laser spot passes through a 2T mark, the effective light beam spot diameter at the recording density of FIG. 7 (a) (equivalent to 33.4 GB) is equivalent to approximately 7T. When data are reproduced from a space 2T followed tag 2T, and when the mark length, which immediately precedes the immediately preceding space is equal to 2T or 3T or longer, left-hand part of the spot of the light beam overlaps the immediately preceding mark, because at which a reproduction signal affects the immediately preceding mark, resulting in occurrence of optical intersymbol interference. On the other hand, when playing back from the same 2T mark, in the case where the immediately preceding space has the length of 2T, the recording density of FIG. 7 (b) (equivalent to 25 GB) only leads to occurrence of optical intersymbol interference which depends on the lengths of spaces immediately preceding to and following gaps. The reason is that the immediately preceding mark is outside the effective light beam spot diameter of the laser spot, and therefore the reproduction signal is not affected by the preceding mark. In addition, when playing from a 2T mark produ goes the same phenomenon when immediately followed by a blank space is 2T.

For the above reasons, in the case of high density recording, when the linear density of the recording marks is greater than or equal to a certain value which is determined according to the relationship between the spot diameter of the light beam and the length of the shortest mark extended adaptive compensation records where the write compensation is made according not only to the lengths of spaces immediately preceding interested mark and following it, but also the length of labels directly preceded by a space and the following (this is an expanded version of the traditional adaptive compensation records, where the front pulse of the write pulse undergo adaptive compensation according to the length of the mark and the length of the blank separately), produced thus, it is possible to compensate not only thermal interference which can adversely affect the high density recording but also optical intersymbol interference. However, in the case where the extended adaptive recording compensation is made according to a combination of the lengths of not only the immediately preceding and succeeding spaces but also the preceding and succeeding marks, the number of classes for the recording compensation is very large, and accordingly, the process of calculating the recording compensation conditions takes a long time. In addition, there are other drawbacks, such as a more complicated LSI configuration.

According to the method the expanded write compensation for optical disc media according to the present invention, extended payment record made according to the length of the mark immediately preceding and / or immediately subsequent marks only when the label interval that is determined according to the relationship between the diameter of the laser spot and the length of the shortest mark is greater than or equal to predetermined value. In particular, in case when the length of the shortest mark is 0.111 m, the write compensation interested mark is provided only when the length of the blank for a space that immediately precedes the interested mark or follows it equals 2T, and the values ​​of the write compensation vary depending on is whether the length of the immediately preceding and / or immediately subsequent label "2T" or "3T or longer". This organization helps to reduce the number of classes for the recording compensation and efficient removal of the optical intersymbol interference.

Some types of optical disc media are experiencing a great influence of thermal interference due to heat transfer from the immediately preceding mark. In the case where the extended recording compensation is applied to an optical disc medium in which such thermal interference from the preceding mark is large, the classification in the recording compensation table can be arranged by the lengths of the immediately preceding and following the gaps, and the length of the mark that precedes the immediately preceding space. Thus, classification arranged without subsequent length of mark tags, whereby the number of classes for the recording compensation can be reduced. Thus, the LSI can be simplified, and can effectively remove thermal noise.

When the thermal noise of the immediately preceding or following the mark is small, the classification table of compensation records can be organized at the lengths of spaces immediately preceding interested mark and following, as well as the length of the label for the preceding or subsequent mark. For example, the edge of the front end of a series of write pulses can be classified according to the length of interest to the label and the length of spaces immediately preceding and following the interest mark. The edge of the rear end of the recording pulse series can be classified according to the length of interest to the label and the length of spaces immediately preceding and following the interest mark.

In that classification procedure, the classification length space for space followed interested mark and the length of the blank for a space with the preceding interested mark is organized through the combination of at least two classes, "the length of the shortest space (n)" and "length of the blank exceeding the length the shortest gap (n + 1 or longer) ", making it possible to more effectively reduce thermal noise. When the length of the blank for a space with the preceding interested mark or further length equal to the lowest (n), the interval between the interested mark and a preceding or subsequent mark adjacent to the interested mark with the space interposed therebetween decreases. Accordingly, the interest of the label is more exposed to the heat generated during the formation of the neighboring labels, which precedes or follows a label interested in her. In view of this, the classification is organized through the combination of at least two classes, "the length of the shortest space (n)" and "length of the blank exceeding the length of the shortest blank (n + 1 or longer)", and different adjustment value provided in case the length of the most short space (n) in the case of gap length greater than the shortest space length (n + 1 or longer). In case the shortest space length (n), adjustment is made so that there may be a more accurate adjustment, and therefore, can be more effectively reduced thermal noise. According to any method of classification, the number of classes for the recording compensation can be reduced, making it possible to simplify the LSI, and can effectively remove thermal noise.

Below, the method of the extended recording compensation within optical recording method according to the present embodiment will be described with reference to the flowchart shown in FIG. 8.

(a) First, record data is encoded to generate encoded data which is a combination of marks and spaces (S01). These coded data corresponding NRZI signal 1202 on the diagram (b), FIG. 3.

(b) With respect to the mark, the mark is classified according to the combination of the length of the mark, the lengths of spaces immediately preceding the label and follow it, and the lengths of marks with the preceding space and followed by a space (S02). In the diagram (e), shown in FIG. 3, the 2T mark is "X-2-2-3-3", 3T mark is "2-3-3-4-5", 5T mark is "3-4-5-2-6", and 6T mark is "5-2-6-2-X". Here, X represents a code lying outside the diagram and is actually a numeric character classified according to the code sequence. The values ​​are aligned right "length of the preceding mark", "length of the preceding space", "length of labels interested in the compensation record label," "length followed by a space" and "length of follow-label."

(c) Position the front of the first and / or second pulse, measured from the end of the series of write pulses to form a label varies according to the result of classification that allows you to manage a series of write pulses (S03). For example, the diagrams (c) - (f), shown in FIG. 4, the position of the front of the first and / or second pulse counted from the leading end is shifted by the change amount dTF1 front and / or dTF2. Furthermore, the position of the front of the first and / or second pulse counted from the trailing end is changed by the movement of the front dTE1 and / or dTE2.

(d) The optical disc medium is irradiated with a series of write pulses, thereby forming a label (S04).

FIG. 9 (a) - (d) are diagrams generally illustrating recording mark 601 mark length 2T in an environment where the position of the fronts of the first and second pulses reckoned from the front end of a series of write pulses vary on the amount of change of the front dTF1 and dTF2. FIG. 9 (a) shows the waveform of the reference time signal 1201 which serves as the time standard for the write operation. FIG. 9 (b) shows the count signal 1204 generated by the counter. FIG. 9 (c) shows the waveform of the recording pulse signal 1206. In the recording pulse signal 1206, the positions of edges of the first and second pulses reckoned from the front end to vary the change amount dTF1 and dTF2 front. FIG. 9 (d) shows a mark image 601 with length of 2T mark, which is recorded by the recording pulse series of FIG. 9 (c). The front end position mark 601 can be precisely controlled using the write pulse series.

The change amount of the front dTF1 and dTF2 are defined based on the classification result in any of a plurality of predetermined classes according to the length of the label for the label to be written, the lengths of the preceding and succeeding spaces, and the lengths of marks that precede the leading and trailing spaces and the following as described in classification tables shown in FIG. 10 (a) and FIG. 10 (c). FIG. 10 (a) shows the amount of displacement of dTF1, dTF2 and dTF3 series of write pulses. For example, "M3224" in the table defines the displacement of the front, which represents the amount of displacement of the front recording pulse when recording a mark 2T under conditions where length of a space with the preceding mark 2T is equal to 4T, the length of a space with subsequent mark 2T is equal to 2T, and the length of the mark followed by a space It is equal to or longer than 3T. Here, as an example different from the values ​​of the shown table, the values ​​of dTF1, dTF2, and dTF3 may be different. FIG. 10 (b) shows the displacement amount dTF1, dTF2 and dTF3 series of write pulses. For example, "S4223" in the table defines the displacement of the front, which represents the amount of displacement of the front recording pulse when recording a mark 2T under conditions where length of a space with subsequent mark 2T is equal to 4T, the length of a space with the preceding mark 2T is equal to 2T, and the length of the label which follows for followed by a space, it is 3T or longer. Here, as an example different from the values ​​of the shown table, the values ​​of dTF1, dTF2, and dTF3 may be different.

FIG. 10 (c) shows the amount of displacement of dTF1, dTF2 and dTF3 series of write pulses. For example, "M32222" in the table defines the edge movement. In particular, it represents the amount of movement of the front recording pulse recording marks 2T in circumstances where the length of a space with the preceding mark 2T is equal to 2T, the length of the label, which immediately follows, followed by a space, equal to 2T, the length of a space followed by the label 2T is equal to 2T, and the length of the label, which immediately precedes the preceding space is equal to or longer than 3T. Here, as an example different from the values ​​of the shown table, the values ​​of dTF1, dTF2, and dTF3 may be different.

FIG. 10 (d) shows the amount of displacement of dTF1, dTF2 and dTF3 series of write pulses. For example, "S22223" in the table defines the edge movement. In particular, it represents the amount of movement of the front recording pulse when recording a mark 2T under conditions where length of a space with subsequent mark 2T is equal to 2T, the length of the mark that immediately precedes the preceding space is equal to 2T, the length of a space with the preceding mark 2T is equal to 2T, and the length label, which immediately follows, followed by a space equal to or longer than 3T. Here, as an example different from the values ​​of the shown table, the values ​​of dTF1, dTF2, and dTF3 may be different.

In particular, in the case shown in FIG. 10 (c) and FIG. 10 (d), the classification of the table write compensation organizovanatak that, if the interests of the mark is 2T (the shortest mark) and the length of a space immediately preceding interested mark or follows it, is 2T (the shortest space), the interests of the mark is classified according as whether the mark length equal to that precedes the immediately preceding or following space or follows it, "2T" or "longer than 2T". Generated pulse signal recording in which the position of the edge of the first, second or third pulse, measured from the end of the series of write pulses for recording each mark is changed according to the result of classification by the movement of the front dTF1, dTF2, dTF3 and / or dTF1, dTF2, dTF3. Use of such organizations to accurately control the position of the front end or the rear end position of the label, which is to be formed on the optical disc medium in recording a mark is more effective.

In addition, the classification table of compensation records organized so that, if the interests of the mark is 3T or longer (the label that differs from the shortest mark), the interests of the mark shall be classified according to whether a space, followed by interest Tagged space 2T (shortest space), space 3T, 4T or 5T space or longer space. It generated pulse signal recording, in which the position of the edge of the first, second or third pulse, measured from the front end portion of the pulse train recording, to record each tag varies according to the result of classification by the movement of the front dTF1, dTF2, dTF3. Use of such organizations to accurately control the position of the front end of the label which is to be formed on the optical disc medium in recording a mark is more effective.

Classification table of compensation records also organized so that, if the interests of the mark is 3T or longer (the label that differs from the shortest mark), the interests of the mark shall be classified according to whether the gap with the previous mark by a space 2T (shortest space) space 3T, 4T or 5T space or longer space. It generated pulse signal recording, in which the position of the edge of the first, second or third pulse measured from the rear end portion of the pulse train for recording each mark is changed according to the result of classification by the movement of the front dTF1, dTF2 or dTF3. Use of such organizations to accurately control the position of the rear end of the label which is to be formed on the optical disc medium in recording a mark is more effective.

As described above, when the shortest space (2T) immediately precedes the shortest mark (2T) or follow it, i.e. successively appear the shortest intervals (2T), the recording compensation is performed by classifying the lengths of the preceding and succeeding marks into classes of "shortest mark length most (2T)" and "longer than 2T". Thus, it is possible to reduce the number of classes in the recording compensation. The optical intersymbol interference and thermal noise can be effectively removed without complicating the configuration of the LSI.

The values ​​change and the front dTF1 dTF2 set of 35 classes. In particular, the length of the label for the label to be written has 4 classes, "2T", "3T", "4T" and "5T or longer", and the length of the preceding space has 4 classes, "2T", "3T", "4T" and "5T or longer". In addition, in circumstances where the previous blank space is 2T, the length of the label that precedes the preceding space has 2 classes, "2T" and "3T or longer". In the case of 2T mark, the length of the following space has 4 classes, "2T", "3T", "4T" and "5T or longer".

Note that here, in relation to the values ​​of the regional shift dTF1, dTF2 and dTF3, there are 4 classes for the length of the label, grade 4 for the length of the previous space, and 2 classes for the length of the earlier mark, although the present invention is not limited to this example. For example, for the length of the label may be 3 classes, 5 classes, or more than 5 classes. For the length of the previous space there may be Class 2, Class 3, 5 classes, or more than 5 classes. For the length of the earlier mark may be a Class 3.

Combined lengths of marks and spaces within the same class, the amount of change in the front and dTF2 dTF1 can have equal value. In this case, the pulse length of the pulse interval of the peak power of the front end is fixed. In particular, when recording is performed by using recording pulse, wherein the number of pulses at the peak power level is one, the recording position of the recording mark can be shifted without changing the size of the recording mark. Thus, it is possible to more accurately adjust the boundary position. When recording is performed by using recording pulse, wherein the number of pulses at the peak power level is one, the change amount of the front dTF1, dTF2 and dTF3 in a combination of lengths of marks and spaces within the same class may have equal values ​​where dTF3 is the amount of change of the front to the position of the third pulse edge counted from the leading end of the recording pulse series. In this case, a series of recording pulses is recorded at the front or rear shift, while itself form a series of write pulses remains unchanged. In addition, the pulse width of the cooling pulse time can be fixed, and therefore change the size or position shift of the recording mark, which would occur according to the time width of the cooling pulse, which is especially true for rewritable recording media, can be prevented. Thus, it is possible to more accurately adjust the boundary position. These edge change amount dTF1 and dTF2 may be set, for example, the absolute time, such as M2222 = 0.5 nsec in FIG. 10 (a). Alternatively, they can be set on the basis of the reference timing signal, such as a value that is an integral multiple of Tw / 16. Alternatively, they can be set as a value that is an integral multiple of Tw / 32.

Regarding tag 2T, marks 3T, marks 4T and 5T or longer mark, one value may be maintained as a reference value for dTF1, dTF2, dTF3, dTE1, dTE2, dTE3, and the value of the write compensation, which depends on the length of the preceding or subsequent gap lengths or preceding or subsequent labels can be prepared as difference information for the aforementioned reference value for the respective mark lengths. In such an arrangement, particularly when the payment records, which depends on the length of the preceding or succeeding space or the write compensation which depends on the length of the preceding or subsequent mark is not provided, only read the reference value for the respective lengths of the marks, but difference information can not be read, in this connection, the recording compensation value can be read from the disk at high speed. In addition, you can save memory recording device that allows you to simplify the configuration of the LSI. Moreover, thanks to the difference in information recording, can reduce the number of bits write compensation values ​​to be written to disk.

As described above, the position of the edge of the first and / or second and / or third pulse counted from the front end recording pulse is changed by the movement of the front dTF1, dTF2, dTF3, that can more accurately control the position of the front end of the label. In addition, the front of the pulse can be controlled in accordance with not only the length of the label for the label to be written, but the lengths of the preceding and subsequent spaces. When recording mark 2T, when the length of the preceding space is 2T, wavefront can be controlled according to the length of the preceding mark. Thus, in case of high density recording which is beyond OTF, the position of the front end mark 601 can be precisely controlled, taking into account the thermal interference or optical intersymbol interference.

FIG. 11 (a) - (d) are diagrams generally illustrating recording marks 1401 mark length 2T in an environment where the position of the fronts of the first, second and third pulses, measured from the rear end of a series of write pulses vary on the amount of change of the front dTE1, dTE2 and dTE3, respectively. FIG. 11 (a) shows the waveform of the reference time signal 1201 which serves as the time standard for the write operation. FIG. 11 (b) shows the count signal 1204 generated by the counter. FIG. 11 (c) shows the waveform of recording pulse 1406. In 1204 count signals, the position of the fronts of the first, second and third pulses, measured from the rear end change in the amount of change in the front dTF1, dTF2, and dTE3. FIG. 11 (d) shows an image label 1401 with a length of 2T mark, which is recorded by the recording pulse series of FIG. 11 (c). It is shown that the position of the rear end of the mark 1401 can be precisely controlled using the write pulse series.

Values ​​change front dTE1, dTE2 and dTE3 are set based on the result of classification generated according to the length of the label for the label to be written, the length of previous and subsequent gaps and length of the marks that precede the leading and trailing spaces, and follow them as indicated in the tables of classification shown in FIG. 10 (b) and FIG. 10 (d).

As previously described in FIG. 3, the classification table of compensation records organized so that, if the interests of the mark is 2T (the shortest mark) and the length of a space, followed by interest mark is 2T (the shortest space), the interests of the mark is classified according to the length of the label for the label that precedes directly preceded by a space. Classification table of compensation records also organized so that, if the interests of the mark is 2T (the shortest mark) and the length of a space with the preceding interested mark is 2T (the shortest space), the interests of the mark is classified according to the length of the label for the label, which follows directly followed by a space. It generated pulse signal recording, in which the position of the edge of the pulse train for recording each mark is changed according to the result of classification by the movement of the front dTF1, dTF2, dTF3 and / or dTE1, dTE2, dTE3. Numeral

the front end or the rear end position of the label, which is to be formed on the optical disc medium can be precisely controlled in recording of data.

Specifically, the classification is shown in FIG. 12. As for dTF1 and dTF2, when recording a mark of 2T, the length of gaps preceding 2T mark and following it, have 4 classes, "2T", "3T", "4T" and "5T or longer". At a time when the length of the space, 2T mark that precedes or follows it, is equal to 2T, the length of the label that precedes the preceding or trailing spaces, or follows it, has two classes, "2T" and "3T or longer". Thus, there are 25 classes (1 to 25). Each of these sets information 1-byte. When recording marks 3T, 4T or 5T or longer, the length of the preceding space has 4 classes, "2T", "3T", "4T", and "5T or longer". Thus, there are 12 classes (26 to 37), and each of them is given information 1-byte.

Likewise, dTE1 is defined such that, when recording a mark of 2T, a subsequent blank length has 4 classes, "2T", "3T", "4T" and "5T or longer". At a time when the length of the subsequent space is 2T, the length of the label, which follows, followed by a space, it has 2 classes, "2T" and "3T or longer". Thus, there are only 10 classes (1 to 10). Each of these sets information 1-byte. When recording marks 3T, 4T or 5T or longer, the length of the subsequent space has 4 classes, "2T", "3T", "4T", and "5T or longer". Thus, there are 12 classes (11 to 22). Each of these sets information 1-byte.

Here, with respect dTF1, dTF2, dTE1 and dTE2, shown in FIG. 12, if the write strategy type N-1 shown in FIG. 4, dTF1 provides information about the position of the front end of the growth momentum, dTF2 provides information about the position of the front end of the fall time, dTE1 provides information about the position of the growth momentum of the cooling and dTE2 provides information about the position of the rear end of the recession pulse 3T or longer mark. Similarly, in case the write strategy L-type shown in FIG. 5, dTF1 represents the position of the front end of the growth momentum, dTF2 represents the position of the front end of pulse decay, dTE1 represents the position growth cooling pulse, and dTE2 represents the position of the intermediate power decay 3T or longer mark. Although dTF2 is set, for example, pulse width TF2 between dTF1 dTF2 and can be set in place dTF2. Similarly, although dTE2 is set, for example, pulse width TE2 between dTE2 dTE3 and can be set in place dTE2.

In the case of small interference by the preceding and succeeding marks, the classification may be simplified as shown in FIG. 13. In particular, with regard dTF1 and dTF2, when recording a mark of 2T, the length of the preceding and succeeding spaces have 4 classes, "2T", "3T", "4T" and "5T or longer", i.e. There are 4 × 4 = 16 classes (1 to 16), and each of them is given information 1-byte. When recording a mark of 3T, 4T, or 5T or longer, the length of the preceding space has 4 classes, "2T", "3T", "4T", and "5T or longer", i.e. There are 12 classes (17 to 28), and each of them is given information 1-byte.

Similarly, with respect dTE1, in recording a mark of 2T, the length of the following space has 4 classes, "2T", "3T", "4T" and "5T or longer", and the length of the preceding space has 2 classes, "2T" and "3T or longer. " Thus, there are 8 classes (1 to 8), and each of them is given information 1-byte. When recording marks 3T, 4T or 5T or longer, the length of the preceding space has 4 classes, "2T", "3T", "4T", and "5T or longer". Thus, there are 12 classes (9 to 20). Each of these sets information 1-byte. As for dTE2, when recording a mark of "3T", "4T" and "5T or longer", the length of the preceding space has 4 classes, "2T", "3T", "4T" and "5T or longer". Thus, there are 12 classes (1 to 12), and each of them is given information 1-byte.

These values ​​change front dTE1, dTE2 and dTE3 defined 4 classes for the length of the label for the label to be written, "2T", "3T", "4T", and "5T or longer", 4 classes for the length followed by a space, "2T" , "3T", "4T", and "5T or longer", and in conditions when followed by a space is a space 2T, 2 classes for the length of the label, which follows followed by a space, "2T", "3T", "4T" and "5T or longer", and in circumstances where the mark is 2T, 4 classes for the length of the previous space, "2T", "3T", "4T", and "5T or longer", ie a total of 35 classes. Note that here, in relation to the values ​​of the regional shift dTE1, dTE2 and dTE3, there are 4 classes for the length of the label, grade 4 for the length followed by a space, and 2 classes for the length of the subsequent mark, although the present invention is not limited to this example. For example, there may be 3 classes, 5 classes, or more than 5 classes for the mark length. There may be a Class 2, Class 3, 5 classes, or more than 5 classes for the length of the following space. There may be 3 classes for the length of follow-up mark. Also preferably, the length of the previous space was grade 2, "2T" and "3T or longer", while the length of the subsequent space also has 2 classes, "2T" and "3T or longer".

We now describe an example where the length of the following space has two classes. In this case, the subsequent gap length must, generally, only be classified into classes of "2T" or "3T or longer". This is clearly shown in FIG. 13, where "subsequent mark" ("S-mark") has two classes, "2T" and "3T or longer". The value for "3T or longer" under conditions where "S-mark" is "2T" or "3T or longer", the values ​​can be used in the "3T space" of FIG. 13. Note that, in the descriptions of FIGS. 13, the mark following the mark 2T ("S-mark") is designated as "X", which means "no definition" (does not matter), in both columns "2T" and "3T or longer". However, this simple notation "X" as an example. It will be appreciated that the columns marked "X", are used to determine whether the gap is equal to that follows the tag 2T, "2T" or "3T or longer".

Combined lengths of marks and spaces within the same class, the amount of change in the front dTE1, dTE2 dTE3 and may have equal values. In this case, the pulse length of the pulse interval of the peak power of the front end is fixed. In particular, when recording is performed by using recording pulse, wherein the number of pulses at the peak power level is one, the recording position of the recording mark can be shifted without changing the size of the recording mark. Thus, it is possible to more accurately adjust the boundary position.

When recording is performed by using recording pulse, wherein the number of pulses at the peak power level is one, the change amount of the front dTE2, dTE3, and dTE1 in the combination of lengths of marks and spaces within the same class may have equal values ​​where dTE1 - is the position of the front of the first pulse measured from the rear end of a series of write pulses. In this case, a series of recording pulses is recorded at the front or rear shift, while itself form a series of write pulses remains unchanged. In addition, the pulse width of the cooling time can be fixed, and therefore change the size or position shift of the recording mark, which would occur according to the time width of the cooling pulse, which is especially true for rewritable recording media, can be prevented. Thus, it is possible to more accurately adjust the boundary position.

These edge change amount dTE2 and dTE3 may be set, for example, the absolute time, such as S2222 = 0.5 nsec in FIG. 10 (b). Alternatively, they can be set based on a reference timing signal at a value that is an integral multiple of Tw / 16.

As described above, the position of the front of the second and / or third and / or the first pulse is measured from the rear end recording pulse is changed by the movement of the front dTE2, dTE3, dTE1, which enables more accurately manage the position of the rear end of the mark. In addition, the front of the pulse can be controlled in accordance with not only the length of the label for the label to be written, but the lengths of the preceding and subsequent spaces. When recording mark 2T, when the length of the following space is 2T, wavefront can be controlled according to the length of the label, which should be followed for a space. Thus, in case of high density recording which is beyond OTF, the rear end position mark 1401 can be precisely controlled, taking into account the thermal interference or optical intersymbol interference.

Although according to the embodiment of the present invention, the front recording pulse when recording a mark of 2T can be controlled according to the lengths of marks that respectively precede the leading and trailing spaces 2T and follow them, the front recording pulse for recording 3T or longer mark may be adjusted according to the length of the marks which, respectively, preceded by leading and trailing spaces 2T and follow them. Adjusting the front recording pulse can be on the label recording 3T or longer at the same time adjusting mark 2T. In such an arrangement, in case of high density recording which is beyond OTF, the position of the front or rear end of the recording mark can be precisely controlled, taking into account the thermal interference or optical intersymbol interference.

We now describe the method of detecting a shift in the playback signal to provide enhanced compensation recording shift detection unit 109. First of all, we describe the operation of the Viterbi decoding circuit according to the method PR (1,2,2,2,1) ML for PRML processing unit 108.

Signal processing in the playback when playing back from an optical disc media of high density of the present invention is carried out according to the method of PR (1,2,2,2,1) ML. As used herein the recording code length limited code series, for example, code RLL (1,7). PR (1,2,2,2,1) ML is described with reference to FIG. 14 and FIG. 15. By combining the PR (1,2,2,2,1) ML with RLL (1,7), the number of possible states of the decoding unit is reduced to 10, the number of ways of transition between the states is equal to 16, and there are 9 levels of play. FIG. 14 shows a state transition diagram commonly used in the description of PRML, showing state transition rules of PR (1,2,2,2,1) ML. Here, ten states are represented by identifying, at a certain point in time, the state S (0, 0, 0, 0) as the S0, the state S (0, 0, 0, 1) as the S1, state S (0, 0, 1, 1) how S2, state S (0, 1, 1, 1) as the S3, state S (1, 1, 1, 1) as the S4, state S (1, 1, 1, 0) as the S5, state S ( 1, 1, 0, 0) as the S6, state S (1, 0, 0, 0) as the S7, state S (1, 0, 0, 1) as an S8, and state S (0, 1, 1, 0 ) as the S9, respectively, where "0" or "1" in parentheses represents a signal sequence on the time axis and shows what state could be produced as a result of the next state transition from the current state. Also, this state transition diagram can be rearranged from a location along the time axis into the trellis diagram shown in FIG. 15.

In transitions between states of PR (1,2,2,2,1) ML, shown in FIG. 15, there are an infinite number of state transition patterns (i.e., combinations of states) that can take two state transition paths in making a transition from a particular state at a certain point in time into another particular state at the next time. If we pay attention only to the templates that are most likely to lead to errors in a specific time range, templates, transitions between states of PR (1,2,2,2,1) ML can be listed in the following Tables 1, 2 and 3:

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<img file="00000003.tif" he="226" wi="153" img-format="tif" img-content="undefined" />

In Table 1, Table 2 and Table 3 shows the transition between states from the initial state via an intermediate state, two recording sequence that would pass through these state transitions, two ideal waveforms that could pass through those state transitions, and the Euclidean distance between two ideal reproduction waveforms.

Table 1 shows 18 different pairs of state transition patterns, each of which can take two different paths and has a Euclidean distance of 14 between them. These templates correspond to the edge portions of the recording mark in the context of the waveform reproduction of the optical disc media. In other words, these templates are one-bit error patterns between recording marks and spaces. By way of example, describes a state transition path leading from S0 (k-5) to S6 (k) according to the state transition rules shown in FIG. 15. In this case, one path is a case where the recording sequence proceeds to "0, 0, 0, 0, 1, 1, 1, 0, 0" and is detected. In the context of the recorded state where zeros (0) and one (1) reproducible data respectively replaced with spaces and marks, this recording sequence is the sequence of spaces length 4T or longer mark and 3T space length of 2T or longer. This is shown as A path waveform in FIG. 16. FIG. 16 shows two waveforms which differ in the relation between the sampling time and output level. FIG. 16, the abscissa is the sampling time, which indicates each cycle in the sequence of recording, and the ordinate is the level of play. As noted above, PR (1,2,2,2,1) ML has nine ideal reproduction levels, from level 0 to level 8.

On the other hand, another way - it is the case when the recording sequence proceeds to "0, 0, 0, 0, 0, 1, 1, 0, 0" and is detected. In the context of the recorded state where zeros (0) and one (1) reproducible data respectively replaced with spaces and marks, this recording sequence is the sequence space length or longer than 5T, 2T mark, and a space length of 2T or longer. This path is shown as B path waveform in FIG. 16. Templates with Euclidean distance of 14 shown in Table 1, characterized by the fact that they always include a single fragment of the edge information that indicates the border-label gap. Edge adjustment method that is optimal for PRML method, which takes advantage of this feature is for example described in patent document number 3.

Similarly, Table 2 shows 18 different pairs of state transition patterns, each of which can take two different paths and has a Euclidean distance of 12 between them. These templates are templates in which errors of the shift 2T mark or 2T space taped 2-bit error. By way of example, describes a state transition path leading from S0 (k-7) to S0 (k) according to the state transition rules shown in FIG. 15. In this case, one path is a case where the recording sequence proceeds to "0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0" and is detected. In the context of the recorded state where zeros (0) and one (1) reproducible data respectively replaced with spaces and marks, this recording sequence is the sequence of spaces length 4T or longer space and 2T mark length of 5T or longer. This is shown as A path waveform in FIG. 17.

On the other hand, another way - it is the case when the recording sequence proceeds to "0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0" and is detected. In the context of the recorded state where zeros (0) and one (1) reproducible data respectively replaced with spaces and marks, this recording sequence is the sequence of spaces length 5T or longer space and 2T mark length of 4T or longer. This is shown as B path waveform in FIG. 17. Templates with Euclidean distance of 12 shown in Table 2, characterized in that they always comprise two fragments edge information of rise and fall 2T mark or 2T space.

Similarly, Table 3 shows 18 different pairs of state transition patterns, each of which can take two different paths and has a Euclidean distance of 12 between them. These patterns are patterns in which a 3-bit error is detected in an area where there are successively at least two 2T intervals, such as "2T mark-2T space" or "2T space-2T mark". By way of example, describes a state transition path leading from S0 (k-9) to S6 (k) according to the state transition rules shown in FIG. 15. In this case, one way - it is the case when the recording sequence proceeds to "0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0" and is detected. In the context of the recorded state where zeros (0) and one (1) reproducible data respectively replaced with spaces and marks, this recording sequence is the sequence space length or longer than 4T, 2T mark, 2T space, 3T mark and space length of 2T or longer. This is shown as A path waveform in FIG. 18.

On the other hand, another way - it is the case when the recording code sequence proceeds to "0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0" and is detected. In the context of the recorded state where zeros (0) and one (1) reproducible data respectively replaced with spaces and marks, this recording sequence is the sequence space length or longer than 5T, 2T mark, 2T space, 2T mark and space length of 2T or longer. This is shown as B path waveform in FIG. 18. Templates with Euclidean distance of 12 shown in Table 3, characterized in that 3-bit error is detected in an area where there are successively at least two 2T intervals, such as "2T mark-2T space" or "2T space-2T mark ".

When adjusting the position of the edge of the front end or the rear end edge of the recording mark, it is necessary to detect the direction and magnitude of the deviation edge for each combination of the respective marks and the corresponding gaps. When using the method PR (1,2,2,2,1) ML, adjustment may be effected using templates with the Euclidean distance of 14 shown in Table 1. This means that recording compensation can be realized by adjusting the front recording pulse trains of pulses according to the length considered the mark and the length of preceding it and following it gaps. FIG. 19 is a table of classification to compensate for the record that is produced using templates with the Euclidean distance 14.

In the case of patterns with a Euclidean distance of 14, the compensation record includes 4 classes considered label, "2T", "3T", "4T", and "5T or longer". Moreover, the length of the preceding space has 4 classes, "2T", "3T", "4T" and "5T or longer". Thus, there are 4 × 4 = 16 classes for adjustment. In this case, a series of write pulses, subjected to the recording compensation includes dTF1 and dTF2, shown in FIG. 4.

To adjust the length of the mark considered label has 4 classes, "2T", "3T", "4T", and "5T or longer", and the length of the space bar to space following the considered label has 4 classes, "2T", "3T "," 4T "and" 5T or longer ", i.e. There are 4 × 4 = 16 classes. In this case, a series of write pulses, subjected to the recording compensation includes dTE2, dTE3, shown in FIG. 4. Payment is made on the recording dTF1, dTF2, dTE2 dTE3 and considered according to the length and the length of the mark preceding it and following spaces, which allows for the payment records for the Euclidean distance 14.

Discloses a method of detecting a shift in the write compensation. For example, FIG. 16, the sum of squares of differences between the value of the reproduction signal from y_k-4 to y_k in the period from time k-4 to time k and the assumed value of path A is denoted Pa. Pa is expressed by Formula 1. The value of the sum of squares of the differences between the value of the reproduction signal from y_k-4 to y_k for a period of time k-4 to time k and the alleged value of the designated route B Pb. Pb is expressed by Formula 2.

Pa = (y_k-4-1) ^ 2 + (y_k-3-3) ^ 2 + (y_k-2-5) ^ 2 + (y_k-1-6) ^ 2 + (y_k-5) ^ 2 ( Formula 1)

Pb = (y_k-4-0) ^ 2 + (y_k-3-1) ^ 2 + (y_k-2-3) ^ 2 + (y_k-1-4) ^ 2 + (y_k-4) ^ 2 ( Formula 2)

We now describe the meaning of the difference Pa-Pb between Pa and Pb, which indicates the reliability of the decoding result of the scheme the maximum likelihood. We can say that if Pa &lt;&lt; Pb, block decoding circuit maximum likelihood confidently chooses the path A, and that if Pa &gt;&gt; Pb, block decoding circuit maximum likelihood confidently chooses the path B. If Pa = Pb, the path chosen scheme decoding unit is a maximum likelihood can be any of path A and path B, i.e. decoding result would be a fifty-fifty chance. Thus, by calculating Pa-Pb from a predetermined time, a predetermined number of chances, and the decoding result, can obtain the distribution of Pa-Pb.

Tracks recorded in the above recording pulse conditions, and then subjected to reproduction, and the edges of position information of the reproduced signal is measured. The light emitting unit 102 operates to perform reproduction on a track of the write pulse conditions established for writing. The reproduced write pulse conditions are transmitted through the block 105 waveform equalization block 106 and A / D conversion. The PLL unit 107 generates a playback clock signal. Detection unit pattern included in the processing unit 108 PRML, performs decoding scheme Viterbi (decoding scheme Maximum Likelihood) to a digital signal, sampled clock signal reproducing and generates a binary signal indicating a result of the decoding scheme of maximum-likelihood for each set of recording conditions .

We now describe a method for detecting edge shift in the signal reproduction waveform is changed in accordance with the alignment of PR (1,2,2,2,1).

FIG. 20 shows sample values ​​of state transition patterns S0 → S6 in Table 1 by way of example the ideal PR equalization waveform. On the x-axis represents time (1 scale period represents 1 channel clock period), and the ordinate is the signal level (0 to 8). The dotted lines and the solid lines correspond to path A and path B, respectively. Each of the sampled values ​​corresponds to any of the estimated values ​​from 0 to 8 v level, at the input of decoding by the maximum likelihood scheme. It is determined that the waveform reproduced from a record mark portion is the waveform oriented upwardly relative to the signal level, and that the waveform reproduced from the unrecorded portion, the waveform is oriented downward. The patterns shown in FIG. 20 correspond to the reproduced waveforms at the borders of the mark-space (at the edge of the front end and the rear end edge of the label). Thus, the patterns shown in FIGS. 20 and the following patterns in Table 1, S0 → S6, S0 → S5, S0 → S4, S7 → S6, S7 → S5, S7 → S4, S6 → S6, S6 → S5, and S6 → S4 correspond to the edge of the front end portion of the label and other patterns in Table 1, S2 → S0, S2 → S1, S2 → S2, S3 → S0, S3 → S1, S3 → S2, S4 → S0, S4 → S1, and S4 → S2 correspond to the edge of the rear end portion of the label.

The reproduced waveforms of FIGS. 20 (a) and 20 (b), constitute a waveform sequence space and 4T 3T mark, which is recorded in this embodiment. We now describe the method for detecting edge shift of the front end of the label, with respect to the reproduced waveforms of FIGS. 20 (a) and 20 (b).

FIG. 20 (a) and 20 (b) shows the correlation between the reproduced waveforms for S0 → S6 in Table 1 and the deviation of the recording mark. FIG. 20 (a) and 20 (b) solid line with open triangles (Δ) represents the input signal, and the path A, represented by a dotted line, is the right way transition between states. The input signal is generated based on record mark A- in FIG. 20 (a) and based on record mark A + in FIG. 20 (b). It is assumed that record mark A has an ideal leading end edge.

FIG. 20 (a) shows the reproduced waveforms where the leading end edge position of the recording mark deviates to the shorter side relative to the ideal leading end edge position. Distance Pa between the path A and the input signal and distance Pb between the path B and the input signal are calculated to obtain 4S3M-A = ΔA- = | Pa-Pb | ​​-Pstd. 4S3M-A means the edge shift between the 4T space and the 3T mark in the path A and represents the value of the edge shift between the 4T space and immediately subsequent mark 3T. Here, with respect Pstd, the value of Pa-Pb, when Pa = 0 is expressed as -Pstd, and the value of Pa-Pb, where Pb = 0 is expressed as Pstd.

FIG. 20 (b) shows the reproduced waveforms where the leading end edge position of the recording mark deviates to the longer side relative to the ideal leading end edge position. Distance Pa between the path A and the input signal and distance Pb between the path B and the input signal are calculated to obtain 4S3M-A = ΔA + = | Pa-Pb | ​​-Pstd. 4S3M-A means the edge shift between the 4T space and the 3T mark in the path A and represents the value of the edge shift between the 4T space and immediately subsequent mark 3T.

The above-described edge shift detection is carried out by only 18 patterns listed in Table 1, for detecting an amount of edge shift which is dependent on the lengths of marks and spaces.

Here, the classification of the edge shift in the patterns in Table 1 which is made separately over the length of the mark and the length of the gap is realized by detecting b_k-4 bits out of 9 bits of the recording code (from b_k-8 b_k) as a boundary deviation of the edge between the mark and space or between space and the mark. For example, in the pattern S0 → S6, it fits over the considered sequence templates "4T or longer space, and mark 3T" and consistency "5T or longer space, and mark 2T". Detected value of the edge shift, which depends on these mark lengths and preceding space lengths. Similarly, in the pattern S2 → S0, it fits over the considered sequence templates "label 3T and 4T or longer space bar" and a sequence of "2T mark and 5T or longer spaces." Detected value of the edge shift, which depends on these mark lengths and the lengths of subsequent gaps.

We now describe the method of detecting a magnitude of phase shift for patterns in Table 2, in which the Euclidean distance between the state transition patterns that can take two state transition paths is 12 and in which a shift error of 2T mark or 2T space, is detected 2- bit error.

FIG. 21 (a) and 21 (b) shows the sample values ​​of patterns to be compared. On the x-axis represents time (1 scale period represents 1 channel clock period), and the ordinate is the signal level (0 to 8). The dotted lines and the solid lines correspond to path A and path B, respectively. Each of the sampled values ​​corresponds to any of the estimated values ​​from 0 to 8 v level, at the input of decoding by the maximum likelihood scheme. It is determined that the waveform reproduced from a record mark portion is the waveform oriented upwardly relative to the signal level, and that the waveform reproduced from the unrecorded portion, the waveform is oriented downward. The patterns shown in FIG. 21 (a) and 21 (b), correspond to the reproduced waveforms of patterns, including at least one 2T mark or 2T space. Thus, in the pattern shown in FIG. 21 (a) and 21 (b), and these templates in Table 2, S0 → S0, S0 → S1, S0 → S2, S7 → S0, S7 → S1, S7 → S2, S6 → S0, S6 → S1 and S6 → S2, position 2T mark makes the front or rear shift, despite the fact that its length is 2T remains unchanged. Other patterns in Table 2, S2 → S6, S2 → S5, S2 → S4, S3 → S6, S3 → S5, S3 → S4, S4 → S6, S4 → S5 and S4 → S4, correspond to the portion where the position of a space 2T commits front or rear shift, despite the fact that its length is 2T remains unchanged.

Waveforms sequence 4T or longer space, 2T mark and 5T or longer space recorded in the present embodiment are the reproduced waveforms of FIGS. 21 (a) and 21 (b). We now describe the method of detecting a shift in the recording position with respect to the 2T mark reproduced waveforms of FIGS. 21 (a) and 21 (b). FIG. 21 (a) and 21 (b) shows the correlation between the reproduced waveforms for S0 → S0 in Table 2 and the deviation of the recording mark. FIG. 21 (a) and 21 (b), a solid line with open triangles (Δ) represents the input signal, and the path A, represented by a dotted line, is the right way transition between states. The input signal is generated based on record mark B- in FIG. 21 (a) and based on record mark B + in FIG. 21 (b). It is assumed that record mark B has an ideal recording position.

FIG. 21 (a) shows the reproduced waveforms where the recording position of the recording mark (2T) is deflected to the rear side relative to the ideal position. Distance Pa between the path A and the input signal and distance Pb between the path B and the input signal are calculated to obtain 4S2M5S-A = ΔB- = | Pa-Pb | ​​-Pstd. 4S2M5S-A signifies a shift position recording 2T in the sequence of 4T or longer space, mark 2T and 5T or longer marks on the path A and represents the deviation position of the recording mark 2T, situated between the 4T or longer space and a 5T or longer space. Here, in regard Pstd, the value of Pa-Pb, when Pa = 0 is expressed as -Pstd, and the value of Pa-Pb, where Pb = 0 is expressed as Pstd.

FIG. 21 (b) shows the reproduced waveforms where the recording position of the recording mark (2T) is deflected to the front side relative to the ideal position. Distance Pa between the path A and the input signal and distance Pb between the path B and the input signal are calculated to obtain 4S2M5S-A = ΔB + = | Pa-Pb | ​​-Pstd. 4S2M5S-A signifies a shift position recording 2T in the sequence of 4T or longer space, mark 2T and 5T or longer marks on the path A and represents the deviation position of the recording mark 2T, situated between the 4T or longer space and a 5T or longer space.

The above-described phase shift detection is carried out only on templates 18, listed in Table 2 for detecting an amount of phase shift that depends on the lengths of X space, 2T mark, and Y space or the lengths of the labels X ', 2T space, and Y mark'.

Here, the classification of the position shift recording "space X, mark 2T, the gap Y" or "mark X ', a space 2T, mark Y'" in the template in Table 2 is realized by detecting b_k-5 bits from the 11 bits of the recording code (from b_k- b_k 10) as a boundary recording position deviation 2T mark or 2T space. For example, in the pattern S0 → S0, it fits over the considered sequence templates "4T or longer space, mark 2T, 5T or longer space bar" and a sequence of "5T or longer space, mark 2T, 4T or longer gap." Detected amount of phase shift that depends on the 2T mark length and the lengths of the preceding and succeeding spaces. Similarly, in the pattern S3 → S4, it fits over the considered sequence templates "label 4T, a space 2T, 4T or longer mark" and a sequence of "label 3T, a space 2T, 5T or longer mark." Detected recording position shift amount which depends on the 2T space length and the lengths of the preceding and succeeding spaces.

We now describe the patterns in which the Euclidean distance patterns of transitions between states, which can take two paths transition between states is 12 and in which the 3-bit error is detected in the portion where successively occur at least two 2T intervals, e.g., "mark 2T -probel 2T "or" blank tag 2T-2T ". In particular, we describe a method for detecting the phase shift amount in the patterns in Table 3, wherein the shift of the sequence error "2T mark-2T space" or the sequence "2T space-2T mark", a 3-bit detected error.

FIG. 22 shows sample values ​​of patterns to be compared. On the x-axis represents time (1 scale period represents 1 channel clock period), and the ordinate is the signal level (0 to 8). The dotted line and solid line correspond to the respective waveforms of path A and path B. Each of the sampled values ​​corresponds to any of the estimated values ​​from 0 to 8 v level, at the input of decoding by the maximum likelihood scheme. It is determined that the waveform reproduced from a record mark portion is the waveform oriented upwardly relative to the signal level, and that the waveform reproduced from the unrecorded portion, the waveform is oriented downward.

The patterns shown in FIG. 22 correspond to the reproduced waveforms which have patterns, including the following sequence of "2T-label gap 2T". Thus, the patterns shown in FIGS. 22 and the following patterns in Table 3, S0 → S6, S0 → S5, S0 → S4, S7 → S6, S7 → S5, S7 → S4, S6 → S6, S6 → S5, and S6 → S4, correspond to the portion where the position the sequence "mark 2T-space 2T" commits front or rear shift and other templates in Table 3, S2 → S0, S2 → S1, S2 → S2, S3 → S0, S3 → S1, S3 → S2, S4 → S0, S4 → S1 and S4 → S2, corresponding to the portion where the position of the sequence "space mark 2T-2T" makes the front or rear shift.

Waveforms sequence 4T or longer space, 2T mark, 2T space and the 3T mark, recorded in the present embodiment are the reproduced waveforms of FIGS. 22. So, now we describe a method for detecting a recording position shift in the sequence "2T mark-2T space" in relation to the reproduced waveforms of FIGS. 22. FIG. 22 shows the correlation between the reproduced f ormami wave S0 → S6 of Table 3 and the deviation of the recording mark. FIG. 22, a solid line with open triangles (Δ) is the input signal, and the path A, represented by the dotted line is correct by transition between the states. The input signal is generated based on the recording mark C- FIG. 22 (a) and based on record mark C + in FIG. 22 (b). It is assumed that record mark C has an ideal recording position.

FIG. 22 (a) shows the case where the recording position of the sequence "2T mark-2T space" is deflected to the rear side relative to the ideal position. Distance Pa between the path A and the input signal and distance Pb between the path B and the input signal are calculated to obtain 4S2M2S3M-A = ΔC- = | Pa-Pb | ​​-Pstd. 4S2M2S3M-A means a shift recording position "label 2T-gap 2T" in the sequence of 4T or longer space, mark 2T, space 2T and tag 3T on the path A and represents the deviation of a recording position "label 2T-gap 2T", located between the 4T or longer space and the mark 3T. Here, in regard Pstd, the value of Pa-Pb, when Pa = 0 is expressed as -Pstd, and the value of Pa-Pb, where Pb = 0 is expressed as Pstd.

FIG. 22 (b) shows the case where the recording position of the sequence "2T space-2T mark" is deflected to the front side relative to the ideal position. Distance Pa between the path A and the input signal and distance Pb between the path B and the input signal are calculated to obtain 4S2M2S3M-A = ΔC + = | Pa-Pb | ​​-Pstd. 4S2M2S3M-A means a shift recording position "gap 2T-mark 2T" in the sequence of 4T or longer space, mark 2T, space 2T and tag 3T on the path A and represents the deviation of a recording position "gap 2T-mark 2T", located between the 4T or longer space and the mark 3T.

The above-described shear detection is carried out by only 18 patterns listed in Table 3 to detect the phase shift amount that depends on the lengths of the spaces X, tag 2T, a space 2T and mark Y or mark length X ', a space 2T, marks 2T and the space Y' .

Here the classification shift recording position "space X, mark 2T, a space 2T, mark Y" or "mark X ', a space 2T, mark 2T, a space Y'" in the template in Table 3 is realized by detecting b_k-6 bits of the 13 bit code records (from 12 to b_k-b_k) as a boundary recording position deviation "label gap 2T-2T" or "blank tag 2T-2T". For example, in the pattern S0 → S6, it fits over the considered sequence templates "4T or longer space, mark 2T, a space 2T, the mark" and the sequence of "5T or longer space, mark 2T, a space 2T, mark 2T". Detected shift amount that depends on the lengths of these 2T mark and 2T space and the length of the preceding space and the length of the subsequent label. Similarly, in the pattern S2 → S0, it is considered appropriate comparisons templates "label 3T, a space 2T, mark 2T, 4T or longer space bar" and "mark 2T, a space 2T, mark 2T, 5T or longer spaces." Taped recording position shift amount which depends on these 2T space and 2T mark and the length of the preceding mark and the length followed by a space.

A method of detecting the shift includes measuring | Pa-Pb | ​​-Pstd, obtained by comparing Viterbi decoding circuit and a reproduction signal for each pattern to detect the shift amount. Based on the result of detection, they are converted into the corresponding table values ​​for the extended recording compensation, and the recording compensation is made with these values. However, there is another example of a method of detecting a shift. For example, the allocated portion including a bit error, and compares the error pattern and a code sequence of the original recording. Based on the trend of shifting the bit errors produced an extended payment record. FIG. 23 shows the result of comparing the correct code sequence and decoded error data based on comparison of a correct pattern actually recorded code sequence and the bit pattern on the Viterbi decoded output from the reproduction signal. The result, shown in FIG. 23 is an exemplary result obtained by comparison with the correct pattern of erroneous plot data decoded by the scheme Viterbi playback of the recording mark, which was recorded with the compensation record produced according to the length of the mark and the length of preceding it and following gaps t. e. only recording compensation of marks and spaces with the Euclidean distance of 14 in Table 1, the extended recording compensation.

FIG. 23, each pair of rectangles includes the correct sequence of the data pattern i.e. sequence data of the original recording on the left. At right is a result of an error in reproduced data obtained by Viterbi decoding circuit of the signal reproduced from part of an optical disc media, where the correct recorded pattern. Each rectangle "0" represents a mark 1T, and "1" represents a space 1T. For example, "00" represents a 2T mark, and "000" represents a 3T mark. Among the pairs of code sequences shown in FIG. 23 (a) and 23 (b), FIG. 23 (a) shows a plurality of code sequences erroneously detected as occurring anterior shift relative to the correct code sequences, and FIG. 23 (b) shows a plurality of code sequences erroneously identified as the perpetrators of the rear shift on the correct code sequences. Recording and playback of code sequences are moving downward in the drawing.

The leftmost pair of code sequences in FIG. 23 (a) it is a part of the code sequence in which an error actually occurs when recording code sequence "space 4T, mark 2T, a space 2T, a space 3T" and which was erroneously detected as "gap 3T, mark 2T, a space 2T, mark 3T" . The recognized error here is that every sequence of "label 2T, a space 2T, mark 3T" made the front shift by 1 bit. The leftmost pair of code sequences in FIG. 23 (b) is part of the code sequence in which an error actually occurs when recording code sequence "mark 3T, a space 2T, mark 2T, a space 3T" and which was erroneously detected as "space 4T, mark 2T, a space 2T, mark 3T" . The recognized error here is that every sequence of "label 3T, a space 2T, mark 2T" has made the shift back to 1 bit.

When checking of all the pairs of error code sequences of FIGS. 23 (a) and 23 (b), code sequences which actually include errors are found as follows. In particular, FIG. 23 (a), in 34 out of 40 patterns, the recorded pattern is detected with an anterior shift in part of "3T or longer space, 2T mark, 2T space" by 1 bit. FIG. 23 (b), in 23 out of 28 patterns, the recorded pattern is detected with a posterior shift in part of "2T space, 2T mark, 3T or longer space" by 1 bit. Thus, most of the errors attributed to the front or rear shift by 1 bit pattern shown in Table 3, which includes the following sequence of "2T space-2T mark" or "2T mark-2T space".

It is understood that the patterns shown in Table 3 above, express code sequence which readily causes a bit error due to optical intersymbol interference or thermal interference in the case of high density recording such as 33.4 GB. Furthermore, with respect to these patterns, in the case where this template comprises a combination of "2T mark-2T space", as shown in FIG. 23 (a), the reproduction signal includes an anterior error. In the case where this template comprises a combination of "2T space-2T mark", as shown in FIG. 23 (b), a reproduction signal includes a posterior error.

Thus, the extended payment records made with the use of different values ​​of the compensation records for the case of the mark 2T followed by a space 2T and is preceded by 3T or longer space bar, and the case where the track mark 2T followed by a space 2T and is preceded by a space 2T, allowing to reduce the bit error.

Similarly, the extended payment records made with the use of different values ​​of the write compensation in the case where the mark 2T is preceded by a space 2T and it is followed by 3T or longer space bar, and the case where the mark 2T is preceded by a space 2T and it is followed by a space 2T, which will reduce bit error.

These examples specifically described below.

First, it is assumed that the mark length for a particular mark length and a space for the immediately preceding it are the smallest space lengths (2T) in encoded data. It is also assumed that the mark length for the label following this space (second mark) is equal to the smallest length (2T). The amount of movement of two or more consecutive pulse edges (e.g., dTF1 and dTF2) in the series of write pulses in this case labeled "x1". The amount of movement of two or more consecutive pulse edges (e.g., dTF1 and dTF2) in the series of write pulses in the conditions when the length of the second label differs from the smallest length (≥3T), designated "y1".

In addition, it is assumed that the length of the label for a particular mark and the length of the gap to just follow it are the smallest gap lengths (2T) in encoded data. It also assumes that the length of the label for the label, preceded by the gap (third mark), is the smallest length (2T). The amount of movement of two or more consecutive pulse edges (e.g., dTE2 and dTE3) in the series of write pulses in this case labeled "x2". The amount of movement of two or more consecutive pulse edges (e.g., dTE2 and dTE3) in the series of write pulses in circumstances when mark length of the third mark is different from the shortest length (≥3T), designated "y2".

According to the above assumptions, changing x1, x2, y1, and y2 so as to satisfy the following formula:

(y1-x1) × y2-x2) ≤0.

In particular, especially effective displacement of the front recording pulse in opposite directions depending on whether the preceding mark labeled "2T" or "3T or longer" and whether the subsequent label labeled "2T" or "3T or longer", according to the distribution errors and implementing shift recording a 2T mark position for a fixed width of a recording pulse at the peak power level (top pulse width). This arrangement allows to reduce inter-symbol interference and thermal noise without changing the size of the recording mark (2T).

Moreover, the code sequence in which an error occurs is compared with original data to detect the type and direction of the code sequence in which an error occurs, and the combination of code sequences having the highest frequency of occurrence or highest probability of bit error is subjected to recording compensation. Thus, the bit error rate is further reduced to enhance the quality of the reproduction signal.

Furthermore, x1, x2, y1 and y2 may be controlled so as to satisfy the following formula:

| y1-x1 | = | x2-y2 |.

As a result, the half recording position of the 2T mark is shifted equally to the front side and rear side. The average size of positions throughout the recording mark 2T remains unchanged even after the shift of the wavefront record. Thus, even when the amount of change of conditions of a write pulse (y1-x1, y2-x2) for the sequence tag 2T, a space 2T with preceding or subsequent mark 2T and 3T or longer mark with the preceding or subsequent blank 2T changed, the absolute values ​​of changes remain unchanged, and the change is made in opposite directions. Thus, the phase change in the PLL as a whole is small, thereby reducing detection error due to phase shift in the PLL.

Here, in the case where the Euclidean distance between the state transition patterns that can take two state transition paths is 12, the target value of the shift adjustment is not modified, whereby each pattern is equal to 0. Instead, in the case where 4 code sequence tags gaps mark and space include two or more correct code sequences, the shift adjustment may be carried out so that the average amount of shift is equal to 0 in two or more code sequences. Each of the transitions "S2k-7 → S1k" and "S3k-5 → S2k" in Table 3 includes the correct code sequence "tag 3T, a space 2T, mark 2T, a space 3T". One of the code sequences to be compared, is a "gap 2T, mark 2T, a space 2T, mark 4T", and the other - "a space 4T, mark 2T, a space 2T, mark 2T". Compares the code sequence with the other shift direction, and adjustment is made so that the average value of the shifts identified in the corresponding template, it is 0, which allows you to effectively adjust the deviation of the shift and reduce inter-symbol interference or thermal noise.

We now describe the recording pattern. In general, the code length increases, the frequency (probability) of occurrence of a recording pattern with respect to the code length decreases. In particular, the frequency of occurrence of 2T&gt; 3T&gt; 4T&gt; ...&gt; 8T. For example, approximately, 2T is 38%, 3T is 25%, and 16% 4T. Note that the code length distribution of a recording pattern, 17PP modulation scheme, which is used in conventional recording of user data also depends on the sequence of the unmodulated data. In the case where recording is carried out under conditions of a write pulse, variable using a recording pattern having different frequencies of occurrence of code lengths, and the recorded mark is read, and the difference between the two conditions of the write pulse is detected as the amount of deviation of the edge, the recording is affected by the above-described frequencies of occurrence of respective lengths codes for modulation codes, in this connection, the phase-synchronized by the PLL presumably undergoes a significant influence of a particular length code in terms of changes. In particular, when recording a mark of 2T, which is the probability of occurrence of 1/3 or higher, the change in position of an edge 2T mark leads to a change in the average phase distribution of all recording marks. Accordingly, phase, presumably synchronized through the PLL shifts. In the case where information edge position of the recording mark is detected using the clock signal PLL, there are significant detection error in data edge positions or in the phase components of marks in the case of long labels which have relatively low frequencies of occurrence, especially in this embodiment, in case labels lengths greater than or equal to 4T.

A recording pattern used to adjust the 2T and 3T marks of the present embodiment are specific patterns in which the frequencies of occurrence of code lengths from 2T to 8T, in general, equal, and are subjected to DSV-control. By using the above-described specific patterns with equal frequencies of occurrence, the frequency of occurrence of each code length is equal to 1/7, so that the frequency of occurrence of each of 2T and 3T is 1/7, and the frequency of occurrence of 4T or longer is 5/7. Thus, the frequency of occurrence of 4T mark length or becomes more predominant. In this case, even when the write pulse conditions of 2T and 3T marks are changed, the edge positions of recording marks 4T or longer whose write pulse conditions are not changed do not vary. Thus, the phase change in the PLL as a whole is small, thereby reducing detection error due to phase shift in the PLL.

Signals to be pre-recording may be generated by performing the first test recording using a code sequence that excludes the length of the shortest mark (2T), to obtain a compensation value recording for the code lengths of the lengths of 3T or longer marks, and then by carrying out a second a test recording using a code sequence including a 2T signal, to obtain recording compensation values ​​for the code lengths including a 2T signal. On the optical disc medium where the storage capacity per data recording layer is 33.4 GB, the amplitudes of short marks and spaces in the reproduction signal are extremely small. At a time when this optical disk storage position of the recording mark 2T signal was not recorded properly, the correct positioning of long marks and spaces that are equal to or longer than 3T, is sometimes difficult. When reproduced signal which includes an extremely large intersymbol interference as described above, the recording signal can be realized by first recording marks with the code length of 3Tw or longer and correctly perform write compensation on the edge positions of marks and spaces 3Tw or longer, with subsequent recording signal which includes a 2Tw signal, and properly compensates for the positions of the recording marks and spaces 2Tw. With this organization, the recording can be performed more accurately and more efficiently, which improves the quality of the reproduction signal.

When the trial recording of the recording mark size and shift amounts of short marks, such as 2T and 3T marks, are different for the respective recording conditions. Since the tap coefficients of the adaptive equalizer filter change with each holding the trial record must also take into account the state of the shift of the signal read, which depends on the changes in the state of play in addition to the changes in the state record. Thus, for proper adjustment of the shift caused by differences in recording conditions, in the case of production adjustment of recording, the preferred values ​​of provisional fixation lifting or playback equalizer tap coefficients of the adaptive equalizing filter to adjust the test recording or recording compensation. This allows precise control of the position shift of each pattern.

Next, the procedure of the extended recording compensation is described with reference to FIG. 24. FIG. 24 shows a flowchart illustrating the procedure of the extended recording compensation on an optical disc medium according to the present embodiment, for optimizing the write pulse conditions. A computer program which defines the process procedure described in this flowchart is executed computer. The computer and hardware required for that process operate as the optical recording / reproducing apparatus shown in FIG. 1.

The first stage set the recording conditions. Condition calculation unit 110 sets a recording pulse recording conditions pre-recorded on the optical disc medium 101 or recording conditions stored in a memory of the optical recording device.

The second phase - a recording step for adjustment of patterns which have the code distance of 14. The recording compensation section 112 controls the laser driving unit 113 and the light emitting unit 102 to perform test recording on the target track on the optical disc medium 101 under the recording conditions defined in the first step.

In the third step, the reproduction of the recorded signal and detecting edge shift with the code distance of 14. The shift detecting section 109 detects 18 edge shift patterns shown in Table 1, the above-described edge shift detection method.

Fourth step - a step of determining whether the value of the edge shift with the code distance of 14 shown in Table 1, less than or equal to the desired value. If the value of the edge shift is suppressed to be less than or equal to a desired value, the procedure proceeds to the next step. On the other hand, if the value of the edge shift is not suppressed to be less than or equal to a desired value, the procedure returns to the above-described second step. Computing unit 110 sets the conditions for the write pulse conditions according to the magnitude of the write compensation of the regional shift for another test session recording.

In the fifth step, the detection of the phase shift with the code distance of 12 shown in Table 2 and Table 3. The shift detecting section 109 detects 18 patterns of phase shift shown in Table 2 and Table 3, according to the above method for detecting the shift.

Note that, with respect to the code distance of 14, revealed "boundary shift", but for the code distance of 12, revealed "phase shift". The reasons for this are described below. Adjusting templates with minimum distance 14 is realized by changing the write pulse to change the "boundary position" mark on the front and rear ends. Therefore it is necessary to detect an edge shift of the trial record label. On the other hand, adjustment patterns with the code distance of 12 is not realized by adjusting the leading end position or trailing end position of the label, but by changing the recording positions of a plurality of consecutive marks and spaces. Thus, it is necessary to detect labels and the gaps trial record as a whole. In this specification, the difference between the detection targets is identified by using different terms, "edge shift" and "phase shift". Note that these different terms are used for convenience and are therefore not subject to the strict interpretation. The fact that the "phase shift" has a broader meaning that refers to detection of edge shift in the respective test recording marks.

Sixth step - a step of determining whether the value of the edge shift with the code distance of 12 shown in Table 2 and Table 3 is suppressed to be less than or equal to a desired value. If the phase shift amount is suppressed to be less than or equal to a desired value, the adjustment procedure ends. If the phase shift amount is not suppressed to be less than or equal to a desired value, the adjustment procedure proceeds to the next step.

Seventh step - a recording step for adjustment of patterns with the code distance of 12. The condition calculation unit 110 sets the write pulse conditions according to the result write compensation of the phase shift detected in the fifth step, and test recording is performed on a target track on the optical disc medium. Then, the procedure returns to step 5.

The procedure according to the present embodiment shown in FIG. 24 includes performing test recording in a test recording area to determine recording compensation values. However, the recording in a test recording is impossible in some devices, for example, in the exposure apparatus for making a master. In this case, test recording may be carried out at the other material of the optical disk drive carrier to determine the condition of the recording to the process of cutting the master disk.

The optical disk medium according to the present embodiment includes optical disc media of the type in which the effects of thermal interference greatly vary according to the lengths of spaces that precede and follow label it. When recording to the optical disk medium of this type, it is necessary to change the terms of the write pulse in accordance with not only the length of the label, but the lengths of the preceding and subsequent spaces. Note, however, that, given the length of the gaps of the preceding mark and following it, the number of combinations of the write pulse conditions increases two-dimensionally, and accordingly, the number of parameters controlled by the trial recording increases. Therefore, increasing the period of time required for learning, and the larger number of tracks is used in learning recording conditions. In optical disc media which allow recording only once in the same area, for example, disk media write-once, the number of training sessions is limited because the area of ​​learning recording conditions has a limited number of tracks, and to use a large number of tracks in a single training session Not recommended. Therefore, a method of optimizing the write pulse conditions according to the present embodiment includes adjustment of the write pulse conditions according to classification for respective mark lengths. In the case of an optical disc medium having properties which need no compensation according to the lengths of spaces preceding the mark and following it, the write pulse conditions are corrected according only mark length, without performing an unnecessary adjustment step. Thus, by limiting the correction of the write pulse control conditions for the respective length of the marks can be reduced and adjusting time can effectively improve the signal quality of recorded marks.

On the other hand, in the case of an optical disc medium which needs adjustment conditions of the write pulse according to the lengths of spaces immediately preceding mark and following it, and the length of the marks with the preceding space and followed by a space, or in the case where only one correction conditions write pulse the respective lengths of the labels and the corresponding lengths of the gaps for leading and trailing spaces are not sufficient to ensure adequate compensation of deviations recorded marks, the conditions of the write pulse is governed by the not only the lengths of spaces preceding the label and following it, but also the length of labels, preceded by a space, and following the them, which improves the signal quality of recorded marks.

In addition, information related to the labeling of, for example, is made whether the extended recording compensation, the number of classes of mark lengths and lengths of spaces for the write compensation is required if the preceding mark compensation is necessary if subsequent payment tag number of classes, etc., can be previously stored in a predetermined area of ​​the optical disc media. The predetermined area may be an area 1003 storing the initial values ​​(Fig. 2) which is provided in the lead-in area on the inner circumference of the optical disk media. This allows you to adjust the write pulse conditions according to the properties of the optical disc medium, without performing unnecessary adjustment steps. In the case where the number of classes for the recording compensation, or whether the payment is needed preceding or subsequent marks thus known in advance, it is possible to reduce the time for adjustment and can effectively improve the signal quality of recorded marks.

After training in the optical disc, information relating to the classification, for example, whether to an extended payment records, the number of classes of the lengths of marks and the lengths of spaces to compensate for the record whether you want the payment preceding the mark is required if the compensation subsequent mark, the number of classes, and so on. g., can be recorded in a predetermined area. The predetermined area may be an area 1003 storing the initial value of which is provided in the lead-in area on the inner perimeter of the optical disc media. This allows you to adjust the write pulse conditions according to the properties of the optical disc medium, without performing unnecessary adjustment steps at the next start. In the case where the number of classes for the recording compensation or whether compensation is needed preceding or subsequent marks thus known in advance, it is possible to reduce the time for adjustment and can effectively improve the signal quality of recorded marks.

A reproducing apparatus or a playback method according to the present invention includes a reproduction unit or reproduction step for irradiating an optical disc medium with laser light for information reproduction. Furthermore, as described previously, the reproducing apparatus or method may include a block or step of extracting information relating to the classification stored in a predetermined area of ​​the optical disk media (e.g., in the field 1003 storing an initial value), for example, is made whether the expanded write compensation , the number of classes of the lengths of marks and spaces to compensate for the lengths of the recording, if necessary compensation leading and trailing spaces, whether compensation is required prior mark whether you want to follow label compensation, the number of classes, etc. This allows you to adjust the write pulse conditions according to the properties of the optical disc medium, without performing unnecessary adjustment steps at the next start. In the case where the number of classes for the recording compensation or whether compensation is needed preceding or subsequent marks thus known in advance, it is possible to reduce the time for adjustment, and can effectively improve the signal quality of recorded marks.

Although the description of the present embodiment was shown the example method PR (1,2,2,2,1) ML, the present invention is not limited to this example. One can choose a combination of PRML methods, which allow to realize the concept of the present invention.

Although the embodiment described herein the present invention provides a method for the optical recording method can be provided an optical recording / reproducing apparatus, which includes recording and playback.

Although the embodiment of the present invention will be described as an example of an optical recording / reproducing optical disk and the write-once media, the present invention is not limited to this example. The present invention is useful for the exposure device for making a master disc for a rewritable optical disc media or optical media for reading only. For example, in step mastering included in the manufacturing process of the optical disk medium is read-only, even when cutting a material disc is performed using a laser beam at a wavelength of about 400 nm on the coating of the inorganic resist, a method of optical recording of the present embodiment gives very good results .

FIG. 25 shows a device stock removal of the material of the disc. Stock removal device material disc includes a lens 2203, the motor 2204, 2205 light modulator, the laser 2706, the compensation scheme in 2207 recording memory 2208 2209 generation circuit patterns record and turntable 2210.

Referring to FIG. 25, memory 2208 contains the values ​​of the extended recording compensation shown in FIG. 10 which were obtained by the apparatus shown in FIG. 1. First of all, the information about how to adjust for dTF1, dTF2, dTF3, dTE1, dTE2 dTE3 and retrieved from the memory 2208. In the circuit 2209 generating record is modulation of templates, add ECC, scrambling, etc., so that it is transformed into binary data for recording (NRZI signal). The laser beam emitted from the laser 2206 is modulated in terms of power of the radiation beam modulator 2205 according to an output signal from write compensation circuit 2207 and is directed through the lens 2203 to 2202 of the inorganic coating a resist deposited on a glass material disc 2201. In this step, the binary recording is realized by having and the absence of irradiation. Thereafter, portions irradiated with the laser are melted, and a metal deposition is performed, for example, nickel, resulting in a metal matrix having holes concavity / convexity. The metal matrix is ​​used as a mold for molding the disk substrate and the recording film and other elements are formed on the disc substrate. Two substrates, at least one side of each of which the recording film is formed, are combined into one disc.

When cutting a material disc is performed using an electron beam, pits can be formed with a high density because of its short wavelength. However, the time required for cutting is significantly higher compared with the case of the laser beam, and accordingly, the cost of manufacturing the master disk of the optical disk media increases. By using optical information apparatus according to the present embodiment, the cutting of the material disc is performed using a laser beam, which enables to produce inexpensive optical disc media.

A method of manufacturing an optical disk medium according to the present embodiment, which uses the above exposure apparatus for making a master, may include a step of forming a predetermined area on the optical disc medium for storing information relating to classification which is necessary for the above-described extended recording compensation. Information concerning the classification may include information about whether to extended payment records, the number of classes of the lengths of marks and spaces to compensate for the lengths of the recording, if necessary compensation prior mark whether you want to follow label compensation, the number of classes, etc. The predetermined area may be an area 1003 storing the initial value of which is provided in the lead-in area on the inner perimeter of the optical disc media. This manufacturing method allows to record information relating to the classification of the optical disc medium. This allows you to adjust the write pulse conditions according to the properties of the optical disc medium, without performing unnecessary adjustment steps. In the case where the number of classes for the recording compensation or whether compensation is needed preceding or subsequent marks thus known in advance, it is possible to reduce the time for adjustment, and can effectively improve the signal quality of recorded marks.

Next, in FIG. 26 schematically shows a configuration of layers of a three-layer optical disc media according to the present embodiment. The three-layer optical disc medium, a substrate 2603, a layer 2600 records data L0 ("L0" - is an abbreviation for "Layer0"), the data recording layer L1 2601, the data recording layer L2 2602, and 2606 cover layer arranged in this order. The laser light comes onto the substrate 2603 by the cover layer 2606.

The thickness of substrate 2603 is about 1.1 mm, the thickness of the cover layer 2606 is at least 53 microns or more, data recording layers L0, L1 and L2 are separated by transparent intermediate layers 2604 and 2605.

In the present embodiment, in the particular example described herein, the thickness of the cover layer 2606 is 57 microns, the thickness of the intermediate layer 2605 between L2 and L1 is 18 mm and the thickness of the intermediate layer 2604 between L1 and L0 is 25 microns. The intervals between the respective data recording layers separated by intermediate layers are preferably set so that the interference of light diffracted at the respective data recording layers (interlayer interference) decreases. The present invention is not limited to the distances between layers given above-described thicknesses of the intermediate layers. In particular, in the case of multi-layer disc, the layers L1 and L2 should transmit light to inner layers and therefore need to have a transmittance of 55% to 65%.

In the case where recording is performed on the recording medium which has a recording layer of such a high bandwidth, high-density recording mark lengths which are beyond the optical resolution, the thicknesses of recording films of the respective layers of data records reflecting films, dielectric films, etc. ., should be reduced to ensure a high transmittance. Thus, the heat dissipation in the dielectric film and reflective film provided on the upper and lower sides of the recording film is smaller whereas the heat dissipation in the plane of the recording film more. In particular, when recording marks, the recording edge positions of marks deviate due to thermal interference. Extended payment record corresponding to the present invention is a recording compensation method especially effective in the case where very small marks that are beyond the optical resolution are recorded on a recording medium having such a layer with high transmittance.

Note that although the examples described herein, using the same optical head as in the conventional BD, the optical head may have any configuration, provided that it is able to emit the beam to the optical storage medium and output a signal according to the beam reflected from the optical medium information.

Industrial applications

An optical recording / reproducing apparatus and optical recording / reproducing apparatus according to the present invention are implemented for the optical disk media have the advantage that can record high density optical recording media, and are applicable to the production of electric and electronic devices, including digital household appliances, information processing device, etc.

The list of symbols

101 an optical disk medium

102 light emitting unit

103 block preamplifier

105 block alignment waveform

PRML processing unit 108

109 block shear detection

110 block calculate the write pulse conditions

Template generation unit 111 records

Compensation unit 112 records

113 block of laser excitation.