JP2006127699A - Optical disk recording/reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording/reproducing device which suppresses the occurrence of a deviation between recording data and a position to be recorded at recording finish time. <P>SOLUTION: A pre-pit detecting means detects pre-pits in a non-recorded area after a recording finish position after a recording operation is finished, and generates a pre-pit sink signal. A write sink signal generating means continues to output the write sink signal after the recording operation is finished. A deviation detecting means detects a time deviation between the pre-pit sink signal and the write sink signal in the non-recorded area after the recording finish position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disk recording / reproducing apparatus for recording data on an optical disk and reproducing data from the optical disk.

  When recording data on an optical disk such as CD-R / RW, DVD-R / RW, DVD + R / RW, etc., when recording additional data from the end position of the already recorded data, the recorded data and the newly recorded data are recorded. Must be recorded so that there is no discontinuity or overwriting. For this reason, it is necessary to perform highly accurate recording position control for accurately detecting the end position of the already recorded data.

  When the recording position is ideally controlled, there is no deviation in the data on the medium as shown in FIG. However, there is a limit to the position specifying accuracy with respect to the absolute position of the write data written in synchronization with a write clock generated from wobble information formed in advance on the optical disk. Furthermore, as shown in FIG. 3, even when the logical position of the recorded data recorded in synchronization with the write clock is shifted from the physical position of the data recorded on the medium (optical disk), the control circuit The additional writing is started from the logical position where it is determined that is the previous end position. Such misregistration accumulates every time additional writing is performed and may cause a major misalignment.

  As a result, serious problems such as inability to record all data correctly on the disc and making a disc that cannot be played back occur.

  In order to solve the above problems, the optical disc apparatus disclosed in Patent Document 1 reproduces a pre-pit sync detection signal obtained by detecting a predetermined pre-pit formed in advance on an optical disc and data recorded on the optical disc, By detecting a time lag from the data sync signal obtained by detecting a predetermined sync signal included in the reproduction data and controlling the frequency of the recording clock so as to correct the detected time lag. Prevents accumulation of recording position deviations.

However, when a land pre-pit is read in an already recorded area, position information may not be obtained accurately due to interference between the pre-pit signal itself and a recording mark. The optical disc apparatus of Patent Document 1 does not give any consideration to the precondition of reproducing a stable prepit signal. Therefore, the problem that discontinuity or overwriting occurs between recorded data and newly recorded data has not been solved.
Japanese Patent Laid-Open No. 2003-30841

  According to the present invention, in the optical disc recording / reproducing apparatus, when data is newly recorded on an optical disc in which recorded data exists, the occurrence of the positional deviation between the pre-pit sync signal and the write sync signal is always grasped and eliminated. Objective.

The present invention has been made to achieve the above object. An optical disc recording / reproducing apparatus according to claim 1 of the present invention provides:
Prepit detecting means for detecting a prepit of an optical disc and generating a prepit sync signal according to the detected prepit;
Wobble information detecting means for detecting wobble information previously formed on the optical disc;
Write clock generation means for generating a write clock according to the write speed in synchronization with the wobble information;
Write sync signal generating means for generating a write sync signal used for determining the timing of data writing in synchronization with the write clock;
A positional deviation detecting means for detecting a deviation between the write data and the absolute position of the optical disc by detecting a temporal deviation between the pre-pit sync signal and the write sync signal;
The prepit detection means generates a prepit sync signal by performing prepit detection in an unrecorded area after the recording end position after the recording operation ends,
The write sync signal generating means continuously outputs a write sync signal after the recording operation is completed,
The positional deviation detection means detects a temporal deviation between the pre-pit sync signal and the write sync signal in an unrecorded area after the recording end position.

An optical disk recording / reproducing apparatus according to claim 2 of the present invention provides:
2. The optical disc according to claim 1, wherein the position deviation detecting means detects an absolute amount of deviation in units of channel clocks, and detects a direction of deviation by comparing a predetermined maximum deviation amount with an absolute value of deviation. A recording / reproducing apparatus.

An optical disk recording / reproducing apparatus according to claim 3 of the present invention is
2. The position shift detector detects a temporal shift between the pre-pit sync signal and the write sync signal immediately after the pre-pit detector detects the pre-pit continuously for a predetermined number of times at predetermined intervals. The optical disc recording / reproducing apparatus described.

An optical disk recording / reproducing apparatus according to claim 4 of the present invention provides:
A recording control means;
A switching timing signal from the recorded area to the unrecorded area for starting the operation in which the prepit detecting means detects the prepit in the unrecorded area,
The end control value detected from the recording data is compared with the target address set in the recording control means, and when the two values coincide with each other, the recording control means generates the end address. An optical disc recording / reproducing apparatus according to any one of the above.

An optical disc recording / reproducing apparatus according to claim 5 of the present invention is
A processor unit;
2. The optical disc recording / reproducing apparatus according to claim 1, wherein the position deviation detection means outputs a deviation detection completion interrupt signal to the processor unit when the detection is completed.

An optical disk recording / reproducing apparatus according to claim 6 of the present invention provides:
Prepit detecting means for detecting a prepit of an optical disc and generating a prepit sync signal according to the detected prepit;
Wobble information detecting means for detecting wobble information previously formed on the optical disc;
Write clock generation means for generating a write clock according to the write speed in synchronization with the wobble information;
Write sync signal generating means for generating a write sync signal used for determining the timing of data writing in synchronization with the write clock;
Reproduction clock generation means for reproducing data recorded on the optical disc and generating a reproduction clock from the reproduction signal;
Data sync detection means for detecting a predetermined sync signal included in the playback data in synchronization with the playback clock, and generating a data sync signal according to the detected sync signal;
A positional deviation detection means for detecting a deviation between the write data and the absolute position of the optical disc by detecting a temporal deviation between the pre-pit sync signal and the write sync signal;
Recording control means for recording new data on the optical disc so as to continue from the previous recording end position in synchronization with the write clock based on the data sync signal;
The write clock generation means generates a write clock that corrects the positional deviation detection amount detected in the unrecorded area after the recording end position at the time of the next recording by the positional deviation detection means at the end of the previous recording operation. An optical disc recording / reproducing apparatus.

  By utilizing the present invention, it is possible to provide an optical disc recording / reproducing apparatus that suppresses the occurrence of a shift between the recording data at the end of recording and the position to be recorded.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a block diagram of an optical disc recording / reproducing apparatus according to a first embodiment of the present invention. In the description of the embodiment, “DVD-R / RW” is assumed as an optical disk, but the present invention is applicable to a recording / reproducing apparatus for other optical disk media (for example, CD-R / RW and DVD + R / RW). Of course it is available.

  The optical disk recording / reproducing apparatus includes an optical disk 2, a spindle motor 4, a motor driver 6, a servo circuit 8, a host interface 10, a read clock generation circuit 12, an optical pickup 14, a read amplifier 16, a DVD decoder 18, a buffer manager 20, a buffer RAM 22, It comprises a laser control circuit 24, a write clock generation circuit 26, a prepit signal decoder 28, a misregistration detection circuit 30, a recording control circuit 32, a DVD encoder 34, and a CPU interface 36.

  The optical disk 2 is rotationally driven by a spindle motor 4. The spindle motor 4 is rotationally controlled by a motor driver 6 and a servo circuit 8. The optical pickup 14 includes a semiconductor laser, an optical system, a focus actuator, a track actuator, a light receiving element, a position sensor, and the like (not shown), and irradiates the optical disc 2 with laser light.

  The reproduction signal obtained by the optical pickup 14 is amplified and binarized by the read amplifier 16 and then output to the read clock generation circuit 12 and the DVD decoder 18.

  The read clock generation circuit 12 generates a read clock based on the input reproduction signal and outputs the read clock to the DVD decoder 18. The DVD decoder 18 detects a sync code included in the reproduction data input from the signal detection amplifier 16 in synchronization with the read clock, and generates a data sync signal for each sector at the detected timing.

  The prepit signal decoder 28 reads wobbles and land prepits on the optical disc via the optical pickup 14 and the read amplifier 16, and generates a prepit sync signal from the timing when the land prepits are detected.

  FIG. 4 is a waveform diagram showing generation of a prepit sync signal. A prepit signal is generated from 1 to 3 land presets detected in the sync frame, and a bit sync signal is generated from the prepit signal. When the land pre-pit is detected to be detected at a given two sync frame interval, the pre-pit signal decoder 28 is set to the bit protect state. When the bit protect state is entered, a pre-pit protect signal indicating the state is generated. The bit sync signal in this bit protect state becomes a pre-pit sync signal. Therefore, if the land pre-pit is normally detected, the pre-pit sync signal is generated every two sync frames.

  The write sync signal will be described. The unit of the channel clock generated by the write clock generation circuit 26 is 1T. When this channel clock is counted up to 1488T, it becomes the sync frame sync timing. A sync signal that is generated once after the sync frame sync is counted twice is a write sync signal. This write sync signal is a sync signal generated once every two sync frames so as to correspond to the interval between the above-mentioned pre-pit sync signals. The write clock is generated by the write clock generator 26 based on the wobble information and according to the write speed. The wobble information on the optical disc is detected via the optical pickup 14 and the read amplifier 16.

  FIG. 5 shows the timing of each waveform when a pre-pit sync signal is generated in an unrecorded area after the recording end position after the recording operation is completed, and a deviation between the pre-pit sync signal and the write sync signal in the unrecorded area is measured. FIG.

  When a pre-pit sync signal is generated in an unrecorded area after the recording end position after the recording operation is finished, and the deviation between the write sync signal and the pre-pit sync signal in the unrecorded area is measured, first, during the recording data writing operation, the CPU Sets an unrecorded area measurement signal via the CPU interface 36. When the unrecorded area measurement signal is set, the recording control circuit 32 changes the write permission signal to L level so that the writing is not performed when the writing of the recording data is finished, and the writing of the data is finished. Here, only the writing of data to the optical disc 2 by the pickup 14 is terminated, and the write sync signal generation operation and the land pre-pit detection operation are continued.

  The recording control circuit 32 outputs a forced prepit search signal to the prepit signal decoder 28 and the positional deviation detection circuit 30 when recording data writing is completed. This forced pre-pit search signal is used as a signal for switching from an already recorded area to an unrecorded area. Here, the target address indicating the position to be additionally written in the recording control circuit 32 is compared with the value of the end address detected from the recording data, and a forced prepit search signal is generated based on the comparison result. May be. In this way, a forced prepit search signal that is a switching timing signal from the recorded area to the unrecorded area can be accurately generated.

  The prepit signal decoder 28 that has received the forced prepit search signal enters a search state for a prepit signal detected in an unrecorded area. FIG. 5 shows an example in which no land pre-pits can be detected in the recorded area (the pre-pit signal indicated by the dotted line indicates that it has not been detected), but the pre-pit signal decoder that has received the forced pre-pit search signal. 28 resets the current state and forcibly enters the pre-pit signal search state.

  After the prepit search state, the prepit signal decoder 28 detects the prepit signal. Thereafter, when a prepit signal is detected a plurality of times at a predetermined interval in an unrecorded area, the prepit signal decoder 28 enters a bit protect state and generates a prepit sync signal.

  The misregistration detection circuit 30 that has received a state where both the forced prepit search signal and the prepit protect signal are at the H level changes to the H level when the write sync signal is input, and when the prepit sync signal is input. A sync difference detection signal that changes to L level is generated. On the other hand, the write clock for each channel clock generated by the write clock generation circuit 26 is input to the misalignment detection circuit 30. Therefore, the misregistration detection circuit 30 measures the H level period of the sync difference detection signal by a “deviation amount counter” that counts in units of channel clocks. In FIG. 5, the measurement result value is indicated as “N”.

  Here, the maximum deviation amount is set in advance as M (for example, M = 127), and the deviation amount is determined and the deviation direction is determined from the measured deviation amount counter value. As in the example of FIG. 6, in an ideal state where the write sync signal and the pre-pit sync signal have the same timing, the shift amount is zero. When the deviation amount counter value is “N1” and smaller than the maximum deviation amount M as in the example of FIG. 7, the write sync signal is earlier than the pre-pit sync signal, and the deviation amount is N1. As in the example of FIG. 8, when the deviation amount counter value is “N2” and is larger than the maximum deviation amount M, the write sync signal is later than the pre-pit sync signal and the deviation amount is (2976−N2).

  When the measurement is completed, a measurement completion signal (the lowest stage in FIG. 5) is generated, and the subsequent shift amount is not detected. Here, the positional deviation detection circuit 30 may output a measurement completion interrupt signal to the CPU via the CPU interface 36 when the measurement of the deviation between the write sync signal and the prepit sync signal is completed. In this way, the measurement completion timing can be notified to the outside, and the optical disk recording / reproducing apparatus can switch the operation to the additional recording operation in accordance with this notification.

  As described above, even when the land pre-pit cannot be detected in the recorded area, the shift amount and shift direction between the position grasped from the recording data and the position to be recorded in the channel clock unit at the end of the recording. I can grasp.

  The procedure for measuring the difference between the pre-pit sync signal and the write sync signal in the unrecorded area shown in FIG. 5 is an example. As long as the shift amount between the pre-pit sync signal, which is the absolute position on the disc, and the write sync signal synchronized with the write data can be accurately detected, the procedure for measuring the shift is not limited to the above. For example, the pre-pit sync signal is a word sync signal that can be obtained once per sector, the write sync signal is a sector sync signal that is obtained by counting the sync frame sync 26 times, and the two are compared to determine the amount and direction of deviation. You may measure.

  Then, based on the measured deviation amount and deviation data, the generation of the write clock at the time of additional writing is controlled. An operation for controlling the generation of the write clock so as to correct the shift amount will be described.

  The write clock is generated by inputting a binarized wobble signal obtained by reproducing the wobble engraved on the disk as a reference signal for the PLL (Phase Locked Loop) function of the write clock generator 26. . That is, the write clock is generated by the PLL function of the write clock generator 26 so as to follow the wobble on the disk.

  Here, the deviation amount of the sync difference detection signal detected by the positional deviation detection circuit 30 is “nT” (T is n), and the write sync signal precedes the pre-pit sync signal. Is assumed. In this case, if the deviation is accumulated in the same state, there is a possibility that a gap is generated between the previous recording area and the additional recording area and increases. Therefore, in order to prevent this shift from occurring, it is necessary to generate the write clock slightly later. For this purpose, the signal generated by the PLL function of the write clock generation unit 26 may be operated in a slow direction. That is, the charge pump output of the PLL circuit may be manipulated so that the write clock is slower than the phase comparison result actually obtained by the PLL circuit. Actually, the down (Down) signal is generated slightly longer in the control signal up (Up) signal and down (Down) signal generator for the charge pump of the PLL circuit.

  Performing the above operation for delaying the write clock at a time leads to a rapid fluctuation of the write clock, and adversely affects the quality of the written data. Therefore, it is preferable to make corrections at regular intervals. Specifically, for example, the correction operation may be repeated until the correction of the nT deviation is reached while the correction is performed in units of (1/4) T once in one sync frame. That is, the correction of the deviation is performed by repeating the correction of (1/4) T (n × 4) times, and accurate additional recording control can be realized.

  When the write sync signal is behind the pre-pit sync signal, the charge pump output of the PLL circuit may be manipulated so that the write clock is slightly faster. In this case, the up (Up) signal is generated slightly longer in the control signal up (Up) signal and down (Down) signal generator for the charge pump of the PLL circuit. This correction may be repeated as appropriate to correct the shift amount.

  The progress of the correction may be adjusted from the CPU. That is, it may be possible to set from the CPU how much correction is performed at what interval.

  The recording control circuit 32 synchronizes with the writing clock controlled as described above, and uses the data sync signal generated from the DVD decoder 18 as a reference to continuously record new data from the previous recording end position on the optical disc 2. The laser control circuit 24 and the optical pickup 14 are controlled so as to record.

  By controlling the generation of the write clock at the time of additional recording based on the data of the measured deviation amount and deviation direction, the deviation between the newly recorded data and the absolute position of the optical disk can be kept to a minimum. Is possible.

  Next, the flow of processing from the end of recording to the start of additional writing is shown in the flowchart of FIG.

  Before the end of the previous recording, an unrecorded area measurement command is issued from the CPU through the CPU interface 36 (S0), the previous recording on the optical disc is ended (S1), and the seek operation is shifted (S2).

  The seek operation is a process of tracing while identifying the position on the optical disc 2 by detecting the wobble land pre-pit formed on the optical disc 2. The seek operation (S2) measures the amount and direction of deviation between the write sync signal and the pre-pit sync signal. When the measurement is completed, a deviation measurement completion signal is output to the CPU via the CPU interface 36.

  Thereafter, the measurement result of the deviation amount is confirmed (S4), and an additional write operation start command is issued from the CPU via the CPU interface 36 (S5). When a write-once operation start command is issued, the operation shifts to a seek operation (S6), and when the seek operation up to the write-once start position is completed (S7), the write-once operation is started and new data is added so as to be continuous with previously recorded data. Is recorded (S8).

1 is a block diagram of an optical disc recording / reproducing apparatus according to a first embodiment of the present invention. FIG. 6 is a waveform diagram of various signals when a logical position of recording data synchronized with a writing clock at the time of recording and a physical position of recorded data on a medium are in a normal relationship. FIG. 6 is a waveform diagram of various signals when there is a difference between a logical position of recording data synchronized with a writing clock during recording and a physical position of recorded data on a medium. It is a wave form diagram which shows the production | generation of a prepit sync signal. It is a wave form diagram which shows the relationship of various signals. It is a waveform diagram of various signals when there is no deviation between the pre-pit signal and the write sync signal. It is a waveform diagram of various signals when a write sync signal precedes a pre-pit signal. It is a wave form diagram of various signals when a prepit signal precedes a writing sync signal. It is a flowchart which shows the flow of a process from the end of last recording to the start of additional recording.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Optical disk, 12 ... Read clock generation circuit, 14 ... Optical pick-up, 18 ... DVD decoder, 26 ... Write clock generation circuit, 28 ... Prepit signal decoder, 30 ... Position shift detection circuit, 32... Recording control circuit, 34.

Claims (6)

Prepit detecting means for detecting a prepit of an optical disc and generating a prepit sync signal according to the detected prepit;
Wobble information detecting means for detecting wobble information previously formed on the optical disc;
Write clock generation means for generating a write clock according to the write speed in synchronization with the wobble information;
Write sync signal generating means for generating a write sync signal used for determining the timing of data writing in synchronization with the write clock;
A positional deviation detecting means for detecting a deviation between the write data and the absolute position of the optical disc by detecting a temporal deviation between the pre-pit sync signal and the write sync signal;
The prepit detection means generates a prepit sync signal by performing prepit detection in an unrecorded area after the recording end position after the recording operation ends,
The write sync signal generating means continuously outputs a write sync signal after the recording operation is completed,
An optical disc recording / reproducing apparatus, wherein the positional deviation detection means detects a temporal deviation between the pre-pit sync signal and the write sync signal in an unrecorded area after the recording end position.   2. The optical disc according to claim 1, wherein the position deviation detecting means detects the absolute amount of deviation in units of channel clocks, and detects the direction of deviation by comparing the absolute value of deviation with a predetermined maximum deviation amount. Recording / playback device.   2. The position shift detector detects a temporal shift between the pre-pit sync signal and the write sync signal immediately after the pre-pit detector detects the pre-pit continuously for a predetermined number of times at predetermined intervals. The optical disk recording / reproducing apparatus as described. A recording control means;
A switching timing signal from the recorded area to the unrecorded area for starting the operation in which the prepit detecting means detects the prepit in the unrecorded area,
The end control value detected from the recording data is compared with the target address set in the recording control means, and when the two values coincide with each other, the recording control means generates the end address. An optical disc recording / reproducing apparatus according to any one of the above. A processor unit;
2. The optical disc recording / reproducing apparatus according to claim 1, wherein the position deviation detection means outputs a deviation detection completion interrupt signal to the processor unit when the detection is completed. Prepit detecting means for detecting a prepit of an optical disc and generating a prepit sync signal according to the detected prepit;
Wobble information detecting means for detecting wobble information previously formed on the optical disc;
Write clock generation means for generating a write clock according to the write speed in synchronization with the wobble information;
Write sync signal generating means for generating a write sync signal used for determining the timing of data writing in synchronization with the write clock;
Reproduction clock generation means for reproducing data recorded on the optical disc and generating a reproduction clock from the reproduction signal;
Data sync detection means for detecting a predetermined sync signal included in the playback data in synchronization with the playback clock, and generating a data sync signal according to the detected sync signal;
A positional deviation detection means for detecting a deviation between the write data and the absolute position of the optical disc by detecting a temporal deviation between the pre-pit sync signal and the write sync signal;
Recording control means for recording new data on the optical disc so as to continue from the previous recording end position in synchronization with the write clock based on the data sync signal;
The write clock generation means generates a write clock that corrects the positional deviation detection amount detected in the unrecorded area after the recording end position at the time of the next recording by the positional deviation detection means at the end of the previous recording operation. Optical disc recording / reproducing apparatus.

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