JP2006302420A - Optical disk recording and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk recording and reproducing method that can correct the spherical aberration due to the uneven thickness of the cover layer even when recording on a recordable optical disk which has a recording layer or many recording layers and does not require to obtain the optimum position to correct the spherical aberration each time loading an optical disk. <P>SOLUTION: Disposing an optical element 20 which corrects the spherical aberration and is movable in the direction of the light axis of the laser beam, it is moved to make the amplitude of the tracking error signals maximum. Then, writing test signals in a test writing area, the optical element is moved to make the amplitude of the reproduced RF signals of the test signals maximum. Obtaining the position information of the optical element after the adjustment, it is recorded in the correction value recording area on the disk. When reproducing the optical disk recorded with the position information of the optical element, the position of the above optical element is adjusted based on the correction data of the spherical aberration read from the correction recording area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc recording / reproducing method, and more particularly to an optical disc recording / reproducing method for correcting spherical aberration due to a thickness error of a cover layer on the surface of an optical disc.

  In an optical disk as an optical recording medium, a transmission substrate having a predetermined thickness is formed as a cover layer for protecting the information recording surface so as to cover the recording surface. In an optical disk recording / reproducing apparatus, reading or recording of information data is performed on the optical disk by irradiating a recording surface with a reading or recording laser beam through the cover layer.

  In order to realize a high density optical disk, in addition to shortening the laser wavelength, a method of increasing the lens numerical aperture has been studied in order to condense the light beam from the light source into a smaller spot. However, when the numerical aperture of the lens is increased, the spot is distorted with respect to a slight warp or tilt of the optical disk, and aberration is likely to occur. Even in such a case, it is advantageous that the cover layer is thinner.

FIG. 6 is a schematic view showing a cross section of a single-sided dual-layer recording optical disc. In this figure, the cover layer refers to a transmission layer and an adhesive layer on the optical disk surface.
The thickness of the cover layer is 1.2 mm for CD and 0.6 mm for DVD. To further increase the density of the cover layer, a transparent sheet is used instead of a transparent substrate. The layer material that forms the permeable layer instead of the permeable sheet is formed by spin coating or the like (in this case, no adhesive is required), but these are all thick due to manufacturing variations. An error is likely to occur.

  For this reason, due to the difference in the thickness of the cover layer, a phenomenon occurs in which the focal point of the laser beam does not form an image on one point on the optical axis but forms a circle and forms a circle. This is a spherical aberration that occurs because the lens is spherical, but there is a problem that information reading sensitivity and information recording accuracy are reduced.

Conventionally, as a means for correcting spherical aberration generated due to such a difference in the thickness of the cover layer, a technique according to the following Patent Document 1 is disclosed.
In this patent document 1, a laser beam emitted from a light source is condensed on a recording surface of an optical disk through an objective lens and irradiated, and a laser beam reflected by the recording surface of the optical disk is transmitted through an objective lens. An optical element that can be moved and adjusted in the direction of the optical axis of the laser beam is disposed in the forward optical path at least in an optical pickup that forms a return optical path that leads to a photodetector. The spherical aberration is corrected by adjusting the optical element so as to maximize the amplitude level.
JP 2001-236684 A

  However, the technique for correcting the spherical aberration disclosed in Patent Document 1 detects and corrects the amplitude level of the RF signal read from the optical disc, so that it is corrected only during reproduction, and when recording in an unrecorded area of a recordable optical disc. There is a problem that spherical aberration cannot be corrected. Furthermore, since the operation for obtaining the optimum position for spherical aberration correction is performed every time an optical disk is loaded, there is a problem that rapid reproduction cannot be performed.

  The present invention has been made in view of such a conventional problem, and it is possible to correct spherical aberration due to the difference in the thickness of the cover layer even during recording of an optical disc having a single or multi-layer recording layer. It is another object of the present invention to provide an optical disk recording / reproducing method that does not require an operation for obtaining an optimum position for spherical aberration correction each time an optical disk is loaded.

The present invention provides an optical disk recording / reproducing method described in the following (1) to (3) as means for solving the above problems. That is,
(1) An optical disc using a recording type optical disc having one or multiple recording layers on one side and having a test writing area and a correction value recording area for recording spherical aberration correction value data in a part of the recording layer In the recording / reproducing method,
A laser beam emitted from a light source is condensed on a track formed on the recording layer of the optical disc via an objective lens and irradiated, and a laser beam reflected by the recording layer of the optical disc is Position adjustment in the optical axis direction of the laser beam in the forward optical path of the optical system in which the return optical path led to the split-type photodetector through the objective lens is formed or in the optical path that simultaneously satisfies the forward optical path and the return optical path An optical element that corrects spherical aberration that can be
The position of the optical element is adjusted so that the amplitude of the tracking error signal obtained from the output signal of the split photodetector is maximized, and then the test writing area of each recording layer of one layer or multiple layers And write a test signal to
When reproducing the test signal recorded in the test writing area of each recording layer of one layer or multiple layers, the amplitude of the reproduction RF signal obtained by calculating from the output signal of the split photodetector is maximized. A method for recording and reproducing an optical disk, comprising: adjusting the position of an optical element for each recording layer of one layer or multiple layers, and acquiring the adjusted position information of the optical element.
(2) The optical disc recording / reproducing method according to claim 1, wherein the acquired position information is recorded in a correction value recording area where the correction value data of the spherical aberration can be recorded.
(3) An optical disc using a recording type optical disc having one or multiple recording layers on one side and having a test writing area and a correction value recording area for recording spherical aberration correction value data in a part of the recording layer In the recording / reproducing method,
A laser beam emitted from a light source is condensed on a track formed on the recording layer of the optical disc via an objective lens and irradiated, and a laser beam reflected by the recording layer of the optical disc is Position adjustment in the optical axis direction of the laser beam in the forward optical path of the optical system in which the return optical path led to the split-type photodetector through the objective lens is formed or in the optical path that simultaneously satisfies the forward optical path and the return optical path An optical element that corrects spherical aberration that can be
The optical disk recording / reproducing method is characterized in that the position of the optical element is adjusted on the basis of spherical aberration correction value data of one or multiple recording layers read from the correction value recording area.

  With the increase in the density of optical discs, the influence of spherical aberration due to the thickness error of the cover layer on the surface of the optical disc has increased. Spherical aberration due to the difference can be corrected, and the optimum correction value is recorded in advance for each optical disk, so that it is not necessary to perform an operation for obtaining the optimal position of spherical aberration correction every time an optical disk is loaded. Playback is possible.

Hereinafter, an optical disk recording / reproducing method according to each embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a first embodiment according to the present invention, FIG. 2 is a block diagram showing a second embodiment according to the present invention, and FIG. 3 explains an operation in the first embodiment. FIG. 4 is a first flowchart for explaining the operation in the second embodiment, and FIG. 5 is a second flowchart for explaining the operation in the second embodiment.

First, the configuration of the first embodiment according to the present invention will be described with reference to FIG.
In FIG. 1, a phase change type optical disc 1 having two recording layers capable of repeatedly recording and reproducing information is rotationally driven by a spindle motor (not shown), and a recording track of the optical disc 1 is emitted from an optical pickup 10. In an optical disc recording / reproducing apparatus for optically recording / reproducing digital data of a predetermined data format by scanning with a laser beam, trial writing (recording) on a predetermined unrecorded portion of the optical disc 1 and reproduction of the trial writing portion 1 illustrates a configuration in which the present invention is applied to a case where

First, the general configuration and signal flow will be described.
In the optical pickup 10, the laser light from the semiconductor laser 11, which is a laser light source, is converted into a parallel light beam by the collimator lens 12, and an optical element for correcting spherical aberration composed of the concave lens 14 and the convex lens 15 via the beam splitter 13. Irradiation is performed so as to be focused on the signal recording surface on the optical disc 1 through the (beam expander) 20 and the objective lens 16.
The reflected light beam (return laser beam) of the laser beam projected and reflected on the signal recording surface of the optical disc 1 is reflected by the beam splitter 13 and guided to the photodetector 18 which is a light receiving element via the cylindrical lens 17. It has become.
Here, the objective lens 16 is controlled to move in the optical axis direction and the direction orthogonal to the optical axis by a so-called biaxial driving device having a focusing driving coil 25 and a tracking driving coil 26. .

The beam splitter 13 distributes a small amount of light for irradiating the optical disc 1 through the objective lens 16 and simultaneously irradiating the photodetector 30 for laser power control. The light amount distributed here is irradiated to the photodetector 30 through the convex lens 19.
The photodetector 30 detects light, and the detected light detection signal is sent to the sample hold circuit 32 via the amplifier 31, and is sampled and held by the signal from the multi-pulse generation circuit 38 (or the signal from the CPU 34). The data is sent to the CPU 34 via the D conversion circuit 33. The CPU 34 performs target setting laser power and calculation, gain adjustment, and phase compensation during reproduction or recording, and sends this signal to the laser drive circuit 36 via the D / A conversion circuit 35 to perform laser APC control.

The photodetector 18 has a structure in which the light receiving unit is divided into four parts, and the light detection signals from these light receiving units are supplied to the matrix circuit 22 via the amplifier 21, so that the sum or difference of these signals is reduced. As a result, it is extracted as an RF signal, a focus error signal (FE), and a tracking error signal (TE). The focus error signal and the tracking error signal are sent to the drive coils 25 and 26 of the biaxial drive device via the phase compensation circuit 23 and the servo drive circuit 24, respectively, thereby performing focus servo and tracking servo. .
When a disc having a multi-layer recording surface is reproduced, the CPU 34 determines the number of layers according to the reproduction designated address, and the CPU 34 passes the D / A conversion circuit 51 via the D / A conversion circuit 51 to lock the focus servo to the recording layer obtained by the CPU 34. A control signal is sent to the servo drive circuit.
The RF signal is a sum signal of output signals from the respective light receiving units, and this RF signal is sent to the amplitude detection circuit 40.

  Next, the RF signal is supplied to the CPU 34 via the A / D conversion circuit 41, and the maximum value of the RF signal is detected by the CPU 34. The tracking error signal is sent to the phase compensation circuit 23 and to the amplitude detection circuit 42, and further sent to the CPU 34 via the A / D conversion circuit 43.

Next, a description will be given of a configuration and a signal flow when the trial writing and the reproduction of the trial writing portion are performed.
In the predetermined unrecorded portion of the optical disc 1, the concave lens 14 of the optical element 20 is moved and adjusted by the motor 47 so that the maximum amplitude of the tracking error signal can be obtained. The CPU 34 sends a drive command to the optical element drive circuit 45 via the D / A conversion circuit 46, adjusts the movement of the concave lens 14 using the motor 47, and the position of the optical element 20 so that the maximum amplitude of the tracking error signal can be obtained. And a driving voltage to be sent to the optical element driving circuit 45 is obtained.
At this time, it is assumed that tilt, focus, tracking, and the like are separately optimally adjusted.

  A test signal 37 (binary data) for performing test writing is sent to the multi-pulse generation circuit 38 when a test write command is sent from the CPU 34, and the multi-pulse generation circuit 38 generates a plurality of pulse trains as multi-pulse signals. It is sent to the laser drive circuit 36. Further, a laser power control signal is sent from the CPU 34 via the D / A 35. As a result, a drive signal is sent from the laser drive circuit 36 to the semiconductor laser 11 and can be pulse-driven by a plurality of levels of laser power values, and the recording laser beam is irradiated toward the recording surface of the test writing area of the optical disc 1 and tested. A signal is recorded.

  As described above, the reproduction signal of the test writing section passes through the optical pickup 10 and is sent to the photodetector 18, and is sent to the matrix circuit 22 via the amplifier 21. An RF signal is obtained by the matrix circuit 22, and the concave lens 14 is moved and adjusted by the motor 47 so that the maximum amplitude or maximum level of the RF signal can be obtained. That is, a drive command is sent from the CPU 34 to the optical element drive circuit 45 via the D / A conversion circuit 46, and the concave lens 14 is moved and adjusted using the motor 47 so that the maximum amplitude of the RF signal 20 can be obtained. A driving voltage for obtaining the position and setting the optimum position of the optical element 20 to be sent to the optical element driving circuit 45 is obtained.

The optimum position information of the optical element 20 obtained in this way is stored in the memory 44 by the CPU 34 and used in the second embodiment to be described later.
When the optimum position information of the optical element 20 is sent to the CPU 34, the optimum position information is sent to the optical element drive circuit 45 via the D / A conversion circuit 46 based on the optimum position information, and the concave lens 14 is moved and adjusted by the motor 47 so as to be optical. The position of the element 20 is moved to the optimum position.

Next, details of the operation in the first embodiment will be described with reference to FIG.
First, when the operation is started, the laser emission and spindle servo of the optical pickup 10 are turned on (step S11 in FIG. 3), and the optical pickup 10 (hereinafter referred to as PU) is moved to the calibration area of the optical disc 1 (S12). Then, an interlayer jump command is sent from the CPU 34, the focus servo and tracking servo are turned on in each recording layer, and calibration is performed (S13).

  Thereafter, in order to reproduce the disc information recording area of the first layer (or the second layer), the tracking servo is turned off with the focus servo turned on (S14), and the PU is moved to the disc information recording area ( S15), tracking servo is turned ON (S16), disk information is read (S17), tracking servo is turned OFF (S18), and then moved to an arbitrary place (it does not need to move) (S19). A command is issued from the CPU 34 to move the optical element 20 using the motor 47 in a state where the focus servo is turned on for the second (or second) layer (S20).

Thereby, since the amplitude of the tracking error signal changes, the amplitude value is detected (S21), and the optical element 20 is shifted until this amplitude value detects the maximum value (S22), so that the tracking error signal is maximized. The optical element 20 is moved (S23).
Then, the PU is moved to the trial writing area (S24), the tracking servo is turned on (S25), a test signal is generated from the test signal source 37 and recorded by trial writing (S26), and this trial written information (RF signal). Is reproduced (S27), a command is issued from the CPU 34 to move the optical element 20 using the motor 47 (S28).

Thereby, since the amplitude of the RF signal changes, the amplitude value is detected (S29), and the optical element 20 is shifted until this amplitude value detects the maximum value (S30), and the optical signal is optically moved to the position where the RF signal becomes maximum. The element 20 is moved (S31).
The optimum position information (optical element driving voltage Vexp1) of the optical element 20 obtained in this way is stored in the memory 44 from the CPU 34 (S32).

  Next, with the focus servo turned on for the second layer (or the first layer) (S33), a command is issued from the CPU 34 to move the optical element 20 using the motor 47 (S34). Thereby, since the amplitude of the tracking error signal changes, the amplitude value is detected (S35), and the optical element 20 is shifted until this amplitude value detects the maximum value (S36), so that the tracking error signal becomes the maximum. The optical element 20 is moved (S37).

Then, the PU is moved to the trial writing area (S38), the tracking servo is turned on (S39), a test signal is generated from the test signal source 37, and trial writing is recorded (S40).
After reproducing the trial-written information (RF signal) (S41), a command is issued from the CPU 34 to move the optical element 20 using the motor 47 (S42). Thereby, since the amplitude of the RF signal changes, the amplitude value is detected (S43), and the optical element 20 is shifted until this amplitude value is detected to the maximum value (S44), and the optical element is positioned at the position where the RF signal becomes maximum. 20 is moved (S45).

As a result, in a recording type optical disc having two recording layers, spherical aberration is corrected both during recording and during reproduction for any optical disc in which the thickness of the cover layer is different. Write and read can be performed.
Needless to say, the movement operation of the optical element 20 according to the present embodiment may be used not only during trial writing but also during normal information data recording / reproduction.
In addition, although the case where there are two recording layers is taken as an example, it is a matter of course that the present invention can also be applied to a single-layer or multilayer optical disk.

Next, the configuration of the second embodiment according to the present invention will be described with reference to FIG.
FIG. 2 shows a phase change type optical disk 1 having two recording layers capable of repeatedly recording and reproducing information. The optical disk 1 is driven to rotate by a spindle motor (not shown), and a recording track of the optical disk 1 is emitted from the optical pickup 10. In an optical disk recording / reproducing apparatus for optically recording / reproducing digital data of a predetermined data format by scanning with a laser beam, the optimum position information of the optical element 20 stored in the memory 44 in the first embodiment 1 is recorded in a predetermined area of the optical disc 1 and reproduced.

First, the general configuration and signal flow will be described.
In the optical pickup 10, the laser light from the semiconductor laser 11, which is a laser light source, is converted into a parallel light beam by the collimator lens 12, and an optical element for correcting spherical aberration composed of the concave lens 14 and the convex lens 15 via the beam splitter 13. Irradiation is performed so as to be focused on the signal recording surface on the optical disc 1 through the (beam expander) 20 and the objective lens 16.
The reflected light beam (return laser beam) of the laser beam projected and reflected on the signal recording surface of the optical disc 1 is reflected by the beam splitter 13 and guided to the photodetector 18 which is a light receiving element via the cylindrical lens 17. It has become.
Here, the objective lens 16 is controlled to move in the optical axis direction and the direction orthogonal to the optical axis by a so-called biaxial driving device having a focusing driving coil 25 and a tracking driving coil 26. .

The beam splitter 13 distributes a small amount of light for irradiating the optical disc 1 through the objective lens 16 and simultaneously irradiating the photodetector 30 for laser power control. The light amount distributed here is irradiated to the photodetector 30 through the convex lens 19.
The photodetector 30 detects light, and the detected light detection signal is sent to the sample hold circuit 32 via the amplifier 31, and is sampled and held by the signal from the multi-pulse generation circuit 38 (or the signal from the CPU 34). The data is sent to the CPU 34 via the D conversion circuit 33. The CPU 34 performs target setting laser power and calculation, gain adjustment, and phase compensation during reproduction or recording, and sends this signal to the laser drive circuit 36 via the D / A conversion circuit 35 to perform laser APC control.

The photodetector 18 has a structure in which the light receiving unit is divided into four parts, and the light detection signals from these light receiving units are supplied to the matrix circuit 22 via the amplifier 21, so that the sum or difference of these signals is reduced. As a result, it is extracted as an RF signal, a focus error signal (FE), and a tracking error signal (TE). The focus error signal and the tracking error signal are sent to the drive coils 25 and 26 of the biaxial drive device via the phase compensation circuit 23 and the servo drive circuit 24, respectively, thereby performing focus servo and tracking servo. .
When a disc having a multi-layer recording surface is reproduced, the CPU 34 determines the number of layers according to the reproduction designated address, and the CPU 34 passes the D / A conversion circuit 51 via the D / A conversion circuit 51 to lock the focus servo to the recording layer obtained by the CPU 34. A control signal is sent to the servo drive circuit.
The RF signal is a sum signal of output signals from the respective light receiving units, and this RF signal is sent to the binarization circuit 49.

  Next, the RF signal is supplied to the CPU 34 via the decoding circuit 50, and the CPU 34 extracts the optimum position information of the optical element 20 written on the optical disk 1 from the RF signal by means described later.

Next, a configuration for recording the optimum position information of the optical element 20 stored in the memory 44 in a predetermined area of the optical disc 1 and a signal flow will be described.
The CPU 34 reads the optimum position information of the optical element 20 stored in the memory 44, and this optimum position information is sent to an encoding circuit 48 that converts it into a data format that can be recorded on the optical disk 1. The encoded data is sent to the multi-pulse generation circuit 38 in response to a command from the CPU 34, and a plurality of pulse trains are generated by the multi-pulse generation circuit 38 and sent to the laser drive circuit 36 as multi-pulse signals. Further, a laser power control signal is sent from the CPU 34 via the D / A 35. As a result, a drive signal is sent from the laser drive circuit 36 to the semiconductor laser 11 and can be pulse-driven by a plurality of levels of laser power values, so that the recording laser beam can cause spherical aberration due to uneven thickness of the optical disc 1 (thickness unevenness of the cover layer). Irradiation is performed toward the recording surface of the area where information for correction can be recorded), and the optimum position information of the optical element 20 is recorded.

Next, a configuration for extracting optimum position information of the optical element 20 recorded in the predetermined area and a signal flow will be described.
The optical disc 1 on which the optimum position information of the optical element 20 is recorded is read out as an RF signal by the optical pickup 10, and as described above, this RF signal passes through the binarization circuit 49 that binarizes data, The data is sent to the decoding circuit 50 and converted into data that can be processed by the CPU 34.

  When the optimum position information of the decoded optical element 20 is sent to the CPU 34, it is sent to the optical element drive circuit 45 via the D / A conversion circuit 46 based on the optimum position information, and the concave lens 14 is moved and adjusted by the motor 47. Then, the position of the optical element 20 is moved to the optimum position.

Next, the recording operation of the optimum position information of the optical element 20 in the second embodiment will be described with reference to FIG.
In the first embodiment, in order to record the optimum position information of the optical element 20 stored in the memory 44 on the optical disc 1, the tracking servo is first turned off (step S51 in FIG. 4), and the PU is placed in a predetermined area of the optical disc 1. (S52), the focus servo is turned on in the first layer or the second layer, the tracking servo is turned on (S53), and the optimum position information of the optical element 20 stored in the memory 44 is read (S54). The position information is encoded by the encoding circuit 48 into a data format that can be recorded on the optical disc 1 (S55).

  The encoded data is sent to the multipulse circuit 38 to be multipulsed (S56), and then the multipulsed data is sent to the laser drive circuit 36 (S57). Also, a recording command is sent from the CPU 34, and information on the recording laser power is sent to the laser drive circuit 36 via the D / A 35 (S58). Then, the optimum position information on the optical disc 1 is recorded in a predetermined area (S59).

Next, the reproducing operation of the optimum position information of the optical element 20 in the second embodiment will be described with reference to FIG.
In order to reproduce the optimum position information recorded in the predetermined area of the optical disc 1, first, laser emission and spindle servo are turned on (step S61 in FIG. 5), and the PU is moved to the calibration area of the optical disc 1 (S62). To send an interlayer jump command from the CPU 34, turn on the focus servo and tracking servo in each recording layer, perform calibration (S63), and then reproduce the disc information recording area of the first layer (or the second layer) The tracking servo is turned off with the focus servo turned on (S64), the PU is moved to the disk information recording area (S65), the tracking servo is turned on (S66), and the disk information is read (S67).

Next, after the tracking servo is turned off (S68), the PU is moved to a predetermined area (the focus servo is turned on in the first layer or the second layer), and the tracking servo is turned on (S69). Here, the optimum position information recorded in the predetermined area is read (S70). This RF signal (optimum position information) is binarized by the binarization circuit 49 (S71), decoded by the decoding circuit 50 (S72), and then a control command is sent to the optical element driving circuit 45 based on the optimum position information (S73). As a result, the drive voltage is sent to the motor 47 to adjust the movement of the optical element 20, and the optical element 20 is adjusted to the optimum position (S74).
As a result, the optimum position information of the optical element 20 recorded on the optical disk can be read and set quickly without obtaining the optimum position for spherical aberration correction each time an optical disk is loaded. It becomes.

  As described above in detail, according to the optical disc recording / reproducing method of the present invention, any optical disc having one or multiple recording layers and having a different cover layer thickness is recorded and reproduced. In both cases, spherical aberration is corrected, and information can be written and read satisfactorily. Furthermore, since it is not necessary to perform an operation for obtaining the optimum position for spherical aberration correction each time an optical disk is loaded, a quick reproduction operation is possible.

It is a block diagram which shows the 1st Example which concerns on this invention. It is a block diagram which shows the 2nd Example which concerns on this invention. It is a flowchart explaining the operation | movement in a 1st Example. It is a 1st flowchart explaining the operation | movement in a 2nd Example. It is a 2nd flowchart explaining the operation | movement in a 2nd Example. It is the schematic diagram which showed the cross section of the optical disk of single-sided double layer recording.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disk 10 ... Optical pick-up (PU)
DESCRIPTION OF SYMBOLS 11 ... Semiconductor laser 12 ... Collimate lens 13 ... Beam splitter 14 ... Concave lens 15 ... Convex lens 16 ... Objective lens 17 ... Cylindrical lens 18 ... Photo detector 19 ... Convex lens DESCRIPTION OF SYMBOLS 20 ... Optical element 21 ... Amplifier circuit 22 ... Matrix circuit 23 ... Phase compensation circuit 24 ... Servo drive circuit 25 ... Focus drive coil 26 ... Tracking drive coil 30 .. Photodetector 31... Amplifier circuit 32... Sample hold circuit 33... A / D conversion circuit 34.
35 ... D / A conversion circuit 36 ... Laser drive circuit 37 ... Test signal source 38 ... Multi-pulse generation circuit 40 ... Amplitude detection circuit 41 ... A / D conversion circuit 42 ... Amplitude detection circuit 43 ... A / D conversion circuit 44 ... Memory 45 ... Optical element drive circuit 46 ... D / A conversion circuit 47 ... Motor 48 ... Encoding circuit 49 ... Binary circuit 50 ... Decode circuit 51 ... D / A conversion circuit

Claims (3)

Optical disc recording / reproducing method using a recording type optical disc having one recording layer or multiple recording layers on one side and having a test writing region and a correction value recording region for recording spherical aberration correction value data in a part of the recording layer In
A laser beam emitted from a light source is condensed on a track formed on the recording layer of the optical disc via an objective lens and irradiated, and a laser beam reflected by the recording layer of the optical disc is Position adjustment in the optical axis direction of the laser beam in the forward optical path of the optical system in which the return optical path led to the split-type photodetector through the objective lens is formed or in the optical path that simultaneously satisfies the forward optical path and the return optical path An optical element that corrects spherical aberration that can be
The position of the optical element is adjusted so that the amplitude of the tracking error signal obtained from the output signal of the split photodetector is maximized, and then the test writing area of each recording layer of one layer or multiple layers And write a test signal to
When reproducing the test signal recorded in the test writing area of each recording layer of one layer or multiple layers, the amplitude of the reproduction RF signal obtained by calculating from the output signal of the split photodetector is maximized. A method for recording and reproducing an optical disk, comprising: adjusting the position of an optical element for each of the recording layers of one layer or multiple layers, and acquiring the adjusted position information of the optical element. The optical disc recording / reproducing method according to claim 1, wherein the acquired position information is recorded in a correction value recording area where the correction value data of the spherical aberration can be recorded. Optical disc recording / reproducing method using a recording type optical disc having one recording layer or multiple recording layers on one side and having a test writing region and a correction value recording region for recording spherical aberration correction value data in a part of the recording layer In
A laser beam emitted from a light source is condensed on a track formed on the recording layer of the optical disc via an objective lens and irradiated, and a laser beam reflected by the recording layer of the optical disc is Position adjustment in the optical axis direction of the laser beam in the forward optical path of the optical system in which the return optical path led to the split-type photodetector through the objective lens is formed or in the optical path that simultaneously satisfies the forward optical path and the return optical path An optical element that corrects spherical aberration that can be
An optical disc recording / reproducing method, wherein the position of the optical element is adjusted based on spherical aberration correction value data of one or multiple recording layers read from the correction value recording area.

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