Abstract: A hologram recording device for irradiating a recording beam (S) to a hologram recording medium (B) at a fixed incident angle (?s) and irradiating a reference beam (R) to an illuminated region (p) of the recording beam (S) by variably controlling an incident angle (?r) of the reference beam (R) on the hologram recording medium (B), whereby a hologram is recorded on the illuminated region (p) in multiple, includes at least a variable reflector (10) directing the reference beam (R) to the illuminated region by reflection and being swung around a predetermined axis (x) for changing the incident angle (?r) of the reference beam (R); and a light shield (11) being swung integrally with the variable reflector (10) for partially shielding the reference beam (R) so that a luminous flux diameter thereof becomes narrower as the incident angle (?r) becomes larger.

Abstract: A hologram recorder (A2) includes: a light source (10) for emitting a coherent beam; a spatial light modulator (20) provided with unit areas having a plurality of beam reflection elements (21) to reflect the beam from the light source (10) in a main direction as a signal beam or a cut-off direction; and a signal beam optical system (30, 31) for directing the signal beam to the hologram recording medium (B). The recorder (A2) further includes: a wavefront reshaper (40, 41, 42) for condensing the beams thinned out in the cut-off direction by the beam reflection element (21) of the modulator (20), and reshaping the wavefront of the condensed beams; and a reference beam optical system (50, 51) for directing the beam from the reshaper (40, 41, 42) to the recording medium (B) as a reference beam to be shone in an overlapping manner with the signal beam.

Abstract: A hologram recorder (A) records holograms in a selected unit recording area (B1) of a hologram recording medium (B) by interference between a recording beam (Lr) which is applied vertically to the unit recording area (B1) and a reference beam (Lr) which is applied obliquely to the unit recording area (B1). The hologram recorder (A) includes a reference beam oblique applier (23A, 23B) for application of the reference beam (Lr) obliquely to the unit recording area (B1) by reflection, and a reference beam swing mechanism (30) for supporting the reference beam oblique applier (23A, 23B) and for swinging the reference beam oblique applier (23A, 23B) about a predetermined rotation axis which is perpendicular to an entering direction of the recording beam (Lw) that makes an entry into the unit recording area.

Abstract: A holographic recorder can vary the optical distance between an object lens and a relay lens near the object lens. This arrangement allows defocus-multiplexing utilizing state variations in the laser beam when the beam reaches a storage medium.

Abstract: A disk-type hologram recording medium and a hologram recording and reproduction device utilizing such a recording medium are provided. The hologram recording and reproduction device includes a spatial optical modulator provided with a plurality of optical elements arranged in a grid-like form. These optical elements are divided into groups each associated with 1 bit of data for performing required light modulation. Thus, a special pattern exhibiting a greater S/N margin for 1 bit can be recorded in the recoding medium. During data recording or data reproduction, the special pattern is read from the recording medium, and based on the retrieved special pattern, fine adjustment by servo control is conducted for adjustment of tilting or focusing of the recording medium and for adjustment of the wavelength of the light emitted from the light source.

Abstract: A hologram recorder records a hologram in a hologram recording medium by interference of a recording beam irradiated at a predetermined incident angle to the medium via a spatial light modulator incliningly in a predetermined direction with a reference beam irradiated incliningly in an opposite direction to the recording beam so that the beams crosses at a predetermined crossing angle. The recorder includes a beam modulator for converting a Gaussian-beam having a Gaussian-distribution of intensity into a parallel beam having an intensity distribution tending to be uniform and allowing the parallel beam to travel to the spatial modulator as the recording beam. The Gaussian-beam has a center axis decentered from an optical axis of the beam modulator in a decentering direction including a directional component of the predetermined direction in which the recording beam is inclined or an opposite directional component thereto.

Abstract: A hologram recording and reproducing apparatus includes a movable galvanomirror, a mirror controller and a reproduction unit. The galvanomirror guides a reference beam toward a hologram recording medium and changes the incident angle of the reference beam. The mirror controller causes the galvanomirror to move for adjusting the incident angle to a predetermined angle for hologram recording. In reproducing the recorded information, the mirror controller causes the galvanomirror to move, so that the incident angle continuously changes within a predetermined range including the predetermined angle. The reproduction unit receives a detection signal from an optical detector while the incident angle changes continuously. The detection signal corresponds to the intensity of a reflected beam from the hologram recording medium. The reproduction unit reproduces the recorded information, based on the detection signal, when the intensity of the reflected beam is over a predetermined level or reaches the maximum.

Abstract: An optical pickup is provided for driving objective lenses in focusing and radial directions. The pickup includes a movable member, and objective lenses at the center portion of the movable member. The pickup also includes coil blocks provided at two side portions of the movable member, and pairs of magnets flanking the coil blocks in a tangential direction perpendicular to the focusing and radial directions. Support members are attached to the side portions of the movable member, permitting the movable member to move in the focusing direction and the radial direction. Each coil block includes focusing and tracking coils for driving the movable member in the focusing direction and the radial direction. The center portion of the movable member, below which a reflector is arranged, is thinner than the side portions of the movable member.

Abstract: A hologram recorder (A) records a hologram in a hologram recording medium (B) by interference of a recording beam (S) irradiated at a predetermined incident angle to the medium (B) via a spatial light modulator (2) incliningly in a predetermined direction with a reference beam (R) irradiated incliningly in an opposite direction to the recording beam (S) so that the beams (S,R) crosses at a predetermined crossing angle. The recorder includes a beam modulator (1) for converting a Gaussian-beam having a Gaussian-distribution of intensity into a parallel beam having an intensity distribution tending to be uniform and allowing the parallel beam to travel to the spatial modulator (2) as the recording beam (S). The Gaussian-beam has a center axis (Gs) decentered from an optical axis (1A) of the beam modulator (1) in a decentering direction including a directional component of the predetermined direction in which the recording beam (S) is inclined or an opposite directional component thereto.

Abstract: A hologram recording device for irradiating a recording beam (S) to a hologram recording medium (B) at a fixed incident angle (?s) and irradiating a reference beam (R) to an illuminated region (p) of the recording beam (S) by variably controlling an incident angle (?r) of the reference beam (R) on the hologram recording medium (B), whereby a hologram is recorded on the illuminated region (p) in multiple, includes at least a variable reflector (10) directing the reference beam (R) to the illuminated region by reflection and being swung around a predetermined axis (x) for changing the incident angle (?r) of the reference beam (R); and a light shield (11) being swung integrally with the variable reflector (10) for partially shielding the reference beam (R) so that a luminous flux diameter thereof becomes narrower as the incident angle (?r) becomes larger.

Abstract: A hologram recording and reproducing apparatus minimizes reproduction errors by servo control on the tilting of a reference beam relative to a hologram recording medium. The apparatus includes an optical detector for servo control and an optical sensor for reproduction signal conversion. A pixel pattern generator generates, on a wave surface of the recording beam, a discretely distributed recording pixel pattern corresponding to the information to be recorded, and a specifically shaped and localized servo pixel pattern for the servo control. A beam splitter splits the reflected beam from the hologram recording medium into a reproduction beam directed to the optical detector for reproduction signal conversion and a servo beam directed to the optical detector for servo control. A servo controller controls the tilting of the reference beam relative to the hologram recording medium, based on an output signal from the servo control optical detector.

Abstract: A holographic recorder (A1) can vary the optical distance between an object lens (8) and a relay lens (7b) near the object lens (8). This arrangement allows defocus-multiplexing utilizing state variations in the laser beam when the beam reaches a storage medium (B1).

Abstract: A hologram recorder (A) records holograms in a selected unit recording area (B1) of a hologram recording medium (B) by interference between a recording beam (Lr) which is applied vertically to the unit recording area (B1) and a reference beam (Lr) which is applied obliquely to the unit recording area (B1). The hologram recorder (A) includes a reference beam oblique applier (23A, 23B) for application of the reference beam (Lr) obliquely to the unit recording area (B1) by reflection, and a reference beam swing mechanism (30) for supporting the reference beam oblique applier (23A, 23B) and for swinging the reference beam oblique applier (23A, 23B) about a predetermined rotation axis which is perpendicular to an entering direction of the recording beam (Lw) that makes an entry into the unit recording area.

Abstract: A hologram recorder (A2) includes: a light source (10) for emitting a coherent beam; a spatial light modulator (20) provided with unit areas having a plurality of beam reflection elements (21) to reflect the beam from the light source (10) in a main direction as a signal beam or a cut-off direction; and a signal beam optical system (30, 31) for directing the signal beam to the hologram recording medium B. The recorder (A2) further includes: a wavefront reshaper (40, 41, 42) for condensing the beams thinned out in the cut-off direction by the beam reflection element (21) of the modulator (20), and reshaping the wavefront of the condensed beams; and a reference beam optical system (50, 51) for directing the beam from the reshaper (40, 41, 42) to the recording medium (B) as a reference beam to be shone in an overlapping manner with the signal beam.

Abstract: A hologram recording medium includes a hologram recording layer and a transparent substrate layer stacked on the hologram recording layer. The recording layer records an interference pattern of a recording beam and a reference beam. The transparent substrate layer has an inner surface facing the hologram recording layer, and this surface is formed with trace zones for guiding the recording beam and the reference beam in a prescribed guide direction. The trace zones have a higher reflectance than that of the remaining area in the inner surface of the transparent substrate layer.

Abstract: An optical pickup, provided with a first objective lens and a second objective lens, includes a first light source and a polarizing beam splitter, where the first light source emits a laser beam of a predetermined wavelength, and the polarizing beam splitter causes a first polarized beam having a predetermined polarization characteristic to be reflected toward the first objective lens and transmits a second polarized beam having a different polarization characteristic so that the second beam is led to the second objective lens. A polarization control element is provided between the first light source and the polarizing beam splitter to convert the laser beam emitted by the first light source into the above-mentioned first and second polarized beams.

Abstract: A hologram recorder A1 includes a light source (1) of a coherent light beam and a spatial light modulator (5A) for modulating a part of the light beam from the light source (1) into a recording beam which carries two-dimensional information. Another part of the light beam is used as a reference beam to interfere with the recording beam. The recording beam and the reference beam are directed to a hologram recording medium (B). A semi-translucent optical device (4) is disposed between the light source (1) and the spatial light modulator (SA) for letting a part of the beam travel to the spatial light modulator (5A) as a transmitted beam while letting another part of the beam travel to the hologram recording medium (B) as a reflected beam. The recording beam and the reference beam, after being separated from each other by the optical device (4) as the transmitted beam and the reflected beam, travel along the same optical path (L) to irradiate the hologram recording medium (B).

Abstract: The resin composition for a platable substrate of the present invention comprises 100 parts by weight of a resin composition (C) comprising 10 to 60% by weight of a graft copolymer (A) prepared by graft polymerization of a rubbery polymer (A1) and a monomer component (A2) containing an aromatic alkenyl compound monomer unit (a) and a vinyl cyanide compound monomer unit (b) and 40 to 90% by weight of the other polymer (B) (provided that the total amount of the components (A) and (B) is 100% by weight), and 5 to 40 parts by weight of a phosphate ester flame retardant (D) having a molecular weight of more than 326 or 2 to 40 parts by weight of a red phosphorus flame retardant (D?). The resin composition for a platable substrate of the present invention is excellent in production stability such as moldability, dimensional stability, mechanical strength and plating properties, and is also environmentally friendly.

Abstract: A hologram recorder is provided for recording a hologram on a hologram recording medium by interference of a recording beam with a reference beam. The recorder includes a light source for outputting coherent light to be split into the recording beam and the reference beam; a spatial light modulator for modulating the recording beam into a form representing information to be recorded; an objective lens for outputting the recording beam; and a phase shift mask provided at a light entering surface of the spatial light modulator. The mask is configured to allow the recording beam to pass through, and also to partially shift the phase of the recording beam passing through the mask.

Abstract: An optical pickup is provided for driving objective lenses in focusing and radial directions. The pickup includes a movable member, and objective lenses at the center portion of the movable member. The pickup also includes coil blocks provided at two side portions of the movable member, and pairs of magnets flanking the coil blocks in a tangential direction perpendicular to the focusing and radial directions. Support members are attached to the side portions of the movable member, permitting the movable member to move in the focusing direction and the radial direction. Each coil block includes focusing and tracking coils for driving the movable member in the focusing direction and the radial direction. The center portion of the movable member, below which a reflector is arranged, is thinner than the side portions of the movable member.