JP2009158063A - Optical disk drive and recording parameter optimizing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk drive capable of obtaining a high quality playback signal by determining an optimal recording parameter for suppressing amplitude fluctuation of the playback signal, and a recording parameter optimizing method. <P>SOLUTION: The optical disk drive includes: an optical part for emitting a main beam, the preceding beam and the following beam to form a recording mark and receiving reflected light from an optical disk; a means for playback test information recorded by the main beam with the following beam; and a means for extracting a prescribed portion of the test information from a playback signal of the following beam. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus, and more particularly to an optical disc apparatus and a recording parameter optimization method capable of controlling an optimum recording power while performing a recording operation on a rewritable optical disc.

  Examples of rewritable optical disks include DVD-RW, DVD-RAM, HD DVD-RW, and HD DVD-RAM. In these rewritable optical discs, it is known that the quality of the reproduction signal depends on recording parameters, such as the recording laser power and the waveform of the recording signal. For this reason, a process is generally performed in which a test period is provided for a fixed period such as immediately after the optical disk is inserted into the optical disk apparatus, and test recording is performed during this test period to obtain optimum recording parameters.

  A conventional optical disc apparatus receives light reflected from an optical disc of an adjustment light beam that is irradiated simultaneously with the recording light beam behind the recording light beam for recording the recording information in the recording direction of the recording information on the optical disc. And recording power control means for controlling the recording power of the recording light beam preceding in the recording direction based on the output signal from the light receiving means (see, for example, Patent Document 1).

  Since this apparatus always measures the amount of light of the adjustment light beam, it cannot measure only a recording mark (hereinafter simply referred to as a mark) or only a space. Therefore, it is difficult to cope with a rewritable optical disk using phase change recording.

  In a rewritable optical disk using phase change recording, a new mark and space sequence can be overwritten on a previously recorded mark and space sequence. Since this overwriting is performed directly without erasing the already recorded mark and space series, it is referred to as direct overwriting.

  When overwriting a new mark, for example, a laser pulse train composed of a plurality of sub-pulses having two power values called peak power and bottom power is irradiated from above the already formed mark or space, and a mark having a predetermined length is irradiated. Newly formed.

  On the other hand, when overwriting a new space, a predetermined level of laser having a power value called erase power is irradiated from above the already formed mark or space to newly form a predetermined length of space.

  When reproducing an overwritten mark or space, it is preferable that the amplitude value of the reproduction signal obtained from these marks is a constant value corresponding to each. This is because, when the fluctuation range of the amplitude value of the reproduction signal is large, unlike the recorded data, there is a possibility of erroneous determination.

However, especially when the space is overwritten (including when it is formed for the first time), the amplitude value of the reproduction signal of the space does not necessarily become a constant value and fluctuates, and the amount of fluctuation is the erase power for forming the space. It was obtained as knowledge of the present inventors that it depends. If the erase power when the space is overwritten is too small, the fluctuation range of the amplitude of the reproduction signal from the formed space becomes large. Conversely, even if the erase power is too large, the amplitude of the reproduction signal from the formed space is large. The fluctuation range of becomes larger. In other words, in order to keep the fluctuation range of the amplitude of the reproduction signal from the space within a certain allowable range, it is necessary to set the erase power within the optimum range. It was also found that the optimum range of erase power depends not only on the characteristics (individual difference) of each optical disc, but also on the peak power. These factors need to be taken into account when determining the optimum range of erase power.
Japanese Patent Laid-Open No. 11-273118

  Thus, when direct overwriting is performed on a rewritable optical disk using phase change recording, it is necessary to distinguish between a reproduction signal from a space and a reproduction signal from a mark, but in the conventional example, an adjustment light beam is used. It was not possible to deal with because the amount of light was constantly measured.

  The present invention has been made in view of the above circumstances, and can determine an optimum recording parameter for suppressing amplitude fluctuation of a reproduction signal of a rewritable optical disk using phase change recording, thereby obtaining a high-quality reproduction signal. An object of the present invention is to provide an optical disk device and a recording parameter optimization method.

  An optical disc device according to an aspect of the present invention is configured to irradiate a main beam, a preceding sub beam, and a following sub beam, form a recording mark on the optical disc, and receive a reflected light from the optical disc, and a test recorded with the main beam Means for reproducing the information with the subsequent sub-beam, and means for extracting a predetermined portion of the test information from the reproduction signal of the subsequent sub-beam.

  A recording parameter optimization method according to an aspect of the present invention is a method for recording test information using a main beam and optimizing a recording parameter based on a reproduction signal. A predetermined part of the test information is extracted from the reproduction signal of the succeeding sub beam, and the recording parameter is adjusted based on the reproduction signal of the succeeding sub beam of the extracted part.

  According to the present invention, the state before recording is determined with the preceding sub-beam during recording with the main beam, the state after recording is determined with the subsequent sub-beam, and a predetermined portion of the reproduction signal of the subsequent sub-beam is determined from these determination results. Thus, it is possible to set an appropriate recording parameter.

  Embodiments of an optical disc apparatus according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a diagram showing a configuration of a portion relating to recording power adjustment of an optical disc apparatus according to a first embodiment of the present invention. The optical disk apparatus records and reproduces information on a rewritable optical disk 10 such as a DVD-RW, a DVD-RAM, an HD DVD-RW, and an HD DVD-RAM. The optical disk 10 has a groove spirally formed. The concave portion of the groove is called a groove, the convex portion is called a land, and one round of the groove or land is called a track. Recording is performed by irradiating an intensity-modulated laser beam along this track (groove only or groove and land) to form a mark and a space corresponding to the code length of user data.

  Information is recorded / reproduced with respect to the optical disc 10 by a PUH (optical pickup head) 12. Although not shown, the PUH 12 is connected to a feed motor via a gear and a screw shaft, and this feed motor is controlled by a feed motor control circuit. The feed motor is rotated by the feed motor drive current from the feed motor control circuit, so that the PUH 12 moves in the radial direction of the optical disc 10. The PUH 12 is provided with an objective lens supported by a wire or a leaf spring. The objective lens can be moved in the focusing direction (the optical axis direction of the lens) by driving the drive coil. Further, it is possible to move in the tracking direction (direction orthogonal to the optical axis of the lens) by driving the drive coil.

  When recording data on the optical disk 10, the recording data is sent from the memory 34 to the modulation circuit 38 via the bus line 36, modulated, and then sent to the write strategy generation circuit 40. The modulation circuit 38 modulates the recording data by an ETM (Eight to Twelve Modulation) system that converts 8-bit data into a 16-bit code. In the write strategy generation circuit 40, timing fine adjustment information for each code pattern is set in advance, and recording data timing adjustment is performed based on this information. Thereafter, the laser power is set by an LDD (laser diode driver) 14 in the PUH (pickup head) 12, a laser driving current is passed through the laser diode, and the laser diode emits light. The emitted laser light is diffracted into three beams (preceding sub-beam, main beam, and trailing sub-beam) by a diffraction grating (not shown) in the PUH 12, and then the disk 10 through the collimator lens, the half prism, and the objective lens. Irradiate the surface.

  The irradiated three beams of return light are passed through an objective lens, a half prism, a condensing lens, and a cylindrical lens (not shown) in the PUH 12, the preceding sub-beam photoelectric conversion element 16, the main beam photoelectric conversion element 18, and the subsequent sub-beam. Each light is incident on the photoelectric conversion element 20, converted into an electric signal, and then amplified by the RF amplifier 22.

  The signal from the preceding sub-beam is binarized by the preceding sub-beam reproduction waveform slicing circuit 46, delayed by a delay time by a delay circuit 48, and then input to the sample pulse mask circuit 50. The sample pulse mask circuit 50 masks the binarized signal of the preceding sub-beam reproduction signal with a signal output from the sample pulse generation circuit 42 and delayed for a predetermined time by the delay circuit 44 (described later with reference to FIGS. 6 to 9). Generate a hold signal.

  The selection circuit 24 receives signals from the main beam and the succeeding sub beam, and the signal selected by the setting from the CPU 32 is held by the sample hold circuit 26 at the timing of the sample hold signal. The held signal passes through the low-pass filter 28, is converted to a digital signal by the A / D converter 30, and is stored in the memory 34. The CPU 32 performs an operation based on the value stored in the memory 34 and sets an appropriate recording power in the LDD 14.

  FIG. 2 shows a schematic diagram of recording power (peak power, erase power, bottom power) and multi-pulse.

  Recording on the optical disk is performed by the temperature rising due to the energy of the laser light applied to the recording film, and the recording film undergoing a phase change (crystalline state / amorphous state). Therefore, the recording mark shape may be distorted depending on the heat distribution on the recording film. Therefore, in order to control the heat distribution on the disk with higher accuracy, recording (distortion) is not performed with a multi-pulse recording waveform that finely turns the laser ON / OFF as shown in FIG. Compensation).

  In a phase change recording medium such as HD DVD-RW, recording is performed by setting several power levels in addition to dividing laser pulses. As an example, FIG. 2 shows a case where three power levels of peak power, erase power, and bottom power are set.

  FIG. 3 shows a time relationship between the reproduction signals of the preceding sub beam, the main beam, and the subsequent sub beam. In this embodiment, in the recording direction on the track of the optical disc, two sub-beams are arranged, a preceding sub-beam in front of the main beam and a trailing sub-beam behind. These sub-beams need to be arranged at positions where a sufficient reproduction frequency band and light quantity can be obtained.

  In FIG. 3, the arrangement used for removing the offset of the tracking error signal is shown as an example. When signals are reproduced in this arrangement, the reproduction signals obtained from the preceding sub beam, the main beam, and the subsequent sub beam have a time difference as shown in the figure. Here, the time based on the preceding sub beam is pre, the time based on the main beam is main, the time based on the following sub beam is post, the time difference between the preceding sub beam and the main beam is dpre, and the main beam and the following beam If the time difference with the sub-beam is dpost, the time relationship can be expressed in accordance with one reference. For example, when pre and main are expressed in terms of the post reference time, pre can be expressed as pre + dpre + dpost, and main can be expressed as main + dpost.

  FIG. 4 shows an outline in the case of sampling an arbitrary position based on the reproduction signal of the subsequent sub beam during recording. As an example, a case where the vicinity of the center of the 11T space is sampled during recording is shown. 4A is a recording waveform signal (reference time is main), FIG. 4B is a sample pulse near the center of the 11T space (reference time is main), and FIG. 4C is a playback signal of the subsequent sub-beam (reference time is post) and (d) indicate sample pulses delayed with respect to the post reference.

  FIG. 4A is a schematic diagram of a recording waveform when a 5T mark, an 11T space, a 6T mark,... Are used as a recording pattern. The signal recorded by the main beam is reproduced after dpost by the subsequent sub beam, and a reproduced signal as shown in FIG. 4C is obtained. In order to sample the vicinity of the center of the 11T space from the subsequent sub beam reproduction signal, a sample pulse as shown in FIG. 4B is used. As a result, the recording signal recorded using the main beam can be reproduced using the rear sub-beam, and an arbitrary recording signal portion can be sampled, so that the optimum recording can be performed based on the mark reproduction signal. Parameters can be set.

  The generation of the sample pulse is performed as follows. First, the CPU 32 sets the sample pulse generation circuit 42 to output a sample pulse near the center of the 11T space. The sample pulse generation circuit 42 waits for the timing to record the 11T space from the write strategy generation circuit 40. Then, when a signal including 11T space, for example, information to record 5T mark, 11T space, 6T mark,... As shown in FIG. A sample pulse as shown in 4 (b) is generated.

  However, since the generated sample pulse signal is generated at the timing from the write strategy generation circuit 40, the reference time is main, which is different from the reference time post of the subsequent sub-beam reproduction signal. Therefore, it is necessary to delay dpost by the delay circuit 44 so that the reference time post is the same as that of the subsequent sub-beam reproduction signal. Thereby, as shown in FIG. 4D, a sample pulse having the same reference time as the reference time (post) of the subsequent sub-beam reproduction signal can be generated. Thereby, the vicinity of the center of the 11T space of the reproduced signal of the rear sub-beam can be sampled.

  As an example, the case where the vicinity of the center of the 11T space is sampled has been shown, but after setting the position of the sample pulse arbitrarily, by delaying the sample pulse by dpost time and setting the reference time as post, the subsequent sub-beam at any position It is possible to measure the reproduction signal.

  FIG. 5 illustrates a combination caused by direct overwrite (DOW). Direct overwrite is to directly overwrite a mark or space already recorded. As a combination, when a part that was marked before DOW is marked by DOW, a part that was marked before DOW is made a space by DOW, a part that was marked before DOW is marked by DOW, a DOW There are four patterns in the case where a portion that was previously a space is made a space by DOW.

  FIGS. 6 to 9 show an outline in the case of sampling an arbitrary position during recording in consideration of the recording state (mark or space) before DOW.

  FIG. 6 shows a case where a position where a mark was written before DOW is rewritten into a space by DOW is sampled. Let the recording state before DOW be an 11T mark, an 8T space, and so on.

  6A shows the reproduction signal of the preceding sub-beam (reference time is pre), FIG. 6B shows the binarized signal of the reproduction signal of the preceding sub-beam (reference time is pre), and FIG. 6C shows the vicinity of the center of the 11T space. Sample pulse (reference time is main), (d) is a reproduction signal of the following sub-beam (reference time is post), (e) is a sample pulse delayed with respect to the post reference, and (f) is a preceding signal delayed with respect to the post reference. The binary signal of the sub-beam reproduction signal, (g) indicates a mark before DOW, and a space sample hold pulse after DOW (reference time is post).

  First, the recording state before DOW is determined by the reproduction signal of the preceding sub-beam (reference time is pre) shown in FIG. This reproduction signal is binarized by the preceding sub-beam reproduction waveform slicing circuit 46 shown in FIG. 1, and becomes a binarized signal (reference time is pre) as shown in FIG. With this signal, the recording state (mark or space) before DOW can be determined.

  Subsequently, the position changed to a space by DOW is sampled. For example, when DOW signals of 5T mark, 11T space, 6T mark,..., As described in FIG. 4, the sample pulse is set near the center of the 11T space, and this sample pulse is set to the reference time dpost of the subsequent sub-beam. By delaying only by this, it is possible to obtain the sample point of the subsequent sub beam. However, the recording state before DOW is not considered in this state.

  Therefore, the binarized signal of the preceding sub-beam (b) which is the recording state before DOW is used. However, since the reference time of (b) is pre, it is delayed by dpre + dpost to match the reference time post of the rear sub-beam. A signal obtained by delaying (b) with respect to the post standard is (f). By taking a common part between the high part of the binarized signal (f) of the preceding sub-beam delayed to the post reference and the high part of (e) which is a sample pulse delayed to the post reference, A sample hold pulse (g) that represents the position of the space after the DOW at the mark can be generated. While the sample hold pulse (g) is High, the light amount of the reproduction signal of the subsequent sub beam may be measured.

  FIG. 7 shows a case where the position where the mark was marked before DOW is sampled by DOW. Let the recording state before DOW be an 11T mark, an 8T space, and so on.

  7A shows the reproduction signal of the preceding sub-beam (reference time is pre), FIG. 7B shows the binarized signal of the reproduction signal of the preceding sub-beam (reference time is pre), and FIG. 7C shows the vicinity of the center of the 11T mark. Sample pulse (reference time is main), (d) is a reproduction signal of the following sub-beam (reference time is post), (e) is a sample pulse delayed with respect to the post reference, and (f) is a preceding signal delayed with respect to the post reference. A binary signal of the sub-beam reproduction signal, (g) indicates a mark before DOW, and a sample hold pulse (reference time is post) of the mark portion after DOW.

  Only the differences from the case of FIG. 6 are described. In FIG. 7, since it is desired to sample a position changed to a mark by DOW, for example, a signal of 5T space, 11T mark, 6T space,. Is set near the center of the 11T mark as shown in FIG. By taking the common part of the high part of the binary signal (f) of the preceding sub-beam delayed to the post reference and the high part of (e) which is the sample pulse delayed to the post reference, the mark before DOW is marked Thus, the sample hold pulse (g) indicating the position of the mark after DOW can be generated as in the case of FIG.

  FIG. 8 shows a case in which a position where a space that was a space before DOW is marked by DOW is sampled. Let the recording state before DOW be an 11T mark, an 8T space, and so on.

  8A shows the reproduction signal of the preceding sub-beam (reference time is pre), FIG. 8B shows the binarized signal of the reproduction signal of the preceding sub-beam (reference time is pre), and FIG. 8C shows the vicinity of the center of the 11T mark. Sample pulse (reference time is main), (d) is a reproduction signal of the following sub-beam (reference time is post), (e) is a sample pulse delayed with respect to the post reference, and (f) is a preceding signal delayed with respect to the post reference. A binarized signal of the sub-beam reproduction signal, (g) indicates a space before DOW, and a sample hold pulse (reference time is post) of the mark portion after DOW.

  The difference from the case of FIG. 6 is that the polarities of the mark and the space are opposite to each other. In FIG. 8, since it is desired to sample the position changed to the mark by DOW, for example, the signal of 5T space, 11T mark, 6T space,... It is set near the center. By taking a common part between the high part of the binarized signal (f) of the preceding sub-beam delayed with respect to the post reference and the high part of (e) with the sample pulse delayed with respect to the post reference, a space before DOW is obtained. Thus, the sample hold pulse (g) indicating the position of the mark after DOW can be generated as in the case of FIG.

  FIG. 9 shows a case where a position where a space was made before DOW is sampled by DOW. Let the recording state before DOW be an 11T mark, an 8T space, and so on.

  9A shows the reproduction signal of the preceding sub-beam (reference time is pre), FIG. 9B shows the binarized signal of the reproduction signal of the preceding sub-beam (reference time is pre), and FIG. 9C shows the vicinity of the center of the 11T space. Sample pulse (reference time is main), (d) is a reproduction signal of the following sub-beam (reference time is post), (e) is a sample pulse delayed with respect to the post reference, and (f) is a preceding signal delayed with respect to the post reference. The binarized signal of the reproduction signal of the sub beam, (g) shows a sample hold pulse (reference time is post) of a space before DOW and a space after DOW.

  Only the differences from the case of FIG. 6 will be described. In FIG. 9, since it is desired to sample a portion that was a space before DOW, for example, a signal of 5T space, 11T mark, 6T space,. As shown in (c), it is set near the center of the 11T space. By taking a common part between the high part of the binarized signal (f) of the preceding sub-beam delayed with respect to the post reference and the high part of (e) with the sample pulse delayed with respect to the post reference, a space before DOW is obtained. Thus, the sample hold pulse (g) representing the position of the space after DOW can be generated as in the case of FIG.

  FIG. 10 shows a schematic diagram of a waveform change of a reproduction signal in a space that occurs when DOW is performed with an inappropriate erase power.

  When DOW is performed with an appropriate erase power, no waveform change occurs as shown in FIG. However, when DOW is performed with an inappropriate erase power, waveform changes are seen as shown in (b), (c), and (d).

  For example, when the erase power is lower than an appropriate value as shown in (b), the space level fluctuates due to DOW. The cause is considered as follows. As shown in FIG. 5, there are a case where a space that is a mark before DOW is used as a space and a space that is a space before DOW. In the former case, when the erase power is low, the phase change from the mark to the space is not stable (an unerased part occurs). On the other hand, in the latter case, since the phase change is unnecessary, the space level is maintained. As a result, it is considered that a random space level variation as shown in (b) occurs due to a random mixture of marks and spaces at the time of previous recording in an area where a space is to be formed by DOW. .

  In contrast to (b) of FIG. 10, when the erase power is higher than the appropriate value as in (c) and (d), the level of the space is increased on an average (DC) basis. This is thought to be because the phase change from space to mark has started due to the increase in erase power.

  In this embodiment, the optimum erase power is determined such that the space level is small and the average level of the space is an appropriate value. However, since the erase power depends on the peak power, the combination of the erase power and the peak power is determined. The optimum recording power is selected from the above.

  FIG. 11 shows the relationship between the erase power and the space level (the light amount of the reproduction signal of the space) when the space is DOWed with a mark or space before DOW. FIG. 11 is a graph in which the horizontal axis represents the erase power during DOW execution, and the vertical axis represents the space level. A curve indicated by a solid line is a mark before DOW, and a curve indicated by a dotted line is a case before DOW.

  When the mark is before the DOW, the phase level is not stable at the low erase power as described with reference to FIG. As the erase power increases, the space level decreases. However, if the erase power is increased too much, the phase change from space to mark begins and the space level increases.

  On the other hand, when the space before DOW is a space, the phase level is not required even if the erase power is low, so the space level is kept low. However, as in the case of the mark before DOW, if the erase power is increased too much, the phase change from the space to the mark starts and the space level increases.

  Therefore, the subsequent sub-beam light amount measured by the method of FIG. 9 (the space before DOW is a space and the space after DOW) is subtracted from the subsequent sub-beam light amount measured by the method of FIG. 6 (mark before DOW and space after DOW). By examining the values, the states of (b), (c), and (d) in FIG. 10 can be detected.

  When the subtraction value is large, it can be seen that the state shown in FIG. 10B, that is, the erase power is lower than the appropriate value. Further, when the subtraction value is close to 0 and the absolute value of the value measured by each method is large, it can be seen that the state shown in FIGS. 10C and 10D is in effect, that is, the erase power is higher than the appropriate value.

  Therefore, as a method for determining the optimum recording parameter, the value obtained by subtracting the subsequent sub-beam light amount sampled and measured by the method shown in FIG. 9 from the subsequent sub-beam light amount measured by the sample hold method shown in FIG. 6 approaches 0. In addition, the erase power may be changed in real time during recording so that the absolute value of the value measured by each method becomes small.

  FIG. 12 is a flowchart showing an erase power optimization process. In block # 12, a predetermined recording pattern is directly overwritten in the test recording area. The recording pattern is a code sequence including a space having the longest code length, that is, an 11T space. In block # 14, based on the binarized signal of the reproduction signal of the preceding sub beam (output of the preceding sub beam reproduction waveform slicing circuit 46), it is determined whether the mark before DOW is a mark or a space.

  If the mark before DOW is a mark, the sample pulse generation circuit 42 generates a sample pulse at the DOW timing of 11T space in block # 16. In block # 18, the delay circuit 44 delays the sample pulse by dpost time. In block # 20, the sample pulse mask circuit 50 masks the binarized pulse of the preceding sub-beam with the delayed sample pulse, and generates the sample hold pulse shown in FIG. 6 (g). In block # 22, the sample-and-hold circuit 26 detects the light amount of the reproduction signal of the subsequent sub-beam based on the sample-and-hold pulse, so that the light amount of the space portion can be measured before DOW and after the DOW.

  On the other hand, if there is a space before DOW, the sample pulse generation circuit 42 generates a sample pulse at the DOW timing of 11T space in block # 26. In block # 28, the delay circuit 44 delays the sample pulse by dpost time. In block # 30, the sample pulse mask circuit 50 masks the binarized pulse of the preceding sub-beam with the delayed sample pulse, and generates the sample hold pulse shown in FIG. 9 (g). In block # 32, the sample and hold circuit 26 detects the light quantity of the reproduction signal of the subsequent sub-beam based on this sample and hold pulse, so that the light quantity in the space portion can be measured before DOW and after the DOW.

  In block # 34, the difference between these two light amounts is calculated. In block # 36, the erase power is optimized based on FIG. 11 so that the absolute value and difference between these two light quantities are equal to or less than a predetermined value close to zero. In block # 38, it is determined whether or not the optimization has been completed (these values are actually less than or equal to a predetermined value). If not, the process in block # 14 is repeated.

  As described above, according to the present embodiment, while recording with the main beam, the recorded signal is reproduced with the subsequent sub-beam, the state before recording is reproduced with the preceding sub-beam, and the sample pulse corresponding to the recording signal and By delaying the binarized signal of the preceding sub-beam according to the positional relationship of the main beam, the preceding sub-beam, and the succeeding sub-beam, it is possible to extract an arbitrary part of the reproduced signal of the succeeding sub-beam. Thereby, it is possible to adjust the erase power suitable for DOW in real time during recording. In the conventional general optimization method, since the recorded signal is read back and learned, it takes time for optimization. However, in the present embodiment, since the adjustment can be performed in real time during recording, the time required for optimum recording power control can be greatly reduced. For this reason, it is expected that the recording performance to the known / unknown media will be greatly improved, and the variation of each media / recording device can be absorbed, leading to improvement in yield and shortening of development time.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Although the above description has described the optimization of erase power, optimization of peak power, bottom power, the number of multi-pulses, and the like can be achieved in the same manner.

  Further, the present invention provides a computer-readable recording recording a program for causing a computer to execute predetermined means (or for causing a computer to function as predetermined means or for causing a computer to realize predetermined functions). It can also be implemented as a medium.

The figure which shows one Embodiment of the optical disk apparatus of this invention. The figure which shows the recording waveform of a multipulse. The figure which shows the relationship of a preceding sub beam, a main beam, and a succeeding sub beam. The figure which shows the operation | movement which samples an arbitrary position from the reproduction signal of a back sub beam during recording. The figure which shows the combination of the state of the mark space produced by direct overwrite (DOW). The figure which shows the operation | movement which samples the position of a mark before DOW and the space after DOW. The figure which shows the operation | movement which samples the position of a mark before DOW and a mark after DOW. The figure which shows the operation | movement which samples the position of a space before DOW and the mark after DOW. The figure which shows the operation | movement which samples the position of a space before DOW and the space after DOW. The figure which shows the outline of the waveform change of the space which arises when DOW is performed with improper erase power. The figure which shows the relationship between the erase power and the space level under the condition of the space before the DOW, the space after the mark / DOW, and the space before the DOW / after the DOW. 6 is a flowchart showing processing for optimizing recording parameters.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Optical disk, 12 ... PUH, 16 ... Leading sub beam photoelectric conversion element, 18 ... Main beam photoelectric conversion element, 20 ... Subsequent sub beam photoelectric conversion element, 40 ... Write strategy generation circuit, 42 ... Sample pulse generation circuit, 46 ... Advance Sub beam reproduction waveform slicing circuit, 50... Sample pulse mask circuit.

Claims (11)

An optical unit that irradiates a main beam, a preceding sub-beam, and a subsequent sub-beam, forms a recording mark on the optical disc, and receives reflected light from the optical disc;
Means for reproducing the test information recorded by the main beam by a subsequent sub beam;
Means for extracting a predetermined portion of the test information from the reproduction signal of the subsequent sub-beam;
An optical disc apparatus comprising: The reproducing means reproduces recorded information before recording test information with a preceding sub-beam, and generates a binary pulse of a reproduced signal of the preceding sub-beam,
The extraction unit according to claim 1, wherein the extraction unit extracts a predetermined portion based on the sample pulse and the binarized pulse, the unit generating a sample pulse corresponding to the value of the test information. Optical disk device.   3. The predetermined portion is a mark before the test recording and a space portion after the test recording, and a space portion before the test recording and a space portion after the test recording. Optical disk device.   The extracting means delays the sample pulse according to the positional relationship between the main beam and the subsequent sub-beam; and the means delays the binarized pulse according to the positional relationship between the preceding sub-beam and the subsequent sub-beam; 3. The optical disc apparatus according to claim 2, wherein the predetermined portion is extracted based on a common portion of the two delay pulses.   5. The apparatus according to claim 1, further comprising a unit that adjusts an erase power of a recording waveform based on a reproduction signal of a succeeding sub-beam extracted by the extraction unit. 6. Optical disk device.   The test signal extracted by the extraction means is a mark and the signal after the test recording after the test recording is a sub-sub-beam reproduction signal, and the test signal before the test recording is a space and the test signal after the sub-beam reproduction signal after the test recording, 4. The optical disc apparatus according to claim 3, further comprising means for adjusting the erase power of the recording waveform so that the difference between them is not more than a predetermined value. In a method for recording test information using a main beam and optimizing recording parameters based on a reproduction signal,
Test information recorded with the main beam is played back with the sub beam,
Extract a predetermined part of the test information from the playback signal of the subsequent sub-beam,
A recording parameter optimization method for adjusting a recording parameter based on a reproduction signal of a succeeding sub beam of an extracted portion. The reproduction step reproduces recorded information before recording test information with a preceding sub-beam, and generates a binary pulse of a reproduced signal of the preceding sub-beam,
8. The recording parameter according to claim 7, wherein the extracting step generates a sample pulse corresponding to a value of test information, and extracts the predetermined portion based on the sample pulse and the binarized pulse. Optimization method.   9. The predetermined portion is a mark before the test recording and a space portion after the test recording and a space portion before the test recording and a space portion after the test recording. Recording parameter optimization method.   The extraction step delays the sample pulse according to the positional relationship between the main beam and the subsequent sub-beam, delays the binarized pulse according to the positional relationship between the preceding sub-beam and the subsequent sub-beam, and the two delays. 10. The recording parameter optimization method according to claim 9, wherein the predetermined portion is extracted based on a common portion of pulses.   The adjustment step includes a reproduction signal of the subsequent sub-beam after extracting the space portion after the test recording and the mark before the test recording, and a reproduction of the subsequent sub-beam after extracting the space portion after the test recording and before the test recording. 10. The recording parameter optimizing method according to claim 9, wherein the erase power of the recording waveform is adjusted so that the difference between the signal and a difference between them is not more than a predetermined value.

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