Abstract: An objective lens for an optical pickup apparatus is disclosed that can record and/or reproduce information compatibly for different optical discs with stability regardless of an environmental temperature change, in spite of its simple structure, and provides an optical pickup apparatus employing the objective lens. The objective lens includes: an optical surface which at least includes a central area, a peripheral area, and a most peripheral area. The objective lens is a single lens formed of plastic. The central area includes a first optical path difference providing structure. The peripheral area includes a second optical path difference providing structure. The objective lens further includes an optical path difference providing structure for correcting a temperature characteristic, where the optical path difference providing structure corrects an aberration caused by a temperature change of the objective lens.

Abstract: An optical head device includes a diffraction grating which diffracts a part of the light beam which is selectively emitted from a semiconductor laser having two luminous points and is divided along a tangential direction of the track of the optical disk, a relationship of arrangement of the second and third regions corresponds to a relationship of the optical axes of the first and second light beams on the diffraction grating, the second region is located at a position crossing an optical axis of the first light beam, a phase difference between phases of the first and third regions is 180°, a phase difference between phases of the third and fourth regions is 180°, and the third region has a width which is not larger than amount of a position deviation of ±first-order diffracted light of the second light beam from zeroth-order diffracted light.

Abstract: An objective lens actuator includes a lens holder, a protector holder, and a protector. The lens holder in which the objective lens is provided has a face configured to oppose the disc. The protector holder is provided on the face of the lens holder. The protector is formed with an opening defined by a first inner face, a second inner face and a bottom face between the first inner face and the second inner face. The protector has a parallelepiped shape elongating in a first direction parallel to the disc. A part of the protector is inserted in the opening so as to contact the first inner face and the second inner face and to extend from the bottom face toward the disc. A first distance between an end of the protector in a second direction in which the protector extends toward the disc and the disc is shorter than a second distance between the objective lens and the disc. A gap is formed between an end of the opening and an end of the protector in the first direction.

Abstract: When it is determined that the disc loaded on a player is a hybrid next generation DVD, the DVD layer is reproduced with a red laser light. In parallel with this reproduction process, a process for notifying the presence of the HDDVD layer is performed. That is, determination is made on whether the notification timing defined in advance has been reached. If the notification timing has been reached, a control instruction is output from a controller to an AV processing circuit, and the image information including the image notifying the presence of the HDDVD layer is output from the AV processing circuit. Thus, the user may learn that the HDDVD layer can be reproduced.

Abstract: A disk-shaped optical information recording medium (115) includes a substrate (101), first to nth information layers (102-104) layered upon the substrate (where n is an integer of 3 or more), kth intermediate layers (105, 106) provided between a kth information layer and a (k+1)th information layer (where k=1, 2, and so on up to n?1), and a protective layer (107) provided upon the nth information layer. The fluctuation range of the thicknesses from the protective layer surface (107a) to each of the information layers (102-104) is no more than ±3 ?m relative to the average value of the thicknesses within a range from a radius of 23 mm to 24 mm from the center of the optical information recording medium.

Abstract: An optical pickup device includes a light source, a movable condensing lens, a rising prism or a rising mirror, an objective lens, and a phase plate. The light source emits laser light, and the movable condensing lens converts the laser light into converging light or diverging light. The rising prism or the rising mirror converts an optical axis of laser light passing through the condensing lens into a substantially vertical direction. The objective lens condenses the laser light, of which the optical axis is converted by the rising prism or the rising mirror, to an optical disk. The phase plate is provided between the condensing lens and the objective lens, and includes stepped portions that are formed at portions facing each other and have different thicknesses. The phase plate corrects astigmatism, which is generated by the rising prism or the rising mirror, by making a part of laser light having a size larger than a predetermined size pass through the stepped portions of the phase plate.

Abstract: An optical pickup device includes a diffraction grating 12 for separating a light beam emitted from a semiconductor laser element into at least three light beams. The diffraction grating 12 is divided into three regions by a straight line extending in a direction parallel to a tangent line of a track of an optical information recording medium. A second region 12B is divided into a first sub-block 13 and a second sub-block 14 by a straight line extending in a direction parallel to a radius direction of the optical information recording medium. The first sub-block 13 has a phase difference of approximately 180 degrees from the second sub-block 14. The first region 12A has a phase difference of approximately 90 degrees from the first sub-block 13 and has a phase difference of approximately 180 degrees from the third region 12C.

Abstract: With an optical disc apparatus of the present invention, the number of tracks of an optical disc crossed by a light spot when the tracking control is inactive is measured and stored in a memory for each passage of a predetermined rotation angle. When the tracking control is active, a lens tilt driving signal is generated by multiplying the value of a memory section corresponding to the disc rotation angle by a gain according to the disc rotation speed, thereby correcting the AC tilt occurring due to a lens shift.

Abstract: The present invention makes it possible to use an optical pickup in common with conventional optical disks. In a three-dimensional mark recording layer (111v) of a voluminal medium (100v), information is recorded by forming a three-dimensional record mark (RM) in the vicinity of the focus (Fb) of a blue light beam (Lb) according to the blue light beam (Lb) that is concentrated and has a light intensity equal to or larger than a predetermined intensity. The information is reproduced from the three-dimensional mark recording layer (111v) on the basis of a reproducing blue light beam (Lbr) deriving from irradiation of the blue light beam (Lb). A servo layer (114v) of the voluminal medium (100v) reflects at least part of the red light beam (Lr) which is irradiated in order to square the position of the blue light beam (Lb) in the three-dimensional mark recording layer (111v) with an arbitrary target mark position and whose wavelength is different from that of the blue light beam (Lb).

Abstract: A compact and inexpensive optical head that enables stable compatible playback and compatible recording with optical discs of different kinds with the use of a single objective lens is achieved. The order of diffracted light at which the diffraction efficiency by a diffraction element forming the objective lens becomes the maximum is set to the third order for blue light, the second order for red light, and the second order for infrared light in the inner peripheral portion of the diffraction element, and to the sixth order for blue light, the fourth order for red light, and the third order for infrared light to limit the aperture for infrared light in the intermediate peripheral portion. In the outer peripheral portion, the aperture for red light is limited by setting the order to an integer other than multiples of 3 for blue light.

Abstract: An optical pickup device includes a diffraction grating 12 for separating an emitted light beam into at least three light beams. The diffraction grating 12 is divided into three regions by dividing lines D1 and D2 extending in a first direction parallel to a tangent line of a track of an optical information recording medium. A second region 12B is divided into four sub-blocks by a dividing line D3 extending in the first direction and a dividing line D4 extending in a second direction that crosses the first direction. The sub-blocks located diagonally opposite to each other have a same phase, and the sub-blocks located adjacent to each other have a phase difference of approximately 180 degrees. The first region 12A has a phase difference of approximately 90 degrees from each sub-block of the second region 12B, and the first region 12A has a phase difference of approximately 180 degrees from the third region 12C.

Abstract: To provide a liquid crystal optical modulation element which is excellent in durability against blue laser and which can maintain the characteristics for a long period of time. A liquid crystal optical modulation element to modulate a laser beam having a wavelength of at most 500 nm, which comprises a layer of a polymer liquid crystal composition sandwiched between a pair of transparent substrates facing each other, characterized in that each of the pair of transparent substrates has an alignment film on the surface which faces the other transparent substrate, and the polymer liquid crystal composition is a polymer liquid crystal containing a hindered amine compound and a hindered phenol compound.

Abstract: An optical pickup includes: a light source emitting a beam having a predetermined wavelength; a plastic objective lens condensing the emitted beam on an optical disc; a light detector receiving and detecting the beam reflected by the optical disc; an objective-lens driving unit driving the objective lens in the tilt direction to tilt the objective lens; and a tilt-sensitivity sensing unit sensing a tilt sensitivity denoted by ?WLT/??, where ?WLT [?rms] is a coma aberration amount ?? [deg] is a tilt amount at the time of tilting the objective lens, wherein, in the case where the sensed tilt sensitivity is equal to or larger than a predetermined value, tilt is corrected by tilting the objective lens so that signal quality detected by the light detector is improved, and in the case where the sensed tilt sensitivity is smaller than the predetermined value, tilt is not corrected.

Abstract: An optical pickup device and an optical disc apparatus which is capable to reduce variation of a detected signal due to unnecessary beam and detect a signal with high quality are provided. Amplification of sup PP signals necessary to produce a tracking error signal by a DPP method can be realized by an amplification factor smaller than a spectral radio of main and sub beams by the following structure. The optical pickup device includes an optical element having an area in which part of beam is diffracted and light shielding zones or insensitive zones having predetermined width are formed on center division lines in the light receiving planes of sub beams of the optical detector. The shape of a diffraction area is optimized to the shift amount of objective lens. The width of the light shielding zones or insensitive zones is optimized from the shift amount of objective lens and the shape of the diffraction area.

Abstract: An information recording/reproducing device includes a light source separately projecting laser light for recording or reproducing, an optical system leading the projected laser light to a recording medium, a diffracting element separating laser light into main- and beam sub-beams, an evanescent light generating element irradiating evanescent light in relation to the separated sub-beam to a track where no recording pit is formed, a sub-light receiving element for receiving return light in relation to the sub-beam, a moving element for moving the evanescent light generating element in relation to the sub-beam to a direction to change a gap with the recording surface, and a control element; for controlling the moving element so as to make the gap become a predetermined target value in accordance with a gap error signal containing a signal indicative of a light amount of the return light in relation to the received sub-beam.

Abstract: The present techniques provide methods and systems for enhancing a data signal in reading optical discs, such as holographic data discs. The techniques involve adjusting the position of a detector, or multi-pixel detector, such that the reflection corresponding to a micro-hologram or micro-reflector is enhanced. For example, the detector position may be adjusted to a position where the surface reflection and the micro-hologram reflection constructively interfere, resulting in an amplified micro-hologram reflection signal. Other parameters such as disc reflectivity and detector pinhole size may be adjusted to increase signal enhancement. Furthermore, the detector position may be adjusted to a position where the phases of the surface reflection and the micro-hologram reflection result in a weaker cross term.

Abstract: Provided are an optical pickup device which is compatible with a plurality of disc standards, and can stably monitor the outputs from light sources, and an objective lens system used in the optical pickup device. An optical pickup device 50 includes a light source 1 emitting light of a first wavelength of a red band and light of a second wavelength of an infrared band; a light source 10 emitting light of a blue-violet band for BD 10; a collimating lens 4; mirrors 5, 7 each transmitting a portion of a light beam outputted from the collimating lens 4 while folding an optical path of the other portion of the light beam; objective lenses 6, 8 each converging the light beam folded by the mirrors 5, 7 on a recording layer of an optical disc; and a light-receiving element 15 detecting an intensity of the light beam transmitted through the mirrors 5, 7.

Abstract: An optical head (31) is provided with a light source (1) for outputting laser light having a wavelength of 430 nm or less; an objective lens (7) for collecting the laser light outputted from the light source (1) to an optical disc (60) having a plurality of information recording surfaces; a light receiving element (10) for receiving laser light reflected on the optical disc (60); and a detecting lens (8) for guiding the laser light reflected on the optical disc (60) to the light receiving element (10). The detecting lens (8) is formed of a resin material. The detecting lens (8) is arranged so that a light collecting position of the laser light reflected on an information recording surface different from an information recording surface having a thinnest protection substrate, among the information recording surfaces, is outside the detecting lens (8), at the time of recording or reproducing information on or from the information recording surface having the thinnest protection substrate.

Abstract: In an optical pickup capable of removing inter-layer crosstalk, a dark line that may appear in a central portion of a beam is removed. Thereby, an error in a data signal is reduced. Reflected light from a multi-layer disc is split into two parallel bundles with a splitting optical system in a way that the light is split at a central line. Thereby, when reflected light from a target layer is focused, the reflected light is not influenced from an attenuation element provided on an optical axis.

Abstract: When first-order diffracted beams leak into a region, which is for receiving only a zeroth-order diffracted beam from an optical disc, due to positional displacement between an objective lens and a hologram element, an offset compensation signal includes an AC component, the offset compensation signal preferably including a DC component only. Accordingly, there may be caused deterioration in a modulation degree of the tracking error (TE) signal. A partial light shielding element 110 is formed on a hologram surface 112a along boundaries between a light receiving region (121a), which receives a zeroth-order diffracted beam, and light receiving regions (121b, 121c), which receive the zeroth-order diffracted beam and first-order diffracted beams, so as to cover the light receiving region (121a). Further, the partial light shielding element 110 shifts phases of transmitted light beams by ?, whereby the TE signal is offset-compensated, and the modulation degree can be improved.

Abstract: An information recording/reproducing device diffracts laser light into main- and sub-beams, irradiates evanescent light in relation to the main beam by an evanescent light generating element to a track where a recording pit provided on a recording surface of a recording medium is formed and evanescent light in relation to the sub-beam to be separated to a track where no recording pit provided on the recording surface of the recording medium is formed. A moving element moves the evanescent light generating element to change a gap with the recording surface. Return light in relation to the sub- and main-beam are received by sub- and main-light receiving elements, respectively. A control element controls the moving element so as to make the gap become a predetermined target value in accordance with a gap error signal containing a signal indicative of an amount of the return light in relation to the received sub-beam.

Abstract: There are provided an objective lens for an optical pickup device which can record and/or reproduce information on/from an optical disk with high density with the use of a light flux with a short wavelength while keeping a temperature characteristic to be satisfactory in spite of having a plastic objective lens, and the optical pickup device. The objective lens suppresses generation of a spherical aberration even if a temperature change arises, by sacrificing wavelength characteristics and by enhancing temperature characteristics. Such satisfactory temperature characteristics can be acquired by the ring-shaped structure formed as a turning structure on an optical surface of the objective lens, in which the ring-shaped structure includes ring-shaped zones whose number is 3 or more and 30 or less and the ring-shaped structure is formed such that adjoining ring-shaped zones cause a predetermined optical path difference for an incident light flux.

Abstract: An optical information recording/reproducing apparatus for an optical disc using a light beam having a wavelength of ? including: an objective lens that converges the light beam onto a recording surface of the optical disc and satisfies a condition: 0.48 < d · ( n - 1 ) f 2 < 0.75 ( 1 ) where f represents a focal length (unit: mm) of the objective lens with respect to the wavelength ?, d represents a thickness (unit: mm) of the objective lens along an optical axis of the objective lens, and n represents a refractive index with respect to the wavelength ?; a photoreceptor to receive the beam reflected from the optical disc; a detector to detect quality of a signal, and an objective lens driving unit to tilt the objective lens in a direction to improve the quality of the signal based on a result of detection by the detector.

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: Provided is an apparatus and method for recording data on a holographic storage medium. The apparatus includes: a light a light processing unit comprising the holographic storage medium and a light modulator, and recording data on the holographic storage medium using a reference beam and a signal beam modulated by the light modulator; and a control unit controlling the light processing unit to record the data on the holographic storage medium, wherein the light modulator is arranged so that an image formed on a surface of the light modulator is shorter in a radial direction that is a scanning direction of the reference beam than in a tangential direction that is perpendicular to the radial direction.

Abstract: A pickup for accessing moving storage media carrying substantially parallel information tracks has a carrier, a movable actuator with a lens, and suspension wires joining the carrier and the actuator. The actuator is movable in at least a tracking direction and a focus direction. The suspension wires are soldered to the actuator by soldering points. According to the invention, the soldering points are made by induction soldering.

Abstract: The invention is able to enhance a recording speed. In the invention, a recording mark (RM) composed of a cavity is formed by vaporizing a two-photon absorbing material by a two-photon absorption reaction as an embodiment of a photoreaction against a recording light beam (L1) as recording light to be condensed at the time of recording information. Also, in a recording layer (101), the information is reproduced on the basis of a return light beam (L3) formed by modulation of a readout light beam (L2) irradiated as prescribed readout light at the time of reproducing inform in conformity with the presence of absence of the recording mark (RM).

Abstract: In an optical disk including at least a rewritable phase change material and comprising a recording layer having a reflectivity of more than 15%, an address output value as an address pit signal component occupying in a reproduced signal in a non recording state is prescribed to be 0.18 though 0.27 or a numerical aperture of an address pit signal occupying in a reproduced signal in a non recording state is prescribed to be more than 0.3.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by phase shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: An optical information recording and reproducing apparatus relating to the invention employs a two-beam interference method. In the optical information recording and reproducing apparatus, a moving device moves an information recording medium between a recording and reproducing position and a retracting position, and a mirror moves together with the information recording medium. When the information recording medium moves to the recording and reproducing position, the mirror moves to a position which is displaced from the at least one of the reference beam and the information beam. When the information recording medium moves to the retracting position, the mirror moves to a position where the mirror can reflect the at least one of the reference beam and the information beam toward a detector for detecting a deviation of the at least one of the reference beam and the information beam.

Abstract: In a method of setting a quantity of light directed onto an optical disc for reproduction purposes, an area of the optical disc in which information has been recorded is reproduced with a test-reproducing light quantity (S14, S24), a reproduction time or number of reproductions up to the time when the reproduced signal quality value reaches a prescribed value is determined (S20, S30), and the quantity of reproducing light used in regular reproduction is set by performing calculations with the determined value (S32). The state in which recorded marks have significantly degraded can also be detected, and degradation of the recorded marks to the unreproducible state can be avoided.

Abstract: An optical head device (optical head) for a multi-layered optical recording medium has a focus control mechanism that makes use of astigmatism. The focus control mechanism has a sensor lens that includes a cylindrical lens. The focus control mechanism causes a light beam having passed through the sensor lens to have astigmatism, thereby being focused linearly in the Y direction on a front focal line located closer to the sensor lens and focused linearly in the X direction at a rear focal line located farther therefrom. The optical head also includes a photodetector which is disposed between the front focal line and the rear focal line to detect a focal position from the shape of a light beam. At the position of the front focal line, a shield plate with a window portion is disposed. The window portion has a size so as to allow the focal line to pass therethrough and shield stray light reflected from an unfocused recording layer.

Abstract: An optical unit includes: a first light emitting device configured to emit a first beam; and a second light emitting device configured to emit a second beam in a direction the same as a direction of the first beam where the second beam is different in wavelength from the first beam. An emission surface of the second light emitting device is arranged at a distance from an emission surface of the first light emitting device in an opposite direction to the direction of the first beam.

Abstract: The present invention relates to an optical pickup actuator which includes a plurality of objective lenses for converging a light on an optical recording medium, a lens holder for holding the objective lenses, a suspension wire for holding the lens holder and projections provided at the lens holder, wherein the projections are provided at the periphery of the objective lens and at least one of the projections is provided on the upstream side of the insertion direction of the optical recording medium. A slope for guiding the optical recording medium upward at the time of inserting the optical recording medium is provided on the side surface of each of the projections. Thus, even when the optical recording medium is inserted so as to slide on the upper surface of a pickup cover, the end portion of the outer periphery of the optical recording medium contacts with the slope provided at the projection and slides to thereby push down the optical pickup actuator in the elevational direction.

Abstract: Provided is an optical pickup apparatus that can be made compact and is capable of producing stable push-pull signals. The optical pickup apparatus includes a light source, an objective lens, a diffraction element, a light-receiving element, and a control-driving section. The diffraction element receives light reflected from an optical recording medium. The light-receiving element receives light beams diffracted by the diffraction element. The light-receiving element has a plurality of light-receiving regions. The light-receiving region produces an output signal responsive to the quantity of the incident light beam. The control-driving section obtains differences among the output signals from a plurality of the light-receiving regions by calculation to derive a push-pull signal, and drives the objective lens under control on the basis of the push-pull signal.

Abstract: In an optical head device that subjects light exiting from a light source to reflection on an information recording layer of an optical disk, to thus guide the light to a photodetector, an optical attenuation device is disposed in an optical path from the optical disk to the photodetector, wherein the optical attenuation device has a first region having high transmissivity, a second region having low transmissivity, and a third region having an intermediate value of transmissivity, whereby light returned from a layer differing from the information recording layer, which will be responsible for crosstalk, is reduced by mean of the photodetector.

Abstract: Light outputted from a semiconductor laser (1) passes through a liquid crystal diffraction optical element (2a) as 0-order light and is collected to a disc (5). Reflection light from the disc (5) is diffracted by the liquid crystal diffraction optical element (2a) as ±primary diffracted light and received by optical detectors (6a, 6b). When information is being recorded on the disc (5), light entered the liquid crystal diffraction optical element (2a) from the side of the semiconductor laser (1) is outputted to the side of an objective lens (4) from the liquid crystal diffraction optical element (2a) at a high efficiency.

Abstract: A light source, an objective lens, and an astigmatism generation element producing for light for focus control, and an optical receiver are provided. The astigmatism generation element is interposed between the objective lens and the optical receiver and produces focal points in front of and behind the optical receiver within two mutually orthogonal cross-sectional planes including an optical axis of the reflected light. The astigmatism generation element is a Fresnel mirror that has a plurality of orbicular zones and steps connecting adjacent orbicular zones to each other and that takes the orbicular zones as reflecting mirrors. A depth “d” of the steps is set substantially one-half of a wavelength ?, and a depth d1 of the innermost orbicular zone of the orbicular zones is made larger than the depth d of the steps. The influence of the steps of the Fresnel mirror is minimized, so that a superior servo characteristic can be exhibited.

Abstract: Disclosed herein are aspects of optical tape technology, tape manufacturing, and tape usage.

Abstract: An optical pickup, mounting a lens actuator 101 thereon, the lens actuator comprises: a lens 1 having an optical axis in direction in parallel with an optical disc; a holder 2, which holds the lens thereon; a first guide shaft 3 holding the holder, so as to regulate the holder to change a position thereof, into an inner surface direction of a surface having the optical axis of the lens as a normal line vector thereof; a second guide shaft 4, which regulates the holder to change the position thereof, into a normal line vector of an optical disc; and a reed screw, which moves the holder into direction of the optical axis of the lens, wherein a distance between the optical axis of the lens and the optical disc, a distance between a central axis of the first guide shaft and the optical disc, and a distance between a central axis of the second guide shaft and the optical disc are lager than a distance between a central axis of the reed screw and the optical disc.

Abstract: An optical-pickup apparatus comprising: a laser-light source; a diffraction grating including first-and-second regions of periodic structures different in phase from each other and a third region whose periodic structure is different in phase from the first-and-second regions; an objective lens focusing main-and-sub-luminous fluxes generated by the diffraction grating on the same optical-disc track; and a photodetector to receive reflected light of the main-and-sub-luminous fluxes from an optical disc and output a detection signal for generating main-and-sub-push-pull signals, a relationship between an incident light width in the objective lens corresponding to the third region and pupil diameters of the objective lens corresponding to first-and-second wavelengths of laser lights being adjusted so that a ratio of minimum value to maximum value of a differential-push-pull-signal is at substantially 50% or more and a ratio of sub-push-pull-signal level to main-push-pull-signal level is at substantially 15% or m

Abstract: An optical element for an optical pickup device which can record and/or reproduce information interchangeably with an optical disc while correcting coma satisfactorily, and a compact optical pickup device employing that optical element and exhibiting excellent energy saving. In the optical element for an optical pickup device where a first objective lens portion and a second objective lens portion are formed integrally, one of the first objective lens portion and the second objective lens portion satisfies a relation |HCM|/|TCM|<0.3 and the other satisfies a relation |HCM|/|TCM|>0.3. The HCM represents the third-order angle of view coma sensitivity in the first objective lens portion or the second objective lens portion, and the TMC represents the third-order inclination angle coma sensitivity in the first objective lens portion or the second objective lens portion.

Abstract: An optical head unit includes, apart from an objective lens toward a light source, an optical device that changes the image height of light incident onto the objective lens, wherein the optical device includes a concave lens and a convex lens. The objective lens is designed so that a coma aberration having a specific polarity occurs if the optical axis of the incident light tilts toward a specific direction. If the disk tilts, the convex lens is moved within the plane perpendicular to the optical axis, to change the image height of the light incident onto the objective lens, to thereby tilt the optical axis of light exiting from the convex lens with respect to the optical axis of light incident onto the concave lens. The objective lens generates a coma aberration having a polarity opposite to the polarity of the coma aberration attributable to the tilt of disk, to thereby cancel the coma aberration attributable to the tilt.

Abstract: Provided are a method and apparatus for recording and/or reproducing data into and/or from an optical disk. The apparatus includes a reference beam optical system to form a focus of a reference beam in an optical data storage layer of the optical disk and including an objective lens; a signal beam optical system to form a focus of a signal beam in the optical data storage layer and also including the objective lens; and a servo optical system to project a servo beam onto the optical disk, receiving a reflection servo beam which is reflected on the optical disk, and performing focusing and tracking control on the objective lens. The reference beam optical system includes a first focus mover to move the focus of the reference beam, and the signal beam optical system includes a second focus mover to move the focus of the signal beam.

Abstract: An image processing method which contains: delivering laser light to a thermoreversible recording medium to heat the medium and record an image thereon, the medium reversibly changing a transparency or tone thereof depending on a temperature thereof; and heating the medium to erase the image recorded thereon, wherein the delivering is carried out using an image processing device containing: a laser light emitting unit; a light scanning unit disposed on a plane onto which laser light emitted from the laser light emitting unit is delivered; a light intensity distribution adjusting unit to change a light intensity distribution of the laser light; and a f? lens to condense the laser light, and wherein energy of the laser light passing through a peripheric portion of the f? lens and traveling onto the medium is lower than energy of the laser light passing through a center portion of the f? lens and traveling onto the medium.

Abstract: Disclosed is a reflecting wavelength plate that deflects and reflects a light path and adds a phase difference with respect to plural incident light having different wavelengths. The reflecting wavelength plate includes a substrate; a reflecting film laminated on the substrate; and a sub-wavelength concavo-convex structure that is laminated on the reflecting film and has a pitch less than or equal to the shortest wavelength of the plural incident light. The filling factor and the groove depth of the sub-wavelength concavo-convex structure are determined so as to add the phase difference obtained by (k?)/8, where k is an integer, to the plural incident light having the different wavelengths.

Abstract: The recording and reproducing apparatus has rotary drive unit (a motor) that rotationally drives a multilayer recordable recording medium 1; a reference-light-side recording and reproducing lens 6 and a recording-light-side recording and reproducing lens 7 that are disposed oppositely to the recording medium 1 which is rotationally driven by the rotary drive unit, an address detection lens 5 that is disposed opposite the recording medium 1 and that is provided separately from the recording and reproducing lenses 6 and 7; a light source 9 for recording and reproducing purpose that supplies recording reproduction light to the recording and reproducing lenses 6 and 7; and the address light source 9 that supplies address light to the address detection lens 5. The apparatus is configured in such a way that light whose center axis portion is optically hollow is supplied from the reference-light-side recording and reproducing lens 6 to the recording medium 1 during reproducing operation.

Abstract: An optical pickup includes: a first emission unit emitting an optical beam with a first wavelength corresponding to a first optical disc; a second emission unit emitting an optical beam with a second wavelength, which is longer than the first wavelength, corresponding to a second optical disc different from the first optical disc; a third emission unit emitting an optical beam with a third wavelength, which is longer than the second wavelength, corresponding to a third optical disc different from the first and second optical discs; a condensing optical device condensing, on a signal recording surface of a corresponding optical disc, the optical beams emitted from the first to third emission units; and a diffraction unit provided in the condensing optical device, which is disposed on the optical path of the optical beams with the first to third wavelengths.

Abstract: An optical scanning device for scanning optical record carriers, the optical record carriers including a first optical record carrier, a second optical record carrier and a third optical record carrier, the scanning device including a radiation source system (7) for producing first, second and third radiation beams for scanning said first, second and third record carriers, respectively, in first, second and third scanning modes, said first, second and third radiation beams having different predetermined wavelengths, the scanning device comprising an objective lens and an optical compensator, the optical compensator having a non-periodic phase structure through which each of said first, second and third radiation beams are arranged to pass, said non-periodic phase structure including a plurality of stepped annular zones separated by steps, the zones forming a non-periodic radial pattern, the stepped annular zones introducing first, second and third different wavefront modifications into at least part of the fi

Abstract: Undesired disturbance components leak eventually into various detection signals and reproduction signals as stray optical beams reflected from recording layers other than a reproduction layer overlap with signal beams on a light reception surface of an optical detector and interference occurs between them when an optical disc having multi-layered recording layers is reproduced. A diffraction grating having a specific grating groove pattern is arranged immediately ahead of an optical detector or in a return optical path. Such optical unit averages the disturbance components resulting from interference between a signal beam and a stray beam and can satisfactorily improve influences of leak.