WO2006092968A1 - 液晶光学素子 - Google Patents
液晶光学素子 Download PDFInfo
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- WO2006092968A1 WO2006092968A1 PCT/JP2006/302847 JP2006302847W WO2006092968A1 WO 2006092968 A1 WO2006092968 A1 WO 2006092968A1 JP 2006302847 W JP2006302847 W JP 2006302847W WO 2006092968 A1 WO2006092968 A1 WO 2006092968A1
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- concentric
- electrode
- liquid crystal
- concentric electrode
- transparent substrate
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Classifications
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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
- G02F1/13—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
- G11B7/1367—Stepped phase plates
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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
- 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
- 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
- G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
- G11B2007/0006—Recording, reproducing or erasing systems characterised by the structure or type of the carrier adapted for scanning different types of carrier, e.g. CD & DVD
Definitions
- the present invention relates to a liquid crystal optical element, and more particularly to a liquid crystal optical element for correcting fluctuation, distortion, aberration or the like of a wavefront of light generated when a light flux is transmitted through a lens and condensed.
- an optical disc such as a compact disc (CD) or a digital versatile disc (DVD) has been used as a medium for recording music information and video information.
- the optical disk apparatus condenses laser light by a lens and irradiates it onto the information recording layer of the optical disk, and reads the recorded information of the optical disk by detecting the reflected light.
- an infrared laser beam with a wavelength of about 780 nm and an objective lens with a numerical aperture of about 0.45 to 0.51 are used.
- an optical disk apparatus compatible with both CD and DVD requires an optical system such as a laser light source of each wavelength and an objective lens.
- optical systems such as an objective lens are common to CDs and DVDs in order to reduce the cost, size, etc. of the optical disk apparatus. Therefore, if the optical system is optimized for CDs (or for DVDs), aberration will occur for DVDs (or CDs). Therefore, in the compatible optical disk apparatus, it is necessary to correct this aberration.
- next-generation optical disks and optical disk devices have been developed in which the recording density is further increased by using blue laser light having a wavelength of about 400 nm. ing.
- blue laser light having a wavelength of about 400 nm.
- spherical aberration is inversely proportional to the wavelength of laser light, how to correct spherical aberration becomes an important issue in this next-generation optical disk device.
- the numerical aperture of the objective lens is 0.85, as compared to the case of conventional CD and DVD using infrared or red laser light.
- the effective diameter increases.
- the peak position of the generated spherical aberration in the lens radial direction is different between the case of using blue laser light and the case of using infrared laser light and red laser light.
- FIG. 20 the horizontal axis and the vertical axis are respectively the radial distance (standardized) of the center force and the like of the objective lens and the generated spherical aberration (standardized).
- the solid curve and the broken W-shaped curve two-dimensionally represent the aberration in the case of using the blue laser light and the aberration in the case of using the red laser light, respectively.
- the peak positions of the effective diameter of the objective lens and the aberration generated are largely different between the case where the blue laser light is used and the case where the red laser light is used.
- the generated aberration is an M-shaped curve obtained by inverting the W-shaped curve in FIG. 20 with respect to the horizontal axis. Therefore, in order to ensure compatibility when using blue laser light, infrared laser light and red laser light with a common optical system such as an objective lens, the wavelength of the laser light used is Another important issue is how to eliminate differences in the objective lens numerical aperture and effective diameter due to differences, and differences in the peak position of spherical aberration.
- the liquid crystal layer, the transparent substrate sandwiching the liquid crystal layer, and the first transparent substrate are provided from the center toward the periphery.
- a voltage drop resistance, a plurality of concentric electrodes provided on the first transparent substrate and connected to the voltage drop resistance, and a voltage applied across the voltage drop resistance It comprises: an extraction electrode; a lower electrode provided on the second transparent substrate and applying the electric field to the liquid crystal layer between the concentric electrodes; and a power supply applying a voltage to the extraction electrode and the lower electrode.
- an optical pickup for reading DVD power information having a plurality of information recording layers it is disposed in the optical path between the light source and the objective lens, and according to the selected recording layer,
- wavefront aberration correcting means for correcting the wavefront aberration of the emitted light is provided, and this wavefront aberration correcting means is constituted by a liquid crystal element (see, for example, Patent Document 2).
- Patent Document 2 it is possible to correct wavefront aberration caused by the difference in the distance from the recording layer optimally designed for the optical pickup to each other recording layer.
- Patent Document 1 Patent No. 3047082
- Patent Document 2 Japanese Patent Application Laid-Open No. 10-269611
- the amount of wavefront aberration is adjusted for each of a CD, a DVD having a single information recording layer and a DVD having a plurality of information recording layers. You can. Further, in the optical pickup described in Patent Document 2 described above, it is possible to correct spherical aberration generated for recording layers other than the optimally designed information recording layer. However, none of them can solve the difference in the effective diameter of the objective lens due to the difference in the wavelength of the laser light and the difference in the peak position of the spherical aberration.
- An object of the present invention is to provide a liquid crystal optical element capable of eliminating a difference in peak position of the generated spherical aberration.
- the liquid crystal optical element according to the present invention is A first transparent substrate having a first electrode, a second transparent substrate having a second electrode, and a liquid crystal layer sealed between the first transparent substrate and the second transparent substrate
- a voltage applied between the first electrode and the second electrode by the power supply means comprising: a liquid crystal cell; and power supply means for supplying a voltage to the first electrode and the second electrode.
- the first electrode is concentrically disposed from the center to the outer periphery of the first transparent substrate.
- the plurality of concentric electrodes are divided into two or more concentric electrode groups, and adjacent ones of the concentric electrodes belonging to each concentric electrode group are connected by resistance. And both ends of the concentric electrodes belonging to each concentric electrode group Concentric electrodes are connected to said power supply means through the electrodes out can bow I wherein the Ru.
- the present invention by applying an appropriate voltage according to the laser beam to be used to each concentric electrode of the first electrode, it is generated in a state where the aberration is not corrected by the liquid crystal optical element. It is possible to generate an aberration (hereinafter referred to as “corrected aberration”) whose phase is approximately opposite to that of the aberration (hereinafter referred to simply as “generated aberration”). Therefore, it is possible to reduce the aberration (hereinafter referred to as residual aberration) after being corrected by the liquid crystal optical element.
- corrected aberration an aberration whose phase is approximately opposite to that of the aberration
- the first transparent substrate is independent without belonging to any concentric electrode group, and has the same center as the concentric electrode.
- the single concentric electrode is further provided, and the single concentric electrode is connected to the power supply means through the drawing electrode. According to the present invention, by changing the voltage applied to the single concentric electrode, the peak position of the correction aberration can be matched to the peak position of the generated aberration which changes according to the laser beam used.
- the single concentric electrode may be a first concentric electrode group near the center of the liquid crystal cell and a first concentric electrode group near the outer periphery of the liquid crystal cell. It is characterized in that it is provided between two concentric electrode groups. According to the present invention, by applying appropriate voltages to the first concentric electrode group, the second concentric electrode group, and the single concentric electrode, it is possible to use an objective lens when the laser light used is changed. It is possible to eliminate the difference in the effective diameter and the difference in the peak position of the generated aberration.
- each concentric electrode belonging to the first concentric electrode group is disposed between each concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that produces a voltage distribution that generates approximately opposite phase aberration with respect to an aberration that increases halfway to the center force toward the outer periphery of the liquid crystal cell. According to the present invention, since the central force of the liquid crystal cell can also be increased to the outer circumference halfway to the midway to almost cancel the generated aberration reaching the peak, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group is disposed between each concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that causes a voltage distribution to generate an aberration of approximately opposite phase with respect to an aberration which decreases between the center and the outer periphery of the liquid crystal cell. According to the present invention, since the peak force decreases between the center and the outer periphery of the liquid crystal cell and the generation aberration can be approximately canceled, residual aberration can be reduced.
- each concentric electrode belonging to the first concentric electrode group is disposed between each concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that generates a voltage distribution that generates approximately opposite phase aberration with respect to the aberration that decreases in the middle of the force toward the outer periphery of the central force of the liquid crystal cell. According to the present invention, since the central force of the liquid crystal cell can also be reduced to the outer periphery halfway to the midway, and the generated aberration reaching the peak can be almost canceled out, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group is disposed between the concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that causes a voltage distribution to generate an aberration of approximately opposite phase with respect to an aberration that increases from the middle to the outer periphery of the liquid crystal cell.
- the peak power is also increased between the center and the outer periphery of the liquid crystal cell and the peak power can be increased to substantially cancel out the generated aberration, thereby reducing the residual aberration. It is possible to
- the power supply means is connected to the one concentric electrode group to a lead-out electrode connected to the single concentric electrode. It is characterized in that the same voltage as that supplied to one extraction electrode is supplied. According to the present invention, by applying an appropriate voltage to the first concentric electrode group and the second concentric electrode group, the difference in the effective diameter of the objective lens when the laser beam used is changed or the generation aberration is generated. The difference in peak position can be eliminated.
- the power source unit is configured to use the single concentric electrode when correcting spherical aberration of a disc having a small effective diameter of an objective lens.
- a liquid crystal optical element includes a first transparent substrate having a first electrode, a second transparent substrate having a second electrode, and the first transparent substrate and the second substrate.
- a liquid crystal cell having a liquid crystal layer sealed between transparent substrates, and power supply means for supplying a voltage to the first electrode and the second electrode; and the first electrode by the power supply means
- a plurality of concentric electrodes arranged concentrically in a direction from the center to the periphery, and a part of which is grouped to form a concentric electrode group, wherein the second electrode is The central force of the second transparent substrate is concentrically arranged toward the outer periphery, and a part of The plurality of concentric electrodes that are formed into concentric electrode groups are formed, and adjacent concentric electrodes of the concentric electrodes belonging to each concentric electrode group are connected by resistance, and each concentric electrode group is connected to each other.
- Concentric electrodes at both ends of the belonging concentric electrodes Is connected to the power supply means via an extraction electrode.
- the concentric electrode group of the first transparent substrate and the other concentric electrodes not belonging thereto are provided. And, by applying an appropriate voltage according to the laser beam to be used to the concentric electrode group of the second transparent substrate and other concentric electrodes not belonging to it, it is possible to generate a correction aberration for the generated difference. Therefore, residual aberration can be reduced.
- the first transparent substrate is independent of any of the concentric electrode groups of the first transparent substrate, A concentric single concentric electrode concentric with the concentric electrode of the first transparent substrate is further provided, and the single concentric electrode is connected to the power supply means through the lead electrode.
- the present invention by changing the voltage applied to the single concentric electrode, it is possible to match the peak position of the correction aberration with the peak position of the generated difference that changes according to the laser beam used.
- the concentric electrode group disposed on the second transparent substrate and near the center of the liquid crystal cell is
- the single concentric electrode is the first concentric electrode group.
- An electrode group is provided between the concentric electrode on the facing first transparent substrate and the second concentric electrode group.
- the first concentric electrode group, the concentric electrode facing the first concentric electrode group, the single concentric electrode, the second concentric electrode group, and the concentric electrode facing the second concentric electrode group are suitable. By applying an appropriate voltage, it is possible to eliminate the difference in the effective diameter of the objective lens and the difference in the peak position of the generated aberration when the laser light to be used is changed.
- each concentric electrode belonging to the first concentric electrode group corresponds to each concentric electrode and the first transparent substrate facing each other.
- the center force of the liquid crystal cell is moved toward the outer periphery between the upper concentric electrode and the center electrode. It has a width that produces a voltage distribution that causes aberrations that are approximately out of phase with respect to the aberration that increases between them.
- each concentric electrode belonging to the second concentric electrode group is the second transparent substrate on which the respective concentric electrodes face each other. It has a width that produces a voltage distribution that generates an approximately antiphase aberration with respect to an aberration that decreases between the center and the outer periphery of the liquid crystal cell, with the upper concentric electrode. It is characterized by According to the present invention, it is possible to approximately cancel out the generation aberration which decreases from the peak between the center and the outer periphery of the liquid crystal cell and to reduce the residual aberration.
- each of the concentric electrodes belonging to the first concentric electrode group corresponds to the respective concentric electrodes, and the first transparent substrate faces them. It has a width that produces a voltage distribution between the upper concentric electrode and the center electrode of the liquid crystal cell that produces an aberration that is approximately out of phase with the aberration that decreases halfway through toward the outer periphery. It is characterized by According to the present invention, it is possible to approximately cancel out the generation aberration reaching a peak by decreasing halfway to the central force outer periphery of the liquid crystal cell, so it is possible to reduce the residual aberration.
- each concentric electrode belonging to the second concentric electrode group corresponds to each concentric electrode and the second transparent substrate facing each other. It has a width that produces a voltage distribution that generates approximately reverse phase aberration with respect to the aberration that increases between the center and the outer periphery of the liquid crystal cell with the upper concentric electrode. It is characterized by According to the present invention, it is possible to approximately cancel out the aberration which increases from the peak between the center and the periphery of the liquid crystal cell and to the periphery, so residual aberration can be reduced.
- the power supply means is connected to the second concentric electrode group to a lead-out electrode connected to the single concentric electrode. Supply the same voltage as the voltage supplied to one extraction electrode I assume.
- an appropriate voltage is applied to the first concentric electrode group, the concentric electrode facing the first concentric electrode group, the second concentric electrode group, and the second concentric electrode group.
- the power source unit is configured to use the single concentric electrode when correcting the spherical aberration of a disc having a small effective diameter of the objective lens.
- a voltage between the supply voltage supplied to the extraction electrode connected to the concentric electrode located adjacent to the single concentric electrode is supplied.
- a liquid crystal optical element comprises a first transparent substrate having a first electrode, a second transparent substrate having a second electrode, and the first transparent substrate and the second substrate.
- a liquid crystal cell having a liquid crystal layer sealed between transparent substrates, and power supply means for supplying a voltage to the first electrode and the second electrode; and the first electrode by the power supply means
- a plurality of concentric electrodes arranged concentrically in a direction from the center to the periphery of the core, and the plurality of concentric electrodes constituting the first electrode being divided into two or more concentric electrode groups
- the second electrode is concentrically arranged from the center of the second transparent substrate toward the outer periphery.
- the plurality of concentric electrodes which are formed of a plurality of concentric electrodes and which constitute the second electrode are divided into two or more concentric electrode groups, and adjacent concentric electrodes among the concentric electrodes belonging to each concentric electrode group It is characterized in that the concentric electrodes at both ends of the concentric electrodes belonging to each concentric electrode group are connected to the above-mentioned power supply means via the extraction electrodes while being connected by resistances.
- the concentric electrode groups of the first transparent substrate and the second transparent substrate are concentric.
- the first transparent substrate is independent of any of the concentric electrode groups of the first transparent substrate, A concentric single concentric electrode concentric with the concentric electrode of the first transparent substrate is further provided, and the single concentric electrode is connected to the power supply means through the lead electrode.
- the present invention by changing the voltage applied to the single concentric electrode, it is possible to match the peak position of the correction aberration with the peak position of the generated difference that changes according to the laser beam used.
- a concentric electrode group closer to the center of the liquid crystal cell Is a first concentric electrode group, and the concentric electrode group near the outer periphery of the liquid crystal cell is a second concentric electrode group, and a plurality of concentric electrode groups provided on the second transparent substrate,
- the concentric electrode group near the center of the liquid crystal cell is a third concentric electrode group and the concentric electrode group near the outer periphery of the liquid crystal cell is a fourth concentric electrode group
- the single concentric electrode is the first concentric electrode group.
- the present invention is characterized in that it is provided between the concentric electrode group and the second concentric electrode group. According to the invention, use is made by applying appropriate voltages to the first concentric electrode group, the second concentric electrode group, the single concentric electrode, the third concentric electrode group and the fourth concentric electrode group. When the laser light is changed, the difference in the effective diameter of the objective lens and the difference in the peak position of the generated aberration can be eliminated.
- each concentric electrode belonging to the third concentric electrode group includes each concentric electrode and the first concentric electrode dip.
- it has a width that produces a voltage distribution that causes aberrations of approximately the opposite phase with respect to the central force of the liquid crystal cell and the aberration that increases in the middle to the force toward the outer periphery of the liquid crystal cell. It is characterized by According to the present invention, since the central force of the liquid crystal cell can also be increased to the outer periphery halfway to the midway to almost offset the generated aberration reaching the peak, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group includes each concentric electrode and the fourth concentric electrode dip.
- the center and the periphery of the liquid crystal cell and has a width that produces a voltage distribution that generates an aberration approximately in antiphase with respect to a decrease in the distance from the middle to the periphery of the liquid crystal cell.
- residual aberration can be reduced because the occurrence aberration can be roughly canceled by decreasing from the peak between the center and the outer periphery of the liquid crystal cell to the outer periphery.
- each concentric electrode belonging to the third concentric electrode group includes each concentric electrode and the first concentric electrode dip.
- the central force of the liquid crystal cell also has a width that produces a voltage distribution that causes an aberration that is approximately in antiphase to an aberration that decreases toward the outer periphery halfway.
- the central force of the liquid crystal cell can also be reduced to the outer periphery halfway to the midway of the force and the generated aberration reaching the peak can be almost offset, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group includes each concentric electrode and the fourth concentric electrode dip.
- the width that produces a voltage distribution that generates an aberration that is approximately in antiphase with respect to a difference that increases from the middle to the periphery of the liquid crystal cell.
- the power supply means is provided on the first transparent substrate at a lead-out electrode connected to the single concentric electrode. It supplies the same voltage as the voltage supplied to one extraction electrode connected to one of the plurality of concentric electrode groups. According to the invention Then, by applying appropriate voltages to the first concentric electrode group, the second concentric electrode group, the third concentric electrode group, and the fourth concentric electrode group, the laser light used is changed. It is possible to eliminate the difference in the effective diameter of the objective lens and the difference in the peak position of the generated aberration.
- the power source unit is configured to use the single concentric electrode when correcting spherical aberration of a disk having a small effective diameter of an objective lens.
- a voltage between the supply voltage supplied to the extraction electrode connected to the concentric electrode located adjacent to the single concentric electrode is supplied.
- the power source unit is configured to provide the single concentric electrode when correcting spherical aberration of a disk having a large effective diameter of an objective lens.
- a liquid crystal optical element comprises: a first transparent substrate having a first electrode; a second transparent substrate having a second electrode; A liquid crystal cell having a liquid crystal layer sealed between the first transparent substrate and the second transparent substrate; power supply means for supplying a voltage to the first electrode and the second electrode; A liquid crystal optical element, comprising: a refractive index distribution in a plane of the liquid crystal cell that changes according to a voltage applied between the first electrode and the second electrode by the power supply unit.
- the first electrode is composed of a plurality of concentric electrodes arranged concentrically from the center to the outer periphery of the first transparent substrate, and the spherical aberration of the disc having a large effective diameter of the objective lens.
- the first correction means for correcting the light intensity is formed using all of the plurality of concentric electrodes, the effective diameter of the objective lens is small, and the second correction means for correcting the spherical aberration of the disc is the plurality of concentric lights. It is characterized by using a concentric electrode from the center of the first transparent substrate to the periphery of the first electrode among the electrodes.
- a liquid crystal optical element includes a first transparent substrate having a first electrode, a second transparent substrate having a second electrode, and the first transparent substrate and the second substrate.
- a liquid crystal cell having a liquid crystal layer sealed between transparent substrates, and power supply means for supplying a voltage to the first electrode and the second electrode; and the first electrode by the power supply means
- the concentric electrodes are arranged concentrically from the center to the periphery of the core, and the plurality of concentric electrodes are divided into two or more concentric electrode groups, and the concentric electrodes belonging to each concentric electrode group are The concentric electrodes adjacent to each other are connected by resistance, and the effective diameter of the objective lens is
- the first correction means for correcting the spherical aberration of the threshold disc is constructed using all of the two or more concentric electrode groups, and the effective diameter of the objective lens is small!
- the first correction for correcting the spherical surface aberration of the disc is characterized in that it is configured using a concentric electrode group in the middle of the force toward the outer periphery of the first transparent substrate of the two or more concentric electrode groups.
- an appropriate voltage corresponding to the laser beam for the disc having a large effective diameter of the objective lens is applied to the concentric electrodes constituting the first correction means.
- corrected aberration an aberration
- generated aberration an aberration generated in a state where the aberration is not corrected by the liquid crystal optical element.
- the first transparent substrate is independent without belonging to any concentric electrode group, and has the same center as the concentric electrode. It is characterized in that a concentric single concentric electrode is further provided. According to the present invention, by changing the voltage applied to the single concentric electrode, it is possible to match the peak position of the correction aberration with the peak position of the generated aberration which changes in accordance with the laser beam used.
- the single concentric electrode is provided between the one concentric electrode group and another concentric electrode group.
- the present invention by applying appropriate voltages to the single concentric electrode and the two concentric electrode groups sandwiching the single concentric electrode, the difference and generation of the effective diameter of the objective lens when the laser light used is changed. The difference in peak position of aberration can be eliminated.
- the first correction means may be a first concentric electrode group near the center of the liquid crystal cell and an outer circumference of the liquid crystal cell.
- a second concentric electrode group is constituted, and the second correction means is constituted by the first concentric electrode group.
- an appropriate voltage is applied to the concentric electrodes belonging to the first concentric electrode group and the concentric electrodes belonging to the second concentric electrode group in accordance with the laser beam to the disc having a large effective diameter of the objective lens. As a result, it is possible to generate a correction aberration for the generated aberration.
- a correction aberration for the generated aberration may be generated by applying, to the concentric electrodes belonging to the first concentric electrode group, an appropriate voltage according to the laser light for the disk having a small effective diameter of the objective lens. it can. Therefore, the residual aberration can be reduced for both the laser beam for a disk having a large effective diameter of the objective lens and the laser beam for a disk having a small effective diameter of the objective lens.
- each concentric electrode belonging to the first concentric electrode group is disposed between each concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that produces a voltage distribution that generates an aberration of approximately the opposite phase with respect to an aberration that increases during the force toward the outer periphery of the central force of the liquid crystal cell. Ru.
- the central force of the liquid crystal cell can also be increased to the outer circumference halfway to the midway to almost cancel the generated aberration reaching the peak, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group is disposed between the concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that causes a voltage distribution to generate an aberration of approximately opposite phase with respect to an aberration which decreases between the center and the outer periphery of the liquid crystal cell. According to the present invention, since the peak force decreases between the center and the outer periphery of the liquid crystal cell and the generation aberration can be approximately canceled, residual aberration can be reduced.
- each concentric electrode belonging to the first concentric electrode group is disposed between the concentric electrode and the second electrode.
- the liquid crystal cell is characterized in that it has a width that generates a voltage distribution that generates approximately opposite phase aberration with respect to the aberration that decreases in the middle of the force toward the outer periphery of the central force of the liquid crystal cell. According to the present invention, since the central force of the liquid crystal cell can also be reduced to the outer periphery halfway to the midway, and the generated aberration reaching the peak can be almost canceled out, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group is disposed between the concentric electrode and the second electrode.
- the voltage distribution has a width that produces an aberration that is approximately in antiphase with an aberration that increases from the middle to the outer periphery of the liquid crystal cell to the outer periphery. According to the present invention, since the intermediate force between the center and the outer periphery of the liquid crystal cell and the peak force increase between the outer periphery as well can almost cancel the generated aberration, it is possible to reduce the residual aberration.
- the power source unit is configured to use the single concentric electrode when correcting spherical aberration of a disk having a small effective diameter of an objective lens. And a voltage supplied to a concentric electrode located adjacent to the single concentric electrode among the concentric electrodes belonging to the first concentric electrode group, and the single concentricity of the concentric electrodes belonging to the second concentric electrode group Supply to the concentric electrode located next to the electrode And supplying a voltage between the pressure and the pressure.
- the peak position of the correction aberration is closer to the center of the liquid crystal cell, the effective diameter of the objective lens is small! / And the spherical aberration of the disc can be corrected.
- a liquid crystal optical element includes a first transparent substrate having a first electrode, a second transparent substrate having a second electrode, and the first transparent substrate and the second substrate.
- a liquid crystal cell having a liquid crystal layer sealed between transparent substrates, and power supply means for supplying a voltage to the first electrode and the second electrode; and the first electrode by the power supply means
- a plurality of concentric electrodes arranged concentrically in a direction from the center to the outer periphery, and the second electrode is arranged concentrically with the central force of the second transparent substrate directed toward the outer periphery Spherical aberration of the disc, which is composed of several concentric electrodes and the effective diameter of the objective lens is large.
- the first correction means for correcting the light intensity is constituted by using all concentric electrodes arranged on the first transparent substrate and all concentric electrodes arranged on the second transparent substrate
- a second correction means for correcting the spherical aberration of the disc having a small effective diameter of the objective lens is a center force of the plurality of concentric electrodes disposed on the first transparent substrate, and It is characterized by using a concentric electrode and a concentric electrode between the center of the plurality of concentric electrodes disposed on the second transparent substrate and the middle of the facing toward the outer periphery.
- a concentric electrode constituting the first correction means is suitable according to the laser beam for a disc having a large effective diameter of the objective lens.
- the concentric electrodes constituting the second correction means are generated by applying an appropriate voltage according to the laser beam to the disc having a small effective diameter of the objective lens. Correction aberrations for aberrations can be generated. Therefore, the residual aberration can be reduced even when the effective diameter of the objective lens is small and the effective diameter of the objective lens is small.
- a liquid crystal optical element includes a first transparent substrate having a first electrode, a second A liquid crystal cell having a liquid crystal layer sealed between the first transparent substrate and the second transparent substrate, the first electrode and the second electrode, and Power supply means for supplying a voltage to the pole, the refractive index distribution in the plane of the liquid crystal cell being responsive to the voltage applied between the first electrode and the second electrode by the power supply means
- the first electrode is concentrically arranged from the center to the outer periphery of the first transparent substrate, and a part of the first electrode is grouped to form a concentric electrode group.
- the second electrode is disposed concentrically toward the outer periphery of the central force of the second transparent substrate, and a part of the second electrode is grouped to be concentric. Consisting of multiple concentric electrodes that make up an electrode group, each concentric electrode Adjacent concentric electrodes of the concentric electrodes belonging to the group are connected by a resistor, and the first correction means for correcting the spherical aberration of the disc having a large effective diameter of the objective lens is all concentric electrode groups.
- a second correction unit configured to correct the spherical aberration of the disk, which is configured using the objective lens having a small effective diameter, is configured using the concentric electrode group halfway to the center force of the liquid crystal cell. It is characterized by
- the concentric electrode group of the first transparent substrate and the other concentric electrodes not belonging thereto are provided. And, by applying an appropriate voltage according to the laser beam to be used to the concentric electrode group of the second transparent substrate and other concentric electrodes not belonging to it, it is possible to generate a correction aberration for the generated difference. Therefore, residual aberration can be reduced.
- the first transparent substrate is independent of the concentric electrode group of the first transparent substrate. It is characterized in that a concentric single concentric electrode having the same center as the concentric electrode of the transparent substrate is further provided. According to the present invention, by changing the voltage applied to the single concentric electrode, it is possible to match the peak position of the correction aberration with the peak position of the generated aberration which changes according to the laser beam used.
- the concentric electrode group disposed on the second transparent substrate and near the center of the liquid crystal cell is of
- the single concentric electrode is the first concentric electrode.
- a group is provided between the concentric electrode on the first transparent substrate and the second concentric electrode group facing each other.
- the first concentric electrode group, the concentric electrode facing the first concentric electrode group, the single concentric electrode, the second concentric electrode group, and the concentric electrode facing the second concentric electrode group are suitable. By applying an appropriate voltage, it is possible to eliminate the difference in the effective diameter of the objective lens and the difference in the peak position of the generated aberration when the laser light to be used is changed.
- each concentric electrode belonging to the first concentric electrode group corresponds to each concentric electrode and the first transparent substrate facing each other. It has a width that produces a voltage distribution between the upper concentric electrode and the center electrode of the liquid crystal cell that causes an aberration that is approximately out of phase with an aberration that increases while traveling toward the outer periphery of the liquid crystal cell. It is characterized by According to the present invention, it is possible to approximately cancel out the generated aberration reaching a peak by increasing the caro in the middle of the force toward the central force outer periphery of the liquid crystal cell, so it is possible to reduce the residual aberration.
- each concentric electrode belonging to the second concentric electrode group corresponds to each concentric electrode and the second transparent substrate facing each other. It has a width that produces a voltage distribution that generates an approximately antiphase aberration with respect to an aberration that decreases between the center and the outer periphery of the liquid crystal cell, with the upper concentric electrode. It is characterized by According to the present invention, it is possible to approximately cancel out the generation aberration which decreases from the peak between the center and the outer periphery of the liquid crystal cell and to reduce the residual aberration.
- each concentric electrode belonging to the first concentric electrode group corresponds to each concentric electrode and the first transparent substrate facing each other. It has a width that produces a voltage distribution between the upper concentric electrode and the center electrode of the liquid crystal cell that produces an aberration that is approximately out of phase with the aberration that decreases halfway through toward the outer periphery. It is characterized by According to the invention, the central force of the liquid crystal cell is The residual aberration can be reduced because the generation aberration which decreases and reaches a peak can be roughly canceled during the course toward the circumference.
- each concentric electrode belonging to the second concentric electrode group is the second transparent substrate on which the respective concentric electrodes face each other. It has a width that produces a voltage distribution that generates approximately reverse phase aberration with respect to the aberration that increases between the center and the outer periphery of the liquid crystal cell with the upper concentric electrode. It is characterized by According to the present invention, it is possible to approximately cancel out the aberration which increases from the peak between the center and the periphery of the liquid crystal cell and to the periphery, so residual aberration can be reduced.
- the power source unit is configured to use the single concentric electrode when correcting the spherical aberration of a disc having a small effective diameter of the objective lens.
- a voltage supplied to a concentric electrode located closer to the single concentric electrode among the concentric electrodes belonging to the first concentric electrode group, and the voltage among the concentric electrodes belonging to the second concentric electrode group is supplied.
- a liquid crystal optical element comprises a first transparent substrate having a first electrode, a second transparent substrate having a second electrode, and the first transparent substrate and the second substrate.
- a liquid crystal cell having a liquid crystal layer sealed between transparent substrates, and power supply means for supplying a voltage to the first electrode and the second electrode; and the first electrode by the power supply means
- the second electrode is concentrically arranged from the center of the second transparent substrate toward the outer periphery. Multiple consists of concentric electrodes, and the plurality of concentric electrodes constituting the second electrode is divided into two or more concentric electrode group, belonging to the concentric electrode group was
- the first correction means for correcting the spherical aberration of the disc in which adjacent concentric electrodes of the concentric electrodes are connected by resistance and the effective diameter of the objective lens is large, is configured using all the concentric electrode groups.
- the second correction means for correcting the spherical aberration of the disc has a small effective diameter of the objective lens, and is constructed using a concentric electrode group in the middle of the force toward the outer periphery of the liquid crystal cell. It is characterized by
- the effective diameter of the objective lens is provided to the concentric electrodes constituting the first correction means.
- the effective diameter of the laser beam and the objective lens for the disk having a large effective diameter of the objective lens are small, and the residual aberration can be reduced even with respect to the displacement of the laser beam for the disk.
- the first transparent substrate is independent of any of the concentric electrode groups of the first transparent substrate, A concentric single concentric electrode concentric with the concentric electrode of the first transparent substrate is further provided. According to the present invention, by changing the voltage applied to the single concentric electrode, it is possible to match the peak position of the correction aberration with the peak position of the generated aberration which changes in accordance with the laser beam used.
- the single concentric electrode is provided between the two concentric electrode groups disposed on the first transparent substrate. It is characterized by According to the present invention, by applying appropriate voltages to a single concentric electrode and two concentric electrode groups sandwiching the single concentric electrode, the difference in the effective diameter of the objective lens when the laser light used is changed, or It is possible to eliminate the difference in peak position of the generated aberration.
- the liquid crystal optical element in the invention described above, among the plurality of concentric electrode groups provided on the first transparent substrate, the liquid crystal optical element may be the same as the one near the center of the liquid crystal cell.
- the cardiac electrode group is a first concentric electrode group
- the concentric electrode group near the outer periphery of the liquid crystal cell is a second concentric electrode group
- a plurality of concentric electrode groups provided on the second transparent substrate is provided on the second transparent substrate.
- the correction means comprises the first concentric electrode group, the second concentric electrode group, the third concentric electrode group, and the fourth concentric electrode group
- the second correction means comprises It is characterized by comprising one concentric electrode group and the third concentric electrode group. According to the present invention, in the concentric electrodes belonging to each of the first concentric electrode group, the second concentric electrode group, the third concentric electrode group and the second concentric electrode group, the effective diameter of the objective lens is large.
- each concentric electrode belonging to the third concentric electrode group includes each concentric electrode and the first concentric electrode dip.
- the center of the liquid crystal cell has a width that generates a voltage distribution such that an aberration having an approximately opposite phase is generated with respect to an aberration that increases in the middle of the force toward the center.
- the central force of the liquid crystal cell can also be increased to the outer periphery halfway to the midway to almost offset the generated aberration reaching the peak, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group is located between the respective concentric electrode and the fourth concentric electrode group.
- a width that causes a voltage distribution such that an aberration of approximately opposite phase is generated with respect to an aberration which decreases between the center and the outer periphery of the liquid crystal cell to the outer periphery. It is characterized by According to the present invention, since it is possible to approximately cancel out the occurrence aberration by decreasing from the peak between the center and the outer periphery of the liquid crystal cell to the outer periphery, it is possible to reduce the residual error.
- each concentric electrode belonging to the third concentric electrode group includes each concentric electrode and the first concentric electrode dip.
- the central force of the liquid crystal cell also has a width that produces a voltage distribution that causes an aberration that is approximately in antiphase to an aberration that decreases toward the outer periphery halfway.
- the central force of the liquid crystal cell can also be reduced to the outer periphery halfway to the midway of the force and the generated aberration reaching the peak can be almost offset, the residual aberration can be reduced.
- each concentric electrode belonging to the second concentric electrode group includes each concentric electrode and the fourth concentric electrode dip.
- the width that produces a voltage distribution that generates an aberration that is approximately in antiphase with respect to a difference that increases from the middle to the periphery of the liquid crystal cell.
- the power source unit is configured to use the single concentric electrode when correcting the spherical aberration of a disc having a small effective diameter of the objective lens.
- a voltage supplied to a concentric electrode located closer to the single concentric electrode among the concentric electrodes belonging to the third concentric electrode group, and the voltage among the concentric electrodes belonging to the second concentric electrode group is supplied.
- the power source unit is configured to use the single concentric electrode when correcting spherical aberration of a disk having a large effective diameter of an objective lens.
- the single concentric of the concentric electrodes belonging to the second concentric electrode group It is characterized in that it supplies the same voltage as the voltage supplied to the concentric electrode located next to the electrode. According to the present invention, since the peak position of the correction aberration is closer to the outer periphery of the liquid crystal cell, it is possible to correct the spherical aberration of the disc having a large effective diameter of the objective lens.
- the resistance value of the resistors connecting the concentric electrodes belonging to the one concentric electrode group is the same. According to the present invention, an electrode can be easily produced on the surface of a transparent substrate.
- the liquid crystal optical element according to the present invention is characterized in that, in the above-mentioned invention, the resistance value of the resistors connecting the concentric electrodes belonging to each of the concentric electrode groups is the same. According to the present invention, an electrode can be more easily produced on the surface of a transparent substrate.
- liquid crystal optical element of the present invention it is possible to eliminate the difference in the effective diameter of the objective lens when using various types of laser light such as blue laser light, red laser light and infrared laser light. Play. In addition, it is possible to eliminate the difference in the peak position of the spherical aberration generated when using various laser beams such as blue laser beam, red laser beam and infrared laser beam.
- FIG. 1 is a view showing a schematic configuration of an optical head device to which a liquid crystal optical element according to the present invention is applied.
- FIG. 2 is a view showing an example of the cross-sectional configuration of a liquid crystal optical element according to the present invention.
- FIG. 3 is a view showing the relationship between the retardation of liquid crystal and the applied voltage.
- FIG. 4 is a diagram showing a first electrode of the liquid crystal optical element according to Embodiment 1 of the present invention.
- FIG. 5 is a diagram showing a second electrode of the liquid crystal optical element according to Embodiment 1 of the present invention.
- FIG. 6 is a view schematically showing the relationship between electrodes of the liquid crystal optical element according to Embodiment 1 of the present invention and applied voltage.
- FIG. 7 shows the correction aberration and occurrence and collection by the liquid crystal optical element according to Embodiment 1 of the present invention. It is a figure explaining the relation of a difference.
- FIG. 8 is a view for explaining correction of aberration by the liquid crystal optical element according to Embodiment 1 of the present invention.
- FIG. 9 is a view showing residual aberration by the liquid crystal optical element according to Embodiment 1 of the present invention.
- FIG. 10 is a view for explaining the relationship between correction aberration and generation aberration by the liquid crystal optical element according to the first embodiment of the present invention.
- FIG. 11 is a view for explaining correction of aberration by the liquid crystal optical element according to the first embodiment of the present invention.
- FIG. 12 is a view showing residual aberration by the liquid crystal optical element according to Embodiment 1 of the present invention.
- FIG. 13 is a view showing a first electrode of the liquid crystal optical element according to Embodiment 2 of the present invention.
- FIG. 14 is a view showing a second electrode of the liquid crystal optical element according to Embodiment 2 of the present invention.
- FIG. 15 is a view schematically showing the relationship between electrodes of the liquid crystal optical element according to Embodiment 2 of the present invention and applied voltage.
- FIG. 16 is a diagram for explaining correction of aberration by the liquid crystal optical element according to Embodiment 2 of the present invention.
- FIG. 17 is a diagram for explaining correction of aberration by the liquid crystal optical element according to Embodiment 2 of the present invention.
- FIG. 18 is a view for explaining aberration correction by the liquid crystal optical element according to Embodiment 2 of the present invention.
- FIG. 19 is a diagram for explaining correction of aberration by the liquid crystal optical element according to Embodiment 2 of the present invention.
- FIG. 20 is a view showing an aberration generated when blue laser light is used and an aberration generated when red laser light is used.
- a liquid crystal optical element according to the present invention is applied to a liquid crystal wavefront control element for correcting fluctuation, distortion or aberration of light wavefront.
- a DV D having a recording capacity of about 5 gigabytes is referred to as a conventional DVD
- a DVD having a higher recording density than the conventional DVD is referred to as a high density DVD to distinguish between the two. .
- FIG. 1 is a view showing a schematic configuration of an optical head device to which a liquid crystal optical element according to the present invention is applied.
- the optical head device comprises a blue laser light source 1 for emitting a blue laser light having a wavelength of about 400 nm, and a blue photodiode for detecting the return light of one laser emitted from the blue laser light source 1.
- a module for DVDZCD that integrates an infrared laser beam with a wavelength of about 780 nm, a laser light source that emits a red laser beam with a wavelength of about 660 nm, and a photodiode that detects each return light 3.
- Spherical aberration A liquid crystal cell 4 constituting a main part of a liquid crystal optical element performing wavefront control such as correction, a drive circuit 5 constituting a power source means of the liquid crystal optical element, and an objective lens 6 are provided.
- the blue laser light 7 emitted from the blue laser light source 1 is a beam shaper 8 and a polarization beam.
- the light passes through an optical splitter 9, a movable collimator 10, a dichroic mirror 11, a liquid crystal cell 4, a broadband wavelength plate 12 and an objective lens 6, and is focused on the information recording layer of the optical disc 100.
- the optical disc 100 in this case is a high density DVD, and has an information recording layer 101 at a depth of, for example, 0.1 mm from the surface on which the laser beam is irradiated.
- the return light 13 of the blue laser light reflected by the information recording layer 101 passes through the objective lens 6, the broadband wave plate 12, the liquid crystal cell 4, the dichroic aperture mirror 11, the movable collimator 10, the polarization beam splitter 9 and the lens 14 Light is collected to the photodiode 2.
- the red laser light (or infrared laser one light) 15 emitted from the module 3 for DVDZCD comprises the lens 16, the dichroic mirror 11, the liquid crystal cell 4, the broadband wavelength plate 12 and the objective lens 6. Then, the light is collected on the information recording layer of the optical disc 100.
- the optical disk 100 in this case is a conventional DVD for red laser light and a CD for infrared laser light.
- the information recording layer 102 of the conventional DVD and the information recording layer 103 of the CD are provided at a depth of, for example, 0.6 mm and 1.2 mm from the surface on which the laser light is irradiated.
- the return light 17 of the red laser light (or infrared laser light) reflected by the information recording layer 102 (or the information recording layer 103) is an objective lens 6, a broadband wave plate 12, a liquid crystal cell 4, a dichroic aperture mirror
- the light is focused on the DVD / CD module 3 through the lens 11 and the lens 16.
- the optical head device according to the present embodiment is designed to minimize the aberration generated when the infrared laser light is irradiated to the CD in the configuration excluding the liquid crystal cell 4 and the drive circuit 5. Therefore, when irradiating a CD with infrared laser light, correction of spherical aberration is not necessary.
- the spherical aberration needs to be corrected by the liquid crystal cell 4 and the drive circuit 5.
- FIG. 2 is a view showing a cross-sectional configuration of the liquid crystal cell 4.
- the liquid crystal cell 4 includes a first transparent substrate 22 having a first electrode 21 on the surface, a second transparent substrate 24 having a second electrode 23 on the surface, and a sealing material 25.
- the liquid crystal layer 26 is sealed.
- Alignment films 27 and 28 are provided between the first electrode 21 and the liquid crystal layer 26 and between the second electrode 23 and the liquid crystal layer 26, respectively.
- the first electrode 21 and the second electrode 23 A voltage is supplied from the drive circuit 5 (see FIG. 1) so that a desired voltage (AC voltage) is applied to the layer 26.
- AC voltage AC voltage
- the force liquid crystal cell 4 in which the first electrode 21 and the second electrode 23 are each formed into a pattern as described later is manufactured by the same manufacturing process as a general liquid crystal display panel. However, after a plurality of liquid crystal cells 4 are simultaneously formed on the substrate, they are cut into individual liquid crystal cells 4.
- FIG. 3 is a view showing an example of the relationship between the retardation of liquid crystal and the applied voltage.
- a voltage range in which the retardation changes substantially linearly with the voltage applied to the liquid crystal layer (the voltage difference between the first electrode and the second electrode) is used. Correction of spherical aberration is performed.
- the characteristics shown in FIG. 3 are for a liquid crystal cell in which the alignment of the liquid crystal layer is homogeneous alignment, the cell gap is 10 m, and the refractive index is 1.5 to 1.7.
- the liquid crystal cell is driven in a voltage range of 1.8 to 3.
- OVrms with 2.4 Vrms as a reference voltage in order to correct spherical aberration.
- FIG. 4 is a view showing a pattern of the first electrode 21.
- the first electrode 21 is concentric with the center force of the first transparent substrate 22 toward the outer periphery centering on the optical axis (not shown) of the light beam passing through the liquid crystal cell 4.
- it is comprised by 13 low resistance concentric electrodes 31-43 arrange
- a gap of 3 m is provided between adjacent concentric electrodes 31 to 43, and they are mutually insulated. This gap is omitted in FIG.
- the innermost concentric electrode (hereinafter referred to as the first concentric electrode) 31 is formed in a circular shape.
- the other concentric electrodes 32 to 43 are formed in an annular shape.
- the inner force is also referred to as the second concentric electrode 32, the third concentric electrode 33,..., And the thirteenth concentric electrode 43 in order.
- the first to fifth concentric electrodes 31 to 35 constitute a first concentric electrode group 44.
- the first concentric electrode group 44 constitutes a second correction means.
- the fifth concentric electrodes 35 are connected by resistances (not shown) (see FIG. 6) of the same resistance (referred to as R1).
- the first extraction electrode 46 and the second extraction electrode 47 are connected to the first concentric electrode 31 and the fifth concentric electrode 35 located at both ends of the first concentric electrode group 44, respectively! Ru.
- the seventh to thirteenth concentric electrodes 37 to 43 constitute a second concentric electrode group 45.
- the second concentric electrode group 45 and the first concentric electrode group 44 together constitute a first correction means.
- the eleventh concentric electrode 41, the eleventh concentric electrode 41 and the twelfth concentric electrode 42, and the twelfth concentric electrode 42 and the thirteenth concentric electrode 43 respectively show the same resistance value (given as R2) Connected by the omitted resistance (see Figure 6).
- the third extraction electrode 48 and the fourth extraction electrode 49 are connected to the seventh concentric electrode 37 and the thirteenth concentric electrode 43 located at both ends of the second concentric electrode group 45, respectively. .
- the sixth concentric electrode 36 is provided between the first concentric electrode group 44 and the second concentric electrode group 45, and the first concentric electrode group 44 and the second concentric electrode group 45 are provided. It is an independent electrode (single concentric electrode) which does not belong to any of them. Thus, the sixth concentric electrode 36 is insulated from its neighboring fifth concentric electrode 35 and seventh concentric electrode 37.
- the fifth extraction electrode 50 is connected to the sixth concentric electrode 36.
- the first lead-out electrode 46, the second lead-out electrode 47, the third lead-out electrode 48, the fourth lead-out electrode 49, and the fifth lead-out electrode 50 have concentric electrodes other than the concentric electrodes to which they are connected. It is connected to the drive circuit 5 (see Fig. 1) in a state of being isolated as much as possible.
- FIG. 5 is a view showing a pattern of the second electrode 23.
- the second electrode 23 is, for example, a circular uniform low resistance electrode.
- the second electrode 23 is larger than or equal to the force that is the same size as the first electrode 21.
- a sixth extraction electrode 51 is connected to the second electrode 23.
- a ground voltage is also supplied to the sixth extraction electrode 51 as the driving circuit 5 power.
- a wavefront aberration correction pattern for correcting coma aberration, spherical aberration, astigmatism and the like may be provided in the whole or a part of the second electrode 23.
- FIG. 6 is a view schematically showing the relationship between each of the concentric electrodes 31 to 43 and the second electrode 23 and the voltage applied between them.
- the ground voltage is supplied to the second electrode 23.
- the first concentric electrode 31 is supplied with a voltage VI relative to the ground voltage.
- the fifth concentric electrode 35 is supplied with a voltage V2 relative to the ground voltage.
- Sixth The concentric electrode 36 is supplied with a voltage V3 relative to the ground voltage.
- the seventh concentric electrode 37 is supplied with a voltage V4 with respect to the ground voltage.
- the thirteenth concentric electrode 43 is supplied with a voltage V5 with respect to the ground voltage.
- an in-plane distribution is generated in the voltage applied to the liquid crystal layer of the liquid crystal cell.
- an in-plane distribution occurs in the refractive index of the liquid crystal cell, and the phase of light transmitted through the liquid crystal cell changes in accordance with the transmitting portion in the plane of the liquid crystal cell. That is, the liquid crystal cell functions as a wavefront control element.
- the voltage values V1 to V5 change, the in-plane distribution of the voltage applied to the liquid crystal layer changes, and the in-plane refractive index distribution of the liquid crystal cell changes.
- the in-plane refractive index changes concentrically. Since the liquid crystal is driven by alternating current, voltages VI, V2, V3, V4 and V5 are effective values.
- V1 to V5 when the blue laser light is irradiated to the high density DVD is determined based on the following equations (1) and (2).
- the reference noise is VO
- the number of divisions between VI and V2 is n.
- V1 to V5 when the first electrode 21 is configured as shown in FIG. 4 and FIG. 6 (n 5) based on the equations (1) and (2).
- V2 1. 92 Vrms.
- the voltage value of the reference bias is 2. 4 Vrms.
- the generated aberration and the correction aberration are two-dimensionally represented, and a value obtained by standardizing the generated aberration amount and the correction aberration amount on the vertical axis and the distance in the radial direction of the horizontal axis.
- the W-shaped generated aberration gradually decreases and reaches a peak gradually from the center of the objective lens 6 (see FIG. 1) to the middle toward the outer circumference, and gradually increases on the outer circumference side. It is shown.
- the M-shaped correction aberration 57 which changes stepwise with respect to the W-shaped generated aberration 56 cancels the aberration and reduces the residual aberration.
- FIG. 8 is a diagram in which a part of the generated aberration 56 in FIG. 7 and the corresponding correction aberration 57 are superimposed in order to see the degree of coincidence between the generated aberration and the correction aberration.
- FIG. 8 only the portion corresponding to the radius of the liquid crystal cell is shown (the same applies to FIGS. 11 and 16 to 19) for the sake of clarity.
- the effective diameter (pupil diameter) of the objective lens 6 (see FIG. 1) is large. Therefore, by providing a difference between V4 and V5, the entire effective area of the liquid crystal cell is obtained. Correct the aberration with.
- the first concentric electrode 43 is equal to or larger than the effective diameter (pupil diameter) of the objective lens 6 (see FIG. 1) for blue laser light.
- An electrode 21 and a second electrode 23 are formed.
- the residual aberration 58 is shown in FIG. When the residual aberration 58 of FIG. 9 is compared with the generated aberration 56 of FIG. 7, it can be seen that the aberration is sufficiently reduced.
- V1 to V5 when the red laser light is irradiated to the conventional type DVD is determined based on the following equations (3) and (4).
- V2-V0 2 (V3-V0) ⁇ ⁇ ⁇ (4)
- the generated aberration and the correction aberration at this time are shown in FIG.
- the M-shaped correction aberration 60 which changes stepwise with respect to the W-shaped generated aberration 59 cancels the aberration and reduces the residual aberration.
- the W-shaped correction aberration which changes stepwise is generated to cancel the aberration and reduce the residual aberration.
- FIG. 11 is a diagram in which a part of the generated aberration 59 in FIG. 10 and the corresponding correction aberration 60 are superimposed in order to see the degree of coincidence between the generated aberration and the correction aberration.
- the effective diameter (pupil diameter) of the objective lens 6 is small, so by making V4 and V5 the same, the effective region of the liquid crystal cell , Aberration correction at the outer peripheral part It is invalidated and the aberration correction target area is narrowed.
- the sixth concentric electrode (single concentric electrode) 36 is smaller than the effective diameter (pupil diameter) of the objective lens 6 (see FIG. 1) for red laser light, and at least a portion of the seventh concentric electrode 37 is red.
- the first electrode 21 and the second electrode 23 are formed so as to be larger than the effective diameter (pupil diameter) of the objective lens 6 (see FIG. 1) for laser light.
- the residual aberration 61 is shown in FIG. When residual aberration 61 in FIG. 12 is compared with generated aberration 59 in FIG. 10, it can be seen that the aberration is sufficiently reduced.
- the widths of the concentric electrodes 31 to 43, the resistance value R1 of the resistance connecting the first to fifth concentric electrodes 31 to 35, and the resistance value of the resistances connecting the seventh to thirteenth concentric electrodes 37 to 43 The resistance values R2 and V1 to V5 are as close as possible to the opposite phase of one or both of the generated aberration 56 for the blue laser light and the generated aberration 59 for the red laser light, and the pattern correction error It is selected appropriately to obtain 57, 60.
- the resistance value R1 and the resistance value R2 may be the same value or different values. Also, the voltage values of V1 to V5 may all be different.
- the values of the resistances connecting the concentric electrodes 31 to 35 belonging to the first concentric electrode group 44 do not have to be the same, and the concentric electrodes 37 to 43 belonging to the second concentric electrode group 45 The values of the resistors to be connected do not have to be all the same.
- FIGS. 13 and 14 show patterns of the first electrode 121 and the second electrode 123 in the second embodiment, respectively.
- FIG. 15 is a diagram schematically showing the relationship between the first and second electrodes 121 and 123 and the voltage applied between them.
- a seventh concentric electrode (a single concentric electrode) 36 is connected to the first electrode 121, and seventh to thirteenth concentrically connected by resistance similarly to the first embodiment. Electrodes 37-43 are provided.
- the inner side of the sixth concentric electrode 36 that is, the first to fifth in the first embodiment.
- the region in which the concentric electrodes 31 to 35 are provided is a uniform circular fourteenth concentric electrode 71.
- a gap of 3 ⁇ m is provided between the fourteenth concentric electrode 71 and the sixth concentric electrode 36.
- a seventh extraction electrode 72 is connected to the fourteenth concentric electrode 71.
- a ground voltage is also supplied to the fourteenth concentric electrode 71 via the seventh lead-out electrode 72.
- the sixth concentric electrode 36, the seventh concentric electrode 37 and the thirteenth concentric electrode 43 are connected to the ground voltage through the fifth extraction electrode 50, the third extraction electrode 48 and the fourth extraction electrode 49, respectively.
- the second electrode 123 is provided with first to fifth concentric electrodes 31 to 35.
- the outer side of the fifth concentric electrode 35 that is, the region where the sixth to thirteenth concentric electrodes 36 to 43 are provided in the first embodiment is a uniform annular fifteenth concentric electrode 73. .
- a gap of, for example, is provided between the fifteenth concentric electrode 73 and the fifth concentric electrode 35.
- An eighth extraction electrode 74 is connected to the fifteenth concentric electrode 73.
- the fifteenth concentric electrode 73 is supplied with a voltage V 2 from the drive circuit 5 with respect to the ground voltage via the eighth lead-out electrode 74.
- the first concentric electrode 31 and the fifth concentric electrode 35 are supplied with voltages VI and V2 with respect to the ground voltage via the first extraction electrode 46 and the second extraction electrode 47, respectively.
- the first to fifth concentric electrodes 31 to 35 correspond to the first concentric electrode group 75
- the seventh to thirteenth concentric electrodes 37 to 43 correspond to the second concentric electrode group 76.
- the fourteenth concentric electrode 71 is an electrode facing the first concentric electrode group 75
- the fifteenth concentric electrode 73 is an electrode facing the second concentric electrode group 76.
- a wavefront aberration correction pattern for correcting coma aberration, spherical aberration, astigmatism and the like may be provided in the whole or a part of the area of the fourteenth concentric electrode 71. The same is true for the fifteenth concentric electrode 73!
- the first correction means is composed of the first concentric electrode group 75, the fourteenth concentric electrode 71, the second concentric electrode group 76 and the fifteenth concentric electrode 73.
- the second correction means is constituted by the first concentric electrode group 75 and the fourteenth concentric electrode 71.
- the other configuration is the same as that of the first embodiment, and therefore redundant description will be omitted.
- the other configuration is the same as that of the first embodiment, and therefore the description will not be repeated.
- V 1 to V 5 when the high density DVD is irradiated with the blue laser light are determined based on the above equations (1) and (2), and red in the conventional DVD V1 to V5 at the time of irradiating a laser beam are determined based on the equations (3) and (4). Therefore, although not particularly limited, the specific example of values of V1 to V5 is the same as that of the first embodiment.
- FIG. 16 and FIG. 17 are diagrams showing the contribution of the first electrode 121 and the contribution of the second electrode 123 to the correction aberration when the high density DVD is irradiated with the blue laser light, respectively.
- the respective portions where the respective concentric electrodes 71, 36, 37-43 constituting the first electrode 121 and the respective concentric electrodes 31 to 35, 73 constituting the second electrode 123 are opposed to each other.
- the voltage applied to the liquid crystal cell is the same as that of the first embodiment. Therefore, the correction aberration obtained by combining the contribution 81 to the correction aberration by the first electrode 121 shown in FIG. 16 and the contribution 82 to the correction aberration by the second electrode 123 shown in FIG. 17 is the correction shown in FIG. Same as aberration 57.
- FIGS. 18 and 19 show the contribution of the first electrode 121 and the contribution of the second electrode 123 to the correction aberration when the conventional type DVD is irradiated with the red laser light, respectively.
- the correction aberration obtained by combining the contribution 83 to the correction aberration by the first electrode 121 shown in FIG. 18 and the contribution 84 to the correction aberration by the second electrode 123 shown in FIG. 19 is the correction aberration 60 shown in FIG. Will be the same.
- the difference in the effective diameter of the objective lens in the case of using various types of laser light such as blue laser light, red laser light and infrared laser light, and There is an effect that it is possible to eliminate the difference in the peak position of the spherical aberration generated in the case of.
- a plurality of transparent high-resistance electrodes having a resistance gradient are used instead of the configuration in which a plurality of low-resistance concentric electrodes belonging to the same concentric electrode group are connected by resistance as in the present embodiment.
- Concentric electrodes are formed, and voltage drop produced when different voltages are applied to the electrodes causes in-plane distribution in the voltage applied to the liquid crystal layer, thereby causing liquid It is conceivable to generate a correction aberration by changing the in-plane distribution of the refractive index of the crystal cell.
- the present invention is not limited to the above-described embodiment, and various modifications can be made.
- the number of concentric electrode groups constituting the first electrode 21 may be three or more.
- the number of concentric electrode groups constituting the first electrode 121 and the second electrode 123 may be two or more.
- the area force of the fourteenth concentric electrode 71 may be a concentric electrode group in which a plurality of concentric electrodes are connected by a resistor, or a plurality of independent concentric electrodes V, Well. The same applies to the area of the fifteenth concentric electrode 73!
- the number of concentric electrodes belonging to each concentric electrode group may be increased or decreased, or the number of single concentric electrodes may be two or more.
- the single concentric electrode may be provided only on the second electrode 123 or may be provided on both the first electrode 121 and the second electrode 123.
- the numerical values described in the embodiments are merely examples, and the present invention is not limited to these values.
- the liquid crystal optical element according to the present invention is useful for an apparatus that requires aberration correction, and in particular, records information on an optical disc or reads information recorded on an optical disc. Suitable for an optical head device incorporated in the device.
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- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Nonlinear Science (AREA)
- Geometry (AREA)
- Mathematical Physics (AREA)
- General Physics & Mathematics (AREA)
- Liquid Crystal (AREA)
- Optical Head (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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JP2007505848A JP4712796B2 (ja) | 2005-03-03 | 2006-02-17 | 液晶光学素子 |
CN2006800067791A CN101133449B (zh) | 2005-03-03 | 2006-02-17 | 液晶光学元件 |
US11/885,180 US7839458B2 (en) | 2005-03-03 | 2006-02-17 | Liquid crystal optical element having grouped concentric electrodes |
Applications Claiming Priority (4)
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JP2005-059304 | 2005-03-03 | ||
JP2005059305 | 2005-03-03 | ||
JP2005-059305 | 2005-03-03 | ||
JP2005059304 | 2005-03-03 |
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WO2006092968A1 true WO2006092968A1 (ja) | 2006-09-08 |
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PCT/JP2006/302847 WO2006092968A1 (ja) | 2005-03-03 | 2006-02-17 | 液晶光学素子 |
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US (1) | US7839458B2 (ja) |
JP (1) | JP4712796B2 (ja) |
CN (1) | CN101133449B (ja) |
WO (1) | WO2006092968A1 (ja) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1930766A1 (en) | 2006-12-04 | 2008-06-11 | Funai Electric Co., Ltd. | Abberation correction apparatus |
EP1942499A1 (en) * | 2006-12-26 | 2008-07-09 | Funai Electric Co., Ltd. | Optical pickup comprising liquid crystal element with diffraction and phase shift electrodes |
US7715298B2 (en) | 2005-12-26 | 2010-05-11 | Hitachi Media Electronics Co., Ltd. | Optical pickup and optical information reproducing apparatus using same |
US20110025955A1 (en) * | 2009-06-19 | 2011-02-03 | Kent State University | Tunable electro-optic liquid crystal lenses and methods for forming the lenses |
US10599006B2 (en) | 2016-04-12 | 2020-03-24 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
US11397367B2 (en) | 2016-04-12 | 2022-07-26 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
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TW201502648A (zh) * | 2013-07-12 | 2015-01-16 | Silicon Touch Tech Inc | 液晶透鏡以及液晶透鏡模組 |
US9151971B2 (en) * | 2013-09-17 | 2015-10-06 | Boe Technology Group Co., Ltd | Liquid crystal lens and stereoscopic display device |
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DE60043531D1 (de) | 1999-09-02 | 2010-01-28 | Asahi Glass Co Ltd | Optischer kopf |
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- 2006-02-17 US US11/885,180 patent/US7839458B2/en not_active Expired - Fee Related
- 2006-02-17 JP JP2007505848A patent/JP4712796B2/ja active Active
- 2006-02-17 WO PCT/JP2006/302847 patent/WO2006092968A1/ja active Application Filing
- 2006-02-17 CN CN2006800067791A patent/CN101133449B/zh not_active Expired - Fee Related
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JP2002014314A (ja) * | 2000-06-28 | 2002-01-18 | Matsushita Electric Ind Co Ltd | 光学素子および光ヘッドおよび光記録再生装置 |
JP2002056559A (ja) * | 2000-08-14 | 2002-02-22 | Asahi Glass Co Ltd | 光ヘッド装置 |
JP2004178773A (ja) * | 2002-11-29 | 2004-06-24 | Asahi Glass Co Ltd | 光ヘッド装置 |
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Publication number | Priority date | Publication date | Assignee | Title |
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US7715298B2 (en) | 2005-12-26 | 2010-05-11 | Hitachi Media Electronics Co., Ltd. | Optical pickup and optical information reproducing apparatus using same |
EP1930766A1 (en) | 2006-12-04 | 2008-06-11 | Funai Electric Co., Ltd. | Abberation correction apparatus |
US7859762B2 (en) | 2006-12-04 | 2010-12-28 | Funai Electric Co., Ltd. | Aberration correction apparatus |
EP1942499A1 (en) * | 2006-12-26 | 2008-07-09 | Funai Electric Co., Ltd. | Optical pickup comprising liquid crystal element with diffraction and phase shift electrodes |
US20110025955A1 (en) * | 2009-06-19 | 2011-02-03 | Kent State University | Tunable electro-optic liquid crystal lenses and methods for forming the lenses |
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US9280020B2 (en) * | 2009-06-19 | 2016-03-08 | Kent State University | Tunable electrode-optic liquid crystal lenses having resistive bridges and methods for forming the lenses |
US10599006B2 (en) | 2016-04-12 | 2020-03-24 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
US11054714B2 (en) | 2016-04-12 | 2021-07-06 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
US11397367B2 (en) | 2016-04-12 | 2022-07-26 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
US11662642B2 (en) | 2016-04-12 | 2023-05-30 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
US11994784B2 (en) | 2016-04-12 | 2024-05-28 | E-Vision Smart Optics, Inc. | Electro-active lenses with raised resistive bridges |
Also Published As
Publication number | Publication date |
---|---|
JPWO2006092968A1 (ja) | 2008-08-07 |
CN101133449A (zh) | 2008-02-27 |
US20080266473A1 (en) | 2008-10-30 |
JP4712796B2 (ja) | 2011-06-29 |
US7839458B2 (en) | 2010-11-23 |
CN101133449B (zh) | 2010-08-11 |
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