Abstract: In a small-sized optical pickup device for enabling to obtain a stable servo-signal, as well as, a focus error signal and a tracking error signal, without receiving ill influences of stray lights from other layers, when recording/reproducing a multi-layer optical disc, a reflection light from the multi-layer optical disc is divided into plural numbers of regions by a diffraction grating. And, it is divided into at least four (4) regions, by a division line in the tangential direction of the optical disc and a division line in the radial direction thereof. Light receiving parts, for detecting either one of grating diffraction lights, i.e.

Abstract: An optical pickup apparatus comprising a first laser unit including a first laser light source and a second laser unit including second and third laser light sources, being respectively disposed on a reflection (transmitting) surface side and a transmitting (reflection) surface side of a first beam splitter, laser lights of the first, second, and third wavelengths being guided onto a common optical path through the first beam splitter and guided to the respective sorts of optical recording mediums, each of the laser lights being divided by a diffraction grating disposed on the common optical path into a main beam and sub-beams, a second beam splitter being disposed on the upstream side of the diffraction grating on a return path of each of the laser lights, the laser lights through the second beam splitter being branched from the common optical path and being received by a photodetector.

Abstract: A method for adjusting a tilt angle of an objective lens with respect to one of a multilayer optical disc having a plurality of recording layers and an optical axis of an optical information recording/reproducing apparatus, wherein a use wavelength ? and a numerical aperture NA are defined by conditions: 390<?<420 and 0.75<NA<0.90. The method includes determining the tilt angle of the objective lens such that a spot quality defined through a predetermined transparent parallel flat plate matches a predetermined standard, and tilting the objective lens to have the determined tilt angle. When t1 represents a thickness of the predetermined transparent parallel flat plate and t2 represents a design protective layer thickness at which a coma caused when off-axis light is incident on the objective lens becomes smallest, t1 and t2 satisfy a following condition: ?0.015<t1?t2<0.005.

Abstract: To provide an optical pickup and an optical information device, capable of obtaining excellent signal characteristics for an optical disk on and/or from which recording and/or reproducing are performed using a laser. The optical pickup includes an optical detector, a support holder for holding the optical detector, and an optical base for fixing the support holder. The support holder has at least two notches at its both ends, the optical base has convex portions corresponding to the notches of the support holder, the optical base and the support holder are fixed by photo-curable adhesives for bonding the convex portions and the support holder to each other, and the shortest distance between the side faces of the convex portions, which do not face each other, is equal to or less than the width of the support holder in the direction of right and left ends.

Abstract: An optical collimator assembly used in an optical pickup device and an optical pickup device are provided. The optical collimator assembly may include a collimating lens, a lens holder for supporting the collimating lens, a piezoelectric element coupled to the lens holder and including a female screw portion disposed along a central axis in one direction and a plurality of pairs of piezoelectric bodies disposed symmetrically with one another around the central axis and for causing deformation in a direction that crosses the central axis, and a male screw type transfer screw coupled to the female screw portion of the piezoelectric element.

Abstract: The present invention provides a plasmonic optical transformer to produce a highly focuses optical beam spot, where the transformer includes a first metal layer, a dielectric layer formed on the first metal layer, and a second metal layer formed on the dielectric layer, where the first metal layer, the dielectric layer, and the second layer are patterned to a shape including a first section having a first cross section, a second section following the first section having a cross-section tapering from the first section to a smaller cross-section, and a third section following the second section having a cross-section matching the tapered smaller cross-section of the second section,

Abstract: [Problems to be Solved] To obtain a laminated quarter-wave plate having a bandwidth of a plurality of wavelengths to be a phase difference of 90 degrees broadened [Means to Solve the Problem] A laminated wave plate of the present invention includes a first wave plate having a phase difference of ?1 and a second wave plate having a phase difference of ?2 with respect to a wavelength ?, the first wave plate and the second wave plate being bonded together so that an optical axis of the first wave plate and an optical axis of the second wave plate are intersected each other to function as a quarter-wave plate as a whole, the laminated wave plate comprising following equations from (1) to (6): ?1=360×(n1+1) . . . (1); ?2=90×(2×n2+1) . . . (2); ??1=(?12a??11a)/(?12??11) . . . (3); ??2=(?12b??11b)/(?12??11) . . . (4); cos 2?1=1?(1?cos ??F)/2(1?cos ??1) . . . (5); and ?2=45°±5° . . .

Abstract: There is provided an optical pickup including: an optical-system having an object-lens illuminating a first light for information recording or reproducing on a recording layer as a target and a second light on an optical-recording medium including a reference plane having a reflection-layer and the recording-layer at a layer position different from that of the reference-plane and on which information recording is performed through mark formation, and a focus-aligned-position-adjusting unit adjusting a focus-aligned position of the first light through the object-lens by changing collimation thereof incident to the object-lens; and a focusing-mechanism driving the object-lens in a focusing direction, wherein, when a depth of focus ?/NA2 defined by a wavelength ? of the first light and a numerical aperture NA of the object lens is set to ? and the maximum-surface-blur range is denoted by D, the optical-system is designed so that a use magnification ratio ? satisfies |?|??(D/?).

Abstract: In an optical pickup for use in an optical disc device, wire rods are wound directly around a lens-coil holder to make tracking coils and focus coils. The lens-coil holder is divided into three holders, one of which holds an optical lens thereon and has on its sides wire-winding protrusions for wiring wire rods therearound to make tracking coils. The remaining holders have focus coils that are wound therearound. Alternatively, the lens-coil holder is divided into two holders, one of which has on its sides wire-winding protrusions for wiring wire rods therearound to make tracking coils. The remaining holder holds an optical lens thereon and has focus coils that are wound therearound. The lens-coil holder has a cavity for letting pass through a laser beam emitted in parallel to an optical disc surface.

Abstract: Various embodiments herein include one or more of systems, methods, software, and/or data structures to test and evaluate unformatted optical media such as optical tape and optical discs. Advantageously, testing and evaluation can be performed earlier in the manufacturing process of the optical media to locate defects and/or other problems or issues with the optical media that can be addressed before additional manufacturing steps are performed and possible wasted. The systems and methods include at least two optical pickup units (OPUs), a first of which may be dedicated to writing digital data and the second of which may be dedicated to scanning, locating, tracking and/or reading the written data (when the optical media is moving in a first direction) in one of a plurality of manners. Information (e.g.

Abstract: Certain embodiments provide an optical recording/reproducing apparatus including: a slider that has a medium facing surface that faces an optical recording medium, and moves along a recording/reproducing face of the optical recording/reproducing medium; a metal nanoparticle structure that is provided in the medium facing surface of the slider; a light illumination device that illuminates the optical recording medium and the metal nanoparticle structure with light that has polarization components in a direction perpendicular to the recording/reproducing face; and a detection device that detects Rayleigh scattering light that is generated from a portion of the optical recording medium and is intensified by the metal nanoparticle structure, the portion being located close to the metal nanoparticle structure.

Abstract: In an optical pick-up used in common with DVD/CD and BD, when the thickness is intended to be reduced by mounting a total reflection mirror, a cavity for passing through a laser light is necessary and, since this decreases the degree of freedom for arranging tracking coils and magnets and secondary resonance caused by a magnetic thrust in the tracking direction tends to be generated, an improvement therefor is necessary. In a lens coil holder of the optical pick-up having an objective lens and tracking coil mounted thereon each of the coils is arranged such that the thrust relative to the vertical center of the suspension wires that support the lens coil holder is well balanced. For example, most of the portion of the tracking coils is situated at one height relative to the suspension wire and the tilt coil is situated at the other remaining height.

Abstract: An optical pickup device that can reduce interlayer crosstalk, without changing the configuration of the optical system, and without excessively increasing the size of the optical system. The optical pickup device reproduces a signal from a multilayered optical information recording medium having a plurality of information recording layers. The optical pickup device uses a collimating lens unit as a collimating optical system that collimates light from a light source, and the collimating lens unit includes a first and second lens group arranged at a predetermined distance from each other so as to form a converged light spot in the interior of the collimating lens unit, and an optical element provided between the first lens group and the second lens group so as to form a light spot at a position defocused from the position of the converged light spot, thereby decreasing quantity of light passing through the collimating lens unit.

Abstract: Provided are an optical pick-up device which can appropriately correct an optical path of a laser beam emitted from a light-emitting chip arranged with a mounting error, and a method of manufacturing the same. An optical pick-up device includes: a first light-emitting chip and a second light-emitting chip which emit laser beams having predetermined wavelengths; a PDIC which receives the laser beams emitted from the first and the second light-emitting chips; and a first optical correction component and a second optical correction component provided between the PDIC and the light-emitting chips. The first and the second optical correction components incline a first laser beam by diffraction, while transmitting a second laser beam and a third laser beam without inclining these beams. With the diffraction of the first laser beam by these two correction components, the optical path of the first laser beam is corrected to a predetermined position.

Abstract: There are provided an optical pickup apparatus which can record/reproduce information properly at a time of temperature change or of using a multilayer disc, and an objective lens for use in the same. When temperature changes, spherical aberration resulting from a change in refractive index of objective lens OBJ increases. Therefore, collimation lens CL is moved by uniaxial actuator AC1 in the direction of the optical axis, to make a finite light flux enter objective lens OBJ, which controls the spherical aberration. When a BD is a multilayer disc, spherical aberration also increases at a time of carrying out an interlayer jump from one layer to another in a plurality of information recording surfaces. Therefore, collimation lens CL is moved in the direction of the optical axis corresponding to the increase. The tilt sensitivity of objective lens OBJ is increased to handle that. Thereby, the occurrence of the third-order coma is effectively controlled even when a finite light flux enters objective lens OBJ.

Abstract: There is provided an optical disc device for reproducing or recording an optical disc. The optical disc device includes an object lens configured to irradiate the optical disc with light emitted from a light source; an actuator for controlling tilt of the object lens in a radial direction of the optical disc at a tilt value; a temperature sensor for detecting a temperature inside the optical disc device; and a controller for correcting the tilt value in accordance with a change in the temperature from the temperature detected at an initial adjustment of the optical disc device which is performed in loading of the optical disc.

Abstract: In recording or reproducing data on or from an optical disc with recording multi-layers, the focusing is likely to be out of control when an inter-layer jumping is carried out for changing a recording layer on or from which data is to be recorded or reproduced to another one. An optical disc apparatus is arranged to obtain an objective lens shift position that makes the focus signal S-character waveform better balanced in advance by learning and to carry out the inter-layer jumping at the shift position when jumping an optical pickup from one layer to another on a multilayered optical disc. The jumping at this shift position makes it possible to prevent out of focus and to stably make the recording or reproducing quality excellent.

Abstract: In this disk unit, a tray has an air intake opening formed to extend from an upstream side in a rotational direction of a disk rotated by a rotating portion toward an optical pickup and to extend inward from outside a receiving region from the upstream side toward a downstream side in the rotational direction for incorporating air into the side a receiving surface of the tray from the side of the back surface thereof.

Abstract: An optical pickup device has a DVD/CD laser diode for emitting a DVD/CD laser beam as linear polarized light, and a BD laser diode for emitting a BD laser beam. The optical pickup device has a dichroic mirror that regularly reflects a part of the DVD/CD laser beam, transmits a part of the DVD/CD laser beam, and transmits return light of the BD laser beam. The dichroic mirror is formed so that a product of reflectance of outward light of the DVD/CD laser beam and transmittance of return light of the DVD/CD laser beam becomes 20% or more to 25% or less. A light receiving element receives the return light of the DVD/CD laser beam transmitted through the dichroic mirror or the return light of the BD laser beam transmitted through the dichroic mirror.

Abstract: It is possible to provide a new information recording/reproduction method and a device which can realize a small-size large-capacity memory having a characteristic equivalent to or higher than a hologram memory. The optical information recording/reproduction device includes: recording light generator (51) which generates a recording light (55) in a polarization state having two mutually orthogonal polarization components with a phase difference at an arbitrary polarization base; reproduction light generator (61) which generates a reproduction light (65) in a polarization state having only a single polarization component at a arbitrary polarization basis; recording medium (71) in which optical information is recorded by recording light (55) and the recorded optical information is reproduced by reproduction light; and optical information detector (polarimeter 81) which retrieves information light (72) after being applied to recording medium (71) and detects the light as optical information.

Abstract: An optical pickup includes a collimator lens having a diverging lens and a converging lens, such that it maintains a constant focal length and has a short optical path length. The collimator lens of the optical pickup device includes a diverging lens located at the side of a light source and a converging lens located at the side of generating parallel light or gentle oscillation light. In addition, the diverging lens and the converging lens of the collimator lens may be integrated, or may also be formed of a hologram optical element. As a result, the optical pickup device can be configured in the form of a slim structure using the collimator lens having a short optical path length.

Abstract: An optical disc apparatus, for executing recording or reproducing on an optical disc having at least two (2) or more of recording/reproducing layers, comprises an optical pickup, having: a sphere aberration compensating portion, which is configured to set up a compensation volume of the sphere aberration; an objective lens; and a driver portion, which is configured to drive the objective lens, wherein the sphere aberration compensating portion sets up the compensation volume to that corresponding to an intermediate position between a deepest layer and a most front layer from the optical pickup; the driver portion drives the objective lens to come close to the optical disc, when the compensation volume is set to that corresponding to the intermediate position; the sphere aberration compensating portion sets up the compensation volume to that corresponding to the deepest layer, when the objective lens is driven in a direction of coming close to the optical disc; and the driver portion drives the objective lens

Abstract: An optical pickup apparatus comprising: a laser light source configured to emit a laser beam; an objective lens configured to apply the laser beam to an optical recording medium; and a beam splitter including a first reflective film configured to reflect the laser beam so as to be directed to the objective lens, the beam splitter interposed in an optical path between the laser light source and the objective lens, an incidence polarization angle of the laser beam relative to the first reflective film being set such that a P-polarization component is greater than an S-polarization component in linear polarization components of the laser beam incident on the first reflective film.

Abstract: A writing condition adjusting apparatus according to the present invention adjusts a writing condition using first and second recording patterns. The first recording pattern is used to adjust a writing condition for recording marks and spaces, of which the lengths are equal to or longer than a predetermined recording length, while the second recording pattern is used to adjust a writing condition for recording marks and spaces, of which the lengths are shorter than the predetermined recording length by one recording unit length. If it has been decided that the writing condition that has once been determined by making the write adjustment on such marks that are shorter by one recording unit length needs to be adjusted again, a signal index value that has been defined based on the first recording pattern is set to be a target value.

Abstract: In connecting flexible printed circuits, a structure with improved connection strength of the connection portion is provided. In this structure in which a first flexible printed circuit and a second flexible printed circuit are connected to each other, a through-hole is provided on the second flexible printed circuit, and a resin member passes through the through-hole and is adhered to the wires of a connection surface of the first flexible printed circuit and the side of the second flexible printed circuit opposite to the connection surface, whereby impact is absorbed by the elasticity of the resin; as for the first flexible printed circuit, adhesion is performed on a metal in a wiring layer with high adhesion strength, while as for the second flexible printed circuit, adhesion is performed on the back side upon which no peeling stress is exerted, improving joining strength to prevent peeling.

Abstract: An optical pickup lens for focusing a light beam from a laser light source on an optical information recording medium is a single lens. The optical pickup lens has two surfaces, and a surface R2 opposite to a surface R1 closer to the laser light source has a continuous shape. When the surface R2 has radii h1, h2 and h3 (h1<h2<h3) from an optical axis to a lens periphery, and where sags in the radii h1, h2 and h3 are sag1, sag2 and sag3, and differentials in the sags are ?sag1, ?sag2 and ?sag3, respectively, 0>?sag1>?sag2 and ?sag2<?sag3 are satisfied.

Abstract: In an optical pickup device and a method of a focus jump, in order to make optimum correction of spherical aberration responsive to the position of a recording layer at one end nearer a target recording layer than a current in-focus recording layer, the recording layer at the one end being one of recording layers at opposite ends of a plurality of recording layers, spherical aberration correcting means is controlled, and then a focus actuator is controlled, thereby causing a focus to jump to the recording layer at the one end. Next, in order to make optimum correction of spherical aberration responsive to the position of a different recording layer shifted by at least one recording layer from the recording layer at the one end toward the target recording layer, the spherical aberration correcting means is controlled, then the focus actuator is controlled, the focus is caused to jump to the different recording layer, and such a focus jump is repeated until the focus reaches the target recording layer.

Abstract: A method for compensating the coma aberration in a pickup of a recording and reproducing device that records or reproduces data on or from an optical disc using the pickup is provided. The method includes a first coma aberration compensating step to compensate coma aberration in a body of an optical system including an objective lens for emitting a light beam to an optical disc including a plurality of recording layers and a second coma aberration compensating step to compensate coma aberration caused by relative inclination of the optical system with respect to the optical disc.

Abstract: According to one embodiment, a write-once type information storage medium comprises a recording layer which is formed by mixing a plurality of organic dye based recording materials whose molecular weights are different from each other, and wherein a mixture ratio of organic dye based recording materials whose molecular weight is small is larger than a mixture ratio of organic dye based recording materials whose molecular weight is large.

Abstract: A method and apparatus for storing data is provided. One implementation involves providing a fiber medium for storing data, wherein the fiber medium has a characteristic configured to irreversibly change when exposed to write irradiation. The fiber medium is logically partitioned into cells along the length of the fiber medium. Data is stored in a cell of the fiber medium by exposing the cell to write irradiation to irreversibly change characteristic of the bulk of the cell.

Abstract: Proposed is an optical disk device capable of appropriately performing focus control. In an optical disk device, an objective lens is moved in the thickness direction of an optical disk by controlling an actuator and a time interval in which each of the recording layers was detected is measured while moving the objective lens, a first time interval from the first detection of the recording layer to the second detection of the recording layer is compared with a second time interval from the second detection of the recording layer to the third detection of the recording layer, and a focal position of the objective lens is determined based on the comparative result.

Abstract: An optical recording head to record information onto a recording medium utilizing light including; a slider provided to move relatively to the recording medium; a light propagation element provided on a side surface of the slider substantially vertical against a recording surface of the recording medium so as to cause propagation of light incident with a predetermined angle to be irradiated on the recording medium; and, a prism provided on the light propagation element so as to oppose to the side surface of the slider having the light propagation element and to deflect the incident light to be incident into the light propagation element with a predetermined angle.

Abstract: An optical pickup device capable of eliminating interlayer crosstalk which is responsible for fluctuation in control signals and error rate in data signals, thereby ensuring stable action for a multilayered recording disc with a narrow interlayer spacing. The reflected beam coming from the multilayered disc is divided along the central line into two parallel portions by the dividing optical system and then condensed. The reflected beam coming from the active layer, which has been condensed, is reflected by the reflecting plane whose reflecting region is limited and the thus reflected beam is detected by the optical detector. The reflected beam coming from other layers is not reflected by the reflecting plane, so that interlayer crosstalk is reduced.

Abstract: An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.

Abstract: An objective lens for an optical information recording/reproducing optical system for an optical disc letting a laser beam impinge on a recording layer of the optical disc, and wherein a center wavelength ? (unit: nm) of the laser beam is in a range defined by a condition: 390???420, a base material of the objective lens is made of resin, the resin has a glass transition temperature Tg and light transmissivity T (unit: %) per a path length of 3 mm at a wavelength of 406 nm defined by conditions: Tg?115° C., 85?T?90, same antireflection films or different types of antireflection films are respectively formed on optical surfaces of the objective lens, and each of the antireflection films formed on the objective lens has a thickness of 100 nm or more in a vicinity of an optical axis of the objective lens.

Abstract: Incident light can be efficiently converted into near-field light whose spot size is small. A waveguide 10 includes: a metallic member 11 made of a metallic material; and a dielectric member 12 made of a dielectric material. The metallic member 11 includes a first interface 16 and a second interface 18 so as to sandwich the dielectric member 12. The first interface and the second interface are provided so that an inter-interface distance therebetween may decrease from ends 16c and 18c to ends 16d and 18d. The first interface 16 and the second interface 18 have flections P16 and P18, respectively.

Abstract: An object of the invention is to provide an optical recording medium and an optical information device that enable to improve the quality of a servo signal and a reproduction signal.

Abstract: An optical system of an optical pickup device includes an astigmatism element which imparts astigmatism to BD light reflected on BD and CD light reflected on CD, and a spectral element which disperses four light fluxes of BD light and four light fluxes of CD light by diffraction, the four light fluxes of BD light and the four light fluxes of CD light being obtained by dividing the BD light reflected on the BD and the CD light reflected on the CD by a first straight line parallel to a converging direction by the astigmatism element, and a second straight line perpendicular to the first straight line. A photodetector of the optical pickup device is provided with first and second sensor groups for respectively receiving the four light fluxes of BD light and the four light fluxes of CD light dispersed by the spectral element.

Abstract: An optical pickup device corresponding to an optical recording medium having a plurality of recording layers, and an optical drive using the device are provided. The optical pickup device includes a collimator lens disposed between an object lens and a light source. The collimator lens adjusts a focal length with respect to the optical recording medium, and the object lens focuses light passing through the collimator lens, on the optical recording medium. The object lens is optically optimized for an upper or second-upper recording layer of the optical recording medium.

Abstract: An objective lens has a numerical aperture of 8.0 or more and focusing a light beam of a wavelength ? of at least 450 nm or less on an optical information recording medium. In this objective lens, a wavefront-aberration deterioration level TOR, accumulative value of aberration deterioration, satisfies the equation (1): TOR=?{square root over (2.52(DCm32+DCm52)+(TSA32+TSA52))}{square root over (2.52(DCm32+DCm52)+(TSA32+TSA52))}?0.07[?rms]??(1) In the equation (1), TSA3 [?rm/?m] and TSA5 [?rm/?m] refer to a third-order thickness sensitivity level and a fifth-order thickness sensitivity level, which are generated when a thickness error from a predetermined thickness is +1 ?m, respectively. DCm3 and DCm5 refer to a third-order decentering sensitivity level and a fifth-order decentering sensitivity level, which are generated when a decentering error of each of lens surfaces is 1 ?m, respectively.

Abstract: An optical pickup device includes a polarization diffraction grating to diverge an optical beam reflected from an optical disc and an optical detector to receive the optical beam diverged by the polarization diffraction grating, a polarization of 0 order diffracted light diffracted through the polarization diffraction grating is substantially perpendicular to that of a +1 order diffracted light diffracted therethrough, and a polarization filter having a plurality of domains is mounted between the polarization diffraction grating and the optical detector.

Abstract: A diffractive optical element having a diffraction region for diffracting a part of a luminous flux is mounted and an unwanted luminous flux generated in a multi-layer optical disc is suppressed from entering a photodetector surface. Using the above-described structure, fluctuation of a tracking error signal can be suppressed from being caused by the unwanted luminous flux and preferable recording or reproduction quality can be obtained also in the multi-layer optical disc.

Abstract: An optical pickup apparatus includes a light generating unit to generate a light to record or reproduce information, an objective lens to focus the light generated from the light generating unit onto a disk, and a multi-sectional polarizer disposed on a light path between the light generating unit and the objective lens and divided into a plurality of sectors having their individual optical axes.

Abstract: An adhesive agent, which contains a light starting agent and is cured by light, is added with fillers in which the difference in refractive indices between the adhesive agent and the fillers is not larger than ±0.02. Even if the adhesive agent is added with functional fillers, this addition method allows the suppression of a lowering in the light penetrability of the adhesive agent. As a result, it becomes possible to suppress the uncuring and shrinkage of the photo-curing type adhesive agent and to perform the bonding of components with high accuracy.

Abstract: An optical pickup device includes an objective lens portion which converges laser light at a first focal point and a second focal point; an actuator which positions the first focal point or the second focal point on a recording layer in a disc; an astigmatism element which sets a first focal line position and a second focal line position of the laser light reflected on the disc away from each other in a propagating direction of the laser light; a spectral element which disperses four light fluxes obtained by dividing the laser light reflected on the disc in four from each other; and a photodetector having a sensor group which receives the four light fluxes dispersed by the spectral element.

Abstract: Where a hybrid disc has different types of media, the light spot moves among recording layers of the different media, after loading the disc into an optical disc apparatus, there is a problem that information on a media type of each recording layer should be recorded in DI etc. of the optical disc. Detailed information on the hybrid disc is stored in DI, by changing a disc layer type identifier or a disc structure in DI such as BCA or PIC on the optical disc.

Abstract: Optical pickup 24 for operation in the far-field and in the near-field mode comprising a movable part 26 having an objective lens 2 comprising a solid immersion lens 4 and a multifocal lens 6, which are both disposed on a common optical axis A. The multifocal lens 6 comprises a central zone 8 and a peripheral zone 10 being circumferential to the central zone 8. The peripheral zone is adapted to constitute an optical system for a far-field mode. The central zone 8 of the multifocal lens 6 together with the solid immersion lens 4 are adapted to constitute an optical system for a near-field mode. The solid immersion lens and the multifocal lens are adapted to be moved in unison.

Abstract: An optical pickup device is provided. In an optical pickup device, a light receiving element has light receiving regions for focusing as part of the plurality of light receiving regions. A diffraction element has diffraction regions for focusing as part of the plurality of diffraction regions. A part of division lines which define the diffraction region for focusing is formed in a shape which is convex from the outer side toward the inner side with respect to the center of the incidence range on the diffraction element where a returning light beam enters. The part of the division lines formed in the shape which is convex from the outer side toward the inner side divides an incidence range on the diffraction element where a returning light beam enters, regardless of whether or not there is a focus error.

Abstract: An optical unit is provided with a light source; a light dividing means for dividing light emerging from the light source into a first light and a second light; a light converging means for converging the first and second lights at the same position in the recording layer in the manner that they face each other; a polarization state switching means for switching the polarization states of the first and second lights at the convergence point in the recording layer; and a light irradiation state switching means for switching between the state in which the optical cording medium is irradiated with both the first light and the second light and the state in which the optical recording medium is irradiated with only one of the first and second lights.

Abstract: An optical pickup device includes an astigmatism element which sets focal line positions to be defined by convergence of laser light away from each other, a diffraction element which diffracts four light fluxes obtained by a light flux of the laser light to disperse the four light fluxes from each other, and a photodetector having a first sensing section and a second sensing section which respectively receive m-th order diffraction light and n-th order diffraction light of the four light fluxes. In this arrangement, the first sensing section receives eight light fluxes obtained by dividing the four light fluxes of the m-th order diffraction light by two straight lines to output detection signals of the number less than eight.