Abstract: An optical pickup according to the present invention includes a plurality of light sources for emitting a plurality of light beams including first and second light beams of respectively different wavelengths, an objective lens for converging the plurality of light beams, and a grating structure shaped axisymmetrically with respect to the optical axis of the objective lens. Pth-order diffracted light (where p is a non-zero integer) which is formed from the first light beam (e.g. blue) by the grating structure is converged on an information layer of an optical disk (e.g. a BD) corresponding to the first light beam, owing to the converging actions of the objective lens and grating structure. Moreover, qth-order diffracted light (where q is a non-zero integer such that q?p) which is formed from the second light beam (e.g. red or infrared) by the grating structure is converged on an information layer of an optical disk (e.g.

Abstract: In order to change the number of light points and light intensities and to move positions of the light points in a real-time manner, an extremely large capacity of a memory is required. In a method according to the present invention, a memory (6) has previously stored therein data indicating a complex amplitude distribution of rays of incident light (L) on a hologram plate (4) and complex amplitude distributions on the hologram plate (4) in a case where the rays are beamed at respective points at which the rays can be beamed. The controller (5) calculates the complex amplitude distribution to be generated on the hologram plate (4) in order to generate a hologram pattern by respectively multiplying, by values indicating degrees of amplitudes of respective rays, complex amplitude distributions of rays of incident light (L) and m light points P1 through Pm to be displayed, and by calculating a sum of the values obtained by the multiplication through performing addition.

Abstract: An optical disk apparatus including: a light source; an objective lens for converging light emitted from the light source toward an optical disk; a first photodetection device for detecting reflected light from the optical disk and outputting a first signal; a signal processing section for receiving the first signal and generating a signal containing information recorded on the optical disk; a second photodetection device for detecting a portion of the light emitted from the light source and outputting a second signal; a light source driving section for receiving the second signal, and based on the second signal, driving the light source so that output power of the light source equals a target value; and an amplitude fluctuation detection section for detecting an amplitude fluctuation amount of the second signal, and if the amplitude fluctuation amount exceeds a predetermined value, changing driving characteristics of the light source driving section.

Abstract: Light emitted from a radiation light source 1 passes through a diffraction grating 3a and is separated into transmitted light a, +1st order diffracted light b, and ?1st order diffracted light c. The transmitted light a, +1st order diffracted light b, and ?1st order diffracted light c are collected through an objective lens 7 on tracks on the signal plane 8a of an optical disc 8 in a partially overlapped state. Light reflected by the tracks on the signal plane 8a passes through the objective lens 7 and is incident upon light diverging means 13a.

Abstract: An information recording/reproducing device includes a radiation light source 1 such as a semiconductor laser, a spatial modulation element 6 that splits laser light 2 emitted from the radiation light source 1 into a large number of diffracted light rays, and an objective lens 7 that converges the large number of diffracted light rays onto different points. The laser light 2 emitted from the radiation light source 1 is split into a large number of diffracted light rays by the spatial modulation element 6, the large number of diffracted light rays are converged onto different points in the photosensitive layer 8b of the information recording medium 8 by the objective lens 7, and information is recorded in the photosensitive layer 8b of the information recording medium 8, using an assembly of these converging points. Accordingly, it is possible to provide an information recording device capable of realizing high-contrast recording in which stray light or diffraction has no influence during signal recording.

Abstract: An optical pickup device according to the present invention includes: first and second light sources that are driven selectively and that emit blue and red light beams, respectively; an optical element for splitting the blue and red light beams emitted into main and sub-blue beams and main and sub-red beams, respectively; first and second photodetectors that receive the main and sub-blue beams reflected from the optical disc, thereby outputting electrical signals; and third and fourth photodetectors that receive the main and sub-red beams reflected from the optical disc, thereby outputting electrical signals. A dead zone that outputs no electrical signal representing the intensity of the light received is provided for respective parts of the second and fourth photodetectors.

Abstract: A tracking error signal is generated with stability without being easily affected by a distribution fluctuation of light reflected from an optical disc or by a lens shift. An optical disc drive according to the present invention includes: an objective lens 5 with an aperture radius r0 for converging a light beam emitted from a light source 1; a polarizing hologram substrate 2 for dividing the beam reflected from the optical disc 6 into branched light beams; a photodetector substrate 6, on which at least some of the light beams are incident to generate signals representing the intensities of the light beams; and a shielding mask 16 for cutting off the beam partially.

Abstract: When recording on and/or reproducing from an information recording medium having a plurality of recording layers is performed, there has been a problem in appropriately detecting a control signal at the time of the recording and/or reproducing, since reflected light from a recording layer, which does not undergo the recording and/or reproducing, enters a photodetector concurrently with reflected light from a recording layer which undergoes the recording and/or reproducing. In the present invention, a polarization hologram is used to diffract light outputted from a light source and to generate a main beam, which is a zeroth-order light beam, and a pair of sub beams, which is a positive first-order light beam and a negative first-order light beam each having a polarization direction perpendicular to a polarization direction of the main beam.

Abstract: An optical head comprises first and second light sources which are arranged next to each other and emit lights of different wavelengths and an optical device which is arranged between the first and second light sources and a conversing lens for reducing the spherical aberration caused by combination of the conversing lens and at least one of first and second optical recording media which correspond to at least one of the lights of first and second wavelengths. The optical axis of the optical device is shifted with respect to the optical axis of the conversing lens in order to reduce the coma aberration that is caused since at least one of optical axes of the lights of first and second wavelengths does not coincide with the optical axis of the conversing lens.

Abstract: There is provided an information processing device which is capable of suppressing generation of stray light at the time of recording and reproduction of information, thus enabling quality information recording and reproduction. The information processing device includes: a radiation light source 2; and a converging section for converging rays emitted from the light source toward an information recording medium having a photosensitive layer 11b, wherein the converging section splits the rays into first and second rays 3? and 3 respectively traveling through first and second spaces as divided by a plane at least containing a point optical axis L, and converges the first and second rays 3? and 3 onto first and second points 12? and 12 in the information recording medium 11, the photosensitive layer 11b being interposed between the first and second points 12? and 12.

Abstract: It is intended to provide an optical disk apparatus which detects a light amount greater than zero even when used in conjunction with an optical disk substrate having a large birefringence, so that it is possible to properly read a signal without errors and properly perform optical disk controls. The optical disk apparatus includes: a light source for emitting light; an objective lens for converging the light onto a signal surface of an optical disk; a polarized beam diffraction element for diffracting the light reflected from the optical disk; a photodetector for detecting the light diffracted from the polarized beam diffraction element; and a wavelength plate disposed between the optical disk and the polarized beam diffraction element.

Abstract: The invention permits stable tracking with few control errors, uninfluenced by stray light reflected by signal surfaces other than the signal surface being used for focusing during recording and playback of a multilayer disc. To this end, the optical splitter element of the optical disc device according to the present invention has first areas (21c-24c), which include the location (20) of the optical axis of light incident from the objective lens, and, around the periphery of the first areas, second areas (21a-24a, 21b-24b) positioned at locations displaced from the optical axis. The detection surface (9a) of the photodetector has first detection areas (97, 98) detecting light incident from the first areas and second detection areas (95, 96) detecting light incident from the second areas. The second detection areas are used for detecting tracking error signals.

Abstract: An optical pickup according to the present invention includes a plurality of light sources for emitting a plurality of light beams including first and second light beams of respectively different wavelengths, an objective lens for converging the plurality of light beams, and a grating structure shaped axisymmetrically with respect to the optical axis of the objective lens. Pth-order diffracted light (where p is a non-zero integer) which is formed from the first light beam (e.g. blue) by the grating structure is converged on an information layer of an optical disk (e.g. a BD) corresponding to the first light beam, owing to the converging actions of the objective lens and grating structure. Moreover, qth-order diffracted light (where q is a non-zero integer such that q?p) which is formed from the second light beam (e.g. red or infrared) by the grating structure is converged on an information layer of an optical disk (e.g.

Abstract: An optical disk apparatus according to the present invention includes: a rotation driving section on which an optical disk is to be mounted and which drives the optical disk so as to be rotated; a light source; an objective lens for converging light from the light source onto an optical disk mounted on the rotation driving section; a photodetector having at least two detection sections for detecting reflected light, from the optical disk, of the light; and an error signal generation section for deriving a difference signal and a sum signal of respective outputs from the two detection sections of the photodetector, adjusting an offset in at least the sum signal among the difference signal and the sum signal, and thereafter dividing the difference signal by the sum signal whose offset has been adjusted to generate a position error signal of the objective lens.

Abstract: An optical pickup device capable of correcting an off-tracking which is ascribable to a phase shift of a differential push-pull signal waveform, even when an optical disk or an objective lens is tilted along a radial direction of the optical disk, so that stable tracking control can be performed; and, an optical disk apparatus comprising such an optical pickup device.

Abstract: It is intended to provide an optical disk apparatus which detects a light amount greater than zero even when used in conjunction with an optical disk substrate having a large birefringence, so that it is possible to properly read a signal without errors and properly perform optical disk controls. The optical disk apparatus includes: a light source for emitting light; an objective lens for converging the light onto a signal surface of an optical disk; a polarized beam diffraction element for diffracting the light reflected from the optical disk; a photodetector for detecting the light diffracted from the polarized beam diffraction element; and a wavelength plate disposed between the optical disk and the polarized beam diffraction element.

Abstract: Light emitted from alight source (5) is reflected by the reflection film of a polarized beam-splitter (6), passes through collimating lens (7) and a mirror (8) to reach a convergence lens (9). The convergence lens (9) forms a light spot on an information medium (1) having a visual information layer (4). Reflected light which is reflected by the visual information layer (4) passes through the convergence lens (9), the mirror (8), and the collimating lens (7), transmits through the reflection film of the polarized beam-splitter (6), passes through a half mirror (14) to reach a second light detector (13). The second light detector (13) detects an FE signal for the visual information layer (4) and feeds back the detected signal to an LPC circuit, thereby restricting power fluctuation due to surface deflection.

Abstract: An optical disk device has a light source which emits light; and light converging means of, in each of signal mark forming regions, each of lands, or each of grooves of an optical disk, converging the light from the light source onto a signal surface of the optical disk with selectively positioning a signal mark at any one of plural positions which are arranged in a direction that is substantially perpendicular to tracks, each of the signal mark forming regions surrounded by adjacent two of boarder lines which are between two the tracks on the signal surface of the optical disk, and which are substantially parallel to the tracks, and each of which substantially divides an area between adjacent tracks in two parts.

Abstract: An optical disk apparatus includes: an optical pickup unit for reading out information recorded on an optical disk; a demodulation circuit for demodulating digital data from an output signal of the optical pickup unit; and a controller for performing a servo control based on the output signal of the optical pickup unit. When performing a focus/tracking control in a recess and a protrusion of a guide groove of the optical disk, the controller obtains a focus control gain difference between the recess and the protrusion by comparing focus offsets with respect to variations in amplitudes of signals from the optical disk for the recess and the protrusion, respectively.

Abstract: A light emitting device according to the present invention includes: a first light source for emitting light having a first wavelength; and a second light source for emitting light having a second wavelength which is different from the first wavelength, wherein the first light source and the second light source are arranged in the same housing, and a relationship of ?h1>?h2 is satisfied, where ?h1 denotes an angle (full-width-half-maximum) of radiation of the light emitted from the first light source in the horizontal direction, and ?h2 denotes an angle (full-width-half-maximum) of radiation of the light emitted from the second light source in the horizontal direction.