WO2005106865A1 - 収差補正装置、収差補正方法、光ピックアップ - Google Patents
収差補正装置、収差補正方法、光ピックアップ Download PDFInfo
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- WO2005106865A1 WO2005106865A1 PCT/JP2005/007218 JP2005007218W WO2005106865A1 WO 2005106865 A1 WO2005106865 A1 WO 2005106865A1 JP 2005007218 W JP2005007218 W JP 2005007218W WO 2005106865 A1 WO2005106865 A1 WO 2005106865A1
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- aberration
- correction
- transparent electrodes
- divided
- divided region
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/061—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on electro-optical organic material
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1343—Electrodes
- G02F1/134309—Electrodes characterised by their geometrical arrangement
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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
-
- 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
- G11B7/13927—Means for controlling the beam wavefront, e.g. for correction of aberration active, e.g. controlled by electrical or mechanical means during transducing, e.g. to correct for variation of the spherical aberration due to disc tilt or irregularities in the cover layer thickness
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/18—Function characteristic adaptive optics, e.g. wavefront correction
-
- 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
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0948—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for detection and avoidance or compensation of imperfections on the carrier, e.g. dust, scratches, dropouts
-
- 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
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/095—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble
- G11B7/0956—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc
Definitions
- the present invention relates to an aberration correction device, an aberration correction method, and an optical pickup.
- an aberration correction device using a liquid crystal panel As a device for dynamically performing aberration correction of an imaging optical system, an aberration correction device using a liquid crystal panel is known.
- a transparent electrode of a liquid crystal panel is formed by a divided region having a pattern capable of correcting aberration, and a phase difference for each divided region is given to a light beam passing through the liquid crystal panel by an electro-optic effect of the liquid crystal panel.
- aberration correction is performed.
- Such an aberration correction apparatus focuses a light beam emitted from a light source on a recording surface of an optical information recording medium, and forms an image of reflected light from the recording surface on a detection surface of a detector. It is applied to an up-forming optical system.
- this imaging optical system coma aberration caused by tilting of the optical information recording medium, spherical aberration caused by thickness error of the optical information recording medium, etc., and astigmatism caused by distortion of optical pickup optical components, etc., occur.
- These aberrations have a great effect on the recording / reproducing performance, and these three types of aberrations are to be corrected by the above-described aberration corrector.
- the wavefront aberration distribution of each aberration on the pupil plane of the objective lens is obtained, and the image is formed according to the wavefront aberration distribution.
- An electrode pattern composed of divided areas is formed on the transparent electrode of the liquid crystal panel inserted into the optical system.
- a pair of optical pickups provided with a laser light source, an objective lens, and a liquid crystal panel provided on the optical axis of a laser beam and provided with aberration correction means.
- One transparent electrode of a liquid crystal panel consisting of transparent electrodes is the first electrode divided into a shape corresponding to the wavefront aberration distribution of coma aberration on the pupil plane of the objective lens, and the other transparent electrode is corrected for spherical aberration It is described that the second electrode is divided into a pattern shape having an aperture function.
- Patent Document 1 discloses one transparent electrode in a liquid crystal panel serving as aberration correction means. It describes that a pole is divided into a pattern shape corresponding to a wavefront aberration distribution of coma aberration on a pupil plane of an objective lens and a pattern shape for correcting spherical aberration.
- Patent Document 2 describes an aberration correction apparatus using a similar liquid crystal panel, and divides a light beam passage area in the liquid crystal panel into a plurality of regions in accordance with the distribution of astigmatism.
- a voltage corresponding to the direction of astigmatism to be corrected is applied to the electrodes provided in each of the divided regions, and the astigmatism is corrected for the light beam passing through each of the divided regions according to the change in the voltage. It is described that a phase difference is provided.
- Patent Document 1 JP-A-10-289465
- Patent Document 2 JP 2000-40249 A
- each of a pair of transparent electrodes of the liquid crystal panel is If a divided region of the electrode pattern that corrects different aberrations is formed, two types of aberrations cannot be corrected.
- Patent Document 1 when one transparent electrode in a liquid crystal panel including a pair of transparent electrodes is divided so as to correspond to two types of aberration correction, two types of transparent electrodes are not necessarily used. It is not possible to form an appropriate divided region for both aberrations.
- a circular division area having a diaphragm function for correcting spherical aberration is divided into three parts in a direction perpendicular to an inclination estimation direction of an optical information recording medium, and divided into parts for coma aberration correction. According to this, when a circular divided region having a diaphragm function is sized to be suitable for spherical aberration correction, coma aberration correction is performed.
- a finely divided electrode pattern is formed on at least one of the transparent electrode sides. It is also conceivable to form divided regions necessary for correcting a plurality of aberrations by combining fine electrode patterns. However, this leads to a problem that the electrode structure becomes complicated, and it becomes difficult to control the parts that interfere with each other by correcting different differences.
- the present invention is directed to addressing such a problem as an example. Ie
- each of the pair of transparent electrodes of the electro-optical panel can form a divided region divided into electrode patterns suitable for correcting aberrations, and the electrode structure of the transparent electrode composed of the divided regions can be realized. It is an object of the present invention that the control of the voltage applied to the divided region can be simplified as much as possible.
- an aberration correction apparatus, an aberration correction method, and an optical pickup according to the present invention include at least a configuration according to the following independent claims.
- the electro-optical panel includes a pair of transparent electrodes.
- the electrode is formed by a divided region divided into an electrode pattern that enables a plurality of types of aberration correction, and forms one part of one type of the divided region relating to one type of aberration correction on one of the transparent electrodes.
- an aberration correction apparatus characterized by forming the remaining portion of the one type of divided area for aberration correction.
- the electro-optical panel includes a pair of transparent electrodes, and the transparent electrodes perform a plurality of types of aberration correction. A part of a divided region related to correction of coma aberration and a divided region related to correction of astigmatism are formed on one of the transparent electrodes, and the transparent electrode is formed by one of the transparent electrodes.
- An aberration correction apparatus characterized in that, on the other side, a remaining portion of a divided region for correcting coma aberration and a divided region for correcting spherical aberration are formed.
- [0015] An optical pickup that focuses a light beam emitted from a light source on a recording surface of an optical information recording medium and forms reflected light of the recording surface force on a detection surface of a detector.
- the electro-optical panel includes a pair of transparent electrodes, and the transparent electrodes perform a plurality of types of aberration correction.
- a voltage is applied to a part of a divided region formed on one of the pair of transparent electrodes and associated with correction of coma aberration, at least at the time of coma aberration correction. And applying a voltage to the remaining portion of the divided region for correcting coma formed on the other of the pair of transparent electrodes.
- an imaging optical system for converging a light beam emitted from a light source on a recording surface of an optical information recording medium and imaging reflected light having a recording surface force on a detection surface of a detector.
- an electro-optical panel for correcting aberration of the imaging optical system is inserted into the imaging optical system, the electro-optical panel includes a pair of transparent electrodes, and the transparent electrodes include a plurality of types of transparent electrodes.
- a part of the transparent electrode is formed by a divided region divided into an electrode pattern that enables aberration correction, and a part of a divided region related to correction of coma aberration and a divided region related to correction of astigmatism are formed on one of the transparent electrodes.
- An optical pickup characterized in that the other of the transparent electrodes is formed with a remaining portion of a divided region for correcting coma aberration and a divided region for correcting spherical aberration.
- FIG. 1 is an explanatory diagram showing a configuration example of an optical pickup including an aberration correction device according to an embodiment of the present invention.
- FIG. 2 is an explanatory view showing a structure of a liquid crystal panel (electro-optical panel) according to an embodiment of the present invention.
- FIG. 3 is an explanatory diagram showing a distribution of occurrence of coma.
- FIG. 4 is an explanatory diagram showing an electrode pattern for correcting coma aberration.
- FIG. 5 is an explanatory diagram showing a distribution of astigmatism.
- FIG. 6 is an explanatory diagram showing an electrode pattern related to correction of astigmatism.
- FIG. 7 is an explanatory diagram showing a distribution of spherical aberration.
- FIG. 8 is an explanatory view showing an electrode pattern relating to correction of spherical aberration.
- FIG. 9 is an explanatory diagram showing an electrode pattern of the aberration correction device according to the embodiment of the present invention.
- FIG. 10 is an explanatory diagram showing a voltage application pattern to the aberration correction device according to the embodiment of the present invention.
- FIG. 11 is a block diagram showing a configuration example of a drive control unit that drives and controls a liquid crystal panel (electro-optical panel) according to an embodiment of the present invention.
- FIG. 12 is an explanatory diagram illustrating voltage-phase characteristics of a liquid crystal panel.
- FIG. 13 is a comparative example for explaining the aberration correction performance of the aberration correction device according to the embodiment of the present invention.
- FIG. 14 is a graph for explaining the aberration correction performance of the aberration correction device according to the embodiment of the present invention.
- the aberration correction device and the aberration correction method according to the embodiment of the present invention are suitable for an optical pickup, the following description will be made taking an example of application to an optical pickup.
- the aberration correction device and the aberration correction method are not particularly limited to these.
- a liquid crystal panel will be described as an example of the electro-optical panel of the aberration correction device.
- the electro-optical panel in the embodiment of the present invention includes a pair of transparent electrodes, and a voltage is applied to the transparent electrodes. It is not particularly limited to the liquid crystal panel if it can adjust the phase difference of the transmitted light beam.
- FIG. 1 is an explanatory diagram showing a configuration example of an optical pickup including an aberration correction device according to one embodiment of the present invention.
- This optical pickup focuses a light beam L emitted from a light source 1 such as a red (wavelength: 650 nm) LD (Laser Diode) on a recording surface 2a of an optical information recording medium 2 such as an optical disk, and records the light beam L on the recording surface 2a. Reflected light L from 2a forms an image on detection surface 3a of detector 3.
- a light source 1 such as a red (wavelength: 650 nm) LD (Laser Diode)
- LD Laser Diode
- Imaging optical system object lens 4A, collimator lens 4B, and condenser lens 4C to make the light beam L and the reflected light L split.
- the linearly polarized light beam transmitted through the polarization beam splitter 5 passes through a 1/4 ⁇ wave plate 6 in which the plane of polarization of the linearly polarized light and the crystal axis intersect at an angle of 45 °.
- the reflected light L2 which becomes circularly polarized light, is condensed by the objective lens 4 °, and reflected by the recording surface 2a, passes through the 1/4 ⁇ wave plate again, becomes linearly polarized light, and reaches the polarization beam splitter 5. At this time, the polarization axis of the reflected light L is rotated by 90 ° with respect to the polarization axis of the light beam L.
- the reflected light L is reflected by the polarization beam splitter 5 and directed to the detector 3.
- a liquid crystal panel (electro-optical panel) 10 for correcting aberration of the imaging optical system is inserted into the imaging optical system of such an optical pickup. Further, a drive control unit 8 for controlling the driving of the liquid crystal panel 10 is provided, whereby the output from the detector 3 (or the output from a tilt sensor or the like for detecting the tilt of the optical information recording medium 2) is provided. Thus, the voltage applied to the liquid crystal panel 10 is controlled.
- FIG. 2 is an explanatory diagram showing the structure of the liquid crystal panel 10 according to the embodiment of the present invention.
- the liquid crystal panel 10 includes at least a pair of transparent electrodes 12a and 12b.
- the transparent electrodes 12a and 12b are formed on opposing surfaces of the pair of transparent substrates 11a and lib, and liquid crystal molecules are formed on the opposing surfaces.
- Alignment films 13a and 13b for giving a predetermined molecular orientation to M are formed, and a liquid crystal layer 14 having birefringence such as a nematic liquid crystal is sealed between the alignment films 13a and 13b.
- aberrations that cause a problem in the image forming optical system of the optical pickup include coma caused by the inclination of the optical information recording medium 2 and a thickness error of the optical information recording medium 2.
- FIG. 3 shows the distribution of occurrence of coma.
- This figure shows the distribution of the occurrence of coma as a value on the pupil plane of the objective lens 4A, and shows the focal spot of the light beam L when the optical information recording medium 2 is tilted by + 1 °.
- FIG. 5 is a diagram showing boundaries between the respective regions A to K indicated by a range width of 50 nm above and below a region ⁇ having a range of m to +25 nm.
- X -X is the direction in which the optical information recording medium 2 tilts.
- the transparent electrodes 12a (12b) of the liquid crystal panel 10 The formed electrode pattern forms a divided region having a shape along the aberration distribution shown in FIG. 3, and a voltage applied to this divided region is generated in each divided region so as to cancel the aberration. It can give a phase difference to the light beam.
- FIG. 4 shows the electrode pattern. As shown in the figure, an electrode pattern suitable for correcting coma aberration is composed of five divided areas E to E (4A is the aperture pupil of the objective lens). Minute
- the split region E is a region including the aberration power ⁇ , and the split regions E and E are large on the + side.
- FIGS. 5A to 5C show the distribution of astigmatism on the pupil plane of the objective lens 4A.
- FIG. 3A shows the astigmatism distribution around the optical axis, and the dark portion indicates a region with large astigmatism.
- FIGS. 7B and 7C show a Yla-Ylb section and an Xla-Xlb section in FIG. 7A, respectively.
- the distribution of astigmatism in the pupil plane of the objective lens 4A is symmetric with respect to the Xla-Xlb axis and the Yla-Ylb axis, and the aberration amount increases toward the periphery. The amount of aberration decreases at an angle of 45 ° with the axis.
- This astigmatism distribution is not unique to each imaging optical system.
- An optical system with astigmatism has a distribution pattern with the same force. The direction differs depending on the optical system. Axis, Yla—Ylb axis is rotated by the optical system. The amount and direction of astigmatism vary depending on the optical system.
- the electrode pattern formed on the transparent electrode 12a (12b) of the liquid crystal panel 10 has a divided area having a shape corresponding to the aberration distribution shown in FIG.
- a phase difference can be given to the luminous flux so as to cancel the difference occurring in each divided region.
- FIG. 6 shows the electrode pattern.
- an electrode pattern appropriate for correcting astigmatism has, for example, nine divided areas E to E with respect to the aperture pupil 4A of the objective lens 4A.
- One divided area E has a circular shape corresponding to the center of the aperture pupil 4A.
- Each of the other divided areas E to E is a pattern radially divided around its outer periphery.
- AS1 AS 5 AS 2 AS 6 AS 3 AS 7 AS 4 AS 8 are arranged symmetrically to the center and face each other.By selecting these pairs and applying the same polarity voltage, it is possible to respond to the specific direction of astigmatism It is possible to correct aberrations.
- FIG. 7 shows the distribution of spherical aberration on the pupil plane of the objective lens 4A.
- This spherical aberration shows a symmetric distribution around the center O of the aperture pupil 4A, and the circumference of the center O and the aperture pupil 4A0.
- FIG. 8 shows an electrode pattern capable of correcting the spherical aberration.
- This electrode pattern forms a divided region having a shape corresponding to the aberration distribution shown in FIG. 7, and is designed to cancel the aberration generated in each divided region by applying a voltage to this divided region. It can give a phase difference to the light beam. That is, the divided area at this time is a circular pattern divided area E corresponding to the center of the aperture pupil 4A of the objective lens 4A.
- the divided area E of 0 S and its surrounding annular pattern, and the divided area E of the surrounding area are included.
- the liquid crystal panel 10 in the aberration correction device can effectively correct three types of aberrations (coma, astigmatism, and spherical aberration) with one liquid crystal panel 10.
- the electrode pattern of the transparent electrodes 12a and 12b is formed on one of the transparent electrodes 12a and 12b as a part of one type of divided region relating to aberration correction, and the electrode pattern is formed on the other of the transparent electrodes 12a and 12b. The remaining portion of the divided region for one type of aberration correction is formed.
- FIGS. 9 (a) and 9 (b) show specific electrode patterns of the transparent electrodes 12a and 12b.
- FIG. 3A shows one electrode pattern of the transparent electrodes 12a and 12b
- FIG. 3B shows the other electrode pattern of the transparent electrodes 12a and 12b.
- a substantially circular pattern E is formed at the center of 0, and this is divided into three divided areas E, ⁇ , ⁇ .
- An area outside the substantially circular pattern ⁇ which forms a part of a divided area for coma aberration correction.
- the substantially circular pattern ⁇ and the divided areas ⁇ , ,, ⁇ are coma aberrations shown in FIG.
- the central force of the aperture pupil 4A is also divided at substantially equal intervals with respect to the peripheral portion.
- the divided areas E to E arranged symmetrically are set as follows, and the divided areas E and E, ⁇ and E
- ⁇ and ⁇ , and ⁇ and ⁇ are arranged so that they face each other and are symmetric
- a circular pattern divided region E is formed at the center of the aperture pupil 4A of the objective lens 4 as a spherical aberration divided region.
- a divided area E which also has a concentric circular pattern force, is formed.
- the remaining part (E, ⁇ , ⁇ , ⁇ ) of the divided area related to the correction is formed.
- the split area E is set to be suitable for spherical aberration correction, and the area outside the area is used.
- the divided areas E, ⁇ , ⁇ , ,, , ,, ⁇ , ⁇ relating to the correction of coma aberration are separated into two sets, and the divided areas ⁇ , ⁇
- ⁇ are formed on one of the transparent electrodes 12a, 12b, and the divided areas E, E, E, E are transparent.
- FIG. 10 shows a voltage application pattern to the liquid crystal panel 10 according to the above-described embodiment.
- FIG. 4A shows a voltage application pattern when correcting coma aberration
- FIG. 4B shows a voltage application pattern when correcting spherical aberration
- FIG. 4C shows a voltage application pattern when correcting astigmatism. .
- a voltage is applied to the above-described divided region E. As shown in FIG.
- FIG. 11 shows a configuration example of the drive control unit 8 that drives and controls the liquid crystal panel 10 described above.
- the drive control unit 8 includes a controller 80 that controls the reproduction signal (RF, PushPull, LPP, etc.) from the detector 3 and the input force of the CPU.
- a bias voltage generator 82 that outputs a bias voltage based on the stored memory 81 and an output from the controller 80, and a coma aberration correction control that outputs a coma aberration correction control voltage based on the output from the controller 80.
- the voltage generation unit 83 outputs the astigmatism correction control voltage based on the output from the controller 80.
- the astigmatism correction control voltage generation unit 84 outputs the astigmatism correction control voltage based on the output from the controller 80.
- the bias voltage output from the spherical aberration correction control voltage generator 85 and the bias voltage generator 82 is added to the output from the coma aberration correction control voltage generator 83 and the output from the astigmatism correction control voltage generator 84.
- the output power from the coma aberration correction control voltage generation unit 83 and the astigmatism correction control voltage generation unit 84 to which the bias voltage has been added is a divided region formed on one of the pair of transparent electrodes 12a and 12b.
- the output from the coma aberration correction control voltage generator 83 and the output from the spherical aberration correction control voltage generator 85 to which the bias voltage has not been added and which is output through the moving unit 87 Is output to each of the divided regions (E 1, E 2, E 3, E 2) formed on the other of the pair of transparent electrodes 12a and 12b.
- the divided area E is in the ground state.
- the voltage phase difference characteristic of the liquid crystal panel 10 has a limited operating range (dynamic range) that can be linearly approximated as shown in FIG.
- the bias voltage V is set near the center of the dynamic range.
- the difference ( ⁇ a ⁇ c) can be controlled, and the control voltage Vb lower than the bias voltage V
- the bias voltage V is applied, so that the bias voltage V is added and a coma aberration correction control voltage that is not c c is applied.
- Astigmatism is an aberration mainly caused by component accuracy and assembly accuracy of an optical pickup. This correction is performed by an objective lens in an optical pickup assembly process. This is done by observing the beam spot focused by 4A. If there is astigmatism, the beam spot to be condensed into a circle becomes elliptical.Observing this, the direction and magnitude of the ellipse and the degree of deformation are measured, and the direction and magnitude of the astigmatism are measured. The value is stored in the memory 81. Actually, a voltage is selectively applied to the divided areas E to E with respect to the elliptical beam spot so that the beam spot becomes circular.
- the controller 80 reads the value from the memory 81 and outputs the value to the astigmatism correction control voltage generator 84, where the correction control voltage is generated.
- the control voltage obtained by adding the aforementioned bias voltage V to the voltage is the transparent electrode 12a.
- the spherical aberration is mainly caused by an error in the thickness of the cover layer of the optical information recording medium 2, and this correction is performed by reproducing the optical information recording medium 2 with an optical pickup. This is performed based on the magnitude of the reproduced signal, jitter, error rate, and the like.
- a signal from the detector 3 causes the controller 80 to control the spherical aberration correction control.
- the spherical aberration correction control voltage is set so that the amplitude value of the tracking error signal or the wobble signal reproduced by applying the focus servo to the optical information recording medium 2 is maximized. Then, this spherical aberration correction control voltage (the bias voltage V is added
- a phase difference is given to the luminous flux passing through the division area E by applying the voltage, so that the spherical aberration
- FIG. 13 is a comparative example for explaining the aberration correction performance of the aberration correction device according to the embodiment of the present invention.
- an electrode pattern for coma aberration correction is formed only in the divided areas E 1 and E and formed on only one transparent electrode.
- Figure 14 shows optical information
- FIG. 6 is a graph comparing the amount of wavefront aberration (coma aberration) with respect to the tilt angle (tilt angle in the radial direction) of the recording medium 2 (optical disc) in the above-described embodiment (example), comparative example, and the case without correction.
- the conditions for calculating the wavefront aberration amount are as follows: NA of the objective lens: 0.67, disk thickness: 0.6 mm, light source wavelength: 660 nm).
- coma can be reduced by 40% compared to a case without correction, and Even higher aberration correction performance can be obtained.
- other aberrations have the effect of reducing spherical aberration by 50% and astigmatism by 60%. That is, according to the aberration correction apparatus according to the embodiment of the present invention, the same effect can be obtained as compared with a case where each aberration correction electrode is independently designed.
- the transparent electrodes 12a and 12b are formed by divided regions divided into electrode patterns capable of correcting a plurality of types of aberrations, and one type is provided for one of the transparent electrodes 12a and 12b.
- a remaining portion of the one type of divided region related to the aberration correction is formed on the other of the transparent electrodes 12a and 12b.
- one of the transparent electrodes 12a and 12b has a part (E, ⁇ , ⁇ ) of a divided region related to correction of coma aberration and correction of astigmatism.
- the other of the transparent electrodes 12a and 12b relates to correction of coma aberration.
- the respective divided regions can be formed without interference with each other.
- a portion related to correction of spherical aberration formed in a pattern at the central portion of the aperture pupil 4A.
- each divided region can be formed without interference with each other.
- a part (E 1, ⁇ , ⁇ ) of a divided area related to coma aberration correction is formed by dividing the substantially circular pattern of the central portion into three on one of the transparent electrodes 12 a and 12 b. And this roughly circular
- the other of the transparent electrodes 12a and 12b has a central circular pattern
- the remaining portion (E 1, E 2) of the divided region for coma aberration correction is formed outside the portion.
- the aberration correction device having the above-described features condenses the light beam emitted from the light source 1 on the recording surface 2a of the optical information recording medium 2, and detects the reflected light from the recording surface 2a with the detector 3.
- the optical pickup is used in an imaging optical system of an optical pickup that forms an image on the detection surface 3a of the optical information recording medium 2, the aberration caused by the tilt of the optical information recording medium 2, the aberration caused by the thickness error of the optical information recording medium 2, the optical pickup A single electro-optical panel can correct any aberrations due to component manufacturing errors, etc., and realizes a highly reliable, low-cost and compact optical pickup capable of recording or reproducing information. Becomes possible.
- a part (E) of the divided region for correcting coma aberration formed on one of the pair of transparent electrodes 12a and 12b is used. , E), and apply the voltage to the other of the pair of transparent electrodes 12a, 12b.
- liquid crystal panel 10 can be driven as in the case where coma aberration correction is performed alone.
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- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Geometry (AREA)
- Mathematical Physics (AREA)
- Optical Head (AREA)
- Liquid Crystal (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP05730462A EP1742210A4 (en) | 2004-04-28 | 2005-04-14 | ABERRATION CORRECTOR, ABERRATION CORRECTION PROCESS, OPTICAL DEVICE |
US11/587,935 US8018814B2 (en) | 2004-04-28 | 2005-04-14 | Aberration correction device, aberration correction method and optical pickup |
JP2006512741A JP4345814B2 (ja) | 2004-04-28 | 2005-04-14 | 収差補正装置、収差補正方法、光ピックアップ |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004133844 | 2004-04-28 | ||
JP2004-133844 | 2004-04-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2005106865A1 true WO2005106865A1 (ja) | 2005-11-10 |
Family
ID=35241900
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2005/007218 WO2005106865A1 (ja) | 2004-04-28 | 2005-04-14 | 収差補正装置、収差補正方法、光ピックアップ |
Country Status (5)
Country | Link |
---|---|
US (1) | US8018814B2 (ja) |
EP (1) | EP1742210A4 (ja) |
JP (1) | JP4345814B2 (ja) |
CN (1) | CN1954374A (ja) |
WO (1) | WO2005106865A1 (ja) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2007199200A (ja) * | 2006-01-24 | 2007-08-09 | Funai Electric Co Ltd | 液晶素子及びそれを備えた光ピックアップ装置 |
JP2007226130A (ja) * | 2006-02-27 | 2007-09-06 | Ricoh Co Ltd | 光走査装置、画像形成装置、及び位相変調方法 |
JP2007273045A (ja) * | 2006-03-31 | 2007-10-18 | Toshiba Corp | 光ヘッド及び光ディスク装置 |
CN100454412C (zh) * | 2005-11-18 | 2009-01-21 | 三洋电机株式会社 | 光拾取装置 |
US7907498B2 (en) | 2004-09-27 | 2011-03-15 | Sony Corporation | Optical pickup and optical disk drive using same |
Families Citing this family (5)
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KR101350988B1 (ko) * | 2012-05-16 | 2014-01-15 | 도시바삼성스토리지테크놀러지코리아 주식회사 | 트랙킹 에러신호 생성 방법 및 장치 및 이를 적용한 광정보저장매체 시스템 |
US9833312B2 (en) | 2012-12-18 | 2017-12-05 | Lensvector Inc. | Liquid crystal optical device with advanced electric field control capability |
CN104155816B (zh) * | 2014-09-02 | 2017-05-17 | 深圳市华星光电技术有限公司 | 阵列基板以及具备该阵列基板的显示面板 |
US20180045960A1 (en) | 2015-12-02 | 2018-02-15 | Augmenteum, LLC. | System for and method of projecting augmentation imagery in a head-mounted display |
JP6883705B2 (ja) * | 2018-03-29 | 2021-06-09 | 株式会社日立ハイテク | 荷電粒子線装置 |
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JP2000067453A (ja) * | 1998-08-19 | 2000-03-03 | Pioneer Electronic Corp | 収差補正装置及び光ピックアップ |
JP2003173562A (ja) * | 2001-12-05 | 2003-06-20 | Ricoh Co Ltd | 光ピックアップ装置及び情報記録再生装置 |
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JP3538520B2 (ja) | 1997-04-16 | 2004-06-14 | パイオニア株式会社 | 収差補正用液晶パネル、光ピックアップ及び情報再生装置 |
US6151154A (en) * | 1998-03-12 | 2000-11-21 | Pioneer Electronic Corporation | Optical pickup, aberration correction unit and astigmatism measurement method |
JP3868119B2 (ja) | 1998-07-17 | 2007-01-17 | パイオニア株式会社 | 収差補正装置、非点収差測定方法及び光ピックアップ |
JP3885921B2 (ja) | 2000-03-07 | 2007-02-28 | パイオニア株式会社 | 収差補正光学装置 |
US6909686B2 (en) * | 1999-12-20 | 2005-06-21 | Pioneer Corporation | Aberration correcting optical unit, optical pickup apparatus and information recording/reproducing apparatus with single and multi-layer electrodes |
TW594711B (en) * | 1999-12-24 | 2004-06-21 | Koninkl Philips Electronics Nv | Optical wavefront modifier |
US7012875B2 (en) * | 2000-09-06 | 2006-03-14 | Hitachi, Ltd. | Optical disk apparatus using focal shift signals to control spherical aberration |
JP2002304762A (ja) * | 2001-04-10 | 2002-10-18 | Nec Corp | 光ヘッド装置および光学式情報記録再生装置 |
KR100418967B1 (ko) * | 2001-05-07 | 2004-02-14 | 엘지전자 주식회사 | 넘버 세븐 신호망에서 신호 메시지의 총괄명 번역 장치 및방법 |
US7006411B2 (en) * | 2001-06-13 | 2006-02-28 | Ricoh Company, Ltd. | Optical pickup unit having electro-optical element and information recording and reproduction apparatus |
JP4082085B2 (ja) | 2002-05-17 | 2008-04-30 | 旭硝子株式会社 | 光ヘッド装置 |
EP1553570B1 (en) * | 2002-10-10 | 2008-10-08 | Matsushita Electric Industrial Co., Ltd. | Optical head and optical disk unit |
-
2005
- 2005-04-14 CN CNA2005800134912A patent/CN1954374A/zh active Pending
- 2005-04-14 JP JP2006512741A patent/JP4345814B2/ja not_active Expired - Fee Related
- 2005-04-14 EP EP05730462A patent/EP1742210A4/en not_active Withdrawn
- 2005-04-14 US US11/587,935 patent/US8018814B2/en not_active Expired - Fee Related
- 2005-04-14 WO PCT/JP2005/007218 patent/WO2005106865A1/ja not_active Application Discontinuation
Patent Citations (2)
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JP2000067453A (ja) * | 1998-08-19 | 2000-03-03 | Pioneer Electronic Corp | 収差補正装置及び光ピックアップ |
JP2003173562A (ja) * | 2001-12-05 | 2003-06-20 | Ricoh Co Ltd | 光ピックアップ装置及び情報記録再生装置 |
Non-Patent Citations (1)
Title |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7907498B2 (en) | 2004-09-27 | 2011-03-15 | Sony Corporation | Optical pickup and optical disk drive using same |
CN100454412C (zh) * | 2005-11-18 | 2009-01-21 | 三洋电机株式会社 | 光拾取装置 |
JP2007199200A (ja) * | 2006-01-24 | 2007-08-09 | Funai Electric Co Ltd | 液晶素子及びそれを備えた光ピックアップ装置 |
JP2007226130A (ja) * | 2006-02-27 | 2007-09-06 | Ricoh Co Ltd | 光走査装置、画像形成装置、及び位相変調方法 |
US8217978B2 (en) | 2006-02-27 | 2012-07-10 | Ricoh Company, Ltd. | Optical scanning apparatus, an image formation apparatus, and a phase modulation method |
JP2007273045A (ja) * | 2006-03-31 | 2007-10-18 | Toshiba Corp | 光ヘッド及び光ディスク装置 |
Also Published As
Publication number | Publication date |
---|---|
US20080055713A1 (en) | 2008-03-06 |
EP1742210A1 (en) | 2007-01-10 |
JPWO2005106865A1 (ja) | 2008-03-21 |
EP1742210A4 (en) | 2008-07-02 |
JP4345814B2 (ja) | 2009-10-14 |
US8018814B2 (en) | 2011-09-13 |
CN1954374A (zh) | 2007-04-25 |
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