Optical disc record and/or reproduction apparatus

Technical Field

0001The present invention relates to an optical disc record and/or reproduction apparatus for recording and reproducing data to and from an optical disc such as an magneto-optical disc capable of recording and reproducing data.

Background Art

0002An optical disc system which records and reproduces digital audio signals to and from an magneto-optical disc with a diameter of 64 mm which is enclosed in a cartridge has been developed. In this optical disc system, with sound compression technologies, the amount of original digital audio signals is compressed to around 1/5 times thereof and recorded. Thus, using a small disc with a diameter of 64 mm, audio signals can be recorded and reproduced thereto and therefrom for around 74 minutes long with high sound quality.

0003In the optical disc system, when data is recorded, compressed input digital audio data is temporarily stored in a buffer memory (RAM). When a certain amount of data is stored in the memory, data is read from the memory and recorded on a disc with the magnetic field modulating method.

0004When data is reproduced, data reproduced from the disc is stored in a buffer memory. Then the amount of data which is required for expansion is read from the buffer memory at a constant rate, expanded and outputted. When the buffer memory becomes full with data, reproduction of data from the disc is stopped. During this time, data reading from the buffer memory is continued. Thus, even when a pickup undergoes track jump due to disturbance or the like during data reproduction from the disc, data stored in the memory can be continuously read, so that sound jump of expanded audio data can be prevented.

0005According to the optical disc system, by performing recording and reproduction using buffer memories as mentioned above, continuous audio data can be recorded in the physically discontinuous position on a disc. Moreover, data recorded in the physically discontinuous position on a disc can be reproduced as continuous audio data.

0006Positions of data recorded on the disc are managed with a TOC (Table of Contents) provided on the inner circumference side of the disc. Non-record areas on the disc are also managed with the TOC.

0007On the other hand, at present, magnetic tapes are mainly used as media on which a user can record music programs. When a user performs recording on a magnetic tape, the user usually starts recording from the position of the magnetic tape with which a magnetic head is in contact at this point. Therefore, there is a fear that data already recorded is erroneously erased. When recording has been performed without erasing data already recorded, the beginning portion of the non-record area must be searched in advance. However, since it takes a certain time to search the beginning portion, when the user wants to start recording immediately, for example, in recording of a meeting, air check for a radio broadcasting, or the like, input information during the search of the beginning portion of the non-record areas cannot be recorded and it is dropped. Particularly, there has been no way to accomplish the desire that while a music program is reproduced, the user can record other informations immediately without erasing the music program.

0008European Published Patent Application EP-A-0,474,377 discloses an optical disc recording and reproducing apparatus in which data is read from or written to a disc at a first rate which is faster than a second rate at which said data is read from a buffer memory to be reproduced or written to a buffer memory prior to recording.

0009European Published Patent Application EP-A-0,275,972 discloses an optical disc recording and reproducing apparatus in which a search for free areas over a predetermined time length and available for recording is made and the results displayed. A user then selects a desired free area in which a recording is to be made.

0010Japanese Published Patent Application JP-A-521,182 discloses an optical disc recording and reproducing apparatus in which the number of the last recorded track is stored in a RAM memory to be available to control immediate reproduction.

0011It is still another object of the invention to provide a record and/or reproduction apparatus capable of recording new data continuously after data previously recorded.

0012It is yet another object of the invention to provide a disc record and/or reproduction apparatus capable of recording new data continuously after data being reproduced.

0013The present invention provides a disc record and reproduction apparatus for recording and reproducing data from a disc having a data area and a management area for managing recorded and recordable position information, said apparatus comprising: <ul id="ul0001" list-style="none" compact="compact"><li>recording means for storing compressed input digital data in a memory, reading a burst of said digital data from said memory, recording said digital data to said data area on said disc, and recording position information of the recorded data on said management area of said disc; and</li><li>reproducing means for reproducing compressed digital data from said disc on the basis of said position information recorded in said management area, storing said compressed digital data in said memory at a first transmitting rate, reading said compressed digital data from said memory at a second transmitting rate lower than said first transmitting rate, expanding said compressed digital data, and outputting expanded digital data, characterised in that</li><li>when a recording commanding means for commanding a start of a recording operation is operated while said reproducing operation is paused, said recording means moves a recording head (13) to a position at which said recording head was located when said pause state was entered and starts a recording operation for new program data from said position so as to overwrite previously recorded program data.</li></ul>

0014When recording is performed, since the non-record area on the disc is accessed, an unintentional erasure of music programs already recorded can be prevented.

0015When a record key is pushed in a stop state of disc reproduction, the address of the end portion of data which has been recorded previously is accessed so as to start recording of the input data from the address. Therefore, an erasure of the data which has been recorded previously.

0016When the record key is pushed during a reproduction or a state in which a reproduction has been paused, recording of the input data is started from the address at which the reproduction has been paused or interrupted, so that the data which has been recorded previously can be followed by the input data.

Brief Description Of Drawings

0017Fig. 1 is a perspective view showing an overall construction of an embodiment of the invention; Fig. 2 is a block diagram showing the construction of the embodiment of the invention; Figs. 3 and 4 are schematic diagrams for explaining a TOC in the embodiment of the invention; Figs. 5 and 6 are flow charts for explaining the embodiment of the invention; and Figs. 7 to 10 are schematic diagrams for explaining the embodiment of the invention.

Best Mode for Carrying Out the Invention

0018An embodiment of the invention will now be described hereunder with reference to the accompanying drawings. Fig. 1 is a perspective view showing an overall construction of an optical record and/or reproduction apparatus to which the invention has been applied. In Fig. 1, on a front panel 1A of the optical record and/or reproduction apparatus 1, a display 9 is disposed. In addition, on the front panel 1A of the optical record and/or reproduction apparatus 1, a power key 2, an open/close key 3, a reproduction key 4, a pause key 5, a stop key 6, music program select keys 7A and 7B, and a record key 10 are disposed. Reference numeral 8 denotes a disc tray which is pulled out of an opening of the front panel 1A.

0019By operating the open/close key 3, the disc tray 8 is pulled out of the apparatus 1 as shown by alternate short and long dash lines. On the disc tray 8, an optical disc (not shown in the figure) is mounted. When the open/close key 3 is operated again, the disc tray 8 is pulled into the apparatus 1. The optical disc is loaded on a record and/or reproduction section in the apparatus 1.

0020On the display 9, time information such as the total play time of the optical disc being loaded, the play time of a music program being reproduced, and the remaining play time of the music program being reproduced and the track number of the music program being reproduced are displayed. In addition, for an optical disc on which a disc name and a track name have been recorded, they are displayed on the display 9.

0021Fig. 2 is a block diagram showing the construction of the optical disc record and/or reproduction apparatus to which the invention has been applied. In Fig. 2, reference numeral 11 denotes a disc cartridge. An optical disc 11B with a diameter of 64 mm is contained in a cartridge 11A. There are three types of the optical disc 11B, one of which is a reproduction only optical disc, another of which is a recordable magneto-optical disc, and the other of which is an optical disc on which a dedicated reproduction area and a recordable area are mixedly provided. It is assumed here that a magneto-optical disc is contained in the disc cartridge 11.

0022Pregrooves which were wobbled in the radial direction are provided in the optical disc 11B on the basis of address data. Recording of data onto the optical disc 11B or reading of data recorded on the optical disc 11B is performed on the basis of address data which was obtained by detecting the pregrooves. Record areas of the optical disc 11B have a first record area on which data based on information such as a general music program is recorded and a second record area on which content information such as a so-called TOC (Table of Contents) is recorded, which will be explained later. Record data corresponding to data, a plurality of programs and a plurality of music programs are recorded on the optical disc 11B along the pregrooves.

0023Reference numeral 12 denotes a spindle motor which rotates the optical disc 11B at a constant linear velocity. The spindle motor 12 is controlled by a servo control circuit 15 which will be described later.

0024Reference numeral 13 shows a magnetic head which generates an external magnetic field. The magnetic head 13 applies a vertical magnetic field modulated according to data to be recorded onto the optical disc 11B. Reference numeral 14 denotes an optical pickup which irradiates a light beam onto the optical disc. The magnetic head 13 and the optical pickup 14 are opposed with the optical disc 11B therebetween. The magnetic head 13 and the optical pickup 14 are connected by a connecting mechanism (not shown) so that they are integrally moved in the radial direction of the optical disc 11B.

0025Reference numeral 15 indicates a servo control circuit. The servo control circuit 15 generates error signals such as a focusing error signal and a tracking error signal corresponding to output signals received from the optical pickup 14 through an RF amplifier 29 which will be described later. The servo control circuit 15 supplies a control signal for performing focusing servo control and tracking servo control to the optical pickup 14 on the basis of error signals being generated.

0026Reference numeral 16 denotes a feed motor which moves the optical pickup 14 in the radial direction of the optical disc 11B. The feed motor 16 moves the optical pickup 14 corresponding to a feed signal received from the servo control circuit 15 so as to perform a track jump operation. The feed motor 16 receives a low frequency - component of the tracking error signal from the servo control circuit 15. When the optical pickup 14 is moved in the radial direction of the optical disc 11B by the feed motor 16, the magnetic head 13 is also moved in the radial direction of the optical disc 11B.

0027Reference numeral 17 indicates a system controller which controls the operations of individual members of the apparatus. The system controller 17 is connected to a display 9 and an input key 18. The input key 18 is disposed on a front panel 1A shown in Fig. 1. The input key 18 includes the power key 2, the open/close key 3, the reproduction key 4, the pause key 5, the stop key 6, the music program select keys 7A and 7B, and the record key 10. The display 9 indicates content information of the optical disc 11B such as time information (for example, a total play time, a play time of a current music program or program, and a remaining time thereof), a track number of a current music program or program, a disc name, a track name, and so forth.

0028Reference numeral 19 denotes a ROM (Read Only Memory). The ROM 19 stores time information corresponding to each cluster and each sector (which will be described later). The ROM 19 is connected to the system controller 17. Time information stored in the ROM 19 is read with data corresponding to a cluster number and a sector number obtained by the system controller 17, i.e., address data.

0029Reference numeral 21 shows an input terminal. Reference numeral 22 denotes an A/D converter which converts an analog audio signal received from the input terminal 21 to a 16-bit digital signal. The sampling frequency of the A/D converter 22 is 44.1 kHz.

0030Reference numeral 23 denotes a first sound compression encoder/decoder. The first encoder/decoder 23 compresses the amount of a digital signal received from the A/D converter 22 into approximately 1/5 times as small as that of the input signal. The first encoder/decoder 23 compresses and expands the amount of a signal by using modified DCT (Modified Discrete Cosine Transform) technique.

0031Reference numeral 24 denotes a memory controller which controls data write/read operations for a memory 25. The memory 25 is for example a dynamic RAM with a storage capacity of 1 Mbits. When data is recorded onto the optical disc 11B, data received from the first encoder/decoder 23 is temporarily stored in the memory 25 through the memory controller 24. When data is reproduced from the optical disc 11B, data received from a second encoder/decoder 26 is temporarily stored in the memory 25 through the memory controller 24. The second encoder/decoder 26 performs an error correction process for data read from the memory 25.

0032The second encoder/decoder 26 performs an eight-to-fourteen modulation (EFM) for data which has been error-corrected with CIRC (Cross Interleave Reed Solomon Code).

0033Reference numeral 27 denotes a driving circuit which drives the magnetic head 13. The drive circuit 27 receives record data from the second encoder/decoder 26. Reference numeral 28 denotes an address decoder which decodes an address signal which has been recorded as the above-mentioned wobbled grooves based on a reproduced signal supplied from an RF amplifier 29.

0034Reference numeral 30 denotes an D/A converter which converts a digital signal, which has been expanded by the first encoder/decoder 23, into an analog audio signal. The analog audio signal is outputted from an output terminal 31.

0035To record record data on the optical disc 11B, a light beam which is in record level is irradiated from the optical pickup 14 to the optical disc 11B so as to heat up a record layer thereof (a magneto-optical layer in this embodiment). At this point, a vertical magnetic field corresponding to record data is applied to the opposite side of the optical disc 11. The magneto-optical record layer, which is a record layer, is magnetized in the direction of the vertical magnetic field when the temperature of the magneto-optical recording layer is lowered as the light beam is moved.

0036Thus, data is recorded on the optical disc 11B. To read data from the optical disc 11B, a light beam with a power lower than that at the time of recording is irradiated to the optical disc 11B. The light beam is reflected by the magneto-optical record layer as an optical record layer of the optical disc 11B. The reflected light beam is detected by a pair of photodetectors of the optical pickup 14. By subtracting output signals of the pair of photodetectors, a reproduced signal of the optical disc 11B can be obtained.

0037Data is recorded on the optical disc 11B cluster by cluster. One cluster is composed of 36 sectors. One sector (equivalent to one subcode block of a compact disc) is composed of 98 frames. when data is recorded, the power of the light beam irradiated from the optical pickup 14 should be controlled. In addition, the length of the interleave of CIRC is 108 frames, which is longer than the length of one sector. Thus, a linking area is required between adjacent two clusters. The first three sectors of one cluster (36 sectors) are linking sectors. The next one sector is used for subdata. Thus, compressed data of one cluster (36 sectors) are recorded in 32 sectors.

0038The position on the disc in the recording mode is designated by an address which has been recorded by wobbling grooves formed on the disc 11B. An address recorded as wobbled grooves is detected by the address decoder 28. The address detected by the address decoder 28 is supplied to the EFM and CIRC encoder/decoder 26.

0039In the reproducing mode, a record signal on the optical disc 11B is reproduced by the optical pickup 14. The reproduced signal is reproduced by the optical disc 11B cluster by cluster. The reproduced signal is sent to the EFM and CIRC encoder/decoder 26 through the RF amplifier 29. The EFM and CIRC encoder/decoder 26 performs EFM demodulation and error correction processes.

0040An output of the EFM and CIRC encoder/decoder 26 is temporarily stored in the memory 25 through the memory controller 24. An output of the memory 25 is supplied to the sound compression encoder/decoder 23. The sound compression encoder/decoder 23 expands the amount of an audio signal.

0041When the sound compression encoder/decoder 23 receives data at 300 kbits/sec, it is possible to expand the compressed data and reproduce continuous sound. On the other hand, as mentioned above, the optical pickup 14 reads a digital signal from the optical disc 11B at a transmission rate of 1.4 Mbits/sec. The memory 15 of 1 Mbits becomes full with a digital signal in approximately 0.9 seconds. Even if a digital signal is not read from the optical disc 11B due to vibration or the like, a reproduced signal can be continuously outputted from the memory 25 for approximately three seconds at 300 kbits/sec. During this period, the optical pickup 14 can reaccess the original position of the optical disc 11B so as to read the record signal. Thus, a so-called sound jump can be prevented.

0042Data which has been expanded by the sound compression encoder/decoder 23 is supplied to the D/A converter 30. The D/A converter 30 restores a digital signal to an analog signal. The resultant analog audio signal is outputted from the output terminal 31.

0043A TOC is disposed on the innermost periphery of the optical disc 11B. The TOC stores information with respect to positions of-data recorded on the optical disc 11B. Fig. 3 shows the construction of the TOC. The TOC is constructed of a header area and a data area. The header area starts with a fixed sync pattern area A1, followed by a header information area A2 which represents a cluster number and a sector number.

0044The data area starts with a fixed pattern area A3. The pattern area A3 is followed by an identification information area A4 which includes a disc type information (for example, a reproduction-only-disc, a recordable disc, or a disc having a reproduction-only region and a recordable region), a record power, a last track number, a lead-out start address, the number of sectors being used, a power calibration start address, a user TOC start address, a start address of a recordable user area, and so forth. The identification information area A4 is followed by a track number point area A5 (P-TNO1, P-TNO2, P-TNO3, and so forth). The track number points (P-TNO1, P-TNO2, P-TNO3, and so forth) are pointers which represent positions in the TOC with respect to information of the start address and end address of each track number. The track number point area A5 is followed by a track information area A6. Record positions in the TOC with respect to the information of the start address and end address of each track are recorded in the track information area A6. The record positions in the TOC with respect to the information of the start address and end address of each track are designated by the track number points (P-TNO1, P-TNO2, P-TNO3, and so forth).

0045In addition, the optical disc 11B has a user TOC which is used to manage an audio signal being recorded. Fig. 4 shows the construction of the user TOC. The user TOC has information Link-P (denoted by B1) for each track information. The Link-P represents information of a track that follows. All the track information can be managed on the user TOC.

0046The TOC information is stored in a part of the memory 25 when the disc is loaded in the apparatus. When the user TOC is changed, it is changed in the memory 25. When a recording operation is completed, updated user TOC is recorded on the optical disc 11B.

0047When the record key 10 of the optical disc record and/or reproduction apparatus is pressed, an audio signal received from the input terminal 21 is converted into a digital signal by the A/D converter 22. The digital signal is compressed by the first encoder/decoder 23. The compressed digital signal is temporarily stored in the memory 25. Thereafter, the second encoder/decoder 26 performs the error correction encoding and EFM modulating processes for the compressed digital signal. The resultant signal is recorded on the optical disc 11B by the optical pickup and the magnetic head 13.

0048In the present invention, when new audio data is recorded on the optical disc 11B, if the record key 10 is pressed while the reproducing operation is being stopped, the optical pickup 14 and the magnetic head 13 are moved to a non-record area of the optical disc 11B based on the information of the user TOC so as to prevent audio data which has been recorded on the optical disc 11B from being erased. Then, recording of audio data is started from the non-record area of the optical disc 11B.

0049When such a control operation is always performed, new audio data cannot be recorded just after audio'data which is being reproduced. To solve this problem, in the optical record and/or reproduction apparatus, when the record key 10 is pressed while audio data is being reproduced or when the record key 10 is pressed (or both the record key 10 and the play key 4 are pressed at the same time) while the reproduction of audio data is being paused, new audio data is recorded just after audio data which has been reproduced.

0050Fig. 5 is a flow chart for explaining the above-described operation. In Fig. 5, when the stop key is pressed (at step 72), while audio data is being reproduced (at step 71), the reproducing operation is stopped. When the record key 10 is pressed (at step 73) while the reproducing operation is being stopped, a blank area of the disc is detected from the TOC information and newly input audio data is recorded in the blank area of the disc (at step 74).

0051When the pause key 5 is pressed (at step 75), while audio data is being reproduced (at step 71), a reproduction pause state takes place. In the reproduction pause state, when the record key 10 is pressed or both the record key 10 and the reproduction key 4 are pressed at the same time (at step 76), newly input audio data is recorded just after audio data which is being paused for reproduction (at step 77). When both the reproduction key 4 and the record key 10 are pressed at the same time (at step 78), while audio data is being reproduced (at step 71), the reproducing operation of the audio data is stopped and newly input audio data is recorded after the position at which the reproducing operation of the audio data has been stopped (at step 79).

0052In the optical record and/or reproduction apparatus, when the reproduction key 4 is pressed, the magnetic head 13 and the optical pickup 14 are moved to the start position of a first music program or a designated music program. The second encoder/decoder 26 performs EFM demodulating and error correcting processes for the audio data which is read from the disc 11B. The resultant data is expanded by the first encoder/decoder 23 and converted into an analog audio signal by the D/A converter 30. The analog audio signal is outputted from the output terminal 31.

0053As mentioned above, normally, audio data is reproduced from the beginning of a first music program or a designated music program. To improve the operability of recording new audio data and checking the recorded state of the recorded audio data, in the optical disc record and/or reproduction apparatus according to the embodiment, when the reproduction key 10 is pressed after a recording operation has been stopped, a reproducing operation is started from the beginning of the audio data which has been just recorded.

0054Fig. 6 is a flow chart for explaining the above-described operation. In Fig. 6, when the record key 10 is pressed (at step 51), a record state is set. When the pause key 5 or the stop key 6 is pressed (at step 52 or 53) while the recording operation is being performed, the record state is stopped. Thereafter, when the reproduction key 4 is pressed (at step 54), audio data which has been just recorded is reproduced from the beginning thereof (at step 55).

0055After the recording operation has been stopped at step 53, when the record key 10 is pressed again (at step 56), recording is started again from the end position of the previous recording (at step 57).

0056When the stop key 6 is pressed (at step 58) while a reproduction state is set at step 55, the reproduction state is stopped. Thereafter, when the record key 10 is pressed (at step 59), next audio data is recorded after the end position of the audio data which has been just recorded (at step 60).

0057Fig. 7 shows recording and reproducing states on the disc. As shown in Fig. 7, when the record key 10 is pressed at position T₁ and then the stop key 6 or the pause key 5 is pressed at position T₂, an audio data stream M1 is recorded from the position T₁ to the position T₂. Thereafter, when the reproduction key 4 is pressed, a reproducing operation is started from the record start position T₁ as shown in Fig. 7B.

0058Now assume that the stop key 6 has been pressed at position T₃ and after the reproducing operation has been stopped, the record key 10 is pressed. In this case, after the record end position T₂ of the audio data M1 which has been just recorded is accessed, next audio data M2 is recorded as shown in Fig. 7C. Thus, the audio data M1 which is just followed by the audio data M2 is not erased.

0059When the reproduction key 4 is pressed again (at step 61) after the stop key 6 has been pressed at step 58, a reproducing operation is started from the first music program of the disc (at step 62).

0060When the pause key 5 is pressed (at step 63) while a reproducing operation is being performed at step 55, the reproducing operation is paused. Thereafter, when the record key 10 is pressed or when both the record key 10 and the reproduction key 4 are pressed at the same time (at step 64), recording of next audio data is started from the pause position. In other words, next audio data is overwritten from the middle portion of the audio data which has been recorded (at step 65). When both the record key 10 and the reproduction key 4 are pressed at the same time (at step 66) while a reproduction state is set at step 55, recording is started from the position where the keys have been pressed (at step 67).

0061More specifically, in Fig. 8, when the record key 10 is pressed at the position T₁ and the stop key 6 or the pause key 5 is pressed at the position T₂, an audio data stream M1 is recorded from the position T₁ to the position T₂. Thereafter, when the reproduction key 4 is pressed, a reproducing operation is started from the record start position T₁ of the audio data M1 which has been just recorded as shown in Fig. 8B. Now assume that after the pause key 5 has been pressed at the position T₃, the record key 10 is pressed. In this case, as shown in Fig. 8C, the next audio data M2 is recorded from the position T₃ where the pause key 5 has been pressed. The hatched portion of the audio data M1 which has been recorded after the position T₃ is overwritten with the current audio data M2 and erased.

0062The record start position and record end position are obtained by reproducing track information of the TOC shown in Fig. 4. When recording is performed, a blank area of the disc is accessed. For example, in the case that an area between the positions T₁₁ and T₁₂ is a data area and other areas (before the position T₁₁ and after the position T₁₂) are blank areas, when next audio data is recorded, the data area between the positions T₁₁ and T₁₂ is skipped so as to prevent the audio data recorded in the data area from being erased. Thus, as shown in Fig. 10, an audio data stream (music programs) is not always recorded in physically continuous positions. The positions of audio data which are continued are represented by the above-mentioned Link-P.