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 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 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: 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: An optical head device and an optical disc apparatus of a simple structure capable of canceling an offset in a tracking error signal caused when an objective lens shifts; in the optical head device, a polarizing hologram 104 has first diffraction areas 112 and 113 including a whole of an area irradiated with overlap of a zeroth-order beam of reflection light from an optical disc 1 and positive/negative first-order beams of the reflection light, and a second diffraction area 111 including an area irradiated with the zeroth-order beam of the reflection light and not irradiated with the positive/negative first-order beams of the reflection light without including the first diffraction area; and a photodetector 109 has a first light receiving section 131 for receiving a first light beam which is a zeroth-order beam of diffraction light generated by the polarizing hologram 104, a second light receiving section for receiving a second light beam which is a positive first-order beam of the diffraction light generated

Abstract: An objective optical system for an optical information recording/reproducing apparatus, at least one surface of the objective optical system being configured to be a phase shift surface having a phase shift structure, wherein: the phase shift surface has a first area contributing to converging first, second and third light beams onto recording surfaces of first, second and third optical discs, respectively; in the first area, the phase shift surface has at least two types of phase shift structures including a first phase shift structure having first steps and a second phase shift structure having second steps; the phase shift surface has a plurality of combinations of annular zones which satisfy a condition: 0.95<P1/P2<1.05??(1), and the phase shift surface satisfies a following condition: ?3.00<??1/??2<?0.10??(2).

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: There is provided an objective lens for information recording/reproducing for three types of optical discs, which includes a first area contributing to converging a third light beam onto a record surface of a third optical disc. The first area includes a phase shift structure having refractive surface zones concentrically formed about a predetermined axis. The phase shift structure includes first and second step groups. The first step group is configured such that an optical path length difference ?OPD1 (nm) given by each step of the first step group to a first light beam satisfies a condition: 2N1+1.10<|?OPD1/?1|<2N1+1.40, where N1 is an integer or zero, and the second step group is configured such that an optical path length difference ?OPD2 (nm) given by each step of the second step group to the first light beam satisfies a condition: 2N2?0.10<|?OPD2/?1|<2N2+0.10, where N2 is an integer.

Abstract: An apparatus for detecting movement direction of object, includes a converging lens, an image sensor and an image processor. The converging lens has an axial chromatic aberration between a first and a second rays in different wavelengths. The image sensor is for receiving and converting the first and second rays into first and second electronic image signals associated with the object. The image processor is configured for analyzing whether the object is closer to an object plane associated with the first ray or closer to an object plane associated with the second ray when the object moves to different positions, and determining the movement direction of the object based on the analyzed positions of the object relative to the object plane associated with the first ray and the object plane associated with the second ray.

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: Means (101a) for evaluating positional control deviation and means (102a) for outputting a corrective signal, this being a set of signals with kick and brake functions, to an actuator (10) on the basis of the evaluation result are provided. Although control deviation may increase due to external shock or vibration acting on the disc device or when a disc having eccentricity, wobble, or another physical deformity is reproduced, the control deviation is suppressed without loss of control stability, and stable recording and reproducing is always possible.

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: 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 device and an optical recording/reproduction device are provided that can suppress a tracking error signal offset generated in the boundary between an unrecorded area and a recorded area. A three-beam diffraction grating is divided into two areas. A division line that divides the diffraction grating into two areas has a step in the direction almost vertical to a groove period structure, and the part of the division line in the step has a staircase shape. The phase difference in the groove period structures between one area and the other area, separated by the division line, is about 180 degrees.

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 are an optical pick up and an optical component used for the optical pickup which are capable of preventing or restraining occurrence of deviation and unbalance which are caused by assembly errors during manufacturing of optical components, a temperature variation or the like. The optical pickup comprises a laser, a polarization changeover element for changing over a direction of polarization of an optical beam emitted from the laser, a beam splitting element for splitting the laser beam into a plurality of optical paths in accordance with a direction of a polarization, a plurality of objective lenses for focusing laser beams onto a recording layer of the optical disc, a rise-up mirror, and a plurality of coupling lenses arranged respectively intermediate of the plurality of optical paths led to the plurality of objective lenses.

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 an objective lens and an optical pickup device which can thin the objective lens and a device on which the objective lens is mounted, and which can prevent that the pitch of the diffraction grating at the outer periphery of the objective lens becomes too small in the manufacturing procedure and so it becomes difficult to manufacture the Fresnel lens or which does not require a high-grade fine processing technique in order to minimize the pitch of the diffraction grating, in an objective lens which condenses a laser light emitted from a light source to irradiate on an optical disk, the outer periphery on the side surface of the objective lens in which the laser light is incident is formed by a refractive lens portion 7a and the inner periphery thereof is formed by a Fresnel lens portion 7b.

Abstract: The present invention provides a first light source (21) that emits light of a first wavelength, that at least either records onto or reproduces information from an information recording medium (30), a light source (22) that emits light of a second wavelength that records onto or reproduces information from an information recording medium (33), a light source (23) that emits light of a third wavelength that records onto or reproduces information from an information recording medium (23), focusing means, an optical element (28) that passes light of the first wavelength and diffracts light of the second and third wavelengths, wherein the optical element (28) is an optical element in which grooves are formed in a substrate, wherein the expression: 380 nm?(n?1)×d?420 nm is satisfied, where n is a refractive index of the substrate at a wavelength of 400 nm, and d (nm) is a depth per step of the grooves, and wherein the grooves are formed in two steps of depth d and depth 2d.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: There is provided an optical pickup apparatus that can obtain a stable servo signal by reducing stray light generated by diffraction in a recording layer other than a recording layer on which light is condensed. A hologram element provided in an optical pickup apparatus for recording information onto a recording medium and/or reproducing information on the recording medium by use of light includes fourth and fifth divisions where at least first-order diffracted light among diffracted light beams obtained by reflection and diffraction on a recording layer other than a light-condensed recording layer on which light is condensed by an objective lens so as not to be directed toward first and second light-receiving elements for detecting focus position information and third to eighth light-receiving elements for detecting track position information.

Abstract: A diffraction element for an optical pick-up apparatus is capable of precisely controlling the tracking of the pick-up apparatus. The diffraction element includes a diffraction grating divided into a first, a second, and a third region. The second region is located between the first and third regions. Any one of the first region and the third region is inclined at a predetermined angle ? with respect to the second region.

Abstract: An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: |?SA1/?U|·|?U|+|?SA2/?T|·|?T|?0.07 ?rms where ? represents a wavelength of a light source, ?SA1/?U represents a change of a spherical aberration for an object-to-image distance change ?U (|?U|?0.5 mm) and ?SA2/?T represents a change of spherical aberration for a temperature change ?T (|?T|?30° C.), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: In order to prevent a spectrum of a wavelength channel from becoming narrower, a device according to the present invention includes a light dividing section capable of dividing a wavelength spectrum in an input light beam and outputting a plurality of divided light beams, which are spatially separated and have wavelength spectrum portions different from each other, and a wavelength-to-special-position-converter capable of spatially multiplexing the wavelength spectrum portions of the plurality of divided light beams from the light dividing section.

Abstract: A peak hold circuit is provided that operates stably even if a peak voltage to be held of a motor-drive-current detection voltage is minute. The peak hold circuit includes: a level shift circuit shifting the motor-drive-current detection voltage by a given voltage; a differential amplifier circuit receiving an output voltage of the level shift circuit and a voltage at an output terminal to amplify and output a difference between the voltages; an output transistor receiving at its base an output voltage of the differential amplifier circuit and outputting from its emitter charging current; a capacitor charged with the charging current to hold the voltage at the output terminal; a bias element generating a voltage substantially equal to the given voltage of the level shift circuit; and a resistance element provided between the bias element and the output terminal for controlling discharging current of the capacitor.

Abstract: A diffraction grating for plural wavelengths includes first grating regions which have periodic protrusions and depressions in sectional shape and are long formed in a depth direction perpendicular to a repeat direction of the protrusions and depressions, and second grating regions which have a configuration similar to that of the first grating regions and have depressions set to depths different from groove depths of the depressions of the first grating regions. The first and the second grating regions are alternately placed, and groove depths of each the depressions of both the grating regions are set so that the first grating regions transmit incident light of a first wavelength and also diffract incident light of a second wavelength different from the first wavelength and the second grating regions transmit incident light of the second wavelength and also diffract incident light of the first wavelength.

Abstract: An optical pickup for recording/reproducing information on/from an optical disc having recording layers, includes a light source; an objective lens for condensing an optical beam emitted from the light source on the recording layer; a photo-detector having a light-receiving section for receiving return light from the optical disc; an optical-path separating unit for separating the optical path of the return light reflected by the optical disc from the optical path of the optical beam emitted from the light source; and a masking member having a masking unit shielding part of a passing-through optical beam, in which the masking unit shields the central region of the optical beam to be incident in the light-receiving section among the optical beams reflected by the other recording layers or surfaces different from the recording layer recording/reproducing information so as not to admit the central region to the light-receiving section.

Abstract: The present invention provides a first light source (21) that emits light of a first wavelength, that at least either records onto or reproduces information from an information recording medium (30), a light source (22) that emits light of a second wavelength that records onto or reproduces information from an information recording medium (33), a light source (23) that emits light of a third wavelength that records onto or reproduces information from an information recording medium (23), focusing means, an optical element (28) that passes light of the first wavelength and diffracts light of the second and third wavelengths, wherein the optical element (28) is an optical element in which grooves are formed in a substrate, wherein the expression: 380 nm?(n?1)×d?420 nm is satisfied, where n is a refractive index of the substrate at a wavelength of 400 nm, and d (nm) is a depth per step of the grooves, and wherein the grooves are formed in two steps of depth d and depth 2d.

Abstract: An optical pickup includes a diffraction grating partitioned into three areas, in which the phase of periodic grating groove structure in an area is successively shifted from that in the adjacent area by 90°. In the generation of a differential push-pull signal, an amplification factor K for sub push-pull signals is varied depending on the type of the optical disk. By such composition of the optical pickup, amplitude deterioration of the tracking error signal accompanying displacement of the object lens is reduced.

Abstract: Variable gain amplifier and a LSI including the variable gain amplifier that expands an output voltage range or control voltage range without increasing power consumption. The variable gain amplifier includes a voltage-current conversion circuit; a variable gain unit; and a voltage output unit. The voltage-current conversion circuit outputs a first positive current and a first negative current in proportion to an input voltage. The variable gain unit inputting the first positive current and the first negative current controlled by a control signal and outputs four output currents including a second positive current, a third positive current, a second negative current and a third negative current. The voltage output unit inputs either the second positive current and the second negative current or the third positive current and the third negative current Iop3, and outputs a positive output voltage and a negative output voltage.

Abstract: Conventional lenses for DVD/CD compatible writing/reading are liable to CD jitter deterioration due to phase shifts in a central area. Setting a corresponding base material thickness of an intermediate area of the circumference A2 to greater than 1.2 mm which is the base material thickness of the CD, that is, converging luminous flux that has passed through the intermediate area of the circumference A2 onto a farther place than the information recording surface of the base material thickness of the CD makes it possible to reduce jitter deterioration due to phase shifts. Further, it makes possible to provide a system with higher precision and higher reliability.

Abstract: A device for scanning a first and second type of optical record carriers (2; 40) generates a first and a second radiation beam for scanning the first and second type of record carriers, respectively, the first radiation beam having a first numerical aperture larger than the second numerical aperture of the second radiation beam. The device includes a non-periodic phase structure that does not affect the first radiation beam. The phase structure introduces an amount of spherical aberration in the second radiation beam for scanning the second type of record carriers for compensating the difference in spherical aberration required for scanning through the different thickness of the transparent layer (3; 41) of the first and second type of record carriers (2, 40).

Abstract: An optical element (16) introduces a first wavefront deviation when a first radiation beam having a first wavelength passes through it and a second wavefront deviation when a second radiation beam having a second wavelength different from the first wavelength passes through it. One surface of the optical element comprises a phase structure in the form of annular areas (52, 53, 54, 55), the areas forming a non-periodic pattern of optical paths of different length. The optical paths for the first wavelength form the first wavefront deviation and the optical paths for the second wavelength form the second wavefront deviation, the difference between the two deviations being proportional to the difference between the first and second wavelength.

Abstract: An optical pickup includes an optical module that detects an information signal and/or an error signal by radiating light to a recording medium and receives light reflected by the recording medium. The optical module includes a light source; an optical path changer that changes a path of light emitted from the light source; a main photodetector that receives light that is reflected off a recording medium back to the optical module to detect an information signal and/or an error signal; and a hologram element that generates an astigmatism of the light incident onto the optical module. Since most optical elements of the optical pickup except an objective lens are packaged in the optical module, the entire structure of the optical pickup can be simplified and the number of bonding points for fixing the optical elements of the optical pickup on a base can be reduced.

Abstract: An optical pickup apparatus for reading/reproducing data on an optical recording medium, includes a plurality of laser diodes configured to emit laser light of different wavelengths respectively, a photodetection device configured to detect each laser light, a diffraction type-optical device configured to transmit each laser light from the plurality of laser diodes to the optical recording medium, and to diffract the light reflected from the optical recording medium to the photodetection device, and wherein the diffraction type-optical device includes a plurality of reflecting type-diffraction elements configured to reflect and diffract each laser light of a corresponding wavelength in the laser light from the plurality of light diodes, to the photodetection device so that the photodetection device can detect each laser light of the corresponding wavelength for monitoring each of the laser light, and a suppression setting device configured to set each of the plurality of reflecting type-diffraction elements t

Abstract: The objective lens is a biconvex plastic lens having first and second surfaces which are both aspheric. The objective lens is divided into an inside area which is inside of a circle of an effective diameter of the objective lens and an outside area which is outside of the circle of the effective diameter. A diffractive lens structure having a plurality of concentric ring-shaped steps is formed in the inside area. A surface of the outside area is continuous with no steps and corresponds to a macroscopic base curve of the inside area. The objective lens has a gap of a spherical aberration between the inside area and the outside area.

Abstract: An optical pickup with two lasers for CD and DVD uses a grating to diffract one beam to the detector used by the other beam. This requires only one beam to be diffracted, allowing the diffraction pattern to be varied to compensate for different spacings between the lasers. A single, 4-quadrant detector is used to detect the returned beams from both lasers. The returned beam of the first laser passes through the grating element undiffracted, by passing through a portion without a grating pattern. The position of the detector is aligned with respect to this first beam. The grating diffracts the returned beam from the second laser to the same detector. The separation of the grating from the detector can be adjusted so that the returned beam from the second laser is also perfectly aligned with the detector.

Abstract: An optical apparatus can eliminate offset resulting from assembling errors and also can correct offset even in the photodetector of any optical system. An optical disk apparatus for reading information from tracks traces the track with the condensed spot of light beam depending on the tracking error signal obtained from the optical system for tracking error detection. The tracking error detecting optical system includes an optical apparatus having a photodetector for outputting, as the tracking error signal, a differential value of outputs of a plurality of light receiving sections for receiving the light beam condensed by the condenser lens. Also, an optical element is provided for relatively increasing and/or decreasing the amount of receiving light of a light receiving section depending on displacement of the optical axis of the light beam, in order to balance the light received by the light receiving sections and compensate for affect.

Abstract: A circuit for detecting the mirror signal from the output signal of an RF (radio frequency) in an optical disk drive, includes a first peak hold circuit for holding the peak value of the output signal of the RF amplifier to provide a first peak value, a first bottom hold circuit for holding the bottom value of the output signal of the RF amplifier to provide a first bottom value, a differential amplifier for amplifying the difference between the first and second peak values, a second peak hold circuit for holding the peak value of the output signal of the differential amplifier to provide a second peak value, a second bottom hold circuit for holding the bottom value of the output signal of the differential amplifier to provide a second bottom value, a centered value extractor for processing the second peak and bottom values to extract the centered value of the output signal of the RF amplifier, a comparator for comparing the centered value with the output signal of the differential amplifier to generate the m

Abstract: The optical pickup according to the present invention includes an integrated unit having a laser beam source, a detecting portion, a diffraction element integrated and an objective lens. In addition, a transparent optical compensation film is provided in the optical path from laser beam source to objective lens. Integrated unit according to the present invention includes the optical compensation film.