JP2007133928A - Recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable data and a clock to be accurately reproduced even when a track pitch is shortened and a recording density is raised. <P>SOLUTION: The device is equipped with: a recording means for recording information data on a disk shape recording medium, by irradiating the track wobbling (meandering) at a constant frequency formed on the disk shape recording medium with an optical beam; and a control means for controlling the recording means so that a leading synchronizing signal, among the information data, is recorded in portions other than designated range including mountains and a valleys of the wobble track. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reproducing apparatus, and more particularly to an apparatus for recording data on a disc-shaped recording medium.

  In recent years, high density optical discs such as DVD (Digital Versatile Disc) and Blu-ray Disc have been developed.

In this type of disk, a spiral groove (groove) is formed on the disk, and information data is written and read by irradiating the groove with the groove as a recording / reproducing track. In addition, in order to superimpose addresses on the disc and to obtain a clock at the time of reproduction, the grooves on the disc are formed in advance so as to meander (wobble) at a constant period. During playback, the wobbling track is irradiated with a light beam, a clock related to the wobbling period is generated from the reflected light, address information is read, and phase synchronization with information data contained in the reflected light is performed. Data is detected by generating a clock (see, for example, Patent Document 1).
JP2004-5926

  In recent years, as the recording density of discs has further improved, the distance between adjacent tracks has become narrower. Even when generating a clock using a wobbling signal in this way, the effects of crosstalk between adjacent tracks can be ignored. It is gone.

  However, the apparatus described in Patent Document 1 has a problem that the reproduction clock cannot be accurately detected without considering the influence of such crosstalk.

  Further, in the optical disk of the phase change medium, when the same data is repeatedly recorded at the same place, the recording / reproducing characteristics of the medium are deteriorated.

  Therefore, in order to avoid the deterioration of the recording / reproducing characteristics due to repetitive recording, a so-called start position shift is performed in which the recording start position is not fixed but is changed randomly within a predetermined range.

  At the time of reproduction, the head synchronization signal is detected in the recorded data, and the reproduction data following thereafter is demodulated. If the detection of the leading synchronization signal fails due to a bit error such as crosstalk, the entire data block thereafter fails to be reproduced, and the error rate is extremely deteriorated.

  An object of the present invention is to solve such problems and to provide an apparatus capable of accurately reproducing data and clocks even when the recording density is increased by shortening the distance between tracks.

  The present invention includes a recording means for recording information data on a track that is formed on a disk-shaped recording medium and wobbles at a constant period, and a leading synchronization signal in the information data includes peaks and valleys of the wobble track Control means for controlling the recording means so as to record in a portion outside the predetermined range.

  Even when the distance between tracks is shortened to increase the recording density, the data and clock can be accurately reproduced.

  FIG. 1 is a diagram showing a configuration of a recording / reproducing apparatus 100 according to an embodiment of the present invention.

  A recording / reproducing apparatus 100 in FIG. 1 records and reproduces data by irradiating a light beam onto an optical disc D that is a phase change recording medium.

  In FIG. 1, reference numeral 101 denotes an input unit for inputting data such as image data. A signal processing unit 102 adds various types of data such as synchronization and ID to the input data to convert it into a form suitable for recording, and detects the original data from the reproduced data. Reference numeral 103 denotes a data modulation unit that modulates data output from the signal processing unit 102, and reference numeral 104 denotes a light emission control unit that controls lighting of the light beam in accordance with the modulated data. An optical unit 105 includes a light emitting unit 106 that emits a light beam, a light receiving unit 107 that receives reflected light from the disk D, and an optical lens 108. Reference numeral 109 denotes an RF detection unit that detects a reproduction RF signal from the output of the light receiving unit 107, and 110 denotes a data demodulation unit that demodulates the reproduction RF signal and detects digital data. An output unit 111 outputs data processed by the signal processing unit 102 to the outside. 112 is a wobble detection unit that generates a wobble signal using the output of the light receiving unit 107, and 113 is an address detection unit that detects the address of the disk D using the wobble signal. Reference numeral 114 denotes a CPU that controls each unit, and 115 is a speed table that stores control information for controlling the spindle motor 119. A clock generator 116 generates a clock PCLK that is phase-synchronized with the wobble signal using the wobble signal. A recording position control unit 117 outputs a start position signal (SPS) for controlling the recording start position using the wobble signal and PCLK. A rotation control unit 118 controls the spindle motor 119 in accordance with an output from the CPU 114, and a spindle motor 119 rotates the disk D.

  FIG. 2 is a configuration diagram of the light receiving unit 107, which includes a quadrant sensor 201, adders 202, 203, 205, and a differential amplifier 204. The outputs of the A part and B part on the inner peripheral side of the sensor 201 are added by the adder 202, and the outputs of the C part and D part on the outer peripheral side are added by the adder 203. A push-pull signal, which is the difference between the outer peripheral side and the inner peripheral side, is generated by the differential amplifier 204 and output as a wobble signal (WBL). The adder 205 generates a push-in signal that is a sum signal of the outer peripheral side and the inner peripheral side, and outputs the push-in signal as an RF signal. WBL is used for tracking control and wobble detection, and RF is used for data reproduction.

  The operation during recording will be described. Prior to the start of recording, the CPU 114 moves the optical unit 105 to the vicinity of the target recording start position. Further, the CPU 114 reads information on the rotational speed corresponding to the address near the target recording start position from the speed table 17 and rotates the motor 119 using the rotation control unit 118 so that the disk D has the target rotational speed.

  Further, the CPU 114 controls the light emission control unit 104 to cause the light emitting unit 106 to emit a laser beam, and irradiates the disk D through the optical lens 106. The laser beam reflected by the disk D is received by the light receiving unit 107 via the optical lens 108, and WBL and RF signals are obtained. The wobble detection unit 112 detects a wobble waveform from the WBL, and the clock generation unit 116 generates a clock PCLK phase-locked to the detected wobble waveform. This will be described later.

  When the clock PCLK generated in synchronization with the wobble of the disk D is generated by the clock generation unit 116, the CPU 114 counts the generated clock every predetermined time in order to perform accurate rotation control with a constant linear velocity. Then, the motor 119 is controlled through the rotation control unit 118 so as to always have a predetermined count number, and CLV control is performed so that the disk D is accurately kept at a constant linear velocity.

  Further, the CPU 114 detects address information by the address detection unit 113 from the wobble signal detected by the wobble detection unit 112. When the target recording address is reached, the recording data is converted into a recording format by the signal processing unit 102 and sent to the data modulation unit 103. The data modulation unit 103 converts the input data into 1-7 modulated channel data and sends the converted data to the light emission control unit 104. The light emission control unit 104 controls the irradiation of the laser beam by the light emission unit 104 according to the modulated data, and records the data by irradiating the disk D through the optical lens 108 with the laser beam. Also at this time, the wobble signal is detected by the wobble detector 112, the clock is generated by the clock generator 116, and the address information of the disk D is continuously detected by the address detector 112 as before.

  Even during reproduction, the CPU 114 performs the same operation as the target address detection operation described in the recording operation until the target address is detected. When the target address is reached, the RF reproduction data is detected by the RF detection unit from the RF signal of the light receiving unit 107. Then, the data demodulator 110 demodulates the RF data, and the signal processor 102 converts it to the original data.

  The relationship between the clock, wobble, and address is shown in FIG. In this embodiment, the frequency of the clock PCLK is 66 MHz. The samples recorded in accordance with the 66 MHz clock are collected for 69 clocks to form one wobble. One unit is formed by 56 wobbles, and one address is formed by 83 units.

  One unit of address information is embedded in one unit, and 83 bits of information bits are embedded in one address period.

  An example of bit allocation is shown in FIG.

  The ADSYNC synchronization pattern TOPSYNC is 9 bits, the address bit ADDRESS is 24 bits, the auxiliary data AUX is 12 bits, the error correction LDC is 24 bits, and the reserve is 24 bits. The entire disk becomes a 24-bit address space (0xFFFFFF).

  Here, how the data information is embedded in the wobble will be described with reference to FIG.

  5A and 5B are diagrams showing one unit, and one square (section) corresponds to one wobble (69 clock length).

  If the wobble of FIG. 5A is formed, “bit 0” is represented, and if the wobble of FIG. 5B is formed, “bit 1” is represented. Thus, one unit of information of 1 bit is represented. Can be expressed.

  One address information is expressed by a set of 83 information bits. In FIG. 5B, most of the sections (K4 to K11, K15 to K56) are coswt (pattern a), and -coswt (pattern c) having an inverted phase called MSK mark is embedded in K1 and K13. ing. Before and after that, in order to smoothly connect coswt and -coswt, cos1.5 wt (pattern b) is embedded in K1 and K12, and -cos1.5 wt (pattern d) is embedded in K3 and K14, respectively. The difference between the embedded MSK marks indicates whether it is “bit 0” or “bit 1”, and one address information can be detected in 83 units.

  FIG. 5C is a diagram showing the state of the wobble waveform in the sections K9 to K16 in FIG.

  FIG. 6 is a diagram showing the relationship between wobble, wobble address delimiter (ADIP address), and actual recording data.

  The wobble TOPSYNC is the head of the ADIP address delimiter. Recording data (cluster data) is recorded in units of addresses, but is not necessarily written continuously as can be seen from FIG. This is because the start position shift is performed in order to increase the durability of the overwrite in the phase change medium, and the cluster data write position is randomized within a predetermined range (± 500 clocks).

  FIG. 7 shows a format of recording data. First, there is a RUNIN (2000 bits) which is a fixed pattern for pulling in AGC and reproduction PLL, a synchronization signal 1ST SYC (9 bits) indicating the beginning of the data area, a first data portion DATA1 (1923 bits), and a resynchronization signal Following RESYC (9 bits), the second data portion DATA2, and after the combination of RESYC and DATA is repeated 164 times, a fixed pattern RUNOUT (1864) is obtained. This group is one cluster, and data recording / reproduction is performed in cluster units. Information data such as actual video data is DATA1 to DATA164.

  During reproduction, the RF detection unit 109 accurately detects the reproduction clock and 1STSYC, and the data demodulation unit 110 demodulates DATA1 to DATA164. RESYC is a resynchronization signal, and the timing can be generated by the integration counter from 1ST SYC if the reproduction clock is correctly reproduced. In addition, error correction is possible for DATA1 to DATA164. Therefore, the most important for the recording data is the first 1ST SYC.

  FIG. 8 is a diagram for explaining the relationship between the wobble and the laser spot. Reference numerals 801, 802, and 803 denote recording tracks, and 804 and 805 denote laser spots. When the recording track 802 is traced, there is no problem in the case of the laser spot 804, but in the case of the laser spot 805, the distance to the adjacent track 803 is close and easily affected by crosstalk.

  Therefore, in the present embodiment, the recording position of 1ST SYC, which is important data, is controlled, and 1ST SYC is recorded at a position where the influence of such crosstalk is small.

  FIG. 9 is a diagram showing the configuration of the recording position control unit 117.

  The wobble detection unit 112 shapes the WBL signal to detect wobble. A PLL circuit 116A constituting the clock generation unit 116 generates a wobble clock WCLK in phase with the wobble, and a 69 multiplication circuit 116B multiplies it by 69 to generate a recording / reproduction clock PCLK. The TOPSYC described above is detected by the TOPSYC detection unit 902 from the wobble detected by the wobble detection unit 112, and the address is detected by the address detection unit 113.

  The counter 901 is a counter that is reset by TOPSYC and counts PCLK, and counts the timing within the ADIP address in FIG. 6 (see CT in FIG. 10).

  A random number generator 903 generates random numbers RND 1 to 315 at the timing of TOPSYC.

  In this embodiment, since the start position shiftable range is within the range of 5 wobbles from TOPSYC, it is within the range of 345 clocks (= 5 × 69). On the other hand, since the range corresponding to 3 clocks is excluded from the wobble peaks and valleys, the range of the random number RND is 315 (= 5 × 63).

  The table conversion unit 57 converts the random number RND having a value of 1 to 315 into a value TBL of 1 to 345. The conversion has a correspondence as shown in FIG. In 1-345, for example, 34-36 corresponding to the valley of wobble and 69-71 corresponding to the wobble peak are converted so as not to be output.

  The coincidence comparison circuit 905 compares the output CT with the output CT of the counter 901. If the values coincide, an SPS pulse indicating the recording start timing is generated and output to the CPU 114. The CPU 114 starts recording 1ST SYC data in response to the SPS. That is, the recording start position is determined according to the value of TBL.

  As apparent from the recording format of FIG. 7, since the RUNIN 2007 clock is exactly equivalent to 300 wobbles, the phase relationship between RUNIN, which is the recording start position, and wobble is the same as that of 1ST SYC.

  In this way, it is possible to record so that the 1ST SYC is positioned at a position excluding the wobble peaks and valleys.

It is a figure which shows the recording / reproducing apparatus in embodiment of this invention. It is a figure which shows an optical unit. It is a figure which shows the relationship between a clock, wobble, and an address. It is a figure which shows an example of the bit allocation of address information. It is a figure which shows the mode of the bit information embedded in a wobble signal. FIG. 6 is a diagram illustrating the relationship between wobble, wobble address delimiter (ADIP address), and actual recording data. It is a figure which shows the format of recording data. It is a figure explaining the relationship between a wobble and a laser spot. It is a figure which shows the structure of a recording position control part. It is a figure which shows the mode of the random number output from a conversion part at the time of a recording start.

Claims (4)

A recording means for recording information data on a track wobbling at a constant period formed on a disk-shaped recording medium;
A recording apparatus comprising: control means for controlling the recording means so as to record a leading synchronization signal in the information data in a portion other than a predetermined range including peaks and valleys of the wobble track. The disc-shaped recording medium is irradiated with a light beam, and using the reflected light, a wobble signal including a frequency component related to the wobbling period of the track, and a reproduction signal including information data recorded on the track Reading means for generating,
2. The recording apparatus according to claim 1, wherein the control unit detects a reference position of the track based on the wobble signal, and determines a recording position of the leading synchronization signal based on the reference position. Clock generating means for generating a clock having a frequency related to the wobbling period using the wobble signal;
The control means includes a counter that counts the clock according to the detection result of the reference position, and determines the recording position of the leading synchronization signal according to the output of the counter. The recording device described. The control means includes a random number generating means for generating a random number according to a recording startable range in the disc-shaped recording medium, and a converting means for converting the output of the random number generating means into a value according to a range other than the predetermined range. 4. A comparison means for comparing the output of the conversion means and the count value of the counter, and determining the recording position of the leading synchronization signal based on the output of the comparison means. The recording device described.

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