JP4554566B2 - Optical disc apparatus and program - Google Patents

Description

  The present invention relates to an optical disc apparatus and program, and more particularly to an optical disc apparatus and program for determining an optimum laser power from reproduction signals in a plurality of laser power recording areas.

  In an optical disc apparatus that records and reproduces information by irradiating a laser to a phase change type optical disc such as a DVD (Digital Versatile Disk) or a CD (Compact Disc), fluctuations in the environmental temperature when information is recorded on the optical disc. In order to determine the optimum laser power between the apparatus and the disc according to the above, trial recording is performed using a trial recording area provided in advance on the optical disc. The laser power is determined by the amplitude of the laser beam and the pulse width of the laser beam.

  The test recording is performed by changing the amplitude of the laser beam or the pulse width of the laser beam, and the signal quality is evaluated by a plurality of reproduction signals in the test recording area to obtain a condition for optimizing the quality of the signal. A technique is known (see, for example, Patent Document 1). Evaluation items for signal quality include jitter, error rate, asymmetry, modulation degree, and the like, and evaluation items suitable for the optical disc apparatus are selected. In the reproduction operation of the reproduction signal in the test recording area of the optical disc, an AGC (Auto Gain Control) circuit for setting the fluctuation of the reflected light from the optical disc, that is, the amplitude of the reproduction signal, functions. As a result, a playback signal having a stable level can be obtained at all times, leading to a reduction in error occurrence probability and an improvement in playback performance.

JP-A-8-124165

  The AGC circuit detects the amplitude of the reproduction signal from the fluctuation of the reflected light, and responds while changing the gain so that the amplitude becomes a predetermined level. For this reason, when the unrecorded area is reproduced, there is almost no fluctuation of the reflected light, so that the gain of the AGC circuit is maximized to increase the fluctuation of the reflected light (reproduction signal amplitude) to a predetermined level (actual The reproduction signal does not fluctuate due to insufficient gain of the AGC circuit). When the laser light for reading information on the optical disc enters the recording area in the state where the gain of the AGC circuit is maximum, the fluctuation of the reflected light is amplified by the AGC circuit having the maximum gain, and the reproduction signal is As shown in FIG. Thereafter, the reproduction signal converges to a predetermined level when the fluctuation time a elapses according to the response time of the AGC circuit. Since the fluctuation of the reproduction signal in the test recording area affects the evaluation of the signal quality, there is a disadvantage that it is not possible to obtain a condition for optimizing the signal quality. As a result, there is a problem that the determined laser power is not an optimum laser power. The fluctuation of the reproduction signal during the fluctuation time a is also caused by the fact that the optical pickup and the AGC circuit are AC-connected through a capacitor in order to extract only the AC component from the output signal of the optical pickup. Even if the gain of the AGC circuit is constant, it cannot be completely removed.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical disc apparatus and a program capable of accurately determining an optimum laser power for the optical disc.

Means for Solving the Problems and Effects of the Invention

In order to achieve the above object, the optical disc apparatus of the present invention records and reproduces information by irradiating the optical disc with laser light. The optical disc apparatus includes a laser power changing unit capable of changing the laser power of the laser beam, and a laser power changing unit in each of a plurality of laser power recording execution areas of the test recording area provided on the optical disc. Recording means for performing recording with a plurality of changed laser powers, determining means for determining an optimum laser power from reproduction signals in a plurality of laser power recording areas, and a moving direction of a position where an optical disc is irradiated with laser light A plurality of laser power recording areas are allocated to the optical disc so as to be continuous with each other, and an optimum position is determined by the determining means at a position adjacent to the rear end of the allocated plurality of laser power recording areas in the moving direction. and determined subjected recording by a laser beam prior to determining the laser power The determination of the optimum laser power in the unit and a assigning means for assigning a dummy recording area that is not used.

  In the optical disk apparatus according to the present invention, as described above, the allocating means performs recording with the laser beam at a position adjacent to the rear end of the rearward direction in the movement direction of the plurality of assigned laser power recording areas, and the determining means. When the optimum laser power is determined by reproducing the reproduction signal in the laser power recording area by providing a dummy recording area that is not used for determining the optimum laser power in the reproduction of the laser power recording area Before reproducing the signal, the reproduction signal in the dummy recording area can be reproduced. This suppresses the fluctuation of the reproduction signal, unlike the case of reproducing the reproduction signal in the laser power recording area where recording is performed with a predetermined laser power from an unrecorded area where no reproduction signal is recorded. Can do. Therefore, when determining the optimum laser power, the optimum laser power can be evaluated using the reproduction signal that has not changed, and therefore the optimum laser power for the optical disc can be accurately determined.

  In the optical disc apparatus, preferably, recording is performed in the dummy recording area with a constant laser power by a recording means.

  In this case, preferably, laser power information for recording with a constant laser power on the dummy recording area is recorded in advance in a predetermined area of the optical disc. With this configuration, the laser power for the dummy recording area can be easily determined.

  In the above optical disk apparatus, preferably, the recording means has the largest laser power in the laser power recording area adjacent to the dummy recording area among the plurality of laser power recording areas, and the laser power increases as the distance from the dummy recording area increases. Recording is performed so that the value becomes smaller. As a result, when the laser power is low, it is possible to prevent problems caused by the laser power recording area not being recorded.

  In the above optical disk apparatus, preferably, the recording means has the largest laser power in the dummy recording area among the dummy recording area and the plurality of laser power recording areas, and the laser power recording area farther from the dummy recording area has a laser power. Recording is performed so that the value becomes smaller. Thereby, a dummy recording area and a plurality of laser power recording areas can be easily created.

  In this case, the recording means records in the dummy recording area with a plurality of laser powers changed by the laser power changing means so that recording is performed with a large laser power as the distance from the plurality of laser power recording areas is increased. May be implemented. Thereby, a dummy recording area and a plurality of laser power recording areas can be created more easily.

  Preferably, the optical disc apparatus further includes control means for controlling the recording means so as to record in the dummy recording area with a predetermined laser power before recording in the laser power recording execution area with a plurality of laser powers. . With this configuration, since the recording can be performed in the order of the movement direction of the position irradiated with the laser light (“dummy recording area” → “laser power recording execution area”), the writing time increases. Can be suppressed.

In the above optical disk apparatus, preferably, the allocating means sets the size of the dummy recording area so that a difference between a top level and a bottom level of the reproduction signal of the optical disk in the dummy recording area recorded with the same laser power is a predetermined value. The size is determined according to the time until the following . With this configuration, the size of the dummy recording area and the trial recording area of the optical disc can be reduced as much as possible while suppressing fluctuations in the reproduction signal in the laser power recording area.

  In the above optical disk apparatus, preferably, the determining means determines an optimum laser power by using a bit error rate obtained from a reproduction signal in the laser power recording execution area as an index. With this configuration, the optimum laser power can be easily determined from the relationship between the bit error rate and the laser power.

  In this case, the bit error is detected using an area smaller than the unit area for logically correcting the error of the reproduction signal.

  In the above optical disk apparatus, the optical disk is preferably a write-once type.

The program according to the present invention includes a computer for controlling each part of an optical disk apparatus that records and reproduces information by irradiating an optical disk with laser light, a laser power changing means capable of changing the laser power of the laser light, and an optical disk Recording means for performing recording with a plurality of laser powers changed by the laser power changing means in each of the plurality of laser power recording execution areas of the test recording area provided in the apparatus, and signal reproduction of the plurality of laser power recording execution areas A plurality of laser power recording areas are allocated to the optical disc so as to be continuous along the moving direction of the position where the laser light of the optical disc is irradiated, and assigned in the moving direction. more after the rear end of the laser power recording carried region At a position adjacent to, to function as a means for assigning a dummy recording area that is not used in the determination of the optimum laser power in the decorated with and determining means recording by laser beam prior to determining the optimum laser power by the determining means .

  In the program according to the present invention, as described above, recording is performed by the allocating means at the position adjacent to the rear end of the rearward direction in the movement direction of the plurality of assigned laser power recording areas by the laser light and the determining means. In order to determine the optimum laser power by reproducing the reproduction signal in the laser power recording area by providing a dummy recording area that is not used for determining the optimum laser power, the reproduction signal in the laser power recording area is Before reproduction, the reproduction signal in the dummy recording area can be reproduced. This suppresses the fluctuation of the reproduction signal, unlike the case of reproducing the reproduction signal in the laser power recording area where recording is performed with a predetermined laser power from an unrecorded area where no reproduction signal is recorded. Can do. Therefore, when determining the optimum laser power, the optimum laser power can be evaluated using the reproduction signal that has not changed, and therefore the optimum laser power for the optical disc can be accurately determined.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram of an optical disc apparatus according to a first embodiment of the present invention. FIG. 2 is a plan view showing a write-once optical disc used in the optical disc apparatus according to the first embodiment, and FIG. 3 is a diagram showing a test recording area allocated by the optical disc apparatus according to the first embodiment. is there. FIG. 4 is a diagram showing the relationship between the amplitude and pulse width of the laser light irradiated to the test recording area and the generated mark and space. 5 and 6 are graphs showing the relationship between laser power and error rate. First, the configuration of the optical disc apparatus 1 will be described in detail with reference to FIGS.

  The optical disc apparatus 1 according to the first embodiment records information on the optical disc 100 by the laser light emitted from the optical pickup 10 and reproduces information by the reflected light from the optical disc 100 of the laser light emitted from the optical pickup 10. I do. Then, the optical disc apparatus 1 has a test recording area 100b (see FIG. 2) provided on the inner periphery of the user data area 100a before recording desired data in the user data area 100a (see FIG. 2) of the optical disc 100. The optimum laser power between the optical disk apparatus 1 and the optical disk 100 is determined by performing trial recording with various laser powers. In the present embodiment, the optical disc 100 is a write-once type.

  As shown in FIG. 1, the optical disc apparatus 1 rotates an optical pickup 100, an optical pickup 10 for recording / reproducing with respect to the optical disc 100, a sled motor 20 as a driving source for moving the optical pickup 10 in a radial direction, and the optical disc 100. A spindle motor 30 as a driving source to be driven, a motor driver 40 that controls the operation of the thread motor 20 and the spindle motor 30, a laser driver 50 that controls the operation of a laser light source 12 of the optical pickup 10 to be described later, and the optical pickup 10. An RF processing circuit 60 that processes the supplied signal to generate a signal required by another block (A / D converter 70 and signal processing circuit 81 of the control circuit 80), and an analog signal that is converted into a digital signal A / D converter 70 (Analog Digital Converter) and each of the optical disk apparatus 1 And a control circuit 80 which controls the locking of the operation, and an interface 90. The optical disc apparatus 1 performs various operations as described below by operating according to a program stored in a ROM (Read Only Memory) provided therein.

  The optical pickup 10 is provided with an objective lens 11 and a laser light source 12. The light emitted from the laser light source 12 is collected by the objective lens 11 and applied to the recording surface of the optical disc 100. Thereby, information is recorded on the optical disc 100. Further, the reflected light from the optical disc 100 is converted into a current signal by a light detection unit (not shown) via the objective lens 11 and output to the RF processing circuit 60. As a result, the information recorded on the optical disc 100 is reproduced.

  In the present embodiment, the optical pickup 10 has a trial recording area 100b of the optical disc 100 with various laser powers determined based on later-described reference recording laser information set in the laser driver 50 during trial recording. Are recorded in the signal quality evaluation target blocks B4 to B15 (see FIG. 3) provided in FIG. In each of the signal quality evaluation target blocks B4 to B15, a plurality of recording units (marks, spaces) are formed by multi-pulse laser light as shown in FIG. The mark is in an amorphous state and there is little reflected light, and the space is in a crystalline state and the reflected light is large. Specifically, the optical pickup 10 sets B4 to “+ 22%” so that the laser power (the hatched area in FIG. 4) decreases along the moving direction (A direction) of the position irradiated with the laser light. B5 is recorded with a laser power of “+ 18%”,..., B14 is recorded with “−18%”, and B15 is recorded with a laser power of “−22%”. The laser power described above is a value based on the laser power determined by the reference recording laser information as a reference (0%), and this reference recording laser information is recorded in a non-rewritable area (not shown) of the optical disc 100.

  In the present embodiment, the optical pickup 10 uses the same laser power recording blocks B0 to B3 as dummy recording areas based on the later-described same laser power information set in the laser driver 50 during trial recording (see FIG. 3) is recorded with the same laser power. The same laser power information described above is also recorded in the non-rewritable area of the optical disc 100.

  The thread motor 20 is configured to receive and drive a thread motor drive signal from the motor driver 40. The rotational driving force of the sled motor 20 is converted into a linear driving force by an intermediate transmission unit (not shown), and the optical pickup 10 is reciprocated in the radial direction of the disk. The thread motor 20 is provided with a ring-shaped magnet in which N poles and S poles are alternately magnetized, and a hall element, and the output is a digital signal constituted by a DSP (Digital Signal Processor). It is transmitted to the servo processing circuit 82.

  The spindle motor 30 is provided to rotate the optical disc 100 when reading information or writing information. The spindle motor 30 is configured to receive and drive a spindle motor drive signal from the motor driver 40.

  The motor driver 40 has a function of transmitting a thread motor drive signal and a spindle motor drive signal for driving the thread motor 20 and the spindle motor 30 described above.

  When a data recording request is generated via the interface 90, the laser driver 50 receives recording data (described later) transmitted from the signal processing circuit 81, and outputs a recording signal for generating laser light corresponding to the recording data. It has a function of outputting to the laser light source 12 of the pickup 10. Thus, desired data is recorded in the user data area 100a of the optical disc 100. The laser driver 50 receives the reference recording laser information recorded in advance in the non-rewritable area of the optical disc 100 when a test recording request is generated via the interface 90, and the multi-pulse laser beam shown in FIG. Is output to the laser of the optical pickup 10. As a result, the laser light source 12 emits pulses, and the light is condensed on the recording surface of the optical disc 100 through the objective lens 11, whereby recording is performed in the user data area 100a and the test recording area 100b of the optical disc 100. . In the present embodiment, the laser driver 50 has a function of changing the laser power by changing the amplitude and pulse width of the laser, which is controlled by the control microcomputer 83 described later. Accordingly, it is possible to form marks and spaces by irradiating each of the signal quality evaluation target blocks B4 to B15 of the optical disc 100 with laser beams having various laser powers.

  The RF processing circuit 60 has a function of converting a current signal detected by the optical pickup 10 into a voltage signal. Among the voltage signals output from the RF processing circuit 60, the photodetection signal corresponding to the RF signal having data is composed of two signals having opposite phases. The photodetection signal is differentially amplified by the RF processing circuit 60, subjected to AGC processing, and transmitted to the signal processing circuit 81.

  The A / D converter 70 is provided for converting an error signal such as a tracking error signal and a focus error signal detected by the optical pickup 10 and processed by the RF processing circuit 60 into a digital signal. This digital signal is transmitted to the digital servo processing circuit 82 of the control circuit 80.

  The control circuit 80 includes a signal processing circuit 81, a digital servo processing circuit 82, and a control microcomputer 83. Note that the optical pickup 10 and the RF processing circuit 60 and the RF processing circuit 60 and the control circuit 80 are AC-connected via a capacitor (not shown), respectively.

  Then, the signal processing circuit 81 performs NRZI (Non-Return-to-Zero Invert) conversion, Viterbi composite, deinterleaving, error correction, etc., on the signal subjected to the AGC processing by the RF processing circuit 60 when the optical disc 100 is reproduced. The data is decrypted through the above process and output to the outside through the interface 90. On the other hand, at the time of recording on the optical disc 100, the signal processing circuit 81 performs parity code addition, interleaving, data modulation, NRZI conversion, and the like on the signal input from the outside through the interface 90 to obtain recording data on the optical disc 100. . The recorded data is output to the laser driver 50.

  The digital servo processing circuit 82 controls the optical disk 100 so as to rotate at a linear velocity corresponding to the position of the optical pickup 10, and always records the laser light emitted from the laser light source 12 through the objective lens 11 on the optical disk 100. It has a function of performing focus control for condensing light onto the surface. The digital servo processing circuit 82 also has a function of performing tracking control so that the optical pickup 10 is along a guide groove carved in the optical disc 100. Specifically, the digital servo processing circuit 82 processes a signal that has been subjected to light detection by the optical pickup 10, conversion processing by the RF processing circuit 60, and digital signal conversion by the A / D converter 70, and rotation error of the optical disc 100. A signal, a focus error signal, and a tracking error signal are transmitted. Then, each signal processed by the digital servo processing circuit 82 becomes a drive signal for the actuator in the spindle motor 30, the thread motor 20, and the optical pickup 10 via the motor driver 40, and the rotation control, focus control, Perform tracking control.

  Further, the digital servo processing circuit 82 demodulates the reproduction signal of the guide groove of the optical disc 100 detected by the optical pickup 10 and transmits it to the control microcomputer 83. Thereby, the control microcomputer 83 can manage the position information of the optical pickup 10.

  The control microcomputer 83 controls the entire optical disc apparatus 1 as the center of the control circuit 80 based on a program built in a ROM or hard disk (not shown). In the present embodiment, the control microcomputer 83 controls the laser driver 50 so as to change the amplitude and pulse width of the laser light emitted from the laser light source 12 of the optical pickup 10. Further, in the present embodiment, the control microcomputer 83, together with the signal processing circuit 81 and the digital servo processing circuit 82, evaluates the reproduction signals of the signal quality evaluation target blocks B4 to B15 in the test recording area 100b of the optical disc 100 based on bit errors. And has the function of determining the optimum laser power. This bit error is detected by using an area smaller than the cluster which is the minimum area for logically correcting the error of the reproduction signal.

  As shown in FIG. 5, the relationship between the laser power of the laser beam and the bit error rate is such that the bit error rate is minimized at a predetermined laser power, and the bit error rate is deteriorated as it deviates from the laser power. The trial recording is performed for the purpose of detecting the vicinity of the best point at which the bit error rate is minimized, and the optimal laser power between the optical disc 100 and the optical disc apparatus 1 is determined by the control microcomputer 83 by this detection. As shown in FIG. 6, the write-once optical disc 100 of this embodiment is more sensitive to changes in laser power than a rewritable optical disc, and has a bit error rate for changes in laser power. The amount of change is large. In addition, with a small laser power, it becomes difficult to form a mark on the optical disc 100 abruptly, and the state is almost the same as unrecorded.

  The control microcomputer 83 is provided with a memory (not shown) and has a function of storing reference recording laser information recorded in a non-rewritable area of the optical disc 100. The reference recording laser information is for generating the multi-pulse laser beam shown in FIG. 4 and is described for each recording speed and recording layer that the optical disc 100 supports.

  Here, in the first embodiment, the control microcomputer 83 performs a plurality of signal quality evaluations so as to be continuous along the moving direction (direction of arrow A shown in FIG. 3) of the position where the laser beam of the optical disc 100 is irradiated. The target blocks B4 to B15 are assigned to the test recording area 100b of the optical disc 100. Further, the control microcomputer 83 performs recording at the position adjacent to the assigned signal quality evaluation target block B4 in the B direction with the same laser power, and is not used for determining the optimum laser power. The same laser power recording blocks B0 to B3 are allocated.

  In the first embodiment, the control microcomputer 83 uses the same laser power for the same laser power recording blocks B0 to B3 before recording the signal quality evaluation target blocks B4 to B15 with various laser powers. It also has a function of controlling the optical pickup 10 so as to perform recording.

  Next, test recording by the optical disc apparatus 1 of the first embodiment will be described in detail.

  As shown in FIG. 2, the optical disc 100 is provided with a trial recording area 100b used for trial recording separately from a user data area 100a in which desired data can be written. The test recording area 100 b is provided near the inner periphery of the optical disc 100. In the trial recording area 100b, as shown in FIG. 3, recording is performed on each block which is a unit obtained by further dividing one cluster, which is a minimum unit for logically correcting an error in a reproduction signal, into 16 divided units. Signal quality evaluation is performed by signal quality evaluation target blocks B4 to B15 in the cluster. In this embodiment, one cluster is divided into 16 parts, but the present invention is not limited to this.

  The signal quality evaluation can be realized by using a method as described in, for example, “Japanese Patent Laid-Open No. 2003-178537”. The optical disc apparatus 1 has a function of measuring relative frequencies R1 and R2 of a portion smaller than the thresholds SL1 and SL2 in addition to the SAM (Sequenced Amplitude Margin) value calculation performed in the process of the Viterbi decoding operation of the signal processing circuit 81. . The control microcomputer sets SL1 and SL2 and extracts R1 and R2, and obtains a bit error rate by referring to a lookup table created in advance in a memory in the control microcomputer 83. Thus, signal quality evaluation is performed.

  Further, as shown in FIG. 3, the test recording area 100b is used in a direction (B direction) opposite to the moving direction (A direction) of the laser light irradiation position on the optical disc 100. Note that the moving direction of the laser beam described above is a relative traveling direction of the irradiation position of the laser beam on the optical disc 100. That is, the recording / reproducing operation of the optical disc 100 is performed along the moving direction (A direction) of the laser beam, but the test recording area 100b is used along the direction (B direction) opposite to the moving direction of the laser beam. Therefore, when a new trial recording is performed, an area adjacent to the same laser power recording block B0 used last time in the B direction is used.

  Hereinafter, it demonstrates along the flowchart of FIG. FIG. 7 is a flowchart showing a procedure for determining an optimum laser power by the optical disc apparatus according to the first embodiment.

  First, when the optical disc 100 is set (step S1: Yes), the control microcomputer 83 performs disc type determination and servo adjustment according to the optical disc 100, and then the reference recorded in the non-rewritable area of the optical disc 100. The recording laser information and the same laser power information are extracted and stored in a memory provided in the control microcomputer 83 (step S2). When the optical disc 100 is not set (step S1: No), this determination is repeated until the optical disc 100 is set.

  When a test recording request is generated from the outside through the interface 90 (step S3: Yes), the control microcomputer 83 extracts the reference recording laser information and the same laser power information stored in the memory and sets them in the laser driver 50. (Step S4). If the trial recording request is not received (step S3: No), this determination is repeated until the trial recording request is generated.

  Next, an unrecorded area (see FIG. 3) in the test recording area 100b of the optical disc 100 is searched, areas used for signal quality evaluation (12 signal quality evaluation target blocks B4 to B15), and signal quality evaluation. The control microcomputer 83 allocates areas (four identical laser power recording blocks B0 to B3) that are not used in the control (step S5). Detection of the boundary between the unrecorded area and the recorded area is determined from the amplitude level of the reproduction signal. For example, a block obtained by dividing one cluster into 16 parts is further divided into four parts, and a recording area block is obtained when the number of areas where an amplitude exceeding a threshold is obtained during reproduction exceeds three (that is, a 3/4 block has a signal). The method is not limited to this. At this time, the number of the same laser power recording blocks is determined in advance by the fluctuation time from the start of playback of the playback signal of the same laser power recording block (the time until the difference between the top level and the bottom level of the playback signal becomes a predetermined value or less). If it is known, a fixed number corresponding to the variation time may be used. When the fluctuation time is expected to be greatly different for each optical disc 100, the maximum amplitude fluctuation value when the area recorded with the reference recording laser power is reproduced (the peak value of the reproduction signal immediately after entering the recording area from the unrecorded area) ) Is measured by the RF processing circuit 5, the fluctuation time is calculated from the maximum amplitude fluctuation value, and the number corresponding to the fluctuation time obtained by the calculation may be obtained. Alternatively, the amplitude fluctuation maximum value measured as described above may be obtained using a lookup table of (number of same power recording blocks) versus (amplitude fluctuation maximum value) provided in the control microcomputer 83. Good. In any of these methods, the number of the same laser power recording blocks, that is, the size of the dummy recording area is determined to be a size corresponding to the variation time from the start of reproduction of the reproduction signal of the optical disc 100.

  Subsequently, in the first embodiment, the same laser power recording blocks B0 to B3 are recorded with the laser power generated from the same laser power information already set in the laser driver 50 (step S6). At this time, the recording by the laser beam is completed by only one rotation of the optical disc 100, but the recording may be completed by a plurality of rotations.

  Next, recording is performed with various laser powers on the signal quality evaluation target blocks B4 to B15 subsequent to the same laser power recording block B3 (step S7). In the first embodiment, “+ 22%” is obtained by changing the three values of Pw, Pe, and Pb shown in FIG. 4 with respect to the laser power generated from the reference recording laser power information already set in the laser driver 50. The recording is performed under a plurality of conditions between the power of “−” and “−22%”. In the first embodiment, B4 is recorded as “+ 22%”, B5 as “+ 18%”,..., B14 as “−18%”, and B15 as “−22%”. Recording to the same laser power recording blocks B0 to B3 and signal quality evaluation target blocks B4 to B15 is completed by only one rotation of the optical disc 100, but recording may be completed by a plurality of rotations.

  The order of laser power in recording is not limited to this, but the higher power region is arranged on the same laser power recording block B0 to B3 side, that is, among the 12 signal quality evaluation target blocks B4 to B15. The laser power of the signal quality evaluation target block B4 adjacent to the same laser power recording blocks B0 to B3 is the highest, and the laser power is decreased as the signal quality evaluation target blocks B4 to B15 separated from the same laser power recording blocks B0 to B3. It is desirable to carry out recording. This is because, in the case of the write once optical disc 100, if recording is performed with a low laser power, the formation of the marks of the signal quality evaluation target blocks B4 to B15 is abruptly lost, and an area that is not different from the unrecorded state is generated. It is. For example, when an unrecorded area is generated at the position B10, the reproduction signal fluctuates as shown in FIG. 9 and B11 to B15 are not correctly evaluated. If the laser power is decreased from B4 to B15, for example, even if B12 is not recorded, it can be seen that B13, B14, and B15 are also unrecorded. By excluding signal quality evaluation target blocks having a bit error rate that does not satisfy the threshold, the influence can be avoided.

  As a result of step S7, the same laser power recording blocks B0 to B3 recorded with the same laser power as countermeasures against fluctuations in the reproduction signal when entering the recording area from the unrecorded area, and recorded with various laser powers as signal quality evaluation targets. The signal quality evaluation target blocks B4 to B15 are formed. In the present embodiment, an example in which the same laser power recording blocks B0 to B3 and the signal quality evaluation target blocks B4 to B15 are configured in one cluster has been described. However, the same laser power recording blocks B0 to B3 may extend over a plurality of clusters. It does not have to be.

  After the same laser power recording blocks B0 to B3 and signal quality evaluation target blocks B4 to B15 are formed, reproduction operation control for performing measurement is performed (step S8). The control microcomputer 83 controls the optical pickup 10 to perform a stable reproduction operation at a position in front of the same laser power recording block B0. Further, the AGC function of the RF processing circuit 60 is changed to a fixed gain before reaching the same laser power recording block B0. This is because the gain is automatically updated by the operation of the AGC, so that the response characteristic at the time of entry from the unrecorded area to the recorded area changes, and the Viterbi decoding and the SAM value in the signal processing circuit 81 are not affected. The purpose is that. However, when the influence on Viterbi decoding and the SAM value is not taken into consideration, it is not necessary to change to a fixed gain.

  The measurement of the reproduction signal starts when the optical pickup 10 moves from the same laser power recording block B0 to B3 to the first signal quality evaluation target block B4. That is, a bit error is obtained using the reproduction signals of the signal quality evaluation target blocks B4 to B15 among the reproduction signals of the blocks B0 to B15. Specifically, in the signal processing circuit 81, the Viterbi decoding operation is started, and the number of SAM values smaller than SL1 and SL2 set in advance by the control microcomputer 83 is set as R1 and R2 from B4 to B15, respectively. Count by each block. The control microcomputer 83 takes out R1 and R2 when the measurement is completed, and obtains a bit error by referring to a lookup table provided in advance in the control microcomputer 83.

  By this measurement, the relationship between the bit error rate and the laser power as shown in FIG. 5 is obtained, and when the optimum laser power can be detected (step S9: Yes), the optimum laser power is calculated. The laser driver 50 is set (step S10). At this time, the optimum recording laser power is obtained by excluding the laser power of the signal quality evaluation target block that does not satisfy the predetermined threshold. Actually, since factors such as variations at the time of measurement and variations in the optical disk 100 are included, the measurement is performed a plurality of times and the average value is used, or the recording of cluster N in FIG. Or the measurement results of two clusters may be used. Further, the relationship between the obtained bit error rate and the laser power may be approximated to a quadratic curve, and the laser power at which the differential coefficient is 0 may be set as the optimum laser power. Further, if the optimum laser power cannot be detected (step S9: No), an error is assumed.

  In the present embodiment, as described above, the same laser power that is recorded at the position adjacent to the signal quality evaluation target block B4 in the B direction with the same laser power and is not used for determining the optimum laser power. When the optimum laser power is determined by reproducing the reproduction signals of the signal quality evaluation target blocks B4 to B15 by providing the recording blocks B0 to B3, before reproducing the reproduction signals of the signal quality evaluation target blocks B4 to B15. The reproduction signals of the same laser power recording blocks B0 to B3 can be reproduced. Thus, unlike the case where the optimum laser power is determined by reproducing the signal quality evaluation target block recorded with the predetermined laser power from the unrecorded area where the reproduced signal is not recorded, as shown in FIG. It is possible to suppress the fluctuation of the reproduction signal. Therefore, when the optimum laser power is determined, the optimum laser power can be evaluated using the reproduction signal that does not vary, so that the optimum laser power for the optical disc 100 can be accurately determined.

  In this embodiment, recording is performed in the order of the relative movement direction (A direction) of the laser light (“same laser power recording blocks B0 to B3” → “signal quality evaluation target blocks B4 to B15”). Thus, an increase in writing time can be suppressed.

(Second Embodiment)
In the second embodiment, unlike the first embodiment, an example is described in which dummy recording areas for performing recording with various laser powers are provided in the area in front of the signal quality evaluation target block in the same manner as the signal quality evaluation target block. To do. In the second embodiment, the portions other than the dummy recording area of the test recording area are the same as those in the first embodiment described above, and thus the description thereof is omitted. FIG. 8 is a diagram showing a test recording area allocated by the optical disc apparatus according to the second embodiment.

  In the second embodiment, the optical pickup 10 has a variety of laser powers determined on the basis of reference recording laser information (described later) set in the laser driver 50 in the trial recording area 100b of the optical disc 100 during trial recording. Recording is performed on the provided dummy recording blocks B0 to B3 and signal quality evaluation target blocks B4 to B15 (see FIG. 8). In each of the dummy recording blocks B0 to B3 and the signal quality evaluation target blocks B4 to B15, a plurality of recording units (marks and spaces) are formed by a multi-pulse laser beam as shown in FIG. Specifically, in the optical pickup 10, B0 is “+ 38%”, B1 is “+ 34%”, and B2 is “+ 30%” so that the laser power decreases along the moving direction (A direction) of the laser light. ..., B14 is recorded with a laser power of "-18%" and B15 is recorded with a laser power of "-22%". The laser power described above is a value based on the laser power determined by the reference recording laser information as a reference (0%), and this reference recording laser information is recorded in a non-rewritable area (not shown) of the optical disc 100.

  Here, in the second embodiment, the control microcomputer 83 includes a plurality of signal quality evaluation target blocks B4 to B15 (see FIG. 8) so as to be continuous along the moving direction of the position where the laser beam of the optical disc 100 is irradiated. ) Is assigned to the test recording area 100b of the optical disc 100. Further, the control microcomputer 83 is located adjacent to the assigned signal quality evaluation target block B4 (see FIG. 8) in the B direction, and dummy recording blocks B0 to B3 (not used for determining the optimum laser power) (See FIG. 8). That is, when comparing the four dummy recording blocks B0 to B3 with the twelve signal quality evaluation target blocks B4 to B15, the four dummy recording blocks B0 to B3 have larger laser power and the four dummy recording blocks B0 to B3. The laser power is smaller in the signal quality evaluation target blocks B4 to B15 that are farther away from each other, and recording is performed with a larger laser power as the distance from the signal quality evaluation target blocks B4 to B15 is larger in the four dummy recording blocks B0 to B3.

  In the second embodiment, the control microcomputer 83 performs dummy recording blocks B0 to B3 (FIG. 8) before performing recording on the signal quality evaluation target blocks B4 to B15 (see FIG. 8) with various laser powers. In addition, the optical pickup 10 is controlled to perform recording with the laser power described above.

  As described above, in the second embodiment, unlike the first embodiment, the dummy recording blocks B0 to B3 and the signal quality evaluation can be easily performed only by reducing the laser power in order from the first block of the cluster N and recording. Target blocks B4 to B15 can be created. In other words, since the second embodiment is simpler in processing than the first embodiment, it is possible to reduce the time required to determine the optimum laser power by trial recording and to reduce the program. Can be connected. In particular, in the case of an application for recording in real time, since it is necessary to have a buffer proportional to the time until the optimum laser power is determined, the influence on the cost is great. It is possible to suppress an increase in the cost spent on the operation.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  As an example, the test recording area and the cluster may be irrelevant, and the test recording area may extend over a plurality of clusters. Further, the magnitude of the laser power in the signal quality evaluation target blocks B4 to B15 does not have to become larger as the laser power recording blocks B0 to B3 or the dummy recording blocks B0 to B3 are closer to each other. There may be. Similarly, the laser power in the dummy recording blocks B0 to B3 may be random.

1 is a block diagram of an optical disc apparatus according to a first embodiment of the present invention. 1 is a plan view showing a write-once optical disc used in an optical disc apparatus according to a first embodiment. It is the figure which showed the test recording area allocated by the optical disk apparatus by 1st Embodiment. It is the figure which showed the relationship between the amplitude and pulse width of the laser beam irradiated to a test recording area | region, and the mark and space produced | generated. It is the graph which showed the relationship between a laser power and an error rate. 6 is a graph showing the relationship between laser power and error rate for a write-once optical disc and a rewritable optical disc. 5 is a flowchart showing a procedure for determining an optimum laser power by the optical disc apparatus according to the first embodiment. It is the figure which showed the test recording area allocated by the optical disk apparatus by 2nd Embodiment. It is the figure which showed the reproduction signal which fluctuated with the AGC function of the optical disk device.

Explanation of symbols

1 optical disk device 10 optical pickup (recording means)
50 Laser driver (Laser power changing means)
83 Control microcomputer (laser power changing means, determining means, assigning means, control means)
100 Optical disc 100b Trial recording area B0 to B3 Same laser power recording block, dummy recording block (dummy recording area)
B4 to B15 Signal quality evaluation target block (Laser power recording area)

Claims (12)

An optical disc apparatus for recording and reproducing information by irradiating an optical disc with laser light,
Laser power changing means capable of changing the laser power of the laser light;
Recording means for performing recording with a plurality of laser powers changed by the laser power changing means in each of a plurality of laser power recording execution areas of a test recording area provided on the optical disc;
Determining means for determining an optimum laser power from the reproduction signals of the plurality of laser power recording areas;
The plurality of laser power recording execution regions are allocated to the optical disc so as to be continuous along the moving direction of the position where the laser beam of the optical disc is irradiated, and the plurality of assigned laser power recordings in the moving direction are performed. A dummy which is recorded by the laser beam before the optimum laser power is determined by the determining means at a position adjacent to the rear end of the area and is not used for determining the optimum laser power by the determining means. An optical disc apparatus comprising: an allocating unit that allocates a recording area.   2. The optical disc apparatus according to claim 1, wherein recording is performed in the dummy recording area with a constant laser power by the recording means.   3. The optical disk apparatus according to claim 2, wherein laser power information for recording with the constant laser power on the dummy recording area is recorded in advance in a predetermined area of the optical disk.   The recording means has the largest laser power in the laser power recording execution area adjacent to the dummy recording area among the plurality of laser power recording execution areas, and the laser power recording execution area farther from the dummy recording area. 4. The optical disc apparatus according to claim 2, wherein recording is performed so that the laser power is reduced.   The recording means has the largest laser power in the dummy recording area among the dummy recording area and the plurality of laser power recording execution areas, and the laser power recording execution area farther from the dummy recording area has a lower laser power. The optical disk apparatus according to claim 1, wherein recording is performed as follows.   The recording means performs recording in the dummy recording area with a plurality of laser powers changed by the laser power changing means so that recording is performed with a large laser power as the distance from the plurality of laser power recording execution areas is increased. The optical disc apparatus according to claim 5, wherein   2. The apparatus according to claim 1, further comprising control means for controlling the recording means so that the dummy recording area recording is performed before the laser power recording execution area is recorded with a plurality of laser powers. The optical disc device according to any one of? The allocating means sets the size of the dummy recording area to a time until a difference between a top level and a bottom level of the reproduction signal of the optical disc in the dummy recording area recorded with the same laser power becomes a predetermined value or less. and determining a magnitude corresponding to the optical disc apparatus according to any one of claims 1-7.   9. The determination unit according to claim 1, wherein the determination unit determines an optimum laser power by using a bit error rate obtained from the reproduction signal in the laser power recording execution area as an index. Optical disk device.   The optical disc apparatus according to claim 9, wherein the bit error is detected using an area smaller than a unit area for logically correcting an error of a reproduction signal. The optical disc apparatus according to claim 1, wherein the optical disc is a write-once type. A computer that controls each part of an optical disk device that records and reproduces information by irradiating the optical disk with laser light;
Laser power changing means capable of changing the laser power of the laser light;
Recording means for performing recording with a plurality of laser powers changed by the laser power changing means in each of a plurality of laser power recording execution areas of a test recording area provided on the optical disc;
Determining means for determining an optimum laser power from signal reproduction of the plurality of laser power recording areas;
The plurality of laser power recording execution regions are allocated to the optical disc so as to be continuous along the moving direction of the position where the laser beam of the optical disc is irradiated, and the plurality of assigned laser power recordings in the moving direction are performed. A dummy which is recorded by the laser beam before the optimum laser power is determined by the determining means at a position adjacent to the rear end of the area and is not used for determining the optimum laser power by the determining means. A program that functions as an allocating unit that allocates a recording area.

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