JP2005093063A - Storage device, optical recording medium, and information recording method - Google Patents

Abstract

The present invention relates to a storage device, an optical recording medium, and an information recording method. Even when information is reproduced from a recording medium by using a magneto-optical effect using MSR, information recorded as an uneven (embossed pit) shape is recorded. An object of the present invention is to realize a high-capacity recording medium that can be accurately reproduced and has high reliability.
When a control area in which control information is pre-recorded in an embossed shape and a data area in which data is recorded by optical means are provided, and the recording density of the control area is N> 1, the data area is recorded. Set to 1 / N times the density, the control area has the same recording density, and includes a data part in which medium information unique to the recording medium is recorded and an identification part for identifying the recording area, The data area includes a data part in which data is recorded and an identification part for identifying the recording area. When the recording density of the identification part of the data area is N> 1, the recording density of the data part of the data area is It is configured to be set to 1 / N times.
[Selection] Figure 6

Description

  The present invention relates to a storage device, an optical recording medium, and an information recording method, and more particularly to a storage device that reproduces information recorded at a high density from a recording medium, an optical information recording medium that records information at a high density, and information. The present invention relates to an information recording method for recording on a recording medium at high density.

  One of the optical recording media is a magneto-optical recording medium represented by a magneto-optical disk. A magneto-optical disk has a substrate and a recording layer made of a magnetic material formed on the substrate, and records information using heating by light and a change in magnetic field. In reproducing information from the magneto-optical disk, the magneto-optical effect is utilized. Such a magneto-optical disk is provided with a data track for recording data and a control track for recording medium information unique to the magneto-optical disk, and each track has an identification (ID) for identifying a sector which is a recording area. ) Part and a data part for recording data. The control track is formed when the manufacturer forms a guide groove (land / groove) on the substrate by a stamper or injection molding to prevent information rewriting. To be recorded. The ID part is also recorded by forming irregularities on the substrate in the same manufacturing process for the same reason.

  Various methods for improving the recording density of the magneto-optical disk as described above have been proposed. In a method using magnetic super-resolution (MSR), which is one of them, the minimum record information that can be reproduced is generally determined by the wavelength, but information below the limit is reproduced. That is, only necessary information can be reproduced from the magneto-optical disk by forming a magnetic mask using the temperature distribution of the laser power during reproduction.

  FIG. 17 is a diagram for explaining the principle of a method using MSR. The upper part of the figure shows a partial plane of one track on the magneto-optical disk, and the lower part of the figure shows a cross section of the magneto-optical disk. A recording layer 101, an intermediate layer 102, and a reproducing layer 103 are provided on a substrate (not shown) of the magneto-optical disk. The arrows in these layers 101 to 103 indicate the magnetization directions, respectively. Note that BM indicates the moving direction of the laser beam, DM indicates the moving direction (rotating direction) of the magneto-optical disk, RM indicates the reproducing magnetic field, and hatching indicates the interface domain wall 104.

The intermediate layer 102 transfers or blocks information recorded on the recording layer 101 to the reproducing layer 103 according to the temperature. When reproducing the information recorded in the data portion of the track in this way, the temperature distribution of the laser power at the time of reproduction is used, and the magnetic front mask 105 and rear mask 106 are formed at portions other than the reproduction portion. As a result, only necessary information can be reproduced from the magneto-optical disk. That is, for example, when information having a shortest mark length of 0.38 μm recorded in the data portion is reproduced using a laser beam having a wavelength of 680 nm, the spot diameter of the laser beam is about 1 μm and about three times the shortest mark length. Even so, by forming the masks 105 and 106, only necessary information can be reproduced from the magneto-optical disk.
Japanese Patent Laid-Open No. 8-249533 JP-A-4-259994 JP-A-11-66749

  However, since the ID part of the control track is recorded by forming irregularities (embossed pits) on the substrate of the magneto-optical disk, MSR is used to record information at the same density as the data part of the control part. There is a problem that the information in the ID part cannot be reproduced accurately. In other words, when the spot diameter of the laser beam is about 1 μm as described above, for example, even if an attempt is made to reproduce a pit having the shortest mark length of 0.38 μm as described above, about 3 pits are included in the beam spot. Information on only one required pit among the three pits cannot be reproduced. This is because there is no means for masking information from pits other than the necessary pits among the pits entering the beam spot.

  Accordingly, the present invention provides a storage device, an optical recording medium, and an information recording method capable of accurately reproducing information recorded as a concavo-convex shape even when information is reproduced from the recording medium by magneto-optical effect using MSR. The purpose is to provide.

  The above-described problem includes a control area in which control information including medium information unique to a recording medium is recorded in advance in an embossed shape, and a data area in which data is recorded by optical means. The control area and the data area And a storage device for reproducing the control information and the data from optical recording media of different recording densities, and a frequency of a read clock used when reproducing the control information and the data from the optical recording medium Is achieved by a storage device including control means for switching between when the control information is reproduced and when the data is reproduced.

  According to the present invention, since the data part and the identification part of the control area are both recorded in an emboss shape in advance, the read clock frequency in the data part and the identification part of the control area is made the same. Frequency control can be simplified. Therefore, control information can be reproduced from the control area even if the recording density of the data area increases.

  The recording density of the control area may be set to 1 / N times the recording density of the data area when N> 1.

  According to the present invention, the frequency of the read clock when reproducing the data part of the data area is set to 1 / N times the frequency of the read clock when reproducing the identification part and the control area of the data area. The required read clock can be obtained with high accuracy.

  When N> 1, the control means may be configured to switch the frequency of the read clock to 1 / N times when reproducing the control information when reproducing the control information.

  According to the present invention, the frequency of the read clock when reproducing the data part of the data area is set to 1 / N times the frequency of the read clock when reproducing the identification part and the control area of the data area. The required read clock can be obtained with high accuracy.

  The control area includes a data part in which the medium information is recorded and an identification part for identifying the recording area, and the data area is for identifying the data part in which the data is recorded and the recording area. May be included.

  The control means is configured to switch the frequency of the read clock to 1 / N times when reproducing the data part of the data area when reproducing the identification part of the data area when N> 1. Also good.

  According to the present invention, the frequency of the read clock when reproducing the data part of the data area is set to 1 / N times the frequency of the read clock when reproducing the identification part and the control area of the data area. The required read clock can be obtained with high accuracy.

  The control means may be configured to control the frequency of the read clock to be the same when reproducing the data portion of the control area and when reproducing the identification section of the control area.

  The control means may be configured to control the frequency of the read clock so as to be different between when the data portion of the data area is reproduced and when the identification portion of the data area is reproduced.

  N may be an integer of 2 or more.

  The optical recording medium has a substrate, a recording layer provided on the substrate for recording data at a recording density smaller than the diameter of the light beam to be used, and data recorded on the recording layer at the time of reproduction transferred. May be included.

  The storage device further includes a clock generation unit that generates a reference clock, and a clock generation unit that generates a first clock and a second clock based on the reference clock, and the control unit includes the control information and the data When reproducing the control information from the control area, the frequency of the read clock used when reproducing the data from the optical recording medium is controlled to the frequency of the first clock, and the data is reproduced from the data area. In such a case, the frequency may be controlled to the frequency of the second clock.

  The frequency of the first clock may be set to 1 / N times the frequency of the second clock, where N> 1.

  The above-described problem includes a control area in which control information is recorded in an embossed shape in advance, and a data area in which data is recorded by optical means, and the recording density of the control area is N> 1, the data This can also be achieved by an optical recording medium set to 1 / N times the recording density of the area.

  According to the present invention, the first and second clocks can be easily synchronized by generating the first and second clocks based on the reference clock. In addition, since the first and second clocks can be easily generated by dividing the reference clock at different division ratios, it is not necessary to provide a plurality of clock generation circuits, and the circuit scale can be simplified. You can also.

  The control area includes a data part in which medium information unique to the recording medium is recorded and an identification part for identifying the recording area, and the data area identifies the data part in which the data is recorded and the recording area. The recording density of the identification part of the data area may be set to 1 / N times the recording density of the data part of the data area, where N> 1.

  According to the present invention, the frequency of the read clock when reproducing the data part of the data area is set to 1 / N times the frequency of the read clock when reproducing the identification part and the control area of the data area. The required read clock can be obtained with high accuracy.

  The optical recording medium has a substrate, a recording layer for recording data at a recording density smaller than the diameter of the light beam used on the substrate, and data recorded on the recording layer during reproduction. A reproducing layer may be further provided.

  According to the present invention, since the data part and the identification part of the control area are both recorded in an emboss shape in advance, the read clock frequency in the data part and the identification part of the control area is made the same. Frequency control can be simplified. Therefore, control information can be reproduced from the control area even if the recording density of the data area increases.

  N may be an integer of 2 or more.

  According to the present invention, since the data part and the identification part of the control area are both recorded in an emboss shape in advance, the read clock frequency in the data part and the identification part of the control area is made the same. Frequency control can be simplified. Therefore, control information can be reproduced from the control area even if the recording density of the data area increases. Further, if N> 1, the recording density of the control area may be set to 1 / N times the recording density of the data area. In this case, the read clock for reproducing the data portion of the data area Is set to 1 / N times the frequency of the read clock when reproducing the data area identification section and the control area, the required read clock can be obtained with high accuracy. Therefore, even when information is reproduced from the recording medium by the magneto-optical effect using MSR, it is possible to accurately reproduce the information recorded as a concavo-convex (embossed pit) shape, and a highly reliable large-capacity recording medium Can be realized.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, an embodiment of a storage device according to the present invention will be described. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of a storage device. In this embodiment, the present invention is applied to an optical disc apparatus. This embodiment of the storage device adopts an embodiment of the information recording method according to the present invention, and creates an embodiment of the recording medium according to the present invention.

  As shown in FIG. 1, the optical disc apparatus generally includes a control unit 10 and an enclosure 11. The control unit 10 is used to read / write data to / from an optical disc (not shown), an MPU 12 that performs overall control of the optical disc device, an interface 17 that exchanges commands and data with a host device (not shown). An optical disk controller (ODC) 14 that performs necessary processing, a digital signal processor (DSP) 16, and a buffer memory 18 are included. The buffer memory 18 is shared by the MPU 12, the ODC 14, and the interface 17, and includes, for example, a dynamic random access memory (DRAM). A crystal resonator 101 used for generating a clock is connected to the MPU 12.

  The ODC 14 is provided with a formatter 14-1 and an error correction code (ECC) processing unit 14-2. At the time of write access, the formatter 14-1 divides the NRZ write data into optical disk sector units to generate a recording format, and the ECC processing unit 14-2 generates and adds ECC in sector write data units. In response, a cyclic redundancy check (CRC) code is generated and added. Further, the ECC processing unit 14-2 converts the sector data after the ECC encoding into, for example, a 1-7 run length limited (RLL) code.

  At the time of read access, 1-7 RLL reverse conversion is performed on the sector data, and then the ECC processing unit 14-2 performs CRC, and then performs error detection and error correction by ECC. Further, the formatter 14-1 concatenates the NRZ data for each sector and transfers it to the host device as a stream of NRZ read data.

  A write large-scale integrated circuit (LSI) 20 is provided for the ODC 14, and the write LSI 20 includes a write modulator 21 and a laser diode control circuit 22. The control output of the laser diode control circuit 22 is supplied to a laser diode unit 30 provided in the optical unit on the enclosure 11 side. The laser diode unit 30 integrally includes a laser diode 30-1 and a monitor detector 30-2. The write modulator 21 converts the write data into a data format in pit position modulation (PPM) recording (also referred to as mark recording) or pulse width modulation (PWM) recording (also referred to as edge recording).

  In this embodiment, any one of 128 MB, 230 MB, 540 MB, and 640 MB can be used as an optical disk that records and reproduces data using the laser diode unit 30, that is, a rewritable magneto-optical (MO) cartridge medium. . The 128 MB and 230 MB MO cartridge media employ PPM recording that records data in accordance with the presence or absence of marks on the optical disk. The recording format of the optical disc is constant angular velocity (CAV) in the case of a 128 MB optical disc, zone constant angular velocity (ZCAV) is adopted in the case of a 230 MB optical disc, and the number of zones in the user area is 128 MB. There are 1 zone for an optical disc and 10 zones for a 230 MB optical disc.

  For the 540 MB and 640 MB MO cartridge media that perform high-density recording, PWM recording is used in which the edge of the mark, that is, the leading edge and the trailing edge are recorded in correspondence with the data. Here, the difference in storage capacity between the 540 MB optical disk and the 640 MB optical disk is due to the difference in sector capacity. When the sector capacity is 2048 bytes, the optical disk is 640 MB, and when the sector capacity is 512 bytes, it is 540 MB. It becomes an optical disk. The recording format of the optical disk is a zone CAV, and the number of zones in the user area is 11 zones for a 640 MB optical disk and 18 zones for a 540 MB optical disk.

  As described above, in this embodiment, 128 MB, 230 MB, 540 MB, and 640 MB optical discs, and 230 MB, 540 MB, and 640 MB optical discs compatible with direct overwrite can be used. Therefore, when an optical disk is loaded into the optical disk apparatus, first, the identification (ID) portion of the optical disk is read, the MPU 12 recognizes the type of the optical disk from the pit interval, and the ODC 14 is notified of the type recognition result.

  A lead LSI 24 is provided as a lead system for the ODC 14, and a lead demodulator 25 and a frequency synthesizer 26 are built in the lead LSI 24. A light reception signal of the laser beam return light from the laser diode 30-1 by the ID / MO detector 32 provided in the enclosure 11 is input to the lead LSI 24 as an ID signal and an MO signal via the head amplifier 34. ing. The read demodulation unit 25 of the read LSI 24 is provided with circuit functions such as an automatic gain control (AGC) circuit, a filter, and a sector mark detection circuit. The read demodulation unit 25 reads a read clock and a read signal from the input ID signal and MO signal. Data is generated and PPM data or PWM data is demodulated to the original NRZ data. In addition, since the zone CAV is employed, the frequency division ratio setting control for generating the clock frequency corresponding to the zone is performed from the MPU 12 to the frequency synthesizer 26 incorporated in the read LSI 24.

  The frequency synthesizer 26 is a phase-locked loop (PLL) circuit having a programmable frequency divider, and generates a reference clock having a predetermined specific frequency according to the zone position on the optical disc as a read clock. That is, the frequency synthesizer 26 is configured by a PLL circuit including a programmable frequency divider, and a reference clock having a frequency fo according to the frequency division ratio m / n set by the MPU 12 according to the zone number is expressed as fo = (m / n) Generated according to fi.

  Here, the division value n of the denominator of the division ratio m / n is a unique value corresponding to the type of the 128 MB, 230 MB, 540 MB or 640 MB optical disc. The frequency division value m of the numerator of the frequency division ratio m / n is a value that changes in accordance with the zone position of the optical disc, and is prepared in advance as table information of values corresponding to the zone numbers for each optical disc. . Further, fi represents the frequency of the reference clock generated outside the frequency synthesizer 26.

  The read data demodulated by the read LSI 24 is supplied to the read system of the ODC 14, subjected to 1-7 RLL inverse conversion, and then subjected to CRC and ECC processing by the encoding function of the ECC processing unit 14-2. To be restored. Next, the formatter 14-1 converts the NRZ sector data into a stream of NRZ read data, which is transferred from the interface 17 to the host device via the buffer memory 18.

  A detection signal from a temperature sensor 36 provided on the enclosure 11 side is supplied to the MPU 12 via the DSP 16. The MPU 12 controls the read, write, and erase light emission powers in the laser diode control circuit 22 to optimum values based on the environmental temperature inside the optical disk device detected by the temperature sensor 36.

  The MPU 12 controls the spindle motor 40 provided on the enclosure 11 side by the driver 38 via the DSP 16. In this embodiment, since the recording domat of the optical disk is the zone CAV, the spindle motor 40 is rotated at a constant speed of, for example, 3000 rpm.

  The MPU 12 controls the electromagnet 44 provided on the enclosure 11 side via the driver 42 via the DSP 16. The electromagnet 44 is disposed on the side opposite to the beam irradiation side of the optical disk loaded in the optical disk apparatus, and supplies an external magnetic field to the optical disk during recording and erasing.

  The DSP 16 has a servo function for positioning the beam from the laser diode 30 with respect to the optical disc, and functions as a seek control unit and an on-track control unit for seeking to the target track and performing on-track. This seek control and on-track control can be executed simultaneously in parallel with the write access or read access to the upper command by the MPU 12.

  In order to realize the servo function of the DSP 16, a focus error signal (FES) detector 45 that receives beam return light from the optical disk is provided in the optical unit on the enclosure 11 side. The FES detection circuit 46 generates FESE 1 from the light reception output of the FES detector 45 and inputs it to the DSP 16.

  The optical unit on the enclosure 11 side is also provided with a tracking error signal (TES) detector 47 for receiving beam return light from the optical disk. The TES detection circuit 48 generates TSE 2 from the light reception output of the TES detector 47 and inputs it to the DSP 16. TSE2 is also input to the track zero cross (TZC) detection circuit 50, and a TZC pulse E3 is generated and input to the DSP 16.

  On the enclosure 11 side, a lens position sensor 52 for detecting the position of the objective lens that irradiates the optical disk with the laser beam is provided, and a lens position detection signal (LPOS) E4 from the lens position sensor 52 is input to the DSP 16. Is done. The DSP 16 controls and drives the focus actuator 60, the lens actuator 64, and the voice coil motor (VCM) 68 via the drivers 58, 62 and 66 in order to control the position of the beam spot on the optical disc.

  FIG. 2 is a cross-sectional view illustrating a schematic configuration of the enclosure 11. As shown in FIG. 2, the spindle motor 40 is provided in the housing 67, and the optical disk (MO disk) 72 accommodated in the MO cartridge 70 is inserted into the spindle motor 40 by inserting the MO cartridge 70 from the inlet door 69 side. The optical disk 72 is loaded on the optical disk apparatus. When the MSR is used, the optical disc 72 has a layer structure as shown in FIG.

  A carriage 76 is provided below the optical disk 72 in the loaded MO cartridge 70 and is movable in the direction crossing the track of the optical disk 72 by the VCM 64. An objective lens 80 is mounted on the carriage 76, and a beam from a laser diode (30-1) provided in the fixed optical system 78 is incident through a rising mirror 82 and is incident on the recording surface of the optical disk 72. Is imaged.

  The objective lens 80 is controlled to move in the optical axis direction by the focus actuator 60 of the enclosure 11 shown in FIG. 1, and can be moved within the range of, for example, several tens of tracks in the radial direction across the track of the optical disk 72 by the lens actuator 64. is there. The position of the objective lens 80 mounted on the carriage 76 is detected by the lens position sensor 54 in FIG. The lens position sensor 54 sets the lens position detection signal to zero at the neutral position where the optical axis of the objective lens 80 is directly above, and the amount of movement with different polarities for the movement of the optical disc 72 toward the outer side and the movement toward the inner side, respectively. A lens position detection signal E4 corresponding to is output.

  FIG. 3 is a block diagram for explaining parameter setting control and settling wait functions for the read LSI 24, ODC 14 and DSP 16 of the MPU 12 in the optical disk apparatus shown in FIG.

  The MPU 12 is provided with a parameter setting control unit 90 that operates based on a read command from the host device, and a settling wait processing unit 92 after parameter setting. The setting control unit 90 performs setting control of parameters necessary for various accesses using a parameter table 94 expanded in a RAM or the like included in the buffer memory 18.

  The read LSI 24 is provided with a frequency synthesizer 26 and an MO signal equalization circuit 95 obtained from the ID / MO detector 32 as parameters to be set by the setting control unit 90 provided in the MPU 12. For the frequency synthesizer 26, three control registers 96, 98, 100 are provided in this embodiment.

  In each of the control registers 96, 98, and 100, parameters for dividing ratio m / n, voltage controlled oscillator (VCO) frequency setting, and PLL damping resistance selection are set by the setting control unit 90 of the MPU 12. A control register 102 is provided for the equalization circuit 95, and an equalizer cutoff frequency is set by the setting control unit 90 of the MPU 12. Further, a control register 106 is provided for the sector mark detection circuit 104 provided in the ODC 14, and the sector mark detection cutoff frequency is set and controlled by the setting control unit 90 of the MPU 12. A seek command is transferred to the DSP 16 when the MPU 12 executes a read command from the host device. The DSP 16 includes a seek control unit 108 that performs seek control for simultaneously positioning the beam spot on the target track of the optical disc 72 in parallel with the processing of the MPU 12 based on the seek command.

  As described above, the setting control unit 90 of the MPU 12 can optimize the cutoff frequency of the MO signal equalization circuit 95 provided in the read LSI 24 by the setting control of the control register 102. The setting control unit 90 optimizes the frequency division ratio m / n, VCO frequency setting, and PLL damping resistor selection parameters of the frequency synthesizer 26 provided in the read LSI 24 by setting control of the control registers 96, 98, and 100. Can be Further, the setting control unit 90 can optimize the cut-off frequency of the sector mark detection circuit 104 provided in the ODC 14 by setting control of the control register 106.

  The firmware of the control unit 10 is installed by being read from, for example, the optical disk 72 inserted into the enclosure 11 and stored in the buffer memory 18 under the control of the host device, and the firmware stored in the buffer memory 18 is executed. Is done. Similarly, the program executed by the MPU 12 is read from, for example, the optical disk 72 inserted into the enclosure 11 under the control of the host device, stored in the buffer memory 18 by the MPU 12, and stored in the buffer memory 18. Executed. That is, the program of the MPU 12 for realizing the identification information recording method according to the present invention may be recorded on the storage medium according to the present invention. In this case, the storage medium according to the present invention is not limited to the optical disc 72. Further, it may be composed of various disks including a magnetic disk, various semiconductor storage devices, various storage cards, and the like.

  When installing the firmware, the version number of the firmware is stored in the version number memory in the buffer memory 18 by a known method. The number of times this firmware has been installed in the storage device shown in FIG. 1 and other storage devices in the past is stored in a version number counter in the buffer memory 18.

  FIG. 4 is a block diagram for explaining the functions of the read LSI 24 of the MPU 12 and the read system of the ODC 14 in the optical disc apparatus shown in FIG. In the figure, the same parts as those in FIGS. 1 and 3 are denoted by the same reference numerals, and the description thereof is omitted.

  The read LSI 24 receives an MO signal (data signal) and an ID signal from the ID / MO detector 32 that receives the return light from the optical disk 72. The ID signal is a signal in which the presence / absence of an emboss bit is detected as a change in the amount of beam light on the detector 32. Since the data of the ID portion and the control track are recorded as emboss pits, the ID signal is read from these. The MO signal is subjected to waveform equalization by the equalization circuit 94 and then amplified by the automatic gain control (AGC) circuit 110. On the other hand, the ID signal is amplified by the AGC circuit 112.

  The setting control unit 90 of the MPU 12 shown in FIG. 3 optimizes the equalizer circuit 94 for the MO signal by setting an equalizer cutoff frequency in the control register 102 according to the zone position on the optical disk 72. The outputs of the AGC circuit 110 for the MO signal and the AGC circuit 112 for the ID signal are respectively input to the multiplexer (MUX) 114, selected by the ID / MO switching signal from the MPU 12, and sequentially supplied to the differentiating circuit 116 and peaked. The level is detected by zero crossing.

  The output of the differentiation circuit 116 is supplied to the data demodulation circuit 117, and a read clock and read data are generated. The frequency synthesizer 26 receives a setting of a frequency division ratio corresponding to the zone ratio of the target track, for example, during a seek in which an ID signal or an MO signal cannot be obtained, and a target reference based on the clock from the frequency divider circuit 119. Generate clock frequency. For example, a clock from the crystal unit 101 shown in FIG. 1 is supplied to the frequency dividing circuit 119, and the frequency is divided by a frequency dividing ratio according to the data / control track switching signal obtained from the MPU 12 or the ODC 14 and then supplied to the frequency synthesizer 26. Supplied. The frequency synthesizer 26 generates a reference clock that follows the peak detection pulse of the ID signal or MO signal from the differentiating circuit 116 when it is on-tracked when the seek is completed based on the clock from the frequency dividing circuit 119.

  The data demodulating circuit 117 generates read data in which the ID signal and the MO signal obtained in the on-track state after completion of the seek are synchronized with the read clock generated by the frequency synthesizer 26. At this time, the data demodulation circuit 117 performs demodulation to return the PPM modulation data or PWM modulation data obtained as read data to the read data before modulation.

  The output of the differentiation circuit 116 is further differentiated by the differentiation circuit 118, and compared with a predetermined threshold level in the comparison circuit 120, thereby outputting a sector mark pulse signal indicating a sector mark recorded in the ID area.

  The read system of the ODC 14 includes an RLL data demodulation circuit 122, a sync byte detection circuit 124, an address mark detection circuit 126, an ECC circuit 128, a CRC check circuit 130, an ID detection circuit 132, and a sector mark detection circuit 104.

  The read data and read clock demodulated by the read LSI 24 are input to the RLL data demodulation circuit 122, the sync byte detection circuit 124, and the address mark detection circuit 126.

  With respect to the read data of the ID signal at the head of the sector obtained first, the sync byte detection circuit 124 performs sync byte detection, followed by the address mark detection circuit 126 to perform address mark detection, each of which is sent to the RLL data demodulation circuit 122. By being supplied, the read data of the data part (MO part) following the ID part is recognized, and the read data is demodulated by 1-7 RLL inverse transformation.

  The read data demodulated by the RLL data demodulation circuit 122 is then supplied to the ECC circuit 128, the CRC check circuit 130, and the ID detection circuit 132. The CRC check circuit 130 detects an error in the data stream composed of data and ECC, and outputs the result to the ECC circuit 128. The ECC circuit 128 performs error detection and correction of the read data based on the ECC code and outputs it as NRZ data.

  The ID detection circuit 132 detects the ID information of the read data and outputs an ID detection update notification signal. The address mark detection circuit 126 outputs an address mark detection signal to the MPU 12, and the sector mark detection circuit 104 outputs a sector mark detection signal to the MPU 12.

  A control register 106 as shown in FIG. 3 is provided for the sector mark detection circuit 104 provided in the read system on the ODC 14 side, and the cut-off frequency thereof is set by the setting control unit 90 provided in the MPU 12. The setting is controlled in accordance with the zone position, and the cut-off frequency characteristic of the sector mark detection circuit 104 is optimized.

  FIG. 5 is a flowchart for explaining clock frequency switching in the present embodiment. The processing shown in the figure corresponds to the operations of the MPU 12 or ODC 14, the frequency dividing circuit 119, and the frequency synthesizer 26. FIG. 6 is an enlarged perspective view showing a part of the optical disc 72.

  Since the physical format is predetermined for the data track (data area) 201 and the control track (control area) 202 on the optical disk 72 shown in FIG. 6, which track (area) is accessed in this embodiment. Based on the above, the clock frequency is switched. In FIG. 6, reference numeral 205 denotes an ID part, and 206 denotes a data part. In this embodiment, the information recorded on the control track 202 is recorded in the ID portion 205 and the data portion 206 in an uneven (embossed pit) shape. On the control track 202, information for identifying the recording area of the data portion 206 is recorded in the ID portion 205, and medium information specific to the optical disc 72 is recorded in the data portion 206. On the other hand, information recorded on the data track 201 is recorded in the ID portion 205 in an uneven (embossed pit) shape, but is recorded in the data portion 206 using the magneto-optical effect. On the data track 201, information for identifying the recording area of the data portion 206 is recorded in the ID portion 205, and data is recorded in the data portion 206.

  In FIG. 5, step S1 determines whether or not the track to be read is the control track 202. If the determination result is YES, step S2 determines the read clock frequency of the ID unit 205 and the data unit 206. Determines that switching is not necessary and continues the read operation. On the other hand, if the decision result in the step S1 is NO, a step S3 judges that it is necessary to switch the read clock frequency between the ID unit 205 and the data unit 206 and performs a necessary switching operation. Specifically, the read clock frequency when reading the ID portion 205 is switched to 1 / N (N> 1) times the read clock frequency when reading the data portion 206.

  That is, when reading the data track 201, the MPU 12 or the ODC 14 divides the data / control switching signal for setting the same read clock frequency when reading the ID portion 205 and the data portion 206. This is supplied to the peripheral circuit 119. On the other hand, when reading the control track 202, the MPU 12 or the ODC 14 sets the read clock frequency when reading the ID portion 205 to 1 / N (N> 1) of the read clock frequency when reading the data portion 206. A data / control switching signal for setting to double is supplied to the frequency dividing circuit 119. In this way, in this embodiment, the read clock frequency when reading the information recorded in the ID portion 205 and data portion 206 of the control track 202 and the ID portion 205 of the data track 201 is the same as that of the data track 201. The setting is switched to 1 / N times the read clock frequency when reading the data portion 206. In order to simplify the circuit configuration and the like, N is preferably an integer of 2 or more.

  Further, when information is written to the data portion 206 of the data track 201 on the optical disc 72, the write clock frequency in the write LSI 20 may be switched and set in the same manner as in the case of reading. In this case, when the data track 201 is written, the MPU 12 or the ODC 14 uses the write clock frequency N (which is the write clock frequency used when writing the ID unit 205) when the data unit 206 is written. N> 1) The write LSI 20 is controlled so as to set the multiple. Also in this case, N is preferably an integer of 2 or more.

  Note that the switching of the clock frequency in the processing shown in FIG. 5 is made possible, for example, when the optical disk 72 loaded in the enclosure 11 is recognized as a medium using MSR during the loading process in the control unit 10. It goes without saying that it is also good.

  Next, a specific example of the format of the optical disc 72 used in this embodiment will be described. For comparison, FIG. 7 shows a track format of a conventional optical disk having a diameter of 90 mm and 640 MB in conformity with ISO / IEC15041, and FIG. 8 shows a sector format of this conventional optical disk. In an optical disk of 90 mm in diameter and 640 MB conforming to ISO / IEC15041, the shortest mark length between the ID part and the data part is set to 0.64 μ in both the control track and the data track, and the wavelength of the laser beam to be used is The limit mark length is approximately 680 nm.

  In FIG. 7, (a) shows the format of the control track, and (b) shows the format of the data track. In FIG. 8, (a) shows the configuration of a 63-byte ID part (header), and (b) shows the configuration of a 2584-byte sector. In FIG. 8, the ID part shown in FIG. 8A is composed of a sector mark SM, a VFO1 field, an address mark AM, an ID1 field, a VFO2 field, an address mark AM, an ID2 field, and a postamble PA. Numbers are shown corresponding to each part. On the other hand, the sector shown in (b) in FIG. 8 is composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown. In the case of the 640 MB optical disk of 90 mm in diameter conforming to ISO / IEC15041, the sector format shown in FIG. 8 is commonly used for both the data track and the control track.

Format example 1:
In order to achieve 1.3 GB, which is about twice the capacity of a 640 MB optical disk compliant with ISO / IEC15041 as described above, it is necessary to set the shortest mark length to 0.32 μm. In the data portion 206 of the data track 201 of the optical disc 72, the shortest mark length of 0.32 μm can be achieved by using MSR, but in the ID portion 205 of the data track 201 and the ID portion 205 and data portion 206 of the control track 202, If the shortest mark length is set to 0.32 μm, reproduction becomes impossible. Therefore, the same mark length as 0.64 μm is set. Even in this case, since the ratio of the ID portion 205 and the control track 202 of the data track 201 to the capacity of the entire optical disk 72 is small, the capacity of the entire optical disk 72 is not significantly reduced. The track format in this case is shown in FIG. 9, and the sector format is shown in FIG. 10, the same parts as those in FIG. 8 are denoted by the same reference numerals.

  In FIG. 9, (a) shows the format of the control track, and (b) shows the format of the data track. 10A shows the configuration of the 126-byte ID part, FIG. 10B shows the configuration of the 5264-byte sector in the control track 202, and FIG. 10C shows the configuration of the 2694-byte sector in the data track 201. The configuration is shown. In FIG. 10, the ID part shown in (a) is composed of parts SM, VFO1, AM, ID1, VFO2, AM, ID2 and PA, and the number of bytes of each part is shown corresponding to each part. . On the other hand, in FIG. 10, the sector shown in (b) is composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown. In addition, the sector shown in (c) in FIG. 10 is also composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown.

  In the specific example 1, the number of bytes of the control track 202 is approximately twice the number of bytes of the data track 201 (N = 2) based on the recording frequency of the data portion 206 of the data track 201. The optical disk 72 is basically compliant with ISO / IEC15041, except that the capacity is about twice that of a 640 MB optical disk with a diameter of 90 mm according to ISO / IEC15041.

  In this case, the recording density in the track direction in the control track 202 and the ID portion 205 of the data track 201 is, for example, 0.57 μm, and the recording density in the track direction in the data portion 206 of the data track 201 is, for example, 0.29 μm. .

Format example 2:
In order to achieve 1.3 GB, which is about twice the capacity of a 640 MB optical disk compliant with ISO / IEC15041 as described above, it is necessary to set the shortest mark length to 0.32 μm. In the data portion 206 of the data track 201 of the optical disc 72, the shortest mark length of 0.32 μm can be achieved by using MSR, but in the ID portion 205 of the data track 201 and the ID portion 205 and data portion 206 of the control track 202, If the shortest mark length is set to 0.32 μm, reproduction becomes impossible. Therefore, the same mark length as 0.64 μm is set. Even in this case, since the ratio of the ID portion 205 and the control track 202 of the data track 201 to the capacity of the entire optical disk 72 is small, the capacity of the entire optical disk 72 is not significantly reduced. The track format in this case is shown in FIG. 11, and the sector format is shown in FIG. In FIG. 12, the same parts as those in FIG.

  In FIG. 11, (a) shows the format of the control track, and (b) shows the format of the data track. In FIG. 12, (a) shows the configuration of the 126-byte ID part, (b) shows the configuration of the 5388-byte sector in the control track 202, and (c) shows the 2694-byte sector in the data track 201. The configuration is shown. In FIG. 12, the ID part shown in (a) is composed of parts SM, VFO1, AM, ID1, VFO2, AM, ID2 and PA, and the number of bytes of each part is shown corresponding to each part. . On the other hand, in FIG. 12, the sector shown in (b) is composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown. In addition, in FIG. 12, the sector shown in (c) is also composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown.

  In the second specific example, the number of bytes of the control track 202 is twice the number of bytes of the data track 201 (N = 2) based on the recording frequency of the data portion 206 of the data track 201. The optical disk 72 is basically compliant with ISO / IEC15041, except that the capacity is about twice that of a 640 MB optical disk with a diameter of 90 mm according to ISO / IEC15041.

Format example 3:
In order to achieve 2.0 GB, which is about three times the capacity of a 640 MB optical disk of 90 mm in diameter and conforming to ISO / IEC15041 as described above, it is necessary to set the shortest mark length to 0.21 μm. In the data portion 206 of the data track 201 of the optical disc 72, the shortest mark length of 0.21 μm can be achieved using MSR. However, in the ID portion 205 of the data track 201 and the ID portion 205 and data portion 206 of the control track 202, If the shortest mark length is set to 0.21 μm, reproduction becomes impossible. Therefore, it is set to 0.64 μm, which is the same as the conventional one. Even in this case, since the ratio of the ID portion 205 and the control track 202 of the data track 201 to the capacity of the entire optical disk 72 is small, the capacity of the entire optical disk 72 is not significantly reduced. The track format in this case is shown in FIG. 13, and the sector format is shown in FIG. In FIG. 14, the same parts as those of FIG.

  In FIG. 13, (a) shows the format of the control track, and (b) shows the format of the data track. 14A shows the configuration of the ID portion of 189 bytes, FIG. 14B shows the configuration of the 7893 byte sector in the control track 202, and FIG. 14C shows the configuration of the 2694 byte sector in the data track 201. The configuration is shown. In FIG. 14, the ID part shown in (a) is composed of parts SM, VFO1, AM, ID1, VFO2, AM, ID2 and PA, and the number of bytes of each part is shown corresponding to each part. . On the other hand, the sector shown in (b) in FIG. 14 is composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown. In addition, the sector shown in (c) in FIG. 14 is also composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown.

  In this specific example 3, the number of bytes of the control track 202 is approximately three times (N = 3) the number of bytes of the data track 201 based on the recording frequency of the data portion 206 of the data track 201. The optical disk 72 is basically compliant with ISO / IEC15041, except that the capacity is about three times that of a 640 MB optical disk with a diameter of 90 mm according to ISO / IEC15041.

Format example 4:
In order to achieve 2.0 GB, which is about three times the capacity of a 640 MB optical disk of 90 mm in diameter and conforming to ISO / IEC15041 as described above, it is necessary to set the shortest mark length to 0.21 μm. In the data portion 206 of the data track 201 of the optical disc 72, the shortest mark length of 0.21 μm can be achieved using MSR. However, in the ID portion 205 of the data track 201 and the ID portion 205 and data portion 206 of the control track 202, If the shortest mark length is set to 0.21 μm, reproduction becomes impossible. Therefore, it is set to 0.64 μm, which is the same as the conventional one. Even in this case, since the ratio of the ID portion 205 and the control track 202 of the data track 201 to the capacity of the entire optical disk 72 is small, the capacity of the entire optical disk 72 is not significantly reduced. The track format in this case is shown in FIG. 15, and the sector format is shown in FIG. In FIG. 16, the same parts as those in FIG.

  In FIG. 15, (a) shows the format of the control track, and (b) shows the format of the data track. In FIG. 16, (a) shows the configuration of the ID portion of 189 bytes, (b) shows the configuration of the 8082 byte sector in the control track 202, and (c) shows the sector of the 2694 byte sector in the data track 201. The configuration is shown. In FIG. 16, the ID part shown in (a) is composed of parts SM, VFO1, AM, ID1, VFO2, AM, ID2 and PA, and the number of bytes of each part is shown corresponding to each part. . On the other hand, the sector shown in (b) in FIG. 16 is composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown. In addition, the sector shown in (c) in FIG. 16 is also composed of fields such as Gap, VFO3, Sync, Data Field, PA, and Buffer in addition to the ID part, and the number of bytes in each field corresponds to each field. It is shown.

  In this specific example 4, the number of bytes of the control track 202 is three times the number of bytes of the data track 201 (N = 3) based on the recording frequency of the data portion 206 of the data track 201. The optical disk 72 is basically compliant with ISO / IEC15041, except that the capacity is about three times that of a 640 MB optical disk with a diameter of 90 mm according to ISO / IEC15041.

  In the above specific example, the mark length is 1/2, 1/3,... Based on a 640 MB optical disk of 90 mm in diameter conforming to ISO / IEC15041. . . However, it is possible to realize a 1.3 GB optical disk by changing the track pitch from 1.1 μm to 0.9 μm and the mark length from 0.64 μm to 0.38 μm, for example. It is. The sector format in this case may be the same as in FIG.

  Thus, in the present invention, the read / write clock frequency for the ID portion (control track) is set to 1 / N (for example, 1/2, 1/3, for example) of the read / write clock frequency for the data portion (data track). Even when switching to 1/4, 1/5,...), The data storage capacity of the optical recording medium is increased without reducing the reading accuracy of the unevenness (emboss pit) shape of the ID portion (control track). Can be achieved.

  In the above embodiment, the present invention is applied to the magneto-optical disk. However, the present invention records the first area in which the first information is recorded by the concavo-convex shape and the second information is recorded using optical means. As long as the recording medium has the second region, the recording medium is not limited to the magneto-optical disk, and can be similarly applied to various recording media such as an optical disk such as a phase change optical disk and a card.

  While the present invention has been described with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made within the scope of the present invention.

It is a block diagram which shows schematic structure of one Example of the memory | storage device which becomes this invention. It is sectional drawing which shows schematic structure of an enclosure. FIG. 3 is a block diagram for explaining parameter setting control and settling waiting functions for an MPU read LSI, ODC, and DSP. It is a block diagram explaining the function of the read LSI of MPU and the read system of ODC. It is a flowchart explaining switching of a clock frequency. It is a perspective view which expands and shows a part of optical disk. It is a figure which shows the track format of the conventional optical disk. It is a figure which shows the sector format of the conventional optical disk. It is a figure which shows the track format of the optical disk in the specific example 1. It is a figure which shows the sector format of the optical disk in the specific example 1. It is a figure which shows the track format of the optical disk in the specific example 2. It is a figure which shows the sector format of the optical disk in the specific example 2. It is a figure which shows the track format of the optical disk in the specific example 3. It is a figure which shows the sector format of the optical disk in the specific example 3. It is a figure which shows the track format of the optical disk in the specific example 4. It is a figure which shows the sector format of the optical disk in the specific example 4. It is a figure explaining the principle of the method of utilizing MSR.

Explanation of symbols

10 Control unit 11 Enclosure 12 MPU
14 ODC
16 DSP
20 Light LSI
24 Lead LSI
26 Frequency synthesizer 72 Optical disc 117 Data demodulating circuit 119 Frequency dividing circuit 201 Data track 202 Control track 205 ID section 206 Data section

Claims (3)

A control area where control information is pre-recorded in an embossed shape;
A data area in which data is recorded by optical means,
The recording density of the control area is set to 1 / N times the recording density of the data area when N> 1.
The control area has the same recording density, and includes a data part in which medium information unique to the recording medium is recorded, and an identification part for identifying the recording area,
The data area includes a data part in which the data is recorded and an identification part for identifying the recording area,
An optical recording medium in which the recording density of the identification part of the data area is set to 1 / N times the recording density of the data part of the data area when N> 1. A substrate,
A recording layer for recording data at a recording density smaller than the diameter of the light beam provided and used on the substrate;
The optical recording medium according to claim 1, further comprising a reproduction layer to which data recorded in the recording layer is transferred during reproduction. The optical recording medium according to claim 1, wherein N is an integer of 2 or more.

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