Abstract: An optical combiner lens includes a lightguide having an input zone at which light enters the lightguide, an output zone from which light exits the lightguide, and a propagation zone between the input zone and the output zone that provides a propagation path for light from the input zone to the output zone. A lens is stacked over the lightguide. A seal engages the lightguide and the lens. The seal is positioned relative to the lightguide such that a portion of the seal is stacked over a portion of the propagation zone. A reflective optical coating is interposed between the portion of the propagation zone and the portion of the seal.

Abstract: Various embodiments disclosed herein include camera equipment having a refractive index layer that causes internal reflection close to an image sensor of the camera. In some examples, internal reflection may occur at a boundary formed with the refractive index layer and located between an image sensor and an upper surface of a lens of the camera. The boundary may be formed between the refractive index layer and another material located between the refractive index layer and the image sensor, wherein the refractive index layer has a lower index of refraction than other material between the refractive index layer and the image sensor. The boundary formed with the refractive index layer may cause light to be reflected back toward the image sensor to improve image quality of images captured by the image sensor.

Abstract: An electronic device may have a display panel for displaying images. A display cover layer having curved portions may overlap the display panel. An image transport layer having an input surface that receives light from the display panel may convey the light from the input surface to an output surface adjacent to an inner surface of the display cover layer. The image transport layer may include fibers with different lengths to form a region of the output surface with a curved profile. Each fiber in the coherent fiber bundle may have a respective output face. The output face of each fiber in the curved edge region of the image transport layer may be parallel to the display panel or may be angled towards the center of the image transport layer. Image distortion control circuitry may modify image data to control the perceived distortion of the display.

Abstract: In order to provide an optical element in which the occurrence of a region where no light beams are present (omission) is prevented, an optical element is provided with a main substrate which is manufactured from a light-transmitting material and in which a front surface and a rear surface are parallel to the setting directions, wherein at least one main beam splitter surface is provided obliquely to the setting directions and formed inside the primary substrate. The optical element is also provided with a sub substrate which is manufactured from a light transmitting material and in which a front surface and a rear surface are parallel to the setting directions, wherein a sub beam splitter surface is arranged at least between the front surface or the rear surface of the single sub substrate, and the rear surface or the front surface of the main substrate.

Abstract: A laser projection module, a depth camera and an electronic device are provided. The laser projection module includes a laser emitter configured to emit laser; a reflection element arranged in a laser emission direction of the laser emitter and configured to reflect the laser emitted from the laser emitter; a diffractive optical element arranged in a light exiting direction of the reflection element and configured to diffract the laser reflected by the reflection element; and an optical detector arranged between the laser emitter and the reflection element, and configured to receive the laser and detect an intensity of a non-zero order beam of the laser.

Abstract: An eyeglass lens for an optical imaging element for producing a virtual image of an initial image includes a main body and at least one complementary element mounted on the main body. The main body has a material with a first index of refraction n1. A viscous or solid intermediate layer is arranged between the complementary element and the main body at least in the region where the complementary element overlaps with a reflection section of the main body. The material of the viscous or solid intermediate layer has a second index of refraction n2 that satisfies the condition n2<n1 sin(?E). ?E is an angle of incidence of the light beams of the imaging beam path proceeding from the incoupling section and incident on the reflection section, selected such that at least 50% of the light beams of the imaging beam path have an angle of incidence of ?>?E.

Abstract: An optical combiner lens for a wearable heads-up display includes a first lens, a second lens, and a lightguide disposed between the first lens and the second lens to form a stack. A first medium gap is defined within the stack and between the first lens and the lightguide, and a second medium gap is defined within the stack and between the lightguide and the second lens. An in-coupler is positioned to receive light into the lightguide. An out-coupler is positioned to output light from the lightguide.

Abstract: A depth camera assembly (DCA) includes a structured light generator, an imaging device and a controller. The structured light generator illuminates a local area with a structured light pattern in accordance with emission instructions from the controller. The structured light generator comprises an illumination source, an acousto-optic device, and a projection assembly. The acousto-optic device generates a structured light pattern from an optical beam emitted from the illumination source. The projection assembly modifies a general intensity envelope of the structured light pattern in order for the structured light pattern to illuminate a larger section of the local area, and projects the modified structured light pattern into the local area. The imaging device captures of portions of the structured light pattern scattered or reflected from the local area. The controller determines depth information for the local area based at least in part on the captured images.

Abstract: Provided is an image display device, including: an image projection optical system projecting, at infinity, image light corresponding to an arbitrary image; a first light guide portion formed like a plate having a first plane and a second plane, in which the image light projected from the image projection optical system is transmitted in part through the first plane with the rest being reflected between the first plane and the second plane, so as to be propagated in the x-direction by repeating the transmission and the reflection; a first spacer plate formed like a plate having a third plane and a fourth plane, the third plane being bonded to the first plane; and a first output deflector formed on or bonded to the fourth plane, the first output deflector diffracting part of the image light transmitted through the first plane, in a direction substantially perpendicular to the first plane.

Abstract: An optical system and methods are disclosed. In an aspect, an optical system can comprise a display device configured to emit an image information and an image guide optically coupled to the display device, wherein the image guide is configured to receive the image information and transmit the image information along a longitudinal axis of the image guide, and wherein the image guide has a thickness along a lateral axis between about 0.3 mm and about 1 mm. The optical system can further comprise a beam combiner disposed in the image guide, the beam combiner configured to transmit at least a portion of the received image information to exit the image guide.

Abstract: An objective lens for an optical pickup device is characterized in that compatibility of three types of optical discs, which are a BD, a DVD, and a CD, may be realized by a common objective lens, and a flare can be created by providing an over-spherical aberration when a third optical disc is used from a size relationship between a pitch on a central region side and a pitch on an intermediate region side across a boundary and a relationship of a direction of a step in the base structures superimposed in a central region and an intermediate region of the objective lens.

Abstract: An optical component, a hologram, and a photodetector are configured in an optical head device of an optical disc device such that a +1-order beam or a ?1-order beam of diffracted light generated from light reflected from an information track in the intended information recording layer strikes the interior of the light-receiving surfaces of the tracking error detection light-receiving sections, a +1-order beam or a ?1-order beam of diffracted light generated from light reflected from an information track in an information recording layer one layer deeper than the intended information recording layer strikes outside the light-receiving sections, and a +1-order beam or a ?1-order beam of diffracted light that is generated from light reflected from an information track in an information recording layer one layer shallower than the intended information recording layer strikes outside the light-receiving sections.

Abstract: An optical pickup includes a light source, a light splitting element generating signal light and position adjustment light by splitting return light from an optical disk and dispersing the return light in different directions, and a light receiving portion having a signal light receiving portion and an adjustment light receiving portion. The light splitting element is configured such that the position thereof is adjusted on the basis of the position adjustment light received by the adjustment light receiving portion of the light receiving portion.

Abstract: In one embodiment of the present invention, an optical pickup for writing and reading data on an optical storage medium comprises a diffractive element for diffracting a light beam to split it into multiple light beams. The diffracted light beams includes a zero-order diffracted light beam for writing data on a track of the land or the groove of the optical storage medium and non-zero-order diffracted light beams for reading the data from the track. The diffractive element has first and second diffraction gratings that have mutually different grating vector directions and pitches. The first diffraction grating forms light beam spots on the same track by the non-zero-order and zero-order diffracted light beams. The second diffraction grating forms a light beam spot to extend to both sides of said track, or forms a light beam spot on one side of said track, by the non-zero-order diffracted light beams.

Abstract: An optical pickup device includes a laser diode for emitting a laser beam, an objective lens for collecting the light beam emitted from the laser diode and irradiating an optical disc with the collected light beam, a diffraction element for making the light beam reflected from the optical disc diverge, and a detector having a plurality of detection parts for receiving the diverging light beams caused by the diffraction element. The diffraction element has first, second, and third divided areas, wherein a 0th-order diffracted light from the first divided area, the second divided area, and the third divided area is detected by at least four divided detection parts; and at least two detection parts for detecting the light beam diffracted at the first divided area into first or higher diffraction order are aligned in a direction generally perpendicular to the track of the optical disc.

Abstract: For obtaining stable servo-signals without receiving ill influences of stray lights from other layers, on both a focus error signal and a tracking error signal, when recording/reproducing a multi-layer optical disc having small gap between layers thereof, a light beam is divided with using a first and a second diffraction gratings. The first diffraction grating is a polarization diffraction grating, and is mounted on an actuator. The second diffraction grating is disposed on a fixed portion. The first diffraction grating has a first region having a center of a light beam and other(s), and among signal lights reflecting from the disc, the light beam entering into the first region is diffracted, and the light beam entering into the second region transmits therethrough. The second diffraction grating transmits the light beam diffracting on the first region of the polarization diffraction grating therethrough, while diffracting the light beam diffracting on the second region.

Abstract: An optical head capable of recording or playing back optical discs is provided. The optical disc comprises a light source to emit a beam, an objective to focus the beam on an optical disc, a beam dividing element having a plurality of divided areas with which to divide a cross section of the beam reflected from the optical disc, and a light detector to receive the beams divided by the beam dividing element, wherein the beam dividing element has in at least one of the plurality of areas an aberration imparting function of imparting an astigmatism or defocus aberration to a beam passing through that area.

Abstract: There is provided a diffraction grating including a convex portion and a concave portion which are used for lights having different wavelengths ?1, ?2 and ?3 and are alternately disposed on at least one surface of a substrate with a predetermined pitch. An average refractive index of the convex portion is smaller than an average refractive index of the concave portion. A phase difference in the lights having the wavelength ?1 which transmit the convex portion and the concave portion and a phase difference in the lights having the wavelength ?2 which transmit the convex portion and the concave portion are both substantially the integral multiple of 2?, and a phase difference in the lights having the wavelength ?3 which transmit the convex portion and the concave portion is substantially the non-integral multiple of 2?.

Abstract: An optical pickup includes: a light source; a first diffractive element which diffracts light polarized in a particular direction; an objective lens; a lens actuator which shifts the objective lens so that the magnitude of shift from its initial position in a tracking direction has an upper limit of 0.3 mm to 0.6 mm; a wave plate; a second diffractive element which has two diffraction regions configured to diffract light polarized in a direction that intersects with the particular direction at right angles and which splits the write beam reflected from the optical storage medium through each diffraction region into a transmitted light beam and at least one diffracted light beam; and a photodetector which detects the transmitted light beam, the diffracted light beams that have left the two diffraction regions, and the read beam reflected from the optical storage medium.

Abstract: In one embodiment, the optical pickup device includes: a light source that emits a light beam; a diffractive element that diffracts the light beam and generates a zero-order and ±first-order diffracted light beams; an objective lens that converges the diffracted light beams onto the same track on the storage medium; and a photodetector that receives the diffracted light beams reflected from the storage medium. If a distance from a light beam spot left by the zero-order diffracted light beam on the track to light beam spots left by the ±first-order diffracted light beams on that track is d [?m], the scanning linear velocity of the storage medium is v [m/s], and a time it takes for a phase-change material of the storage medium that has once been melted by the zero-order diffracted light beam to solidify is T [?s], vT?d is satisfied.

Abstract: A complex objective lens composed of a hologram and an objective lens, capable of realizing stable and high-precision compatible reproducing/recording of a BD with a base thickness of about 0.1 mm for a blue light beam (wavelength ?1) and a DVD with a base thickness of about 0.6 mm for a red light beam (wavelength ?2). In an inner circumferential portion of the hologram, a grating is formed, which has a cross-sectional shape including as one period a step of heights in the order of 0 time, twice, once, and three times a unit level difference that gives a difference in optical path of about one wavelength with respect to a blue light beam, from an outer peripheral side to an optical axis side. The hologram transmits a blue light beam as 0th-order diffracted light without diffracting it, and disperses a red light beam passing through an inner circumferential portion as +1st-order diffracted light and allows it to be condensed by an objective lens.

Abstract: A disclosed optical element includes three or more sub-wavelength convexo-concave structures having pitches less than a wavelength of an incident light incident to the optical element and having groove depths equal to each other and a periodic structure having the three or more sub-wavelength convexo-concave structures, the pitch of the periodic structure greater than the wavelength of the incident light, in which a predetermined polarization direction of the incident light is diffracted mainly into a specific order.

Abstract: An optical head includes a blue-violet laser light source for emitting a blue-violet laser beam, a mirror with a diffraction grating for transmitting and reflecting the blue-violet laser beam at a predetermined ratio, and a front monitor sensor for receiving transmitted light or reflected light from the mirror with a diffraction grating and creating an APC signal for controlling an output of the blue-violet laser light source. The mirror with a diffraction grating includes a first surface which the blue-violet laser beam enters, and a second surface facing the first surface. The first surface and the second surface are mutually parallel. A reflecting coat for transmitting and reflecting the blue-violet laser beam at a predetermined ratio is formed on the first surface, and a diffraction grating is formed on the second surface.

Abstract: There is provided a diffraction grating including a convex portion and a concave portion which are used for lights having different wavelengths ?1, ?2 and ?3 and are alternately disposed on at least one surface of a substrate with a predetermined pitch. An average refractive index of the convex portion is smaller than an average refractive index of the concave portion. A phase difference in the lights having the wavelength ?1 which transmit the convex portion and the concave portion and a phase difference in the lights having the wavelength ?2 which transmit the convex portion and the concave portion are both substantially the integral multiple of 2?, and a phase difference in the lights having the wavelength ?3 which transmit the convex portion and the concave portion is substantially the non-integral multiple of 2?.

Abstract: Two light flux areas are disposed in a direction along which a pair of vertically opposite angles defined by first and second straight lines are aligned, and the other two light flux areas are disposed in a direction along which the other pair of vertically opposite angles are aligned. A spectral element sets propagating directions of divided elements of each of light fluxes obtained by dividing each of the light fluxes by a third straight line intersecting with the first and second straight lines by an angle of 45 degrees, or by a fourth straight line orthogonal to the third straight line to disperse the divided elements on a photodetector. The photodetector is provided with sensors which individually receive the divided elements of the light fluxes.

Abstract: An astigmatism element converges laser light in first and second directions to generate focal lines. A spectral element makes propagating directions of light fluxes entered into first through fourth areas different from each other to disperse the four light fluxes from each other. The direction along which the first and second areas are aligned is in parallel to a direction of a track image of a recording medium projected onto the spectral element. Each of the first and second areas has a surface area larger than a surface area of each of the third and fourth areas, and a boundary portion between the first and second areas, and the third and fourth areas includes a straight portion extending in a direction perpendicular to the direction of the track image.

Abstract: An optical pickup apparatus according to an embodiment includes a semiconductor laser, an objective lens, a grating, and a light detecting device. The grating is installed between the semiconductor laser and the objective lens to divide the light beam emitted from the semiconductor laser into three beams or more including a main beam and a sub-beam. The light detecting device receives the divided light reflected by the optical recording medium. The grating includes a first diffraction grating and a second diffraction grating. The first diffraction grating has patterns formed for dividing a sub-beam with respect to a first optical recording medium having a first track pitch, and second diffraction grating has patterns formed for dividing the sub-beam divided by the first diffraction grating into sub-beams with respect to a second optical recording medium having a second track pitch.

Abstract: An optical pickup apparatus includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical unit having a first optical path difference providing structure and a second optical path difference providing structure. Magnifications of the objective optical unit for the first-third light fluxes have almost same value. The first optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be one of under-correction and over-correction for all of the first light flux, the second light flux, and the third light flux. The second optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be the other of under-correction and over-correction of the spherical aberration only for the second light flux.

Abstract: An objective lens element that can suppress occurrence of an aberration is disclosed. Sawtooth-like diffraction structures having different height and cycles (pitches) are provided on an inner part R21 and an outer part R22, respectively. A curved surface M211 extending at an intermediate level of recesses and projections of the sawtooth-like diffraction structure provided on the inner part R21, and a curved surface M212 extending at an intermediate level of recesses and projections of the sawtooth-like diffraction structure provided on the outer part R22 are smoothly connected to each other. Even when wavelength of the light source and/or the environmental temperature change, a phase shift does not occur between the inner part R21 and the outer part R22, and a decrease in diffraction efficiency and occurrence of an aberration can be suppressed.

Abstract: An optical head includes a blue-violet laser light source for emitting a blue-violet laser beam, a mirror with a diffraction grating for transmitting and reflecting the blue-violet laser beam at a predetermined ratio, and a front monitor sensor for receiving transmitted light or reflected light from the mirror with a diffraction grating and creating an APC signal for controlling an output of the blue-violet laser light source. The mirror with a diffraction grating includes a first surface which the blue-violet laser beam enters, and a second surface facing the first surface. The first surface and the second surface are mutually parallel. A reflecting coat for transmitting and reflecting the blue-violet laser beam at a predetermined ratio is formed on the first surface, and a diffraction grating is formed on the second surface.

Abstract: For obtaining stable servo-signals without receiving ill influences of stray lights from other layers, on both a focus error signal and a tracking error signal, when recording/reproducing a multi-layer optical disc having small gap between layers thereof, a light beam is divided with using a first and a second diffraction gratings. The first diffraction grating is a polarization diffraction grating, and is mounted on an actuator. The second diffraction grating is disposed on a fixed portion. The first diffraction grating has a first region having a center of a light beam and other(s), and among signal lights reflecting from the disc, the light beam entering into the first region is diffracted, and the light beam entering into the second region transmits therethrough. The second diffraction grating transmits the light beam diffracting on the first region of the polarization diffraction grating therethrough, while diffracting the light beam diffracting on the second region.

Abstract: An objective lens includes a diffraction structure for distributing much of a quantity of an incident light beam into two diffracted lights having different diffraction orders from each other, wherein recording or reproduction of information on an optical disk is performed by converging the diffracted light having a longer focal length of the two diffracted lights onto an information recording surface through a protective layer of the optical disk, and a distance from the objective lens to a surface of the protective layer along an optical axis is longer than a distance between focuses of the two diffracted lights along the optical axis when the diffracted light having the longer focal length is converged onto the information recording surface of the optical disk.

Abstract: A disclosed optical pickup for performing at least recording, reproduction, or deletion of information on a first, second, third, and fourth optical recording media having different recording densities includes a first light source configured to emit first light having a first wavelength ?1 corresponding to the first and second optical recording media; a second light source configured to emit second light having a second wavelength ?2 corresponding to the third optical recording medium; a third light source configured to emit third light having a third wavelength ?3 corresponding to the fourth optical recording medium; an objective lens configured to focus the first light, the second light, and the third light on corresponding recording surfaces of the first, second, third, and fourth optical recording media; and an aberration correcting unit between the objective lens and the first, second, and third light sources.

Abstract: An objective optical system for information recording/reproducing, at least one of optical surfaces of the objective optical system comprising a diffraction surface including a first region contributing to converging first, second and third beams and including a diffraction structure formed such that use diffraction orders for the first, second and third beams are 1st-orders and a condition 0.03<(?B11??1)/?1<0.40 is satisfied; a second region contributing to converging only the first and second beams and including a diffraction structure formed such that the use diffraction orders are 1st-orders and a condition: ?0.35<(?B12??B11)/?1<0.35 is satisfied; and a third region contributing to converging only the first beam and including a diffraction structure formed such that the use diffraction order for the first beam is an odd order and a condition: ?0.23<m13×((?B13??1)/?1)<0.23 is satisfied.

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: The present invention provides an optical pickup in which the transmission diffraction efficiency of plural recording and/or reproducing light beams of different wavelengths, radiated from plural light sources, may be prevented from being lowered, and in which the transmission diffraction efficiency and the angle of diffraction are both optimized.

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: 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 pickup apparatus comprising: a laser diode; an objective lens configured to focus laser light emitted from the laser diode on a signal recording layer of an optical disc; a first aberration correction element arranged in an optical path between the laser diode and the objective lens; and a second aberration correction element arranged in the optical path between the laser diode and the objective lens and having an aberration correction speed lower than the aberration correction speed of the first aberration correction element, the first aberration correction element and the second aberration correction element being selectively operated according to the required aberration correction speed.

Abstract: A diffracting portion is disposed in an optical path between a light source and an optical disc. The diffracting portion diffracts the reflected light from recording layers of the optical disc toward a light receiving portion. The diffracting portion includes a first diffraction region having a first diffraction efficiency and a second diffraction region having a second diffraction efficiency lower than the first diffraction efficiency. The first diffraction region includes a FES diffracting portion and first to fourth TES diffracting portions. The second diffraction region includes fifth and sixth TES diffracting portions. First-order diffraction lights from the non-light-collecting recording layer enter on the fifth and the sixth TES diffracting portions, and are diffracted toward the light receiving portion by the fifth and the sixth TES diffracting portions.

Abstract: An optical controller includes a light source for emitting light, an object lens for condensing light emitted from the light source, a light detection unit for receiving light reflected on an optical information recording medium and outputting a signal corresponding to the amount of the light, and a laser control unit for controlling the amount of the light emitted from the light source to the information recording surface on which information is to be recorded or reproduced, based on the recording state of an information recording surface disposed closer to the object lens than an information recording surface on which the information is to be recorded or reproduced.

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: An optical pickup including a light source, two light focus devices, a light reception device, a polarization selective light path splitting device, a polarization switching device, a first diffraction element including a periodic structure including two kinds of sub-wavelength convexo-concave structures while the two kinds of sub-wavelength convexo-concave structures alternately arranged at right angles to each other, and the filling factors of the two kinds of sub-wavelength convexo-concave structures are determined to substantially equalize effective refractive indices of the two kinds of sub-wavelength convexo-concave structures with regard to the polarization direction of the outgoing light beam, and the second diffraction element having a structure similar to that of the first diffraction element except that the filling factors are determined to substantially equalize effective refractive indices of the two kinds of sub-wavelength convexo-concave structures with regard to a polarization direction perpen

Abstract: A grating element is provided with diffraction members wherein protrusions and recesses are periodically arranged, respectively, on one surface of each of transparent substrates. The diffraction members are laminated in the substantially perpendicular direction to the transparent substrates, the protrusions of the diffraction members are made of a dielectric multilayer film, and the dielectric multilayer film has dielectric films of two or more types laminated in the substantially perpendicular direction on the transparent substrates. The wavelengths of laser beams diffracted at predetermined diffraction efficiencies by the diffraction members are different from one another.

Abstract: An optical pick-up apparatus including an optical source module having a CD optical source and a DVD optical source, a diffracting grating dividing a light beam from the optical source module to at least three divided light beams, a first optical divider changing a path of the divided light beams to an optical disk, a second optical divider reflecting and forwarding the divided light beams reflected from the optical disk in a predetermined ratio, a first optical detector including a single optical sensor receiving reflected light from the second optical divider, and a second optical detector including at least three optical detection sensors receiving forwarded light from the second optical divider. Embodiments of the present invention can provide support for multi-type optical disks with a simple optical structure.

Abstract: A lens-side grating diffracts, in a direction of an emitter-side grating, two laser beams passed through the lens-side grating from an optical disk side. The emitter-side grating substantially passes the laser beam having a longer wavelength than the other laser beam, and directs it to a desired region of the light receiving element. The emitter-side grating diffracts the laser beam having a shorter wavelength than the other laser beam to direct a +1st diffracted beam of the laser beam thus diffracted to the same light receiving region as a 0th diffracted beam of the other laser beam. Such a structure may be employed that a ?1st diffracted beam of the laser beam of the longer wavelength is directed to the same light receiving region as the 0th diffracted beam (passed beam) of the laser beam of the short wavelength.

Abstract: A diffraction optical element is provided to reduce harmful lights and also suppress deterioration in the optical characteristics of the element. The diffraction optical element 22 is formed with a plurality of diffraction gratings 17?, 18?, 19? and 20?. From these diffraction gratings, there are selected the diffraction gratings 18?, 19? and 20? whose groove apex angles are less than a predetermined angle. The diffraction gratings 18?, 19? and 20? has chamfer surfaces 18c?, 19c? and 20c? formed on the lower side of respective slanted surfaces 18a?, 19a? and 20a?. The chamfer surfaces 18c?, 19c? and 20c? are slanted to the slanted surfaces 18a?, 19a? and 20a?, respectively.

Abstract: In a photo pickup device, an incident area 30 for a reflection light of a light spot is divided into four areas 30a˜30d by parting lines 31, 32 making axial-symmetrical angles with a direction Y of a projected track on an optical disc. In these areas, the so-divided areas 30a, 30c are formed so as to diffract the light in one or more directions in a range of 90 degrees±20 degrees to the direction Y and impress misalignment on each diffraction light. In each diffraction light, two focal lines produced due to the astigmatism make approx. 45 degrees with the direction Y of the projected track. Further, the divided areas 30b, 30d are characterized by diffracting the light in one or more directions in a range of 90 degrees±20 degrees to the direction Y.

Abstract: A diffractive optical element whose two diffraction gratings diffract three different wavelength light beams is provided. The diffractive optical element includes a first diffraction grating and a second diffraction grating that is located opposite the first one, and is configured in such a way that, among three different wavelength incident light beams, the diffraction efficiency in one light beam diffracted on the first diffraction grating is a predetermined value or less, and the diffraction efficiencies in the other two different incident light beams diffracted on the second diffraction grating are predetermined values or less. This arrangement can achieve a diffractive optical element capable of diffracting the three different wavelength light beams in a simple configuration.

Abstract: An optical pickup head device includes a diffraction grating for generating zero-order diffracted light and at least first-order diffracted light and provides a tracking error signal with a DPP method. The diffraction grating includes grating patterns with a nonuniform period or phase. The size of the first-order diffracted light converged on an optical recording medium is larger in the direction parallel to a tangent to the track than in the direction perpendicular to the tangent. P1/P0>PW2/PW1 is established, where PW1 represents the power that is required to record information on the optical recording medium, PW2 represents the maximum power that allows information recorded on the optical recording medium to be reproduced without being erased, P0 represents the light amount of the zero-order diffracted light converged on the optical recording medium, and P1 represents the light amount of the at least first-order diffracted light converged on the optical recording medium.