Abstract: An optical member driving mechanism is provided, including a movable portion, a fixed portion, a driving assembly, a light emitter, and a light receiver. The driving assembly is configured to drive the movable portion to move relative to the fixed portion. The light emitter emits light toward an object, and the light receiver receives the light reflected by the object.

Abstract: A LiDAR system includes a first lens, a second lens, a first set of light sources and a first set of detectors positioned at a focal plane of the first lens, and a second set of light sources and a second set of detectors positioned at a focal plane of the second lens. Each detector of the second set of detectors is located at a respective detector position on the focal plane of the second lens that is optically conjugate with a position of a corresponding light source of the first set of light sources. Each detector of the first set of detectors is located at a respective detector position on the focal plane of the first lens that is optically conjugate with a position of a corresponding light source of the second set of light sources.

Abstract: This specification describes an improved automated luminaire including a plurality of light emitting modules, each including a laser module and an optical module, which expands the width of the laser light beam emitted from the laser module.

Abstract: A surface-emitting light source includes a substrate including a light emitting region where plural light emitting points are disposed and a non-light emitting region located around the light emitting region; and a lens array including plural lenses and a non-lens region around the plural lenses. The substrate and the lens array are directly bonded with each other at the non-light emitting region and the non-lens region such that the plural light emitting points and the plural lenses face each other, and the lens array has a linear expansion coefficient not greater than a linear expansion coefficient of the substrate.

Abstract: An optical head device (11) provided with: an optical element (36) for transmissively diffracting a light beam emitted from a semiconductor laser (34), generating a zero-order diffracted light beam and ±1-order diffracted light beams; and a photodetector (40) for receiving the zero-order diffracted light beam and the +1-order diffracted light beam after reflection from an optical disc (2). The photodetector (40) includes a primary light receiving section (400) for receiving the zero-order diffracted light beam, and a first secondary light receiving section (401) disposed outward from the primary light receiving section (400). The first secondary light receiving section (401) is positioned to detect an outer portion of the received light spot of the +1-order diffracted light beam, performs photoelectric conversion of this portion, and outputs a secondary detected signal.

Abstract: An optical head device (11) provided with: an optical element (36) for transmissively diffracting a light beam emitted from a semiconductor laser (34), generating a zero-order diffracted light beam and ±1-order diffracted light beams; and a photodetector (40) for receiving the zero-order diffracted light beam and the +1-order diffracted light beam after reflection from an optical disc (2). The photodetector (40) includes a primary light receiving section (400) for receiving the zero-order diffracted light beam, and a first secondary light receiving section (401) disposed outward from the primary light receiving section (400). The first secondary light receiving section (401) is positioned to detect an outer portion of the received light spot of the +1-order diffracted light beam, performs photoelectric conversion of this portion, and outputs a secondary detected signal.

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 element having compatibility among two or more wavelengths and having an excellent converging performance for light with each wavelength, and an optical head apparatus using the optical element are provided. An optical element according to the present disclosure has a first region including an optical axis and a second region formed around the outer circumference of the first region. The first region and the second region respectively have a first diffraction structure and a second diffraction structure each cyclically formed on an aspheric surface and having a step-like cross section. In the first region, the number of steps included between top portions of the first diffraction structure is different from the number of steps included between the optical axis and a top portion that is closest to the optical axis in the first diffraction structure.

Abstract: Provided are an optical pickup and an optical information storage system including the same. The optical pickup includes a diffracting element that splits incident light into main light and a plurality of sub light. The diffracting element has at least three regions including first through third regions. A second region is disposed between a first region and a third region and has a phase difference from the first and third regions. The optical pickup detects a tracking error signal by using light diffracted by the diffracting element.

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: 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: 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: The present invention provides a unit and method for implementing an optical head and optical drive device whose configuration is simple, and which allows the generation of a track error signal in which no offset is caused to occur. The optical drive device includes a light source for emitting light beams, an objective lens for converging the light beams onto an optical disc, an optical-signal generation element for dividing the light beams into at least four regions by using a division line extending in the radial direction of the optical disc, and a division line extending in the track direction of the optical disc, the light beams being reflected by the optical disc, and an optical detector for receiving the light beams divided by the optical-signal generation element, wherein the up and down or right and left areas of the four regions are made different from each other.

Abstract: An optical pickup and an information storage medium system using the same. The optical pickup includes a light source that emits light having a plurality of different wavelengths. The optical pickup includes a diffraction device having a plurality of diffraction patterns corresponding to the plurality of different wavelengths to divide the light incident from the light source unit into main light and sub light. The optical pickup further includes a photo-detector having a first main light reception unit that receives the main light and a first sub light reception unit that receives the sub light so as to detect an information signal and/or an error signal by receiving reflected light. The first sub light reception unit of the photo-detector is shaped so as to reduce reception of noise sub light due to diffraction based on an undesired diffraction pattern of sub light generated the diffraction device.

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 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: Provided is an objective lens manufactured well by using a mold and an optical pickup apparatus including the same. The objective lens of the present invention includes a first region that focuses laser beams of a BD, DVD, and CD standards, a second region that focuses the laser beams of the DVD and CD standards, and a third region that focuses the laser beams of the BD and the DVD standards are provided in this order from a center portion of the objective lens. A first annular zone step provided in the first region has a step amount larger than step amounts of annular zone steps provided in other regions.

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 apparatus is provided. Segmented regions included in a focus diffraction region includes focus segmented regions corresponding in number with different light emitted by a light source. Different focus segmented regions are arranged adjacent to each other alternately in a direction perpendicular to a parallel dividing line. Segmented regions included in a tracking diffraction region includes tracking segmented regions corresponding in number with different light emitted by the light source. Different tracking segmented regions are arranged adjacent to each other alternately in a direction perpendicular to the parallel dividing line.

Abstract: A tracking signal and a focusing signal are stabilized by eliminating multi-layer crosstalk. The diffraction position, with respect to a semiconductor detector, from a center region of a multi-region diffraction grating disposed along the return path of reflection light from the layer of interest is placed further away from the optical axis than the diffraction position from a peripheral part of the diffraction grating. Stray light from other layers is thus prevented from being incident on a sensing region for a peripheral region of the diffraction grating. Further, the area of the semiconductor detector is reduced by dividing the center region.

Abstract: Provided are an optical pickup apparatus and an objective lens which can appropriately record and/or reproduce information on three types of discs with different recording densities and improve the light-utilization efficiency using a simple structure. A first optical path difference providing structure is formed on an optical surface of the objective lens. The first optical path difference providing structure is a step structure in which plural ring-shaped step units each including the same number of steps are arranged concentrically about the optical axis as the center. The width w1 in the direction perpendicular to the optical axis of the highest step or the lowest step in at least one step unit in the step structure is approximately half of the average value w2 of two steps at both sides of the highest step or the lowest step in the direction perpendicular to the optical axis.

Abstract: In an optical pickup device for both CD and DVD disk media using a two-wavelength laser diode (1), a diffraction grating (11) is commonly used for both laser beams (L1, L2) for CD and DVD to diffract each laser beam into a main beam and a pair of side beams. The diffraction grating includes a first diffraction grating region (11a) and a second diffraction grating region (11b) having a same pitch as the first diffraction grating region and being laterally offset from the first diffraction grating region, and at least one of the first and a second laser beams are diffracted by both of the first and second diffraction grating regions.

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: 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: 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 divides signal light so as to detect the divided signal light. For example, a photodetector can include a region “A” and another region “B.” Among diffracted light diffracted from a track on an optical disc, only zeroth-order diffraction light enters region “A”, whereas the zeroth-order diffraction light, + first-order diffraction light, and ? first-order diffraction light enter region “B”. A focusing error signal from the photodetector is produced based upon a signal detected by the photodetector, whereas a tracking error signal is produced based upon signals detected from the regions “A” and “B.” A stable focusing error signal and a stable tracking error signal can be detected with respect to a dual layer optical disc, or a multi layer optical disc.

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 device is provided with a spectral element which imparts diffraction in such a manner that four light fluxes of the first laser light are separated from each other, when a light flux of the first laser light and a light flux of the second laser light reflected on a recording medium having laminated recording layers and servo layers are divided into four by a first straight line in parallel to a converging direction by an astigmatism element, and a second straight line perpendicular to the first straight line, and that the four light fluxes of the first laser light propagate on an outer side than the light flux of the second laser light; and a photodetector including a first sensor group which receives the first laser light, and a second sensor group which receives the second laser light.

Abstract: Provided is an objective lens used in an optical pickup that performs recording and/or reproducing of information signals on three different types of optical discs using different wavelengths. The objective lens is configured to collect light beams with the at least three wavelengths ?1, ?2, and ?3, which satisfy a relationship of ?1<?2<?3, on signal recording surfaces of compatible optical discs corresponding to the respective wavelengths. The objective lens includes: a diffractive portion that has a predetermined diffraction structure formed on an incident side surface. The diffractive portion has a first region that is provided in an innermost peripheral portion so as to diffract the light beams, a second region that is provided outside the first region so as to diffract the light beams, and a third region that is provided outside the second region.

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: Provided is an optical pickup device which can properly record and/or reproduce information on and/or from three types of discs having different recording densities and is simple in configuration and low cost. An objective lens is also provided. On the optical surface of the objective lens, an optical path difference giving structure is formed. Out of diffracted light generated when a first luminous flux enters the structure, second order diffracted light has the maximum diffraction volume. Out of diffracted light generated when a second luminous flux enters the structure, zero order diffracted light has the maximum diffraction volume. Out of diffracted light generated when a third luminous flux enters the structure, the minus first order diffracted light has the maximum diffraction volume.

Abstract: Provided is an objective lens for selectively focusing each of light beams having three wavelengths ?1, ?2, and ?3 on a signal recording surface of a corresponding optical disc, the wavelengths ?1, ?2, and ?3 satisfying at least a relationship ?1<?2<?3, the objective lens including a diffraction section disposed on an entry-side surface thereof, the diffraction section including a first region disposed in an innermost radius portion, a second region disposed outside the first region, and a third region disposed outside the second region, the first to third regions being formed so that an aperture of the light beams are appropriately limited, the first region including a staircase-like diffractive structure having a certain number of levels configured so that diffracted light of a predetermined order has the highest diffraction efficiency and optical-path-difference phase amounts for the levels of the diffractive structure has a certain relationship.

Abstract: An optical pickup with a simplified structure in which, according to the type of optical disc, diffracted light from three types of laser light can be directed efficiently onto a photodetector and appropriate focus control can be performed based on the signals detected by the photodetector, and a diffractive optical element that can be used in the optical pickup, which has a semiconductor laser 10 that can emit three types of laser light, a diffractive optical element 42 that diffracts the laser light reflected from the optical disc 31, and a single photodetector 43 that detects the diffracted light exiting the diffractive optical element 42.

Abstract: An optical pickup apparatus changes a propagation direction of luminous fluxes, out of a laser light reflected by a disc, in four luminous flux regions set about a laser optical axis so as to mutually disperse these luminous fluxes. A signal light region in which only a signal light is present appears on a detection surface of a photodetector. A plurality of sensors for a signal light are placed at positions irradiated with the signal light within the region. When an arithmetic process is performed on a detection signal outputted from each sensor, a DC component occurring in a tracking error signal is suppressed.

Abstract: There is provided an optical disk apparatus causing a hologram device to diffract a reflected light beam and causes each of reflected light beams of primary light in a longitudinal direction to generate received light signals by receiving the reflected light beams through receiving regions of a receiving unit before a preformatted signal being generated by a signal processing unit based on the received light signals. Therefore, the preformatted signal that excludes an influence of a stray light pattern by an interlayer stray light beam from a plurality of recording layers can be generated.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: A hologram optical device, and a compatible optical pickup having the hologram optical device and an information storage medium system employing the hologram optical device. The hologram optical device includes a hologram having a pattern having a period in a 4-step stairway shape. At least one of first, second, third, and fourth steps of the 4-step stairway shape is formed in a different width from at least one other step.

Abstract: An optical-pickup apparatus comprising: a laser-light source including first-and-second-light-emitting points for laser lights with first-and-second wavelengths which points are disposed at positions deviating in a direction optically corresponding to an optical-disc-tracking direction; a diffraction grating including a plurality of periodic structures which are joined to be different in phase from each other in the direction and each of which includes a recess and projection repeated in a direction optically corresponding to an optical-disc-tangential direction, the diffraction grating being configured to generate main-and-sub-luminous fluxes from the laser light; a holder to hold the diffraction grating to be movable in the direction corresponding to the tracking direction; a collimating lens; an objective lens to focus the main-and-sub-luminous fluxes from the collimating lens on the same track of an optical disc; and a photodetector to be applied with reflected lights of the main-and-sub-luminous fluxes f

Abstract: An optical pickup apparatus is provided with: an astigmatic element for introducing astigmatism to a reflected light from a recording medium; and an optical element for varying advancing directions of luminous fluxes within four different luminous flux regions with one another, out of the reflected light, so as to scatter the luminous fluxes within the four luminous flux regions with one another. When an intersecting point of two mutually crossing straight lines respectively parallel to a first direction by the astigmatic element and a second direction vertical to the first convergence direction is aligned to an optical axis of the reflected light, the two luminous flux regions are placed in a direction where a set of vertical angles created by the two straight lines forms a line, and the remaining two luminous flux regions are placed in a direction where the other set of vertical angles forms a line.

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: 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: An optical pickup includes a light source configured to emit light, a beam splitter configured to transmit or reflect light, an object lens configured to condense the light transmitted by the beam splitter onto an optical storage, and a diffraction grating having a first grating pattern and a second grating pattern. The first grating pattern is configured to diffract and divide the light reflected by the optical storage into a main beam and two sub beams. The second grating pattern is configured to diffract the light along a different diffracting direction than the first grating pattern. A condensing lens is configured to generate astigmatism to the light diffracted by the first grating pattern, and a light sensor is configured to receive the light via the condensing lens and detect a tracking error signal.

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.

Abstract: An optical pickup includes: a light source that emits a light beam; an object lens that condenses the light beam on a target recording layer of an optical disk; a lens moving unit; a condensing lens; a hologram element that diffracts, in diffracting a reflected light beam and separating it into reflected zeroth-order and first-order light beams, parts of the reflected first-order light beam in a first direction and sets them as first and second beams, diffracts parts of the reflected first-order light beam in a second direction and sets them as third and fourth beams; and a photodetector that receives the first and second beams and the third and fourth beams and generates light reception signals, and receives interlayer stray light of a part of the light beam reflected by the other recording layers other than the target recording layer and generates a stray light reception signal.

Abstract: The present invention relates to an optical element for use in an optical pickup apparatus and an optical pickup apparatus. An optical element is provided for use in an optical pickup apparatus which records or reproduces information by converging a light flux from a light source onto an information recording surface of an optical disc and by receiving a light flux reflected by the information recording surface by a photodetector. The optical element includes: a first area including an optical axis of the optical element; and a second area surrounding the first area and including a diffractive structure in a radial shape. The first area transmits a light flux from the light source, and the second area diffracts a light flux with the predetermined wavelength from the light source.

Abstract: An optical pickup apparatus is provided with an angle adjusting element. The angle adjusting element changes a propagation direction of luminous fluxes of four luminous flux regions set about an optical axis of the laser light, out of laser light reflected by a disc, and mutually disperses the luminous fluxes. A signal light region in which signal light only is present appears on a detecting surface of a photodetector. A sensor pattern for signal light is placed at a position irradiated with the signal light within this region. A sensor pattern for a spherical aberration detection is placed on an inner side of this region.

Abstract: An optical pickup apparatus is provided with an angle adjusting element. The angle adjusting element changes a propagation direction of luminous fluxes of four luminous flux regions set about an optical axis of the laser light, out of laser light reflected by a disc, and mutually disperses the luminous fluxes. A signal light region in which signal light only is present appears on a detecting surface of a photodetector. A sensor pattern for signal light is placed at a position irradiated with the signal light within this region. A sensor pattern for a coma aberration detection is placed on an inner side of this region.

Abstract: A method and apparatus for recording/reproducing data is disclosed. The apparatus for recording/reproducing data comprises a diffraction element splitting light diffracted or reflected from a recording medium into a main beam and first and second sub beams, the main beam and the first and second sub beams having no interference from one another; a light-receiving part detecting the main beam and the first and second sub beams; and a controller controlling a position of the diffraction element based on at least one light capacity of the detected beams or the detected position.

Abstract: An optical pickup apparatus is provided with a dividing element having a plurality of regions. The dividing element is capable of dividing a light flux reflected by the optical disc into a plurality of light fluxes having different outgoing directions. Each region of the dividing element and light receiving parts of a light detector are structured such that when a target information recording layer of the optical disc is brought into focus, a light flux reflected from the target information recording layer is focused on the light receiving parts of the light detector, and a light flux reflected from other information recording layer than the target information recording layer is not irradiated onto the light receiving parts of the light detector.

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.