Optical disk cassette and apparatus for recording on and/or playing recorded signals from such disk signals from

The present invention relates to a method and apparatus for recording / reproducing information signals on an optical disc.

In disc devices intended for recording / playing back optical discs with a centralized path system on which digital information signals are recorded in the form of a series of pits, the path of the disc is illuminated with a laser beam, while the disc is rotated at a constant linear speed by a spindle motor. The digital information signal data is reproduced as a result of detecting changes in the intensity of reflected light, as a result of the presence or absence of pits.

As an optical recording medium for music, images and other information signals, optical read-only discs are used on which useful information signals, e.g. musical information signals, are previously recorded for playback, after the user has placed the disc in playback device. In addition, an optical recording medium is used on which the previously recorded signals can be deleted and rewritten. These are magneto-optical discs in which a thin magnetic layer is used as the recording layer.

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In the case of a read-only optical disc, the information signals are previously recorded in the form of a specific pattern of protrusions and recesses on the main surface of the disc substrate, formed of a synthetic, light-permeable resin, preferably a polycarbonate resin. A layer reflecting the light beam, for example made of aluminum, is placed on the main surface of the plate substrate containing the cavities. When a magnetic disc is used as an optical disc to be erased, the signal recording layer of thin magnetic material is located on the main surface of the disc substrate formed of a light-permeable material.

The optical recording medium is housed in a sealed cassette to prevent scratches or foreign matter from accumulating during recording, handling or storage when the recording medium is not inside the recording / playback device.

Information signals are read from an optical disc using a recording / reproducing device, using a light beam directed at the signal recording area. The light beam is sent by the optical transducer assembly of the disc recording and playback device, which also detects the reflected return beam.

Information signals are recorded on an optical disc by means of a device, using a light beam directed to the signal recording area on the disc and by means of a magnetic field affecting the recording layers. The magnetic fields are applied to the recording area by means of a magnetic head, which is an external magnetic field generator located on the opposite side of the optical plate from the optical transducer assembly.

It is advantageous if the disc recording / reproduction device can be used both with an optical disc intended for playback only and a magneto-optical disc as an information carrier. In such a device it is necessary to switch the output light beam directed at the plate by means of an optical transducer assembly, depending on the type of plate.

The light reflection coefficient for the read-only optical disc, i.e. the optical disc on which the aluminum layer was deposited, is 80% or more, while the reflection coefficient for the erasing type optical disc, i.e. the magneto-optical disc, is much smaller and approximately it ranges from 15% to 30%.

In disc recording / reproducing devices, the magnetic head must be switched between its operational state and the disconnected state, depending on which optical disc is used.

The transducer optical assembly and magnetic head can be switched by the user of the device by manual switching operation. An erroneous switching operation may, however, cause damage to the magnetic head or transducer optical assembly. Such a mistaken operation may also cause unintentional deletion of recorded information signals. Therefore, it is necessary that the switching operation in the device for recording and playing the disc, depending on the type of disc, is carried out reliably, without allowing the possibility of erroneous operations.

EP-A-0312 105 describes a system in which the reproduction process is controlled based on the signal received from the disc size detector. The type of plate is distinguished by the return light. Particularly, for small plate sizes, the control process is carried out so that the positioning servo stops in position in front of the outer edge of the plate.

EP-A-0210 629 describes a system in which the controller controls the operation of the optical head based on the read signal identifying a specific part, especially the bar code in which the cassette is provided.

In addition, DE-A-3 533 647 discloses a method for distinguishing two different types of panels. In this solution, the light beam from the source is directed directly to the plate. The size of the plate can be checked without problems, but plates with different reflection coefficients are not always correctly distinguished.

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The listed publications present solutions in which the detected beam of light reflected from the plate is received by two photodetectors and the distinction is made on the basis of the photodetector output signal.

The object of the invention is to develop a method and apparatus for recording / reproducing information signals on optical discs with different reflection coefficients, with the possibility of automatic detection of the reflection coefficient, i.e. the type of disc in the cassette.

The method according to the invention is used to record / reproduce information signals on an optical disc placed in a cassette equipped with disc type discriminating elements indicating the reflection coefficient of the light radiation of the optical disc covered by the cassette body. According to this method, discriminating elements are detected on the disc cassette in the position of loading the cassette into the recording / playback device, the output power level of the light beam directed at the optical disc is determined, depending on the results of discriminating elements detection, the recorded data is read out using the beam light whose output power level has been determined on the basis of the results of detecting distinguishing elements, and, furthermore, a recording / reproducing assembly is controlled for recording / reproducing information signals based on the read data of the optical disc content. This type of method is characterized in that the final distinction of the optical disc is carried out by reading the data recorded in the TOC table of contents area, whereby the output power level of the light beam directed at the optical disc in the cassette is determined on the basis of the discriminating elements detection results and at the same time the gain is determined recording / playback unit.

The device according to the invention is used for recording / reproducing information signals on an optical disc placed in a cassette equipped with disc type discriminating elements, indicating the reflection coefficient of the light radiation of the optical disc covered by the cassette body. This device includes an optical unit for recording / reproducing signals on an optical disc, connected to a microcomputer controlling the operation of the device, which microcomputer is connected to a detection element detecting discriminating elements of disc cassettes. This type of device is characterized by the fact that the microcomputer is connected to the laser light beam level control system.

The laser control system is connected to the optical transducer unit, which is a set of recording / reading information signals on the optical disc, to which it is connected via the control coil, the follower control system. This follower control system is connected to a second follower control system connected to a spindle motor rotating the optical disc.

The solution according to the invention is explained in more detail in the embodiment in the drawing, in which Fig. 1 is a perspective view of the plate cassette cooperating with the invention, Fig. 2 - an important part of the plate cassette of Fig. 1 in top view, Fig. 3 a block diagram of a part of a recording and reproducing device of a disc in a cassette, and Fig. 4 is a flowchart of controlling the processor of the recording and reproducing apparatus of Fig. 3, for distinguishing the type of disc, which is read-only, or for writing and reading.

Figs. 1 and 2 show a plate cassette 110 cooperating with the device according to the invention. The cassette body 111 comprises an upper and a lower part of the cassette, connected to each other. The optical disc 112 is rotatably located in the body of the cassette 111. Optical disc 112 is any optical disc with a low reflection coefficient on which recording is made, preferably a magneto-optical disc, a read-only optical disc with a high reflection coefficient, having on its base a highly reflective layer, e.g. an aluminum layer, or an optical disc with low reflectivity, read-only, having a reflective layer with substantially the same reflectivity, like a magneto-optical plate with low reflection coefficient. An opening 113 is formed in the center of the bottom surface of the cassette body 111. When the cassette 110 is loaded into the recording / reproduction apparatus, a turntable is inserted through the oblique opening so that the plate 112 is positioned on the plate. The cassette body 111 is also provided with an opening 114 whereby the transducer optical assembly of the recording / reproduction apparatus is opposite the signal recording area on the optical disc 112. The opening 114 is usually closed by a shutter 115.

When the cassette 110 is inserted in the direction of arrow A in Fig. 1 to insert inside the recording / reproduction apparatus, the shutter 115 is moved to open the opening 114. The cassette 110 also has retaining holes 103, 104, which are shaped accordingly as a circular and oblong hole. The notch 105 is adapted to engage the overlapping assembly when inserting the cassette into the recording / playback device. When a disc cassette 110 is inserted in the recording / reproducing apparatus, the shutter 115 is opened by the shutter opening assembly located in the recording / reproducing apparatus at the same time as the retaining holes 103, 104 engage by means of locating pins located in that apparatus. to determine the loading position of the cassette 110.

The cassette 110 described has several indicators that are part of the disc type discrimination in the rear corners of the bottom of the cassette body 111. The disc well hole 101 to distinguish the type of cassette serves to prevent unintentional deletion.

A detection unit, not shown, made in the recording / reproducing apparatus, detects whether the discriminating hole 101 is open or closed to determine if recording is feasible or not. A slider knob 116, not shown, is used to open or close the discriminating hole 101.

The second cassette-type discrimination element, constituting the second discernise hole 102, indicates the reflection coefficient of the optical disc 112 located inside the cassette body 111. It is located in the cassette body 111 next to the first discriminating hole 101 to prevent unintentional erasure. The second discrimination element in the form of the discrimination hole 102 opens and closes when the plate placed inside the cassette body 111 has a low reflection or high reflection, or vice versa. This is detected by the recording / reproducing apparatus to adjust the laser power level accordingly, sending a radiation beam to the optical disc by means of an optical transducer assembly.

Fig. 3 is a block diagram of a system for detecting a second aperture 102 for discriminating the type of disc cassette 110 forming part of the recording / reproducing apparatus for adjusting the laser power as a function of the reflection coefficient of the optical disc 112. In Fig. 3 there is shown a rotating plate 117 for positioning the optical plate 112 within the cassette 110, a spindle motor 118 rotatably driving the rotating plate 117 and an optical pickup unit 119 sending a radiation beam to the signal recording area on the optical plate 112 constituting a laser beam for recording or reading information signals. The detection element 120 is used in conjunction with the second discriminating opening 102 of the cassette 110. The detection element 120 is not subject to pressure and is therefore disconnected when the second discriminating hole 102 is open. In contrast, the detection element 120 is subjected to pressure and is activated when the second discriminating aperture 102 is closed, so that the laser output power level changes accordingly.

In the illustrated solution, when the disc cassette 110 is loaded into the recording / playback device and the disc 112 is set on the rotary plate 117, the microcomputer orders 121 are transmitted to the servo mechanism 122 to drive the spindle motor 118 and rotatably drive the optical disc 112. At the same time, the detection element 120 detects whether the second discriminating aperture 102 of the cassette 110 is open or closed. Depending on the output of the detection element 120, the microcomputer 121 determines whether the optical plate 112 inside the cassette 110 has a low reflection or high reflection. Accordingly, the microcomputer 121 sets the transducer optical beam light to the optimal output level to pass the appropriate control signal to the laser beam level control system 123, whose output power depends on the reflection coefficient of the optical disc 112. The beam is directed to the disc via the transducer optical assembly 119. At the same time, the microcomputer 121 sets the servo gain in proportion to the reflection coefficient of the plate 112 to send the appropriate signal to the follower control 124 and satisfactorily achieve focusing and tracking of the control operations as well as the read operations using the control coil 126 of the transducer optical unit 119 to read signals from optical disc 112. At the same time, radio frequency signals are read by the transducer assembly

170 Optical 946 is provided via radio frequency amplifier 125 to follow-up control circuits 122, 124 so as to continuously follow focusing, tracking and shifting operations based on these radio frequency signals through the spindle motor 118 and the transducer optical device 119. Part of the output signal of the RF frequency amplifier 125 is transmitted to the signal processor 127 to decode or perform similar processing operations before the signal is fed to the output terminal 128. The megnetic head 129 is an external magnetic field generator that is controlled by microcomputer control signals 121.

Since in the described embodiment there is only one discriminating hole 102, indicating the reflection coefficient of the plate, in this solution one can only distinguish a plate with a high reflection coefficient from a plate with a low reflection coefficient. If different optical discs have three to four different reflectance values, a second discriminating aperture 102 'may be used, as shown by the dashed line in Fig. 2. In this case, four different reflectance values ​​from R1 to R4 can be distinguished, as shown in Table 1, by a combination of states and closing the distinctive holes 102 and 102 '.

Table 1

<td>Distribution hole 102</td><td>Distribution hole 102 '</td><td>Reflection coefficient</td>

<td>OPEN</td><td>OPEN</td><td>R1</td>

<td>OPEN</td><td>CLOSED</td><td>R2</td>

<td>CLOSED</td><td>OPEN</td><td>R3</td>

<td>CLOSED</td><td>CLOSED</td><td>R3</td>

The presence or absence of a plate cassette is preferably detected by setting the reflection coefficient R1 to a value of approximately 0%.

By detecting the distinctive hole (s) of the disc cassette and the reflection coefficient of the disc, as well as adjusting the laser power and amplification of the servo drive of the optical assembly accordingly, information signals recorded on the optical disc can be reliably read.

When reading the information signals recorded on the optical disc, the shifting motor is controlled by microcomputer control signals 121 from the internal optical disc. TOC table of contents data (content data) is recorded in the peripheral internal area, radially towards the inside of the signal recording area. The transducer optical unit reads the content data by means of a laser beam with the power set in accordance with the detected discriminating hole type of disc. The content data includes various data about the optical disc. This means that with the aid of an optical transducer reading the content data, the microcomputer 121 determines the type of the disc, i.e. whether the disc is of the recordable type, or of the read only type, and the recording format, such as the signal format. Then, depending on the type of optical disc, the signal processing operation is performed with the signal processor 127, or the magnetic head control state is changed to perform playback record operations.

Fig. 4 shows the order of said operations via the process control flowchart. When the cassette 110 is loaded in step 201 into the recording / playback device, the discriminating holes 102, 102 'are detected in step 202 to distinguish the reflection coefficient of the disc. The laser beam power of the transducer optical assembly 119 is determined according to the results of step 202 to direct the radiation beam to the plate according to step 203.

Then, the data recorded in the TOC area of ​​the optical disc is read to determine if the disc is a writable disc or a read-only disc, as well as the type of the signal format in step 204. If the disc is a read-only disc, the read operation is performed in step 206. Then, the presence of the discrimination hole 101 to prevent unintentional deletion is ignored.

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If the discrimination results indicate that the disc is of the recordable type, the discriminating hole 101 of the cassette 110 is detected to determine if the optical disc 112 is in a writable state or not, i.e., it is in an inadvertent blocking blocking state (steps 207, 208) . If the optical disc 112 is in a non-writable state, only read operation is performed (step 209).

If the optical disc 112 is writable, the recording system appropriate for the optical disc 112 is selected (step 210). This means that if a magneto-optical disc is used as a recordable disc, the recording system is a light modulated recording system and a magnetic field modulated recording system.

If the recording system is a magnetic field modulation recording system, the magnetic head 129 as an external magnetic field generator for generating the modulating magnetic field recording changes according to the magneto-optical plate. In contrast, a light beam with a recording power level is directed at the disc through the optical transducer assembly at the same time when an active servo mechanism is used to control the magnetic head 129 to move the magnetic head and set it at a certain distance from the magneto-optical plate. Alternatively, the magnetic head 129 slidably contacts the magneto-optical plate to record information signals on the plate. Reading information from the optical disc is performed in step 212, only by means of a light beam coming from the transducer optical assembly. In the case of a light modulation system, the light beam from the transducer optical unit is controlled in such a way that it is switched on or off on the basis of information signals to be recorded, while a unidirectional magnetic field is supplied from the magnetic head as an external magnetic field generator , for recording information signals on an optical disc. The information from the optical disc is read in step 213 only by means of an optical transducer, as in the case of a magnetic field modulation system.

According to the method according to the invention, the basic elements are defined, i.e. a distinction is made between recordability or non-recordability (prohibition of inadvertent deletion) of a disc. It depends on the distinguishing holes in the plate cassette. However, distinguishing between other elements is based on the results of reading optical disc content information.

When the described plate cassette is used, the first and second plate type indicators placed on the outer surfaces of the cassette body containing the rotatably arranged plate are in a closed or open state and are adapted to indicate one of four indicator states.

When using a cassette, by detecting indicator states associated with the plate types and disc type discriminating elements, the disc type can be easily distinguished. Detection of disc type discriminating elements is easily achieved by microswitches or similar devices.

The method according to the invention ensures easy differentiation of the type of disc housed in the cassette body and enables the device according to the invention for recording / playing discs to perform predetermined switching operations reliably, depending on the type of disc, without complicating or increasing the size of the device.

Disc type discriminating elements for indicating the light reflection coefficient for the optical disc are located in a part of the cassette body containing the optical disc. The disc recording / reproducing apparatus comprises a device for detecting the discriminating elements of the cassette and a laser beam power setting device directed at the optical disc, depending on the output signal of the detection unit, so that the reflection coefficient of the optical disc is determined automatically and the laser beam power is set according to with detected reflection coefficient, for reliable reading of signals recorded on an optical disc. If the reflection coefficient of the optical disc is first distinguished by the disc cassette discriminating means as described, and the content information stored on the optical disc will be read to distinguish between the type of optical disc, any type of optical disc can easily be operated.

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LOADED CASSETTE CASSETTE nn rufj.ann μιρεπιτ pt

DETERMINING THE COORDINATE REFLECTION BY THE SECOND DISTRICT

ILLUMINATING THE BOARD WITH LASER CONTROLLED POWER

201

202

203

READING THE DISC CONTENT TO DETERMINE WHAT THE DISC IS

RECORDABLE OR PLAYBACK ONLY

205

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PLAYING

207

RECORD

DETERMINING IF THE BOARD IS WRITTEN OR NOT SAVED. THROUGH THE FIRST DISTINCTIVE HOLE

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MODUŁ.ŚWIATŁA

LASER ENTRY WHEN THE FIELD OF MAGNES IS DETERMINED. PLAYBACK ONLY LA-SER.OHa

-204

206 f

READING ONLY (PLAYBACK) ONLY (SKIP ON THE FIRST OPENING OF THE DIFFERENT. TRAYS AND

writable

209

READING ONLY (PLAYBACK)

MAGNETIC FIELD MODULE

212 (

RECORDING OF THE ACTIVE SERVO-SYSTEM WITH A SWITCHING MAGN HEAD OR A SLIDING HEAD, WZGL-PLATE, LASER PLAYBACK ONLY

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UP Department of Publications. Circulation of 90 copies

Price PLN 2.00