DISC RECORDING APPARATUS

Abstract: A disc recording apparatus for recording data such as information concerning musical performance on a recording disc (1) to which absolute addresses have been imparted in advance. Vibration during the recording operation and unexpected track jump due to defect in the recording disc are detected relying upon the discontinuity of absolute addresses reproduced from the recording disc (1). In case the track jumping has taken place, the laser power of the optical head (12) is dropped to the reproduction level and the track jump control is effected to give access to a desired track. The recording operation is then resumed for the track.

Description: Technical Field This invention relates to a disk recording apparatus for recording data such as the performance information on a recordable disk to which absolute addresses have been imparted in advance. It is applicable for instance to a performance device for a compact disk (CD) adapted for both recording and reproduction. Background Art There has so far been marketed a disk player device dedicated to reproduction, such as a CD player designed to reproduce a so-called compact disk (CD), which is an optical disk on which audio signals such as the voice or musical sounds are recorded in the digitized form. While the conventional CD player is dedicated to reproduction, attempts have been made to develop a disk system which, through the use of a magneto-optical disk formed by a photo-magnetic recording medium allowing to rewrite the information, is adapted for both recording and reproduction and able to maintain superior compatibility with respect to the compact disk. As shown diagrammatically in Fig. 1, the recordable disk 1 employed in the above disk system is formed with spirally extending pregrooves 2 having a depth equal to λ/8, wherein λ indicates the wavelength of the laser beam used for information recording. On a land 3 between the adjacent pregrooves 2, a prerecorded region 4 in which patterns of projections and recesses formed by pits each λ/4 deep are previously recorded and a data recording region 5 in which magneto-optical recording is performed, are formed alternately in the circumferential direction, each at an equal pitch. A lead-in region 7 is provided at the inner periphery of the program region 6 in which the performance information is recorded. In this lead-in region, there is recorded a TOC or table of contents information indicating the record contents of the program region 6. In the prerecorded region 4 of the recordable disk 1, there are recorded 24 bits of sync signals and 14 bit or 1 symbol of subcodes as patterns of projections and recesses formed in advance by a molding operation as indicated in Fig. 3. These subcodes represent the absolute time information or absolute addresses from the start position of the program region 6. The above 24 bit sync signals and 14 bit subcodes are a part of the 588 channel bit data making up one frame of the data format, as shown in Fig. 2, standardized for the compact disk (CD), and including, in addition to the above sync signals and subcodes, 14 x 32 bits (32 symbols) of the data such as the performance information and parities and margin bits, each of 3 bits, provided between adjacent symbols. In a disk system employing the above described recordable disk 1, disk rotation control etc. is performed at a constant linear velocity (CLV), utilizing the aforementioned absolute addresses reproduced from the prerecorded region 4 of the recordable disk 1, so that the information is recorded in the data format standardized for the compact disk (CD). It will be noted that, in the disk system employing the recordable disk, such as the magneto-optical disk formed by the magneto-optical recording medium, when a track jump takes place, that is, when the scanning beam from an optical head jumps from a presently recorded track or current track to another track due to vibrations caused during the recording operation or disk defects, the recorded performance information may be discontinuous or become discrete as a function of the amount of such track jump, such that the performance may be interrupted depending on the amount of the track jump during reproduction and, in the worst case, a performance information is over-written on the previously recorded track to destruct the previously recorded performance information. The EP-A-0 093 427 discloses a disk recording apparatus in which information is recorded by scanning with a modulated high power laser beam. Said recording normally is performed in a current track guided by a guiding track as described above. After detection of a track jump recording is stopped. Further immediate recording is performed in a separate sector of said disk until normal recording can be continued as usual. Further details of said known apparatus are disclosed in the introductory part of claim 1. The EP-A-0 139 332 discloses another recording apparatus and refers to the problem of rythm discrepancy when returning to the location of track loss. Generating the return address is done by using a table of return times as a function of the jump distance which is obtained by comparing the timecodes in a subcode, and adding derived therefrom to the timecode at the location of the track loss so as to obtain the return time code. It is therefore an object of the present invention to provide a disk recording apparatus of a novel construction in which a track jump is detected during the recording operation and the mistaken recording of the information on the tracks other than the target track is avoided. DISCLOSURE OF THE INVENTION For accomplishing the above object, the present invention provides a disk recording apparatus in which information is recorded by a scanning modulated high power laser beam in a current track on a recordable disc, on which a guiding track can be read out by said laser beam, said read out being used for a track digression signal, said apparatus comprising a digression track error detection signal producing detecting means for detecting and indicating that said scanning beam from an optical head has jumped from a current track to another track during the recording operation, whereby on occurrence of said track jumping detection signal said recording operation is interrupted, thereby preventing already correctly recorded information from destruction by the writing power laser beam, said laser beam being switched into the reproduction mode and, after said scanning laser beam being accessed to a selected address position, said laser beam again being switched for reverting the recording mode, wherein absolute addresses have been recorded in advance in said guiding track and comprising counting means generating said target address by counting clocks synchronized with said absolute addresses periodically reproduced from said guiding track during the recording mode, means setting the counting means in an autonomous running state upon occurrence of said track jumping detection signal and said selected address position being indicated by the count value of said counting means. According to the present invention, the values of the absolute addresses reproduced from the recordable disk are preset in the interpolation counter to start the recording operation. On occurrence of a track jump due to, for example, vibrations or disk defets, in the course of the recording operation, the laser power of the optical head is lowered to the reproduction level and the track jump control is performed so that the value of the absolute address reproduced from the disk coincides with the count value of the interpolation counter so that the recording operation is resumed at the target track. Thus there is but little risk that discontinuity be introduced into the data on the disk to interrupt the performance, or that the prerecorded performance information be destroyed, so that a stable recording operation is assured. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagrammatic view for illustrating a recording format of a recordable disk employed in on embodiment of the present invention; Fig. 2 is a diagrammatic view showing a data format of the information recorded on the recordable disk; Fig. 3 is a diagrammatic view showing a constructional example of a pattern of projections and recesses formed in a prerecorded region; Fig. 4 is a block diagram showing a diagrammatic construction of an embodiment in which the present invention is applied to a disk recording/reproducing device; Fig. 5 is a block diagram diagrammatically showing a functional construction of essential parts of a micro-computer provided in the disk recording/reproducing device; Fig. 6 is a flow chart for illustrating the operation of the setup mode of the disk recording/reproducing device; Fig. 7 is a flow chart illustrating the operation of the recording mode; Fig. 8 is a flow chart illustrating the ejection mode; and Fig. 9 is a block diagram diagrammatically showing an example of the functional construction of other essential parts of the micro-computer. BEST MODE FOR PRACTICING THE INVENTION In the following embodiment, the present invention is applied to a disk recording/reproducing device in which a magneto-optical disk having a perpendicular magnetizing film exhibiting magneto-optical effects is used as a recordable disk 1 having the above described recording format shown in Fig. 1, and in which the recordable disk 1 is driven into rotation at a constant linear velocity (CLV) for recording and/or reproducing the performance information having the data format show in Fig. 2. Referring to the block diagram of Fig. 4, the disk recording/reproducing device includes an optical head 12 and a magnet 13, provided for facing to each other and on both sides of a recordable disk 1 driven into revolutions by a disk motor 11. The optical head 12 is connected to an amplifier for reproducing pre-recorded signals 14 and to an amplifier for reproducing photo-magnetic signals, while also being connected to a recording amplifier 27. The optical head 12 is composed of optical components, such as a laser diode, photo-detector, lens or a beam splitter and performs the recording and/or reproduction of the information by irradiating the recordable disk 1 with a laser beam. The magnet 13 affords a magnetic field for recording or erasing the information on or from the recordable disk, by taking advantage of the photo-magnetic effects. The orientation of the magnetic poles of the magnet is inverted at the time of shifting from the recording to the erasure modes and vice versa. The optical head 12 and the magnet 13 are adapted to be moved along a radius of the disk 1 by a feed system, not shown, driven by a tracking control circuit 30. A laser diode, not shown, of the optical head 12 emits a laser light having a power proportionate to the drive current supplied from a laser drive circuit 31. Among the reproduced RF signals read out from the recordable disk 1 by the optical head 11, the reproduced signals from the prerecorded region 4 are transmitted by way of the amplifier for reproducing prerecorded signals 14 to a decoder 16. The absolute address data decoded by the decoder 16 are supplied to a micro-computer 17. The reproduced signals reproduced from a data recording region 5 on the recordable disk 1 are transmitted by way of the amplifier for reproducing photo-magnetic signals 15 to a reproduced signal processing circuit 18 so as to be subjected to a predetermined signal processing operation. The performance information reproduced from the program region 6 of the recordable disk 1 is transmitted by way of the reproduced signal processing circuit 18 to a digital to analog (D/A) converter 20 where it is converted into an analog form so as to be outputted at a signal output terminal 22 by way of a buffer amplifier 21 as a reproduced voice or audio signal So. The TOC information reproduced from the lead-in region 7 of the recordable disk 1 is transmitted from the reproduced signal processing circuit 18 to a TOC buffer memory 19 where it is stored. In the above described disk recording/reproducing apparatus, the voice or audio signals Si to be recorded in the program region 6 of the recordable disk 1 are transmitted from a signal input terminal 23 by way of a buffer amplifier 24 to an analog to digital (A/D) converter 25 where it is digitized. The performance information digitized at the A/D converter 25 is subjected to a prescribed signal processing at a recording signal processing circuit 26, after which it is transmitted by way of the recording amplifier 27 to the optical head 12 so as to be recorded in the program region 6 of the recordable disk 1. The output of the A/D converter is also transmitted to the micro-computer 17. To this micro-computer 17 are connected an operating key 28 for inputting control data and a display 29 for displaying various data. The micro-computer 17 has its essential functional construction shown in the block diagram of Fig. 5 and is composed of a key input processor 40, an interpolation counter 41, an address comparator 42, an access control 43 and a laser power control 44. The key input processor 40 monitors the operating state of the operating key 28, acknowledges the input of control data and transmits control signals to the interpolation counter 41, access control 43 and the laser power control 44. To the interpolation counter 41 are supplied absolute address data obtianed at the decoder 16. At the start of the recording operation, the value of the absolute address data is preset by control signals transmitted from the key input processor 40 to start the count operation of the interpolation clock. The address data obtained as the result of counting are transmitted to the address comparator 42 and the access control 43. To the address comparator 42 are transmitted the absolute address data obtained at the decoder 16. The comparator 42 compares the value of the absolute address data with the value of the address data supplied from the interpolation counter 41 and transmits a comparison output, which is at a logical "1" in case of the non-coincidence between these values, to the access control 43 and to the laser power control 44. The access control 43 operates responsive to control signals supplied from the key input processor 40, interpolation counter 41 and the address comparator 42 to produce tracking control signals which are transmitted to the tracking control circuit 30. The laser power control 44 is responsive to control signals transmitted from the key input processor 40 and the address comparator 42 to produce laser power control signals which are transmitted to the laser drive circuit 31. As shown in the flow chart of Fig. 6, when the recordable disk 1 is mounted in position, at the start of the operation, the disk recording/reproducing device operates so that the TOC information recorded in the lead-in region 7 of the recordable disk 1 is read at the optical head 12 and stored in the buffer memory 19 at steps 101 and 102. The device is then at a stand-still state. Referring to the flow chart of Fig. 7, when the record mode is designated by the operation of the key 28 in the stand-by state, the microcomputer 17 sets the record mode at step 201 and reproduces the absolute address data at step 202 from the prerecorded region 4 of the recordable disk 1 at the time of initiation of the recording operation. The micro-computer 17 then presets the value of the absolute address data in the interpolation counter 41 at step 203. It is then decided by the address comparator 42 at step 205 whether the value of the absolute address data (ADR) reproduced from the prerecorded region 4 coincides with the value of the address data (CNT) from the interpolation counter 41. If the result of decision is YES, that is, if the two values coincide with each other, the recording is performed at step 206. It is then decided at step 207 whether the end of the recording operation is designated. If the result of decision at step 207 is NO, that is, if the recording operation is to be continued, the absolute address data reproduced from the prerecorded region 4 are reproduced at step 204. The program then reverts to the decision operation at step 205 to perform the recording operation at step 206 repeatedly. If the result of decision at step 207 is NO, that is, if the end of the recording operation is designated, the recording/reproducing device proceeds to the stand-by state. If the result of decision at step 205 is NO, that is, when the value of the absolute address data (ADR) reproduced from the prerecorded region 4 and the value of the absolute address data (CNT) from the interpolation counter 41 are not coincident with each other, which means that the scanning beam from the optical head 12 has made track jumping from a current track to some other track, the reproducing mode is set at step 208 at once and the laser power of the optical head 12 is dropped to the reproduction level to establish the reproducing mode. As the interpolation counter 41 is caused to run autonomously at step 209, access is made at step 210 by track jumping, with the address data from the interpolation counter 41 as the target value, whilst it is decided at step 211 whether the value of the absolute address data (ADR) reproduced from the prerecorded region 4 coincides with the value of the address data (CNT) from the interpolation counter. It is noted that the access by track jumps at step 210 is made by fine tracking control achieved by supplying a drive current to an object lens or to a tracking mirror. If the result of decision at step 211 is NO, the access by track jumps at step 211 is repeated until the result of decision becomes YES. When the result of decision becomes YES, the recording mode is set at step 212 and the absolute address data are reproduced from the prerecorded region 4 at step 204. The program then proceeds to the decision step 205 to perform the recording at step 206. The recording operation at step 206 is repeated until the result of decision at step 207 becomes YES. The device proceeds to the stand-by state when the recording operation is terminated. When the eject mode is designated by the operation of the key 28 in the above standby state, the disk recording/reproducing device records the TOC information stored in die TOC buffer memory 19 at step 301 in the lead-in region 7 of the recordable disk 1 by the optical head 12. The eject operation is then performed at step 302 to terminate the operation. It is noted that the functional construction of the micro-computer 17 is not limited to the construction of the block diagram shown in Fig. 5, For example, as shown in the block diagram of Fig. 9, the micro-computer 17 may be formed by a latch circuit 51, addition circuit 52, first and second address comparators 53 and 54, interpolation counter 55, key input processor 56, access control 57 and a laser power control 58. In this case, the absolute address data obtained at the decoder 16 are transmitted to the latch circuit 51 and each of the address comparators 53 and 54. The absolute address data are latched at the latch circuit 51 by clock inputs synchronized with the absolute address data, with the latch output being supplied to the addition circuit 52 while also being supplied as the load data to the interpolation counter 55. The addition circuit 52 performs an operation of adding "1" to the absolute address data latched at the latch circuit 51, with the addition output being supplied to the first address comparator 53. The first address comparator 53 compares the value of the current absolute address data obtained at the decoder 16 with the value of the absolute address data latched at the latch circuit at the immediately preceding latching operation plus the value of the address data added to by "1" at the addition circuit 52. A comparison output which is at logic level "1" when the two values are not coincident with each other is supplied to the access control 57 and to the lasser power control 58, at the same time that the comparison output is supplied as the load and count start instructions to the interpolation counter 55. When the comparison output from the first address comparator 53 is at logic level "1", the absolute address data latched at the latch circuit 51 are loaded at the same timing to the interpolation counter 55, which then process to the cuonting operation of the clock inputs synchronized with the absolute address data, starting from the loaded absolute address data, with the count output being supplied as the target address data to the second address comparator 54 and the access control 57. The second address comparator 54 compares the value of the current absolute address data obtained at the decoder 16 with the value of the target address data supplied from the interpolation counter 55 and transmits a comparison output, which is at logic level "1" when the values are not coincident with each other, to the access control 57 and to the laser power control 58. The operating modes for the access control 57 and the laser power control 58 are designated by control signals from the key input processor 56. In the normal operating state in which both comparison outputs of the first and second address comparators 53 and 54 become logic level "0", the access control 57 performs an access with a reference being made to the current absolute address data obtained at the decoder 16. When an incorrect track jump occurs in the course of the recording operation such that the comparison output of the first address comparator 53 is at logic level "1", the access control 57 performs an access with a reference being made to the target address data supplied from the interpolation counter 55. When the comparison output of the first address comparator 53 is at logic level "1", the laser power control 58 causes the laser power to drop compulsorily to the reproduction level, despite the fact that the recording mode is designatd by the control signal supplied from the key input processor 56. The access by track jumping is performed in the reproduction mode, with the access by the track jumps being repeated until the value of the current absolute address data produced at the decoder 16 coincides with the value of the target address data obtained at the interpolation counter 55, so that the comparison output of the second address comparator 54 is at logic level "0". When the value of the absolute address data obtained at the decoder 16 and the value of the target address data obtained at the interpolation counter 55 coincide with each other, as a result of the aforementioned access performed by track jumping in the reproduction mode, at the same time that the comparison output of the first address comparator 53 is also at logic level "0", the laser power control 58 causes the laser power to be increased to the original value for reversion to the recording mode.

Claims: A disk recording apparatus in which information is recorded by a scanning modulated high power laser beam in a current track (5) on a recordable disc (1), on which a guiding track (2) can be read out by said laser beam, said read out being used for a track digression signal, said apparatus comprising a digression track error detection signal producing detecting means for detecting and indicating that said scanning beam from an optical head (12) has jumped from a current track to another track during the recording operation, whereby on occurrence of said track jumping detection signal said recording operation is interrupted, thereby preventing already correctly recorded information from destruction by the writing power laser beam, said laser beam being switched into the reproduction mode and, after said scanning laser beam being accessed to a selected address position, said laser beam again being switched for reverting the recording mode, characterized by absolute addresses (4) having been recorded in advance in said guiding track and counting means generating said target address by counting clocks synchronized with said absolute addresses periodically reproduced from said guiding track (2) during the recording mode, means setting the counting means in an autonomous running state upon occurrence of said track jumping detection signal and said selected address position being indicated by the count value of said counting means. The disk recording apparatus according to claim 1 wherein said counter means initiates its counting operation after the value of the absolute address reproduced from said disk is preset at the time of initiating the recording operation. The disk recording apparatus according to claim 1 wherein the access of said scanning beam to the address position indicated by the count value of said counter means is the access made by crack jumping.

Inventors: ANDO RYO, YOSHIDA TADAO, ANDO, RYO, YOSHIDA, TADAO
Applicants: SONY CORP, SONY CORPORATION
Application year: 1988
Main classification: G11B7
IPC codes: G11B7