WO2010023901A1 - 光ディスク装置、前記光ディスク装置を用いた映像再生装置、サーバー及びカーナビゲーションシステム、集積回路、並びに記録再生方法 - Google Patents
光ディスク装置、前記光ディスク装置を用いた映像再生装置、サーバー及びカーナビゲーションシステム、集積回路、並びに記録再生方法 Download PDFInfo
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- WO2010023901A1 WO2010023901A1 PCT/JP2009/004133 JP2009004133W WO2010023901A1 WO 2010023901 A1 WO2010023901 A1 WO 2010023901A1 JP 2009004133 W JP2009004133 W JP 2009004133W WO 2010023901 A1 WO2010023901 A1 WO 2010023901A1
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- Prior art keywords
- recording layer
- coma aberration
- optical
- recording
- correction
- Prior art date
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1392—Means for controlling the beam wavefront, e.g. for correction of aberration
- G11B7/13925—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1365—Separate or integrated refractive elements, e.g. wave plates
- G11B7/1369—Active plates, e.g. liquid crystal panels or electrostrictive elements
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
- G11B2007/0009—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage
- G11B2007/0013—Recording, reproducing or erasing systems characterised by the structure or type of the carrier for carriers having data stored in three dimensions, e.g. volume storage for carriers having multiple discrete layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
- G11B7/08505—Methods for track change, selection or preliminary positioning by moving the head
- G11B7/08511—Methods for track change, selection or preliminary positioning by moving the head with focus pull-in only
Definitions
- the present invention relates to an optical disc apparatus and recording / reproducing method for recording or reproducing information on a multilayer optical recording medium, an integrated circuit used in the optical disc apparatus, and a video reproducing apparatus, server, and navigation system using the optical disc apparatus. It is about.
- DVDs digital versatile discs
- CDs compact discs
- NA numerical aperture
- a multilayer optical recording medium having a recording layer having a multilayer structure has become widespread.
- the reflectance may change greatly between the layers, and even when the recording layer is changed during reproduction of such an optical recording medium, stable tilt servo can be performed.
- An optical disc player that can be used is proposed in Patent Document 1.
- FIG. 19 is a schematic diagram showing a configuration of a conventional optical disc player.
- 171 is an optical disk
- 172 is an optical head
- 173 is a photodetector
- 174 is a liquid crystal element
- 175 is a motor
- 176 is an Rf amplitude intensity detector
- 177 is a reproduction processing unit
- 178 is a focus / tracking drive circuit
- Reference numeral 179 denotes a liquid crystal driving circuit
- 1700 denotes a focus servo unit
- 1701 denotes a tracking servo unit
- 1702 denotes a tilt servo unit
- 1703 denotes a microcomputer.
- the optical head 172 irradiates the optical disc 171 with laser light, receives the reflected light from the optical disc 171, and generates a signal corresponding to the amount of received light.
- the optical disk 171 is rotated by a motor 175.
- a liquid crystal element 174 for correcting aberration in the radial direction of the disk is disposed on the optical axis of the light beam.
- the output from the photodetector 173 is sent to the Rf amplitude intensity detector 176, the focus servo unit 1700, and the tracking servo unit 1701.
- the focus servo unit 1700 supplies a control signal to the focus / tracking drive circuit 178 so that the light beam emitted from the optical head 172 is condensed on a desired recording layer.
- the tracking servo section 1701 supplies a control signal to the focus / tracking drive circuit 178 so as to focus the light beam emitted from the optical head on a desired track on a desired recording layer.
- the focus / tracking drive circuit 178 drives the optical head 172 so that the light beam emitted from the optical head 172 is condensed on a desired track on a desired recording layer based on the control signal. To do.
- the Rf amplitude intensity detector 176 receives the Rf detection signal from the photodetector 173 and supplies the Rf amplitude signal to the tilt servo unit 1702.
- the tilt servo unit 1702 outputs a tilt drive signal to the liquid crystal drive circuit 179 using the Rf amplitude signal so that the intensity of the envelope is maximized, and the liquid crystal drive circuit 179 receives the liquid crystal element based on the control signal. 174 is driven. These controls are performed in accordance with instructions from the microcomputer 1703.
- the tilt servo unit 1702 holds and outputs the tilt drive value immediately before the jump. That is, the tilt servo unit 1702 keeps outputting a constant value during the jump without depending on the strength of the envelope during the jump. As a result, a situation in which the tilt control performance is deteriorated or the control is lost can be avoided, and a stable servo operation can be obtained.
- Patent Document 2 Patent Document 3, Patent Document 4, and Patent Document 5 it is possible to devise a pulse or offset signal to be given to a focus error signal in order to stably perform focus control at the time of interlayer jump as described above. It is disclosed.
- the interlayer jump of the multilayer optical recording medium having a higher density than that of the DVD becomes unstable.
- An optical head for recording / reproducing a Blu-ray disc which is an optical recording medium having a higher density than DVD.
- An optical head for recording / reproducing a Blu-ray disc has a light source with a wavelength of about 405 nm and an objective lens with a very large numerical aperture (about 0.85).
- FIG. 20 shows a configuration diagram of a multilayer optical recording medium having three recording layers.
- the three-layer optical disk 181 includes a base 182, a first recording layer 183, a first intermediate layer 184, a second recording layer 185, and a second intermediate layer in order from the optical head side 180. 186, the third recording layer 187, and the protective layer 188 on the back surface.
- the base 182 and the first and second intermediate layers 184 and 186 are made of a transparent medium such as resin.
- first intermediate layer 184 between the first recording layer 183 and the second recording layer 185
- second intermediate layer 184 between the second recording layer 185 and the third recording layer 187
- intermediate layer 186 the thickness from the surface of the optical disk 181 on the optical head side 180 to the second recording layer 185 is thicker than the thickness to the first recording layer 183 by the thickness of the intermediate layer 184, and the optical head side 180.
- the thickness from the surface of the optical disk 181 to the third recording layer 187 is thicker than the thickness to the second recording layer 185 by the thickness of the intermediate layer 186.
- the distance from the surface of the optical disk 181 on the optical head side 180 to each recording layer is referred to as the base material thickness in each recording layer.
- the condensing position of the minute spot is moved onto the second recording layer 185, or conversely, the second recording layer 185 is moved.
- the light condensing position is moved from the first to the first recording layer 183.
- the operation of moving the condensing position to different recording layers in this way is called “interlayer jump”. In the example shown in FIG. 20, there are three recording layers, so other combinations exist.
- each substrate thickness is 100 ⁇ m, 75 ⁇ m, and 50 ⁇ m in a multilayer optical disc having three recording layers
- coma aberration generated at each substrate thickness is 100 m ⁇ , 75 m ⁇ , and 50 m ⁇ , which are greatly different.
- the tilt drive value immediately before the interlayer jump is held, that is, the optimum coma aberration correction amount is maintained in the recording layer before the interlayer jump.
- the objective lens is moved so that the light is condensed at the recording layer position where the interlayer jump is to occur, the optimum coma aberration correction amount differs for each recording layer as described above. Aberration cannot be corrected.
- the focus error signal is deteriorated, the focus pull-in operation in the recording layer after the movement of the focal position becomes unstable, and stable interlayer jump cannot be performed.
- An object of the present invention is to provide an optical disc capable of performing stable interlayer jump in a multilayer optical recording medium in which coma aberration varies greatly depending on the substrate thickness of each recording layer even when the inclination of the multilayer optical recording medium is the same. Is to provide a device.
- An optical disc apparatus is an optical disc apparatus that records or reproduces information on a multilayer optical recording medium including a first recording layer and a second recording layer, and includes a light source and the light source.
- a condensing optical system including an objective lens that receives a light beam emitted from the multilayer optical recording medium and forms a minute spot on the multilayer optical recording medium; and a light beam reflected by the multilayer optical recording medium;
- An optical head having a coma aberration correcting unit that corrects coma aberration of the condensing optical system, and a control unit that controls the condensing optical system and the coma aberration correcting unit.
- the controller is configured to determine the second value from a value suitable for the first recording layer before the movement of the focal position of the micro spot from the first recording layer to the second recording layer is completed. Before the specified value for the recording layer To start the correction of the coma, it controls the said and the light converging optical system coma corrector.
- FIG. 1 It is a schematic diagram which shows an example about the optical disk apparatus by Embodiment 1 of this invention. It is a schematic diagram which shows an example about the optical head mounted in the optical disk apparatus shown in FIG. It is sectional drawing which shows an example of the coma aberration correction element shown in FIG. It is a figure which shows an example of the pattern of the radial transparent electrode of the coma aberration correction element shown in FIG. It is a figure which shows an example of the pattern of the tangential transparent electrode of the coma aberration correction element shown in FIG.
- FIG. 3 is a flowchart showing an example of a procedure of a focusing position moving operation, a spherical aberration correcting operation, and a coma aberration correcting operation during an interlayer jump operation of the optical disc apparatus shown in FIG. 2 is a timing chart showing an example of changes in various signals during an interlayer jump operation of the optical disc apparatus shown in FIG. 6 is a timing chart showing another example of changes in various signals during the interlayer jump operation of the optical disc apparatus shown in FIG. 1.
- 10 is a flowchart showing an example of a procedure of a movement of a condensing position, a spherical aberration correction operation, and a coma aberration correction operation during an interlayer jump operation of the optical disc device according to the second embodiment of the present invention.
- 10 is a timing chart showing an example of changes in various signals during an interlayer jump operation of the optical disc device according to the second embodiment of the present invention.
- 12 is a timing chart showing another example of changes in various signals during an interlayer jump operation of the optical disc device according to the second embodiment of the present invention.
- 12 is a timing chart showing another example of changes in various signals during an interlayer jump operation of the optical disc device according to the second embodiment of the present invention.
- 12 is a timing chart showing another example of changes in various signals during an interlayer jump operation of the optical disc device according to the second embodiment of the present invention.
- It is a schematic diagram which shows an example about the computer by Embodiment 3 of this invention. It is a schematic diagram which shows an example about the video recording / reproducing apparatus by Embodiment 4 of this invention.
- FIG. 1 is a configuration diagram of the optical disc apparatus according to the first embodiment
- FIG. 2 is a schematic diagram showing an example of an optical head mounted on the optical disc apparatus shown in FIG.
- the optical disk apparatus shown in FIG. 1 includes an optical head 1, a motor 2, and a processing circuit 3.
- the optical head 1 includes a light source 21, a light amount attenuating element 22, a polarizing beam splitter 23, a collimator lens 24, a mirror 25, a coma aberration correcting element 26, a quarter wavelength plate 27, an objective lens 28, 1
- a shaft actuator 30, a cylindrical lens 200, a photodetector 201, a condenser lens 202, and a light source light quantity control photodetector 203 are provided.
- the optical recording medium 29 is a multilayer optical recording medium having two or three or more recording layers.
- a Blu-ray disc having two recording layers can be used.
- a high-density optical recording medium having three layers or four layers or more configured in the same manner may be used.
- the light source 21 constitutes an example of a light source
- the light amount attenuating element 22, the polarization beam splitter 23, the mirror 25, the coma aberration correcting element 26, the quarter wavelength plate 27, and the objective lens 28 are the light source.
- the light collecting system includes an example of a condensing optical system including an objective lens that receives a light beam emitted from the optical recording medium 29 and forms a minute spot on the optical recording medium 29.
- the condensing optical system moves the objective lens 28 in the focus direction and tracking.
- Various actuators such as a focus actuator and a tracking actuator that are driven in the direction are included.
- the photodetector 201 is an example of a photodetector that receives the light beam reflected by the multilayer optical recording medium and outputs an electrical signal according to the amount of light.
- the coma aberration correcting element 26 constitutes an example of a coma aberration correcting unit that corrects coma aberration of the condensing optical system.
- the collimator lens 24 and the uniaxial actuator 30 (for example, a stepping motor) constitute an example of a spherical aberration correction unit that corrects the spherical aberration of the condensing optical system by changing the degree of light divergence in the condensing optical system. is doing.
- the processing circuit 3 includes a CPU (central processing unit), a memory (RAM, ROM), various detection circuits, various drive circuits, an A / D converter, a D / A converter, and the like, and a condensing optical system and coma aberration correction.
- the example of the control part which controls a part is comprised.
- the processing circuit 3 includes a part or all of an integrated circuit, and constitutes an example of a first control unit that controls the condensing optical system and a second control unit that controls the coma aberration correction unit. Yes.
- the processing circuit 3 may not only perform various controls described later, but also function as an Rf amplitude intensity detector, a reproduction processing unit, a focus control circuit, a tracking control circuit, and a tilt control circuit.
- the light source 21 is constituted by, for example, a GaN-based semiconductor laser element (wavelength 390 to 450 nm), and is a light source that outputs recording or reproduction coherent light to the recording layer of the optical recording medium 29.
- the wavelength of the light source 21 is, for example, 405 nm.
- the light amount attenuating element 22 is an optical element for reducing noise of the light source 21, and is movable in the direction of the arrow A1.
- the light amount attenuating element 22 includes a glass substrate, and a film (for example, a Cr film) that attenuates the light amount is formed on a part of the glass substrate.
- the polarization beam splitter 23 has, for example, 5% transmittance and 95% reflectance for a certain linearly polarized light, and 100% transmittance for a linearly polarized light orthogonal to the linearly polarized light.
- the collimator lens 24 is a lens that converts divergent light emitted from the light source 21 into parallel light.
- the collimator lens 24 and the uniaxial actuator 30 constitute a spherical aberration correction unit.
- the spherical aberration correction unit corrects spherical aberration that occurs when the substrate thickness of the optical recording medium 29 is different from the optimum substrate thickness.
- the spherical aberration can be corrected by changing the position of the collimator lens 24 by the uniaxial actuator 30.
- the mirror 25 is an optical element that reflects incident light and directs it in the direction of the optical recording medium 29, and has a characteristic of reflecting 100% of incident light.
- the coma aberration correcting element 26 is configured by using a liquid crystal element, and is an optical element capable of giving coma aberration to incident light.
- the quarter wave plate 27 is an optical element that is made of a birefringent material and converts linearly polarized light into circularly polarized light.
- the objective lens 28 is a lens that condenses light on the recording layer of the optical recording medium 29 and has a numerical aperture (NA) of 0.85.
- the numerical aperture (NA) of the objective lens 28 is not particularly limited to this example, and a value of 0.83 or more and 0.86 or less may be used. Further, since the coma and spherical aberration increase as the numerical aperture (NA) increases, the numerical aperture (NA) of the objective lens is 0.83 or more, more preferably 0.85 or more, and further preferably 0.86 or more. In this case, the present invention can be preferably used. Further, when a solid immersion lens (SIL) is used for the light condensing member, a higher numerical aperture, for example, an equivalent NA of the light condensing member can be made larger than 1, so a solid having such a high numerical aperture. When using the condensing member containing an immersion lens, this invention can be used more suitably.
- SIL solid immersion lens
- the cylindrical lens 200 has an incident surface that is a cylindrical surface and an output surface that is a rotationally symmetric surface with respect to the lens optical axis, so that a focus error signal can be detected for the incident light by a so-called astigmatism method. Astigmatism is given to achieve this.
- the photodetector 201 receives light reflected by the recording layer of the optical recording medium 29 and converts the light into an electrical signal.
- the condensing lens 202 condenses the light transmitted through the polarization beam splitter 23 onto the light source light quantity control photodetector 203.
- the light source light quantity control light detector 203 receives the light transmitted through the polarization beam splitter 23, converts the light into an electrical signal, and outputs a signal for detecting the light quantity of the light source 21.
- the processing circuit 3 When the optical recording medium 29 is set in the optical disc apparatus, the processing circuit 3 outputs a signal for rotating the motor 2 and rotates the motor 2. Next, the processing circuit 3 drives the light source 21 to emit light. The light emitted from the light source 21 is reflected by the optical recording medium 29 and enters the photodetector 201. The photodetector 201 outputs a focus error signal indicating the focused state of light on the optical recording medium 29 and a tracking error signal indicating the light irradiation position to the processing circuit 3.
- the processing circuit 3 Based on these signals, the processing circuit 3 outputs a signal for controlling the objective lens 28, thereby condensing the light emitted from the light source 21 onto a desired track on the optical recording medium 29. Further, the processing circuit 3 reproduces information recorded on the optical recording medium 29 based on a signal output from the photodetector 201. In addition, a signal output from the light source light quantity control photodetector 203 is input to the processing circuit 3, and the processing circuit 3 controls the light source 21 so that the signal becomes a desired value, thereby the objective lens 28. The amount of light emitted from is set to a desired value.
- the linearly polarized light emitted from the light source 21 is transmitted through the light amount attenuating element 22, most of it is reflected by the polarization beam splitter 23, and part of it is transmitted.
- the reflected light is incident on the collimator lens 24 and converted into one of divergent light, parallel light, and convergent light depending on the position of the collimator lens 24.
- the light whose degree of convergence has been converted is incident on the mirror 25 and reflected 100%, and the traveling direction is changed in the direction of the optical recording medium 29.
- the reflected light is transmitted through the coma aberration correcting element 26, and the coma aberration correcting element 26 gives coma aberration to the incident light so as to correct coma generated when the optical recording medium 29 is tilted.
- the light transmitted through the coma aberration correcting element 26 is incident on the quarter-wave plate 27 and linearly polarized light is converted into circularly polarized light, and this circularly polarized light is incident on the objective lens 28 and divergence of the incident light is performed.
- a spherical aberration is generated in accordance with the degree or the degree of convergence, and is condensed on the optical recording medium 29.
- the circularly polarized light reflected from the optical recording medium 29 passes through the objective lens 28, enters the quarter-wave plate 27, and becomes linearly polarized light in a direction orthogonal to the linearly polarized light emitted from the light source 21. Converted.
- the linearly polarized light converted by the quarter wavelength plate 27 passes through the coma aberration correcting element 26, and all the transmitted light is reflected by the mirror 25.
- the reflected light is transmitted through the collimator lens 24, is completely transmitted by the polarization beam splitter 23, and does not return to the light source 21.
- astigmatism is given to the light transmitted through the polarization beam splitter 23 by the cylindrical lens 200, and the light transmitted through the cylindrical lens 200 is collected on the photodetector 201.
- the photodetector 201 outputs a focus error signal indicating the focused state of light on the optical recording medium 29 to the processing circuit 3 and outputs a tracking error signal indicating the light irradiation position to the processing circuit 3.
- the focus error signal and the tracking error signal are detected by a known technique, for example, by an astigmatism method and a push-pull method.
- a focus control circuit (not shown) in the processing circuit 3 moves the position of the objective lens 28 in the optical axis direction so that light is always focused on the optical recording medium 29 in a focused state based on the focus error signal. Control.
- a tracking control circuit (not shown) in the processing circuit 3 controls the position of the objective lens 28 so that the light is condensed on a desired track on the optical recording medium 29 based on the tracking error signal. Further, information recorded on the optical recording medium 29 is also obtained from the photodetector 201.
- the light transmitted through the polarization beam splitter 23 is condensed on the light source light quantity control photodetector 203 by the condenser lens 202, and the light source light quantity control light detector 203 adjusts the light quantity of the light emitted from the light source 21. A corresponding electrical signal is output.
- the coma aberration correcting element 26 will be described in detail.
- the coma aberration correcting element 26 an optical element capable of correcting coma aberration perpendicular to the radial direction and the tangential direction can be used.
- the optical element disclosed in JP-A-11-110802 is used.
- the coma aberration correcting element 26 can be used.
- FIG. 3 is a cross-sectional view showing an example of the coma aberration correcting element 26
- FIGS. 4 and 5 are views showing an example of an electrode pattern used in the coma aberration correcting element 26.
- the coma aberration correcting element 26 includes a first substrate 31, a second substrate 32 disposed substantially parallel to the first substrate 31, and a first voltage disposed on the first substrate 31.
- the application electrode 33 and the first voltage application electrode 33 are formed so as to cover the second voltage application electrode 34 and the first voltage application electrode 33 arranged substantially parallel to the first voltage application electrode so as to face the first voltage application electrode 33.
- the translucent resin film 35, the translucent resin film 36 formed so as to cover the second voltage application electrode 34, and the translucent resin films 35 and 36 (the first voltage application electrode 33 and the second voltage application electrode 33).
- Liquid crystal 37 disposed between the voltage application electrode 34 and a sealing resin 38 disposed between the translucent resin films 35 and 36 so as to surround the liquid crystal 37.
- the first substrate 31 and the second substrate 32 are made of glass, for example, and are translucent.
- the first voltage application electrode 33 is an electrode for applying a desired voltage to the liquid crystal 37.
- the first voltage application electrode 33 is formed on the main surface on the inner side (the liquid crystal 37 side) of the first substrate 31.
- the second voltage application electrode 34 is an electrode for applying a desired voltage to the liquid crystal 37 and is synthesized using the first and second voltage application electrodes together with the first voltage application electrode 33.
- a desired voltage is applied to the liquid crystal 37.
- the second voltage application electrode 34 is formed on the main surface on the inner side (the liquid crystal 37 side) of the second substrate 32.
- the first and second voltage application electrodes 33 and 34 are translucent, and are made of, for example, ITO (Indium Tin Oxide), and a pattern is formed to give a desired voltage.
- the translucent resin films 35 and 36 are alignment films for aligning the liquid crystal 37 in a predetermined direction, and are made of, for example, a polyvinyl alcohol film. By rubbing the translucent resin film 35 or the translucent resin film 36, the liquid crystal 37 can be aligned in a predetermined direction.
- the liquid crystal 37 functions as a phase change layer that changes the phase of incident light.
- the liquid crystal 37 is made of, for example, nematic liquid crystal. By changing the voltage difference between the first voltage application electrode 33 and the second voltage application electrode 34, the refractive index of the liquid crystal 37 can be changed, thereby changing the phase of the incident light. be able to.
- the sealing resin 38 is for sealing the liquid crystal 37 and is made of, for example, an epoxy resin.
- One of the first and second voltage application electrodes 33 and 34 is composed of segment electrodes S1 to S3 as shown in FIG. 4, and the other is segment electrodes S4 to S6 as shown in FIG. It is configured. 4 and 5, the arrow TD indicates the tangential direction, the arrow RD indicates the radial direction, the pattern shown in FIG. 4 is the pattern of the radial transparent electrode, and the pattern shown in FIG. , Tangential transparent electrode pattern.
- a control voltage is applied from the outside to the segment electrodes S1 to S6 of the first and second voltage application electrodes 33 and 34 of the coma aberration correcting element 26, and the pattern shown in FIG. A phase corresponding to is given.
- FIGS. 4 and 5 it is possible to give the wavefront of coma aberration in the radial direction and the tangential direction to the incident light.
- this coma aberration deteriorates the recording / reproducing performance. Therefore, the coma aberration is generated by tilting the objective lens with respect to the optical axis, and the coma aberration of the optical element constituting the optical head using this coma aberration is reduced. By canceling, the optical head itself is adjusted so as not to have coma aberration.
- the greater the influence of the substrate thickness of each recording layer of the multilayer optical recording medium the greater the amount of coma aberration generated depending on the thickness of each substrate even if the inclination of the multilayer optical recording medium is the same.
- a coma aberration that corrects the coma aberration immediately before the interlayer jump is generated, in the recording layer after the interlayer jump, A large coma aberration occurs, which affects the focus error signal. Therefore, if the correction amount of the coma aberration immediately before the interlayer jump is maintained, a stable interlayer jump operation cannot be obtained.
- the optimal coma aberration correction amount for the recording layer before the interlayer jump is set to the recording layer after the interlayer jump before the interlayer jump.
- the objective lens 28 is moved after changing to the optimum coma aberration correction amount.
- the optimum coma aberration correction amount of each recording layer for example, the tilt amount of the optical recording medium 29 is learned before reproduction / recording, and the coma aberration correction amount necessary for the tilt amount is learned. Is stored in a memory or the like in the processing circuit 3, an optimal coma aberration correction amount can be obtained for each layer.
- step 51 when the processing circuit 3 issues an interlayer jump command (or not shown) while performing a recording or reproducing operation while performing focus control on the first recording layer of the optical recording medium 29 (not shown).
- step 51 When the processing circuit 3 receives an interlayer jump command from another circuit (step 51), the processing circuit 3 issues a spherical aberration correction signal, a coma aberration correction signal, and an interlayer jump signal substantially simultaneously (steps 52 and 53). , 54).
- FIG. 7 shows a timing chart showing an example of changes in various signals in the interlayer jump operation.
- the horizontal axis represents time
- the vertical axis represents various signal voltages.
- the spherical aberration correction signal is output, and the spherical aberration correction amount is changed from the spherical aberration correction amount S1 suitable for the first recording layer to the second recording.
- a voltage (spherical aberration correction signal) for changing the position of the collimator lens 24 is applied to the spherical aberration correction unit (single-axis actuator), and is predetermined.
- the spherical aberration correction signal is not applied.
- spherical aberration correction unit using a collimator lens of about f16
- spherical aberration correction of about 12 m ⁇ can be performed, so that the thickness of the substrate is increased from 100 ⁇ m to 75 ⁇ m.
- Change it is necessary to move the collimator lens by about 2 mm, and when the substrate thickness changes from 100 ⁇ m to 50 ⁇ m, it is necessary to move the collimator lens by about 4 mm.
- several hundred milliseconds are required when the screw feeding mechanism is used to move the collimator lens.
- the coma aberration generated in the recording layer having a substrate thickness of 100 ⁇ m, 75 ⁇ m, and 50 ⁇ m is 100 m ⁇ , 75 m ⁇ , and 50 m ⁇ , respectively, and the substrate thickness is increased from 100 ⁇ m to 75 ⁇ m.
- the coma changes by 25 m ⁇ .
- the substrate thickness changes from 100 ⁇ m to 50 ⁇ m
- the coma changes by 50 m ⁇ .
- the focus is changed almost simultaneously (for example, simultaneously or substantially simultaneously) with the start of the change of the correction amount of the spherical aberration and the change of the correction amount of the coma aberration.
- the change of the correction amount of the coma aberration and the change of the correction amount of the spherical aberration are completed as shown in FIG.
- the movement of the focal position to the second recording layer may be completed (for example, time T4 in FIG. 8), which causes an interlayer jump.
- the effect that time can be shortened can be acquired.
- the movement of the focal position of the minute spot and the correction of coma and / or spherical aberration may be completed almost simultaneously. In this case, the time for the interlayer jump can be shortened.
- the relationship with the number of recording layers of the multilayer optical recording medium will be described.
- the coma aberration changes by 25 m ⁇ when the substrate thickness is changed from 100 ⁇ m to 75 ⁇ m. .
- This 25 m ⁇ is large because it corresponds to 40% of the Marshall criteria (70 m ⁇ ), but it is possible to process within the margin of the optical head.
- the effect of the present invention is particularly effective when an interlayer jump is made from a recording layer corresponding to a substrate thickness of 100 ⁇ m to a recording layer corresponding to a substrate thickness of 50 ⁇ m, that is, when an interlayer jump is performed across one recording layer. become. That is, when an interlayer jump is made across the recording layers without changing the correction amount of the coma aberration, the amount of coma generated is smaller in the recording layer closer to the original recording layer (the substrate thickness of 100 ⁇ m).
- a coma aberration of 25 m ⁇ is generated in a recording layer having a substrate thickness of 75 ⁇ m
- a coma aberration of 50 m ⁇ is generated in a recording layer having a substrate thickness of 50 ⁇ m.
- the focus error signal of the recording layer is better than the focus error signal of the recording layer having a substrate thickness of 50 ⁇ m.
- the correction amount is obtained by learning the correction amount, and the difference between the acquired spherical aberration correction amounts for the respective recording layers is calculated as the change amount of the spherical aberration correction amount, that is, the spherical aberration correction amount suitable for the first recording layer and the first correction amount. It may be a difference from the spherical aberration correction amount suitable for the second recording layer.
- the standard intermediate layer thickness defined in the Blu-ray disc standard is:
- the amount of change in the correction amount of the spherical aberration is provisionally determined, and when the optical recording medium is inserted into the optical disc apparatus or when the optical disc apparatus is turned on, the processing circuit 3 performs focus control on each recording layer.
- the processing circuit 3 performs focus control on each recording layer.
- the provisionally determined spherical aberration correction amount The amount of change can be corrected.
- the processing circuit 3 learns the inclination of the optical recording medium when the optical recording medium is inserted into the optical disk apparatus or when the optical disk apparatus is turned on.
- the processing circuit 3 stores in advance an optimal coma aberration correction amount with respect to the tilt of the optical recording medium. In this way, the processing circuit 3 calls the stored coma aberration correction amount based on the learning value of the tilt of the optical recording medium and uses that value.
- the processing circuit 3 performs focus control on each recording layer so that an information signal is sent to each recording layer.
- the optimal correction amount of the coma aberration is learned and acquired, and the difference in the correction amount of the coma aberration with respect to each acquired recording layer is determined as the change amount of the correction amount of the coma aberration, that is, the coma suitable for the first recording layer
- the difference between the correction amount of aberration and the correction amount of coma aberration suitable for the second recording layer may be used.
- the optimal spherical aberration and coma aberration are recorded on the recording layer before the interlayer jump.
- FIG. 9 is a flowchart showing a procedure of the movement of the condensing position, the spherical aberration correction operation, and the coma aberration correction operation during the interlayer jump operation in the optical disc apparatus according to Embodiment 2 of the present invention.
- the processing circuit 3 issues an interlayer jump command (or from other circuits not shown in the drawing) while performing the recording or reproducing operation while performing the focus control on the first recording layer.
- the processing circuit 3 receives the jump command (step 81)
- the processing circuit 3 first issues a spherical aberration correction signal (step 82), and the processing circuit 3 determines the spherical aberration correction amount in the spherical aberration correction unit.
- the value suitable for the first recording layer is changed to a predetermined value considering the correction amount suitable for the second recording layer as the jump destination (step 83).
- the processing circuit 3 issues a coma aberration correction signal (step 84), and the processing circuit 3 sets the correction amount of the coma aberration in the coma aberration correction unit to a jump destination from a value suitable for the first recording layer.
- the value is changed to a predetermined value considering a correction amount suitable for the second recording layer (step 85).
- the processing circuit 3 issues an interlayer jump signal (step 86), and the processing circuit 3 controls the condensing optical system to move the focal position from the first recording layer to the second recording layer (step 87). ). Thereafter, the processing circuit 3 performs focus control on the second recording layer using the condensing optical system, and information is recorded or reproduced (step 88).
- the spherical aberration correction amount is first changed, and then the coma aberration correction amount is changed to perform focus control on the second recording layer.
- spherical aberration correction and coma aberration correction suitable for the second recording layer are almost completed.
- stable focus control can be performed on the second recording layer without being adversely affected by spherical aberration, and it is possible to prevent focus control from being lost due to an interlayer jump failure.
- FIG. 10 is a timing chart showing an example of changes in various signals in the above-described interlayer jump operation.
- the horizontal axis represents time
- the vertical axis represents various signal voltages.
- the spherical aberration correction signal changes, and the spherical aberration correction amount changes from the spherical aberration correction amount S1 suitable for the first recording layer to a predetermined correction amount.
- a voltage (spherical aberration correction signal) for changing the position of the collimator lens 24 is applied to the spherical aberration correction unit (uniaxial actuator) until the spherical aberration correction amount S2 suitable for the second recording layer is reached.
- the processing circuit 3 changes the coma aberration correction signal (step 84).
- the coma aberration correction unit (coma aberration correction unit) adjusts the coma aberration correction amount from the coma aberration correction amount C1 suitable for the first recording layer to the coma aberration correction amount C2 suitable for the second recording layer.
- a voltage (coma aberration correction signal) is applied to the correction element 26 and the coma aberration reaches a predetermined value, the coma aberration correction signal is maintained to maintain this.
- the interlayer jump signal is a kick for starting the movement of the objective lens in order to move the focus position to the second recording layer by escaping the focus control loop for the first recording layer which has been recorded or reproduced so far. It consists of a pulse KP and a brake pulse BP for ending the movement of the objective lens in order to shift to the focus control loop for the second recording layer.
- the interlayer jump is performed before the movement of the focal position of the micro spot from the first recording layer to the second recording layer is completed. Since the change of the spherical aberration correction amount and the change of the coma aberration correction amount are started before the completion time (for example, time T4 in FIG. 10) (for example, time T1 and T5 in FIG. 10), the second When the focus control is performed on the recording layer, spherical aberration correction and coma aberration correction suitable for the second recording layer are performed, and stable focus control can be performed. There is an effect that the focus control can be prevented from being lost.
- spherical aberration is performed before the time (for example, time T6 in FIG. 10) at which the movement of the focal position from the first recording layer to the second recording layer is started. Since the change of the correction amount and the change of the correction amount of the coma aberration are started (for example, times T1 and T5 in FIG. 10), the spherical aberration amount and the coma aberration amount when the focal position reaches the second recording layer are determined. Thus, it is possible to reduce more reliably, and it is possible to obtain an effect that stable focus control can be more reliably performed on the second recording layer.
- the interlayer is changed after the time when the change of the spherical aberration correction amount and the change of the coma aberration correction amount are completed (for example, times T2 and T3 in FIG. 10).
- a jump signal for example, time T6 in FIG. 10
- the timing for issuing the interlayer jump signal is not particularly limited to the above example, and the movement of the focal position of the minute spot may be started almost simultaneously with the completion of the correction of the spherical aberration and / or the coma aberration. In this case, since the spherical aberration and / or coma aberration in the recording layer after the movement of the focal position is in a good state, a stable interlayer jump can be performed and the interlayer jump can be performed earlier. it can.
- the change of the correction amount of the spherical aberration and the change of the correction amount of the coma aberration are completed (for example, the time in FIG. 11).
- T6 The movement of the focal position may be started by issuing an interlayer jump signal.
- the change of the correction amount of the spherical aberration and the change of the correction amount of the coma aberration are completed, stable focus control can be performed on the second recording layer.
- the required time can also be shortened.
- spherical aberration correction is first performed, then coma aberration correction is performed, and interlayer jump is finally performed.
- spherical aberration correction and coma aberration correction are completed. Therefore, the order of the coma aberration correction and the spherical aberration correction may be first, or may be performed simultaneously.
- the spherical surface When the time for changing the aberration to the predetermined correction amount is longer than the time for changing the coma aberration to the predetermined correction amount, as described in the present embodiment, the correction amount of the spherical aberration is changed first, and then It is preferable that the correction amount of the coma aberration is changed first, and the focus movement is finally performed.
- the time when the change of the correction amount of the spherical aberration and the correction amount of the coma aberration is completed for example, (Time T2, T3 in FIG. 12) (for example, time T4 in FIG. 12), the movement of the focal position to the second recording layer may be completed.
- the effect that it can shorten can be acquired.
- the spherical aberration correction and the coma aberration correction are completed before the start of the interlayer jump, if the corrected spherical aberration amount and / or coma aberration amount is large, the spherical aberration correction and Focus control and tracking control in the period from completion of coma aberration correction to before the start of interlayer jump may become unstable.
- a value smaller than the amount of spherical aberration and coma aberration that should be corrected is set as an intermediate correction amount, and after correcting with this intermediate correction amount, it is corrected to the amount of spherical aberration and coma aberration that should be corrected originally. May be.
- half the value of the spherical aberration that should be corrected is the intermediate correction amount S3 of spherical aberration
- the correction amount of spherical aberration is the spherical aberration suitable for the first recording layer.
- the first spherical aberration correction is performed by changing the correction amount S1 to the spherical aberration intermediate correction amount S3, and then the spherical aberration correction amount is changed from the spherical aberration intermediate correction amount S3 to the spherical surface suitable for the second recording layer.
- the second spherical aberration correction is performed by changing to the aberration correction amount S2, and similarly, the half value of the coma aberration amount to be originally corrected is set to the intermediate correction amount C3 of the coma aberration, and the correction amount of the coma aberration is set to
- the coma aberration correction amount C1 suitable for the first recording layer is changed from the coma aberration correction amount C3 to the first coma aberration correction amount C3, and then the coma aberration correction amount is changed to the coma aberration correction amount.
- the coma aberration correction amount C2 suitable for the second recording layer is changed from the amount C3. It may be performed a second spherical aberration correction.
- the spherical aberration correction amount is changed from the spherical aberration correction amount S1 suitable for the first recording layer to the spherical aberration intermediate correction amount S3.
- the coma aberration correction amount is changed from the coma aberration correction amount C1 suitable for the first recording layer to the coma aberration intermediate correction amount C3 (for example, FIG. 13).
- the first spherical aberration correction and the first coma aberration correction are completed (for example, time T7 in FIG. 13).
- an interlayer jump from the first recording layer to the second recording layer is started (for example, time T6 in FIG. 13), and after the interlayer jump is completed (for example, time T4 in FIG. 13), the correction amount of the spherical aberration Is changed from the spherical aberration intermediate correction amount S3 to the spherical aberration correction amount S2 suitable for the second recording layer, and the coma aberration correction amount is changed from the coma aberration intermediate correction amount C3 to the second recording layer.
- the remaining aberration amount is corrected instead of the correction amount C2 of the coma aberration, and the second spherical aberration correction and the second coma aberration correction are completed (for example, times T8 and T9 in FIG. 13).
- the focus control and tracking control before performing the interlayer jump and after performing the interlayer jump do not become unstable, and stable interlayer jump can be performed.
- the spherical aberration correction amount and the coma aberration correction amount are changed in two steps.
- the correction amount is not particularly limited to this example, and the step is performed in three or more steps using two or more intermediate correction amounts.
- Various modifications such as sequentially changing the correction amount of the spherical aberration and the correction amount of the coma aberration, or making the number of steps different between the spherical aberration and the coma aberration, are possible.
- the intermediate correction amount is not particularly limited to the above example, and the spherical aberration correction amount or coma aberration correction amount suitable for the first recording layer and the spherical aberration correction amount suitable for the second recording layer.
- the difference from the coma aberration correction amount may be divided into three or four or more, and each intermediate value may be used as two or three or more intermediate correction amounts.
- the difference between the correction amount of spherical aberration or the correction amount of coma aberration suitable for the first and second recording layers and each intermediate correction value is not particularly limited to a constant value by equal division, and the difference between the correction values is sequentially increased. Various changes such as increase or decrease, use of arbitrary values due to unequal division, and the like are possible.
- the recording after the jump from the optimum spherical aberration correction amount and coma aberration correction amount to the recording layer before the jump is performed.
- each aberration correction amount is in an optimal state for the recording layer after jumping until the focal point movement is completed, so the focus error signal is good
- stable interlayer jump can be performed.
- the spherical aberration correction unit uses a method in which the collimator lens 24 is moved in the optical axis direction.
- an optical system that changes the divergence and convergence of incident light using a concave lens or a convex lens.
- a system may be used.
- an optical element having a phase change layer for example, an optical element using liquid crystal may be used.
- an optical element having a phase change layer liquid crystal
- the objective lens and a driving unit an objective lens actuator with a tilt mechanism
- the time to correct the coma aberration becomes very fast, so even if the coma aberration correction unit is driven immediately before or simultaneously with the focus movement or after the focus movement starts, the focal position moves to the second recording layer. It is possible to complete the correction of coma before doing so.
- the servo stability in the recording layer before the focal point movement is improved and the time for the interlayer jump can be shortened, and the coma aberration correction is completed after the focal point movement, so that the stable interlayer jump can be performed. Can do.
- FIG. 14 schematically shows the configuration of the computer according to the third embodiment.
- the computer includes a computer main body including the optical disc device 121 according to the first embodiment, a keyboard 122 for inputting information, and a monitor 123 for displaying information.
- a computer equipped with the optical disk device of the first embodiment as an external storage device can stably record or reproduce information on a multi-layer optical recording medium, and can be used for a wide range of purposes.
- the optical disk device is compatible with taking advantage of its large capacity to back up a hard disk in a computer, the medium (optical disk) being inexpensive and easy to carry, and the information being readable by other optical disk devices. You can exchange programs and data with people or carry them for yourself. In addition, it can cope with reproduction / recording of existing media such as DVD and CD.
- FIG. 15 schematically shows a configuration of the optical disk recorder (video recording / reproducing apparatus) according to the fourth embodiment.
- the optical disk recorder 131 incorporates the optical disk device (not shown) of the first embodiment, and is used by being connected to a monitor 132 for displaying recorded video.
- the optical disk recorder 131 provided with the optical disk apparatus of the first embodiment described above can record or reproduce video on a multilayer optical recording medium stably and can be used for a wide range of purposes.
- the optical disc recorder 131 can record a video on a medium (optical disc) and reproduce it at any time. With optical discs, there is no need to rewind after recording or playback, as with tape, and follow-up playback that plays back the beginning of a program while recording a program, or a program that was previously recorded while recording a program. Simultaneous recording and playback can be performed. Taking advantage of the fact that the medium is inexpensive and easy to carry, and that other optical disc recorders can read information, the recorded video can be exchanged with people or carried for yourself. It also supports playback / recording of existing media such as DVDs and CDs.
- a hard disk may be incorporated or a video tape recording / playback function may be incorporated. In that case, the video can be temporarily saved and backed up easily.
- FIG. 16 schematically shows the configuration of the optical disk player (video playback apparatus) according to the fifth embodiment.
- An optical disk player 141 provided with a liquid crystal monitor 142 incorporates the optical disk device (not shown) of Embodiment 1, and can display images recorded on the optical disk on the liquid crystal monitor 142.
- the optical disc player 141 equipped with the optical disc apparatus of the first embodiment described above has an effect that it can stably reproduce images of different types of optical discs and can be used for a wide range of purposes.
- the optical disc player 141 can play back the video recorded on the medium (optical disc) at any time.
- the medium optical disc
- FIG. 17 schematically shows the configuration of the server according to the sixth embodiment.
- the server includes a server main body 151, the optical disk device 152 according to the first embodiment built in the server main body 151, a monitor 153 for displaying information, and a keyboard 154 for inputting information.
- a network 155 is connected.
- the server provided with the optical disk device 152 of the first embodiment as an external storage device can stably record or reproduce information on different types of optical disks and can be used for a wide range of purposes.
- the optical disk device utilizes the large capacity to send information (image, sound, video, HTML document, text document, etc.) recorded on the optical disk in response to a request from the network 155. It also records the information sent from the network at the requested location. Further, since information recorded on an existing medium such as a DVD or a CD can be reproduced, it is possible to send out the information.
- FIG. 18 schematically shows the configuration of the car navigation system according to the seventh embodiment.
- the car navigation system incorporates the optical disk device (not shown) of Embodiment 1 and is used by being connected to a liquid crystal monitor 161 for displaying topography and destination information.
- the car navigation system provided with the optical disk device of the first embodiment described above has an effect that video can be stably recorded or reproduced on different types of optical disks and can be used for a wide range of purposes.
- the car navigation system calculates the current position based on the map information recorded on the media (optical disk) and information on the ground position determination system (GPS), gyroscope, speedometer, odometer, etc. Display on the LCD monitor.
- GPS ground position determination system
- gyroscope gyroscope
- speedometer gyroscope
- odometer odometer
- a single disc can cover a wide area and provide detailed road information.
- information about restaurants, convenience stores, gas stations, and the like associated with the vicinity of the road can be stored and provided on the optical disc at the same time.
- road information becomes old with time and does not match reality, but since optical discs are compatible and the media is inexpensive, the latest information can be obtained by exchanging with discs containing new road information. Can be obtained.
- in order to support playback / recording of existing media such as DVDs and CDs it is also possible to watch movies and listen to music in a car.
- the optical recording medium for recording information only by light has been described. Needless to say, the same effect can be obtained for an optical recording medium for recording information by light and magnetism.
- the optical recording medium is an optical disk
- the present invention can be applied to an optical information recording / reproducing apparatus that realizes a similar function, such as a card-like optical recording medium.
- an optical disc apparatus is an optical disc apparatus that records or reproduces information on a multilayer optical recording medium having a first recording layer and a second recording layer, and includes a light source and the light source.
- a condensing optical system including an objective lens that receives a light beam emitted from the multilayer optical recording medium and forms a minute spot on the multilayer optical recording medium; and a light beam reflected by the multilayer optical recording medium;
- An optical head having a coma aberration correction unit that corrects coma aberration of the condensing optical system, and a control unit that controls the condensing optical system and the coma aberration correction unit.
- the controller is configured to determine the second value from a value suitable for the first recording layer before the movement of the focal position of the minute spot from the first recording layer to the second recording layer is completed.
- the multilayer optical recording medium includes at least the first recording layer and the second recording layer, and the movement of the focal position of the minute spot from the first recording layer to the second recording layer is completed. Since the coma aberration correction is started by changing the correction amount of the coma aberration from the value suitable for the first recording layer to the predetermined value defined for the second recording layer before, The coma aberration in the recording layer after the movement of the position becomes good, a good focus error signal can be obtained, and an optical disc apparatus capable of performing stable interlayer jump can be realized.
- control unit starts the movement of the focal position of the minute spot and the correction of the coma aberration almost simultaneously. In this case, the time for the interlayer jump can be shortened.
- the controller may start correcting the coma aberration before starting to move the focal position of the minute spot.
- the change of the coma aberration is started before the focal position is moved, the coma aberration in the recording layer after the movement of the focal position becomes good, and a good focus error signal can be obtained. And stable interlayer jumping can be performed.
- control unit starts moving the focal position of the minute spot after the correction of the coma aberration is completed.
- the control unit starts moving the focal position of the minute spot after the correction of the coma aberration is completed.
- the control unit may start moving the focal position of the minute spot almost simultaneously with completion of the correction of the coma aberration.
- a stable interlayer jump can be performed and the interlayer jump can be performed earlier.
- control unit completes the correction of the coma aberration during the movement of the focal position of the minute spot. In this case, the time for the interlayer jump can be shortened.
- control unit completes the movement of the focal position of the minute spot before the correction of the coma aberration is completed. In this case, the time for the interlayer jump can be further shortened.
- the control unit may complete the movement of the focal position of the minute spot and the correction of the coma aberration almost simultaneously. In this case, the time for the interlayer jump can be shortened.
- the change amount of the correction amount of the coma aberration is suitable for the first recording layer obtained by learning when the multilayer optical recording medium is inserted into the optical disc apparatus or when the optical disc apparatus is turned on.
- the coma aberration correction amount is preferably a difference between the coma aberration correction amount suitable for the second recording layer. In this case, since the coma aberration can be corrected with high accuracy, a stable interlayer jump can be performed.
- the multilayer optical recording medium has three or more recording layers, and the control unit moves the focal position of the minute spot across one or more recording layers.
- the control unit moves the focal position of the minute spot across one or more recording layers. In this case, stable interlayer jump can be performed even if the aberration changes greatly.
- the optical head further includes a spherical aberration correction unit that corrects spherical aberration of the condensing optical system by changing a degree of light divergence in the condensing optical system, and the control unit includes the spherical aberration correcting unit. It is preferable to control. In this case, since spherical aberration can be corrected with high accuracy, stable interlayer jump can be performed.
- control unit starts correction of the spherical aberration and correction of the coma aberration almost simultaneously. In this case, the time for the interlayer jump can be shortened.
- the control unit may start correction of the coma aberration after starting correction of the spherical aberration. In this case, the stability in the recording layer before the movement of the focal position can be maintained.
- the amount of change in the spherical aberration correction amount corresponds to the thickness of a standard intermediate layer between the first recording layer and the second recording layer. In this case, learning time is not required and the rise time of the apparatus can be shortened.
- a video playback apparatus includes any one of the above optical disk devices, and plays back video from the multilayer optical recording medium.
- This video reproduction apparatus can correspond to a multilayer optical recording medium.
- the car navigation system according to the present invention includes any one of the above optical disk devices as an external storage device.
- This car navigation system can correspond to a multilayer optical recording medium.
- the computer according to the present invention includes any one of the above optical disk devices as an external storage device.
- This computer can correspond to a multilayer optical recording medium.
- the above-described computer, video recording / reproducing apparatus, video reproducing apparatus, server, and car navigation system having good recording / reproducing performance with respect to a multilayer optical recording medium are realized. Is possible.
- An integrated circuit includes a light source, a condensing optical system including an objective lens that receives a light beam emitted from the light source and forms a minute spot on the multilayer optical recording medium, and the multilayer optical recording medium.
- the first recording is performed using an optical head that includes a photodetector that receives the reflected light beam and outputs an electrical signal according to the amount of light, and a coma aberration correction unit that corrects the coma aberration of the condensing optical system.
- An integrated circuit used in an optical disc apparatus for recording or reproducing information on a multilayer optical recording medium including a layer and a second recording layer, the first control unit controlling the condensing optical system; A second control unit that controls the coma aberration correction unit, wherein the first and second control units are focal positions of the minute spots from the first recording layer to the second recording layer. Suitable for the first recording layer before the movement of To start the correction of the coma aberration to a predetermined value defined for the second recording layer from the controls and the said focusing optical system coma corrector.
- the recording / reproducing method includes a light source, a condensing optical system including an objective lens that receives a light beam emitted from the light source and forms a minute spot on the multilayer optical recording medium, and the multilayer optical recording medium.
- a condensing optical system including an objective lens that receives a light beam emitted from the light source and forms a minute spot on the multilayer optical recording medium, and the multilayer optical recording medium.
- the optical head having the photodetector that receives the light beam reflected by the optical signal and outputs an electrical signal according to the amount of light and the coma aberration correcting unit that corrects the coma aberration of the condensing optical system.
- Suitable for the first recording layer before the first step of moving the focal position of the micro spot and the movement of the focal position of the minute spot from the first recording layer to the second recording layer are completed.
- the location specified for the second recording layer from the value And a second step of initiating the correction of the coma aberration to the value.
- the optical disc apparatus can realize good recording / reproducing performance for a multilayer optical recording medium, and can be applied to a computer, a video recording / reproducing apparatus, a video reproducing apparatus, a server, and a car navigation system.
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Abstract
Description
実施の形態1では、本発明の光ディスク装置の一例について説明する。
次に、本発明の第2の実施の形態に係る光ディスク装置の一例を、図面を参照して説明する。本実施の形態が上記した実施の形態1と異なるのは、層間ジャンプ動作のタイミングが異なることに関する点のみであり、それ以外は、実施の形態1と同様である。従って、本実施の形態において、特に説明のないものについては、実施の形態1と同じとし、実施の形態1と同一符号を付与している構成部材については、特に説明のない限り、図1及び図2に示す実施の形態1の構成部材と同様の機能を持つものとし、第2の実施の形態に係る光ディスク装置の構成については、新たに図示することなく、上記の図1及び図2を代用して説明するものとする。
実施の形態3では、実施の形態1の光ディスク装置を具備した、コンピュータの一例について説明する。
実施の形態4では、実施の形態1の光ディスク装置を具備した、光ディスクレコーダー(映像記録再生装置)の一例について説明する。
実施の形態5では、実施の形態1の光ディスク装置を具備した、光ディスクプレーヤー(映像再生装置)の一例について説明する。
実施の形態6では、実施の形態1の光ディスク装置を具備した、サーバーの一例について説明する。
実施の形態7では、実施の形態1の光ディスク装置を具備した、カーナビゲーションシステムの一例について説明する。
Claims (21)
- 第1の記録層と第2の記録層とを備えた多層光記録媒体に対して情報の記録又は再生を行う光ディスク装置であって、
光源と、前記光源から出射される光ビームを受け、前記多層光記録媒体上へ微小スポットを形成する対物レンズを含む集光光学系と、前記多層光記録媒体で反射した光ビームを受け、光量に応じて電気信号を出力する光検出器と、前記集光光学系のコマ収差を補正するコマ収差補正部と、を有する光ヘッドと、
前記集光光学系と前記コマ収差補正部とを制御する制御部とを備え、
前記制御部は、前記第1の記録層から前記第2の記録層への前記微小スポットの焦点位置の移動が完了する前に、前記第1の記録層に適した値から前記第2の記録層に対して規定された所定の値への前記コマ収差の補正を開始するように、前記集光光学系と前記コマ収差補正部とを制御することを特徴とする光ディスク装置。 - 前記制御部は、前記微小スポットの焦点位置の移動と、前記コマ収差の補正とをほぼ同時に開始することを特徴とする、請求項1に記載の光ディスク装置。
- 前記制御部は、前記微小スポットの焦点位置の移動を開始する前に、前記コマ収差の補正を開始することを特徴とする、請求項1に記載の光ディスク装置。
- 前記制御部は、前記コマ収差の補正が完了した後、前記微小スポットの焦点位置の移動を開始することを特徴とする、請求項3に記載の光ディスク装置。
- 前記制御部は、前記コマ収差の補正の完了とほぼ同時に、前記微小スポットの焦点位置の移動を開始することを特徴とする、請求項3に記載の光ディスク装置。
- 前記制御部は、前記微小スポットの焦点位置の移動途中に、前記コマ収差の補正を完了することを特徴とする、請求項1に記載の光ディスク装置。
- 前記制御部は、前記コマ収差の補正が完了する前に、前記微小スポットの焦点位置の移動を完了することを特徴とする、請求項1に記載の光ディスク装置。
- 前記制御部は、前記微小スポットの焦点位置の移動と、前記コマ収差の補正とをほぼ同時に完了することを特徴とする、請求項1に記載の光ディスク装置。
- 前記コマ収差の補正量の変更量は、前記光ディスク装置に前記多層光記録媒体を挿入した際、あるいは前記光ディスク装置の電源を入れた際に学習して得た、前記第1の記録層に適したコマ収差の補正量と、前記第2の記録層に適したコマ収差の補正量との差であることを特徴とする、請求項1~8のいずれか1項に記載の光ディスク装置。
- 前記多層光記録媒体は、記録層を3層以上有し、
前記制御部は、前記記録層を1つ以上跨いで前記微小スポットの焦点位置を移動させることを特徴とする、請求項1~9のいずれか1項に記載の光ディスク装置。 - 前記光源の波長は、405nm程度であり、
前記対物レンズの開口数は、0.85程度であることを特徴とする、請求項1~10のいずれか1項に記載の光ディスク装置。 - 前記光ヘッドは、前記集光光学系における光の発散度合いを変化させることによって前記集光光学系の球面収差を補正する球面収差補正部をさらに備え、
前記制御部は、前記球面収差補正部を制御することを特徴とする、請求項1~11のいずれか1項に記載の光ディスク装置。 - 前記制御部は、前記球面収差の補正と、前記コマ収差の補正とを、ほぼ同時に開始することを特徴とする、請求項12に記載の光ディスク装置。
- 前記制御部は、前記球面収差の補正を開始した後に、前記コマ収差の補正を開始することを特徴とする、請求項12に記載の光ディスク装置。
- 前記球面収差の補正量の変更量は、前記第1の記録層と前記第2の記録層との間の標準的な中間層の厚さに対応していることを特徴とする、請求項12~14のいずれか1項に記載の光ディスク装置。
- 前記球面収差の補正量の変更量は、前記光ディスク装置に前記多層光記録媒体を挿入した際、あるいは前記光ディスク装置の電源を入れた際に学習して得た、前記第1の記録層に適した球面収差の補正量と、前記第2の記録層に適した球面収差の補正量との差であることを特徴とする、請求項12~15のいずれか1項に記載の光ディスク装置。
- 請求項1~16記載のいずれか1項に記載の光ディスク装置を備え、前記多層光記録媒体から映像を再生することを特徴とする映像再生装置。
- 外部記憶装置として、請求項1~16記載のいずれか1項に記載の光ディスク装置を備えることを特徴とするサーバー。
- 外部記憶装置として、請求項1~16記載のいずれか1項に記載の光ディスク装置を備えることを特徴とするカーナビゲーションシステム。
- 光源と、前記光源から出射される光ビームを受け、前記多層光記録媒体上へ微小スポットを形成する対物レンズを含む集光光学系と、前記多層光記録媒体で反射した光ビームを受け、光量に応じて電気信号を出力する光検出器と、前記集光光学系のコマ収差を補正するコマ収差補正部と、を有する光ヘッドを用いて、第1の記録層と第2の記録層とを備えた多層光記録媒体に対して情報の記録又は再生を行う光ディスク装置に用いられる集積回路であって、
前記集光光学系を制御する第1の制御部と、
前記コマ収差補正部を制御する第2の制御部とを備え、
前記第1及び第2の制御部は、前記第1の記録層から前記第2の記録層への前記微小スポットの焦点位置の移動が完了する前に、前記第1の記録層に適した値から前記第2の記録層に対して規定された所定の値への前記コマ収差の補正を開始するように、前記集光光学系と前記コマ収差補正部とを制御することを特徴とする集積回路。 - 光源と、前記光源から出射される光ビームを受け、前記多層光記録媒体上へ微小スポットを形成する対物レンズを含む集光光学系と、前記多層光記録媒体で反射した光ビームを受け、光量に応じて電気信号を出力する光検出器と、前記集光光学系のコマ収差を補正するコマ収差補正部と、を有する光ヘッドを用いて、第1の記録層と第2の記録層とを備えた多層光記録媒体に対して情報の記録又は再生を行う記録再生方法であって、
前記第1の記録層から前記第2の記録層へ前記微小スポットの焦点位置を移動させる第1のステップと、
前記第1の記録層から前記第2の記録層への前記微小スポットの焦点位置の移動が完了する前に、前記第1の記録層に適した値から前記第2の記録層に対して規定された所定の値への前記コマ収差の補正を開始する第2のステップとを含むことを特徴とする記録再生方法。
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