JP4794409B2 - Optical disk device - Google Patents

Description

  The present invention uses an optical disc in which an image recording layer is provided on the label surface side which is the back surface of a signal surface on which a laser beam for reading a signal recorded on the signal recording layer is incident, and a laser is used for the image recording layer. The present invention relates to an optical disc apparatus configured to be able to form an image by irradiating light.

  2. Description of the Related Art Optical disk apparatuses that can perform signal reading operation and signal recording operation by irradiating a signal recording layer of an optical disk with laser light emitted from an optical pickup device have been widely used.

  Among optical disk devices using an optical disk called a CD, not only a data signal recorded but also a data signal recorded on the optical disk is widely used.

  When organizing optical discs recorded in this way, the contents of the data signals personally recorded on the optical discs are not understood, so the contents of the recorded data are recorded on the label surface provided on the back side of the optical disc with a sign pen or the like. Writing is done. However, such a method is not convenient because it is written by handwriting, and it is very inconvenient because it requires a writing instrument. Although a method of printing an image on a label surface with a printer is also employed, it is not practical because a special printer is required.

As a method for improving such a point, a technique has recently been developed in which an image recording layer is provided on the label surface, which is the back surface of an optical disc, and an image is formed by irradiating the image recording layer with laser light. Yes. Such a technique allows the optical disc to be placed on the turntable so that the front and back are reversed with respect to the state in which the signal recorded on the signal recording layer is reproduced, and the image formation drive is performed while the user-desired image is input. By changing the signal supplied to the laser diode by the action of the circuit and controlling the spot position of the laser beam, the image is formed on the image recording layer provided on the label surface of the optical disc. Yes. (See Patent Document 1.) (See Patent Document 2.)
JP-A-2005-93052 JP 2005-216468 A

  FIG. 4 shows a cross section of an optical disc D provided with an image recording layer capable of recording not only a signal recording layer but also an image with a laser beam, and a laser beam for reading a signal recorded on the signal recording layer. A transparent cover layer D2, a signal recording layer D3, a reflective layer D4, a protective layer D5, and an image recording layer D6 are provided from the signal surface D0 side where the light is incident toward the label surface D1 which is the back surface.

  In order to read a signal recorded on the signal recording layer D3 from the signal surface D0 side of the optical disc D or to record a signal on the signal recording layer D3, the reflection layer D4 performs signal recording on the incident laser light. Since it is provided on the label surface D1 side of the layer D3, it is configured so as not to have any influence on the image recording layer D6.

  In the optical disc D having such a configuration, the image recording operation on the image recording layer D6 is performed by irradiating the image recording layer D6 with laser light from the label surface D1 side. In order to perform such an operation, the optical disc D is placed on a turntable provided to rotate the optical disc D, but on the turntable for recording a signal on the signal recording layer D3, It will be placed upside down.

  FIG. 5A is a diagram showing the relationship between the objective lens L and the optical disc D during a read operation of a signal recorded in the signal recording layer D3 or a recording operation of recording a signal in the signal recording layer D3. FIG. 5B is a diagram showing the relationship between the objective lens L and the optical disc D during an image recording operation for recording an image on the image recording layer D6.

  As apparent from FIG. 5, since the position of the signal recording layer D3 with respect to the optical pickup device and the position of the image recording layer D6 with respect to the optical pickup device are largely different, in order to focus the laser beam on the desired recording layer, an objective lens is used. It is necessary to move the position of L to a position suitable for each operation.

  In the optical pickup device, the objective lens L is provided so as to be able to be displaced in the vertical direction with respect to the signal surface of the optical disk D and to be displaced in the radial direction of the optical disk D by four support wires. The operation of focusing the laser beam as a spot on the signal recording layer is generally called a focus control operation, and the focus error obtained from the photodetector by irradiating the photodetector with the laser beam reflected from the signal recording layer. Such a focus control operation is performed using a signal.

  In the optical pickup devices currently on the market, the optical system parts are designed to perform the read operation of the signal recorded in the signal recording layer D3 and the recording operation of the signal to the signal recording layer D3. In order to manufacture an optical pickup device suitable for recording an image on the image recording layer D6, it is necessary to change the arrangement of optical system parts or to provide a special photodetector, which increases the price. .

  The optical pickup devices currently on the market can respond by widening the movable range in the vertical direction with respect to the signal surface of the optical disk D of the objective lens L in order not to raise the price of the optical pickup device. I am letting.

  As a result, the photodetector and the like are designed with priority given to the reading operation of the signal recorded in the signal recording layer D3 and the recording operation of the signal to the signal recording layer D, so that the image recording layer D6 It is difficult to perform an operation for focusing the laser beam, that is, a focus control operation, and it is impossible to irradiate the surface of the optical disc D with a laser beam spot in a suitable state on the image recording layer D6. There is a problem.

  As a method for solving such a problem, there is a technique described in Patent Document 2, and an image recording operation to the image recording layer D6 is performed using such a technique, but the focus control operation is unstable. There is a demand for improvement in image recording characteristics.

  The present invention intends to provide an optical disk device using an optical pickup device that can solve such a problem.

The optical disk apparatus according to the present invention has a signal reproducing operation position for converging laser light emitted from a laser diode on a signal recording layer and an image recording operation position for converging laser light on an image recording layer of an optical disk placed opposite to the front and back. Aberration correction that incorporates a displaceably supported objective lens and a focus coil that drives the objective lens in a direction perpendicular to the signal surface of the optical disc and corrects spherical aberration that occurs during image recording operations The element is incorporated into the optical pickup device, and the objective lens is displaced away from the optical disk by a drive current supplied to the focus coil during the image recording operation, and the aberration correction element incorporated in the optical pickup device is moved to the image recording operation position. The objective lens is changed to the image recording operation position. It is configured to form an image on the image recording layer by spot obtained by correcting the spherical aberration by.

Further, the present invention, when changing the magnitude of the drive signal supplied to the focusing coil for driving the vertical direction the objective lens while rotating the optical disk to the signal surface of the optical disk, an image of the optical disk recording The relationship between the voltage value of the drive signal, which is the defocus amount of the objective lens, and the rotational position of the optical disk from the magnitude of the signal obtained from the photodetector provided at the position where the laser beam reflected from the layer is irradiated In other words, the magnitude of the drive signal supplied to the focus coil is set in accordance with the rotational position of the optical disk.

  The present invention is configured to obtain the relationship between the voltage value of the drive signal, which is the defocus amount of the objective lens, and the rotational position of the optical disk in a state where the spherical aberration is corrected by the aberration correction element.

  Furthermore, the present invention is configured to control the position of the objective lens by providing a defocus data memory circuit that stores the relationship between the voltage value of the drive signal, which is the defocus amount of the objective lens, and the rotational position of the optical disk. ing.

  Further, according to the present invention, when the aberration correction element is displaced in the optical axis direction of the laser beam and is displaced to a position where the level of the signal obtained from the photodetector is maximized, the aberration correction operation of the aberration correction element is performed at the position. It is configured to set as a position.

  The present invention is configured to perform an operation for obtaining the relationship between the voltage value of the drive signal, which is the defocus amount of the objective lens, and the rotational position of the optical disk at every predetermined angle.

  The present invention can be displaced to an image recording operation position for focusing laser light on an image recording layer of an optical disc placed opposite to the signal reproducing operation position for converging laser light emitted from a laser diode to a signal recording layer. An aberration correction element that corrects spherical aberration generated during an image recording operation is incorporated into an optical pickup device in which a supported objective lens is incorporated, and an image is recorded on the image recording layer at a spot that has been corrected for spherical aberration by the aberration correction element. Since recording is performed, the spot shape can be made suitable for image recording, and as a result, the image can be recorded and formed accurately on the image recording layer.

  In addition, since the spherical aberration that appears in the spot of the laser beam is corrected, it is possible to suppress the spread of the irradiation range of the laser beam reflected from the image recording layer of the optical disc and irradiated to the photodetector. The focus amount detection operation can be performed accurately.

  Therefore, according to the present invention, during the image recording operation on the image recording layer, the objective lens is displaced by following the surface vibration of the optical disc so that the spot size of the laser beam irradiated onto the image recording layer is constant. The focus control operation can be performed accurately, and as a result, the image can be recorded and formed accurately on the image recording layer.

  FIG. 1 is a diagram for explaining the operation of the optical disk device according to the present invention, FIG. 2 is a diagram showing the relationship between the laser beam and the photodetector in the optical pickup device according to the present invention, and FIG. 3 shows the operation of the present invention. It is a figure for demonstrating.

  In FIG. 1, 1 is a laser diode that emits laser light that is infrared light having a wavelength of 785 nm, 2 is a diffraction grating on which laser light emitted from the laser diode 1 is incident, and is a 0th order that is a main beam. The light and the sub beam are generated to generate + 1st order light and −1st order light.

  Reference numeral 3 denotes a collimator lens on which a laser beam, which is a divergent light transmitted through the diffraction grating 2, is incident. The collimator lens 3 changes the incident divergent light into parallel light. Denoted at 4 is a deflecting beam splitter into which a laser beam, which is a parallel beam emitted from the collimator lens 3, is incident. The deflecting beam splitter 4 transmits the laser beam incident from the collimator lens 3 side and is reflected from the optical disc D as described later. A reflective film 4a for reflecting the returning light returning in this way is formed.

  5 is provided in the optical path of the laser light transmitted through the reflecting film 4a of the polarizing beam splitter 4 and corrects spherical aberration by displacing in the optical axis direction of the laser light, that is, in the directions of arrows A and B in the figure. This is an aberration correction element having an action, and is composed of a lens in this embodiment. The aberration correction element 5 displaces between a signal reproduction operation position for reproducing a signal recorded on the signal recording layer D3 by an aberration correction coil 6 and an image recording operation position for recording an image on the image recording layer D6. In addition, it is configured to improve the quality of a spot generated by condensing laser light when in each operating position.

  Reference numeral 7 denotes a rising mirror which is provided at a position where the laser light transmitted through the aberration correction element 5 is incident and which reflects the incident laser light in the direction of the objective lens L, and 8 is reflected from the rising mirror 7. The quarter-wave plate on which the laser beam incident is incident has a function of polarizing the laser beam from linearly polarized light to circularly polarized light, and conversely from circularly polarized light to linearly polarized light.

  The laser light reflected by the rising mirror 7 and then polarized by the quarter-wave plate 8 is incident on the objective lens L and is recorded on the signal recording layer D3 or the image recording layer of the optical disc D by the objective lens L. It is configured to be focused as a spot on the layer D6.

  In such a configuration, the laser light emitted from the laser diode 1 is transmitted through the diffraction grating 2, the collimator lens 3, the polarization beam splitter 4, the aberration correction element 5, the rising mirror 7, and the quarter wavelength plate 8. After being incident on L, the signal recording layer D3 or the image recording layer D6 of the optical disc D is irradiated as a spot by the focusing operation of the objective lens L. The laser irradiated to the signal recording layer D3 or the image recording layer D6 Light is reflected from each recording layer as return light.

  The return light reflected from the signal recording layer D3 or the image recording layer D6 of the optical disk D passes through the objective lens L, the quarter wavelength plate 8, the rising mirror 6, and the aberration correction element 5, and the reflection film of the polarization beam splitter 4 4a. The return light incident on the reflection film 4a of the polarization beam splitter 4 in this way has its polarization direction changed by the polarization operation by reciprocating through the quarter-wave plate 8, so that the reflection film 4a passes through the reflection film 4a. It is not transmitted but reflected as control laser light Lc.

Reference numeral 9 denotes a sensor lens on which the control laser light Lc reflected by the reflective film 4a of the polarizing beam splitter 4 is incident, and the control laser light Lc is applied to a light receiving portion provided in a photodetector 10 called a PDIC. The light is condensed and irradiated. The photodetector 10 is provided with a known quadrant sensor or the like, and a signal generating operation and astigmatism accompanying a reading operation of a signal recorded on the signal recording layer of the optical disc D by the main beam irradiation operation. The signal generating operation for performing the focusing control operation by the method and the signal generating operation for performing the tracking control operation by the irradiation operation of the two sub beams are configured. Since such control operations for generating various signals are well known, the description thereof is omitted.

  As described above, the optical pickup device according to the present invention is configured. In this configuration, the objective lens L is perpendicular to the signal surface of the optical disc D by four support wires on the base of the optical pickup. It is fixed to a lens holding frame that is supported so as to be capable of displacement in the direction and displacement in the radial direction of the optical disc D. The configuration of the optical pickup device including such a support structure for the objective lens L is generally well known, and the description thereof is omitted.

  Reference numeral 11 denotes a focus coil provided on a lens holding frame on which the objective lens L is fixed. The focus coil 11 is perpendicular to the signal surface of the optical disc D in cooperation with a magnet fixed to the base. It has the effect of displacing in the direction. Reference numeral 12 denotes a tracking coil provided on a lens holding frame to which the objective lens L is fixed. The tracking coil 12 has a function of displacing the objective lens L in the radial direction of the optical disc D in cooperation with a magnet fixed to the base. have.

  The configuration of the optical pickup apparatus in which the focus coil 11 and the tracking coil 12 described above are incorporated and the focusing control operation and tracking control operation by the driving operation of each coil are well known, and the description thereof is omitted.

  Reference numeral 13 denotes a sensor that receives the main beam constituting the photodetector 10, for example, a four-divided sensor 100 as shown in FIG. 2 corresponding to a signal reading operation recorded on the signal recording layer D 3 of the optical disc D. An RF signal generation circuit that generates an RF signal that is a received signal, and 14 is a focus error signal generation circuit that generates a focus error signal that is a signal obtained in accordance with a laser beam focusing operation from the quadrant sensor 100 that receives the main beam. , 15 is a tracking error signal generating circuit for generating a tracking error signal which is a signal obtained from a sensor (not shown) for receiving the sub beam in accordance with the tracking operation of the laser beam.

  A control circuit 16 performs various control operations of the optical pickup device based on signals obtained from the RF signal generation circuit 13, the focus error signal generation circuit 14, the tracking error signal generation circuit 15, and the like. Reference numeral 17 denotes a focus coil drive circuit to which a focus control signal output from the control circuit 16 is input based on a focus error signal generated and input from the focus error signal generation circuit 14. It is configured to provide a signal. Reference numeral 18 denotes a tracking coil drive circuit to which a tracking control signal output from the control circuit 16 is input based on a tracking error signal generated and input from the tracking error signal generation circuit 15. It is configured to provide a signal.

  Reference numeral 19 denotes an objective lens drive voltage detection circuit that detects a DC voltage value included in a drive signal supplied from the focus coil drive circuit 17 to the focus coil 11, and outputs the detected DC voltage value to the control circuit 16. Is configured to do. Reference numeral 20 denotes a disk rotation angle detection circuit for detecting the rotation angle of the optical disk D. For example, a pulse generator that generates a pulse signal corresponding to the rotation of a spindle motor (not shown) provided to rotate the optical disk D A rotation angle can be detected by providing means and counting the number of pulses generated from the pulse generation means.

As the pulse generation means described above, for example, a reflecting plate having a reflecting surface and a non-reflecting surface formed at a predetermined angle interval is provided on the lower surface of the turntable, and the reflecting plate is irradiated with light emitted from the light emitting diode. It can be easily configured by providing a light receiving element such as a photodiode at a position for receiving light reflected from the reflecting plate. Such a configuration is well known in many technical fields and will not be described.

  Defocus data 21 recognizes the DC voltage value detected by the objective lens drive voltage detection circuit 19 as defocus data that is a focus shift, and stores it in correspondence with the angle obtained from the disk rotation angle detection circuit 20. It is a memory circuit.

  Reference numeral 22 denotes an aberration correction coil drive circuit for supplying a drive signal to the aberration correction coil 6 for displacing the aberration correction element 5 to a signal reproduction operation position and an image recording operation position, and the signal is controlled by a control operation of the control circuit 16. When performing the reproducing operation of the signal recorded in the recording layer D3 or the operation of recording the signal in the signal recording layer D3, the aberration correction element 5 is displaced to the signal reproducing operation position and the image is recorded on the image recording layer D6. When performing the recording operation, the aberration correction element 5 is displaced to the image recording operation position.

  In such a configuration, the aberration correction element 5 performs a reproducing operation of a signal recorded in the signal recording layer D3 or an operation of recording a signal in the signal recording layer D3, that is, a normal signal recording / reproducing operation. In this state, the drive signal is not supplied to the aberration correction coil 6 when in the signal reproduction operation position. That is, when a special operation of recording an image on the image recording layer D6 is performed, a drive signal is supplied from the aberration correction coil drive circuit 22 to the aberration correction coil 6 so that the aberration correction element 5 has a spherical aberration. It is configured to be displaced to the image recording operation position where the correction operation is performed.

  As described above, the embodiment according to the present invention is configured. Next, the operation will be described.

  First, an operation when reproducing a signal recorded on the signal recording layer D3 provided on the optical disc D will be described. When such an operation is performed, the optical disk D is placed on the turntable so that the signal surface D0 side on which the laser light is incident is opposed to the objective lens L. Such a state is shown in FIG. As shown in

  In such a state, the aberration correction element 5 incorporated in the optical pickup device is in the signal reproducing operation position. In this state, when a driving current for performing a reproducing operation is supplied to the laser diode 1, laser light is emitted from the laser diode 1. The laser light emitted from the laser diode 1 is incident on the diffraction grating 2 to generate one main beam M and two sub beams. The laser beam composed of the three beams generated from the diffraction grating 2 is incident on the collimator lens 3 and changed into parallel light.

  The laser light changed into parallel light by the collimator lens 3 is incident on the polarization beam splitter 4, but is not reflected by the reflection film 4a but is transmitted as it is. The laser beam that has passed through the reflection film 4a passes through the aberration correction element 5 at the signal reproduction operation position, and then enters the rising mirror 7, and is reflected by the rising mirror 7 in the direction of the objective lens L.

  The laser beam reflected by the rising mirror 7 is incident on the quarter-wave plate 8, converted from linearly polarized light into circularly-polarized light by the quarter-wave plate 8 and incident on the objective lens L. The laser light incident on the objective lens L is condensed as a spot on the signal recording layer D3 by the focusing operation of the objective lens L.

The laser light applied to the signal recording layer D3 is reflected as return light from the signal recording layer D3 and enters the objective lens L. The return light incident on the objective lens L is incident on the reflection film 4 a of the polarization beam splitter 4 through the rising mirror 7 and the aberration correction element 5 after being incident on the quarter-wave plate 8. Since the return light in this case is converted from circularly polarized light into linearly polarized light by the quarter wavelength plate 8, it is reflected as control laser light Lc by the reflective film 4a.

  The control laser light Lc reflected by the reflective film 4a is collected by the sensor lens 9 and applied to the sensor unit provided in the photodetector 10. The control laser beam Lc irradiated to such a sensor unit is composed of a main beam M and a sub beam. The main beam M is irradiated to the four-divided sensor 100 shown in FIG. Irradiation is performed on two sensor units (not shown) provided at the front and rear.

  A focus error signal is generated by the focus error signal generation circuit 14 based on astigmatism generated from the main beam M irradiated on the quadrant sensor 100. Further, a tracking error signal is generated from the tracking error signal generation circuit 15 based on differential signals obtained from two sensor units on which two sub beams are incident.

  Since the focus error signal generated from the focus error signal generation circuit 14 based on the signal obtained from the photodetector 10 and the tracking error signal generated from the tracking error signal generation circuit 15 are input to the control circuit 16, A focus control signal output from the control circuit 16 is supplied to the focus coil drive circuit 17 and a tracking control signal is supplied to the tracking coil drive circuit 18.

  As a result, the displacement operation of the objective lens L in the signal plane direction of the optical disk D based on the drive signal supplied from the focus coil drive circuit 17 to the focus coil 11, that is, the focus control operation and the tracking coil drive circuit 18 to the tracking coil Accordingly, a displacement operation of the objective lens L in the radial direction of the optical disk D based on the drive signal supplied to 12, that is, a tracking control operation is performed.

  By performing the focus control operation and the tracking control operation described above, the spot of the laser beam can be made to follow the signal track provided in the signal recording layer D3. When such an operation is performed, a signal corresponding to the data signal recorded in the signal recording layer D3 is generated as an RF signal from the RF signal generation circuit 13 and input to the control circuit 16. By demodulating the input signal by the demodulation circuit incorporated in the control circuit 16 in this way, the data signal recorded on the optical disc D can be reproduced.

  As described above, the reproduction operation of the signal recorded on the signal recording layer D3 of the optical disk D is performed. However, since the normal operation of the objective lens L is in the normal use position, the spherical aberration is generated. It can be suppressed. Also, when performing an operation of recording a signal in the signal recording layer D3, each control operation in the optical pickup device can be similarly performed.

  As described above, the normal operation using the signal recording layer D3 is performed. Next, the image recording operation to the image recording layer D6 which is the gist of the present invention will be described. The operation of the signal processing system for recording the image data on the image recording layer D6 is omitted.

  When performing an operation of recording an image on the image recording layer 6 of the optical disc D, the optical disc D is such that the label surface D1 side, which is the surface opposite to the signal surface D0 on which the laser light is incident, faces the objective lens L. It is placed on the turntable, and such a state is as shown in FIG.

  In such a state, a drive current is supplied to the laser diode 1, and the drive current is set so that the laser output is at a level that does not change the color of the image recording layer D6. When such a drive signal is supplied to the laser diode 1, laser light is emitted from the laser diode 1, and the laser light is incident on the objective lens L through the optical path described above.

  During such an image recording operation, the objective lens L is largely displaced in the direction away from the optical disk D by the drive current supplied from the focus coil drive circuit 17 to the focus coil 11, and the aberration correction coil drive circuit 22 performs aberration correction. The aberration correction element 5 is displaced to the image recording operation position by the drive current supplied to the coil 6.

  Here, the setting operation of the image recording operation position at which the aberration correction element 5 is displaced will be described. The return light reflected from the image recording layer D6 of the optical disc D is applied to the sensor provided in the photodetector 10 as described above, but the signal obtained by irradiating the quadrant sensor 100 with the main beam M. The image recording operation position can be set from the size of.

  That is, as the spherical aberration generated in the main beam M increases, the primary ring component of the spot generated in the image recording layer D6 becomes stronger and the main spot component becomes weaker. Then, there is a characteristic that the level of the signal obtained from the quadrant sensor 100 becomes smaller as the spot shape changes due to the spherical aberration described above.

  A signal corresponding to the level of the signal obtained from the quadrant sensor 100 can be obtained from the RF signal generation circuit 13 provided to generate the RF signal based on the signal obtained from the quadrant sensor 100. By detecting the signal by the control circuit 16, the level of the signal obtained from the quadrant sensor 100 can be recognized.

  Accordingly, the level of the signal obtained from the quadrant sensor 100 is detected while changing the level of the drive signal supplied from the aberration correction coil drive circuit 22 to the aberration correction coil 6 in a stepwise manner, for example. What is necessary is just to perform the operation | movement which moves the aberration correction element 5 to the position where a level becomes the maximum. That is, the position of the aberration correction element 5 set in this way is a position where the spherical aberration can be minimized, and this position is the optimum position for the image recording operation.

  As described above, the setting operation of the image recording operation position of the aberration correction element 5 is performed. However, if a favorable spot cannot be obtained even if the spherical aberration is corrected by the above-described operation, the method described below is used. .

  In a state in which the above-described aberration correction element 5 is set to the image recording operation position, the drive voltage supplied from the focus coil drive circuit 17 to the focus coil 11 is in a predetermined range in the + -direction centered on the reference voltage. An operation that changes the voltage is performed. This reference voltage is a DC voltage supplied to the focus coil 11 in order to displace the objective lens L to the position shown in FIG. 5B, that is, the position where the objective lens L is subjected to an image recording operation.

  When a drive signal whose voltage is changed in such a predetermined range is supplied to the focus coil 11, the objective lens L is displaced in the vertical direction with respect to the surface direction of the optical disc D. When the objective lens L is displaced in this way, the main beam M irradiated to the quadrant sensor 100 provided in the photodetector 10 is changed from (A) to (B) and (C) in FIG. To change.

As can be seen from FIGS. 2A, 2B and 2C, the irradiation area of the main beam M changes as the objective lens L is displaced. The smaller the irradiation area, the more the signal obtained from the quadrant sensor 100 is. The level increases. When the level of the signal obtained from the four-divided sensor 100 is maximized, the spot diameter of the laser beam condensed by the objective lens L and formed on the image recording layer D6 is minimum, that is, the focus is best. It can be determined that it is in the state.

  As described above, by changing the voltage of the drive signal supplied from the focus coil drive circuit 17 to the focus coil 11, the position of the objective lens L can be displaced to a position where the focus is in the best state. When the objective lens L is displaced to the position, the objective lens drive voltage detection circuit 19 detects the drive voltage supplied to the focus coil 11.

  The value of the drive voltage obtained in this way is stored as defocus data in the defocus data memory circuit 21 by the control operation by the control circuit 16, and such storage operation is performed in accordance with the rotation angle of the optical disc D. It is configured to be

  That is, when the optical disk D is rotated, the rotation angle of the optical disk can be recognized by the angle detection operation by the disk rotation angle detection circuit 20 as described above. Since the rotation angle of the optical disk D can be recognized in this manner, the position of the objective lens L from the focus coil drive circuit 17 to the focus coil 11 described above becomes the best focus position every time the rotation angle of the optical disk D is changed. The driving voltage supplied in this manner is detected by the objective lens driving voltage detection circuit 19, and the defocus data that is the voltage value is stored in the defocus data memory circuit 21 in association with the rotational position of the optical disk D.

  FIG. 3 shows the relationship between the rotation angle of the optical disc D and the defocus amount detected at that position, and the defocus amount changes according to surface blurring that occurs during one rotation of the optical disc D. I understand that.

  Since the defocus data at each position is stored in the defocus data memory circuit 21 in accordance with the rotation angle of the optical disc D by the above-described operation, focus control when performing an operation for recording an image on the image recording layer D6. The operation can be performed using data stored in the defocus data memory circuit 21. That is, data stored in the defocus data memory circuit 21 is read according to the rotational position of the optical disc D, and a drive signal having a voltage value set based on the data is supplied from the focus drive circuit 17 to the focus coil 11. By doing so, it is possible to perform a focus control operation of focusing the laser beam on the image recording layer D6.

  Since such a control operation is performed, image data obtained from a personal computer or the like can be recorded on the image recording layer D6 by controlling the laser output and controlling the displacement operation in the radial direction of the optical pickup device. .

  In this embodiment, the CD standard optical disk using laser light which is 785 nm infrared light is used. However, the present invention can of course be applied to an optical disk of another standard, for example, a DVD standard. .

  In this embodiment, the case where a lens is used as the aberration correction element 5 has been described. However, it is also possible to use a liquid crystal element or the like to correct spherical aberration.

It is a figure for demonstrating operation | movement of the optical disk apparatus based on this invention. It is a figure which shows the relationship between the laser beam and the photodetector in the optical pick-up apparatus which concerns on this invention. It is a figure for demonstrating operation | movement of this invention. It is sectional drawing of the optical disk which concerns on this invention. It is a figure which shows the relationship between an objective lens and an optical disk.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser diode 2 Diffraction grating 4 Polarization beam splitter 5 Aberration correction element 6 Aberration correction coil 8 1/4 wavelength plate 10 Photo detector 11 Focus coil 14 Focus error signal generation circuit 16 Control circuit 17 Focus coil drive circuit 19 Objective lens drive Voltage detection circuit 20 Disk rotation angle detection circuit 21 Defocus data memory circuit 22 Aberration correction coil drive circuit D Optical disk L Objective lens

Claims (6)

An optical disk having an image recording layer provided on a label surface opposite to a signal surface on which a laser beam for reading a signal recorded on the signal recording layer is incident is used, and laser light is applied to the image recording layer. An optical disc apparatus configured to be able to form an image by irradiating an optical disc mounted on the opposite side of a signal reproducing operation position for focusing laser light emitted from a laser diode on a signal recording layer. An objective lens supported so as to be displaceable at an image recording operation position for focusing the laser beam on the image recording layer and a focus coil for driving the objective lens in a direction perpendicular to the signal surface of the optical disc are incorporated. and incorporate the aberration correcting element for correcting a spherical aberration generated when the image recording operation in the optical pickup device, Together be displaced in a direction away said objective lens from the optical disc by the drive current supplied to the focus coil during the image recording operation, an aberration correction element that is built into the optical pickup device is displaced in the image recording operation position, the objective lens An optical disc apparatus characterized in that an image is formed on the image recording layer at a spot whose spherical aberration has been corrected by displacing it to an image recording operation position . When varying the magnitude of the drive signal supplied to the focusing coil while rotating the optical disc, a photodetector laser light reflected from the image recording layer of the optical disc is provided in a position to be irradiated The relationship between the voltage value of the drive signal, which is the defocus amount of the objective lens, and the rotational position of the optical disc is obtained from the magnitude of the signal obtained from the above, and the magnitude of the drive signal supplied to the focus coil according to the rotational position of the optical disc 2. The optical disk apparatus according to claim 1, wherein: is set. The relationship between the voltage value of the drive signal, which is the defocus amount of the objective lens, and the rotational position of the optical disk in a state where the spherical aberration is corrected by the aberration correction element, is obtained. Optical disk device. 3. The optical disc apparatus according to claim 2, further comprising a defocus data memory circuit for storing a relationship between a voltage value of a drive signal that is a defocus amount of the objective lens and a rotational position of the optical disc. When the aberration correction element is displaced in the optical axis direction of the laser beam and is displaced to a position where the level of the signal obtained from the photodetector is maximized, the position is set as an aberration correction operation position of the aberration correction element. The optical disk apparatus according to claim 1 , wherein 3. The optical disc apparatus according to claim 2, wherein an operation for obtaining a relationship between a voltage value of a drive signal, which is a defocus amount of the objective lens, and a rotational position of the optical disc is performed at every predetermined angle.

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