Abstract: A method for producing a sand mold includes mixing artificial sand with a furan resin composition including a furan resin precursor, preparing molding sand having the artificial sand and a surface-modified layer containing a resin cured product covering the artificial sand and including a curing agent attached to the surface-modified layer by mixing the curing agent including xylene sulfonic acid with the artificial sand with which the furan resin composition is mixed, and curing the furan resin composition, after mixing the artificial sand with the furan resin composition, and curing an added portion of the binder in the molding sand by adding the binder to the molding sand. In the step of curing the added portion of the binder, the curing agent for curing the furan resin composition is used also as a curing agent for curing the binder.

Abstract: A laser processing apparatus and a laser processing method for improving the processing speed and forming uniform and highly accurate through holes when processing for forming fine through holes in a matrix in a long thin plate, and a thin plate having through holes in a matrix formed by such laser processing. A laser processing apparatus includes a cylindrical body having an opening on a circumferential surface around which a thin plate to be processed is wound obliquely, a thin plate transfer for transferring a thin plate wound around the cylindrical body in the longitudinal direction of the thin plate, a motor having a rotation axis arranged coaxially with a central axis of the cylindrical body, a reflecting member fixed to a rotating shaft of the motor, a laser light emitting means for emitting pulsed light. The apparatus continuously opens through holes in the thin plate.

Abstract: A method for producing a sand mold includes mixing artificial sand with a furan resin composition including a furan resin precursor, preparing molding sand having the artificial sand and a surface-modified layer containing a resin cured product covering the artificial sand and including a curing agent attached to the surface-modified layer by mixing the curing agent including xylene sulfonic acid with the artificial sand with which the furan resin composition is mixed, and curing the furan resin composition, after mixing the artificial sand with the furan resin composition, and curing an added portion of the binder in the molding sand by adding the binder to the molding sand. In the step of curing the added portion of the binder, the curing agent for curing the furan resin composition is used also as a curing agent for curing the binder.

Abstract: A laser processing apparatus and a laser processing method for improving the processing speed and forming uniform and highly accurate through holes when processing for forming fine through holes in a matrix in a long thin plate, and a thin plate having through holes in a matrix formed by such laser processing. A laser processing apparatus includes a cylindrical body having an opening on a circumferential surface around which a thin plate to be processed is wound obliquely, a thin plate transfer for transferring a thin plate wound around the cylindrical body in the longitudinal direction of the thin plate, a motor having a rotation axis arranged coaxially with a central axis of the cylindrical body, a reflecting member fixed to a rotating shaft of the motor, a laser light emitting means for emitting pulsed light. The apparatus continuously opens through holes in the thin plate.

Abstract: A method for producing molding sand includes mixing an artificial sand with a furan resin composition including a furan resin precursor, and mixing a curing agent with the artificial sand with which the furan resin composition is mixed, wherein the curing agent includes xylene sulfonic acid.

Abstract: In some examples, an optical encoder may consist of a light source that shines light onto a wheel which then reflects the light onto a sensor. Using information encoded in the reflected light, the rotation of the wheel may be determined. In some examples, rotation of the wheel may be determined by detecting an encoding pattern in light reflected from an exterior surface of the wheel. In some examples, the encoding pattern can be a pattern of light and dark stripes. In some examples, a pattern of light stripes can be generated from light reflecting off of reflective portions of the wheel. Some examples of the disclosure relate to using a surface topology for a wheel that can be used to generate an encoding pattern of light and dark stripes in light reflected from the surface of the wheel, even when the surface of the wheel is uniformly reflective.

Abstract: In some examples, an optical encoder may consist of a light source that shines light onto a wheel which then reflects the light onto a sensor. Using information encoded in the reflected light, the rotation of the wheel may be determined. In some examples, rotation of the wheel may be determined by detecting an encoding pattern in light reflected from an exterior surface of the wheel. In some examples, the encoding pattern can be a pattern of light and dark stripes. In some examples, a pattern of light stripes can be generated from light reflecting off of reflective portions of the wheel. Some examples of the disclosure relate to using a surface topology for a wheel that can be used to generate an encoding pattern of light and dark stripes in light reflected from the surface of the wheel, even when the surface of the wheel is uniformly reflective.

Abstract: A light irradiation device includes: a focus servo control unit including a light source, a spatial light modulating unit, and a light irradiating unit, for focus servo control so that the ideal focal position of light via an objective lens is such that distance between an ideal focal position and a hologram recording medium surface is smaller than distance from the surface to the lower layer side face of the recording layer, and the focal position of light via the objective lens is constant at the ideal focal position; an objective-lens/relay-lens distance adjusting unit to adjust distance between the objective lens and a relay lens close to the objective lens; a light reception unit to receive marker light; and a constant distance control unit to control the objective-lens/relay-lens distance adjusting unit based on error between the ideal position of the marker light, and the actual position of the marker light.

Abstract: A hologram device includes: a light source for applying light to a hologram recording medium having a recording layer in which information recording is performed by interference fringes between signal light and reference light; a spatial modulation unit that generates the signal light and/or the reference light and generates a marker light in a predetermined position within an incident surface of the light from the light source by performing spatial light modulation on the light from the light source; a light applying unit that applies the light subjected to spatial light modulation by the spatial light modulation unit to the hologram recording medium via an objective lens; a light receiving unit that receives the light applied via the objective lens through the hologram recording medium; and a tilt detection unit that obtains a tilt error signal representing an error from an ideal angle of a tilt angle as an incident angle of the applied light via the objective lens to an information recording surface of the

Abstract: An optical pickup apparatus includes: a light source to irradiate light onto a hologram recording medium onto which information is recorded by interference fringes of signal light and reference light; a spatial light modulation portion to generate the reference light by performing a spatial light modulation on the light from the light source; and an optical system to irradiate the reference light onto the hologram recording medium via a relay lens system and an objective lens and guide reproduction light obtained from the hologram recording medium in accordance with the irradiation of the reference light to an image pickup device via the objective lens and the relay lens system, the optical system being provided with, in an optical path between the relay lens system and the image pickup device, an angle permselective device that selectively transmits light with an incidence angle of a predetermined angle or less.

Abstract: A hologram device includes: a light source for applying light to a hologram recording medium having a recording layer in which information recording is performed by interference fringes between signal light and reference light; a spatial modulation unit that generates the signal light and/or the reference light and generates a marker light in a predetermined position within an incident surface of the light from the light source by performing spatial light modulation on the light from the light source; a light applying unit that applies the light subjected to spatial light modulation by the spatial light modulation unit to the hologram recording medium via an objective lens; a light receiving unit that receives the light applied via the objective lens through the hologram recording medium; and a tilt detection unit that obtains a tilt error signal representing an error from an ideal angle of a tilt angle as an incident angle of the applied light via the objective lens to an information recording surface of the

Abstract: A light irradiation device includes: a focus servo control unit including a light source, a spatial light modulating unit, and a light irradiating unit, for focus servo control so that the ideal focal position of light via an objective lens is such that distance between an ideal focal position and a hologram recording medium surface is smaller than distance from the surface to the lower layer side face of the recording layer, and the focal position of light via the objective lens is constant at the ideal focal position; an objective-lens/relay-lens distance adjusting unit to adjust distance between the objective lens and a relay lens close to the objective lens; a light reception unit to receive marker light; and a constant distance control unit to control the objective-lens/relay-lens distance adjusting unit based on error between the ideal position of the marker light, and the actual position of the marker light.

Abstract: A reproducing device including a light source that emits light for reproducing recorded information to a hologram recording medium subjected to recording of information by interference fringes of signal light and reference light, a light irradiating unit that generates the reference light for obtaining a reproduced image according to the recorded information and DC light having uniform intensity and phase, and irradiates the hologram recording medium with both the reference light and the DC light and with only the DC light, a light receiving unit that performs light-reception for the DC light and the reproduced image, and performs light-reception for the DC light, and a difference calculating unit that calculates a difference between an image signal obtained based on a light-reception result of the reproduced image and the DC light, and an image signal obtained based on a light-reception result of the DC light.

Abstract: There is provided a light illuminating apparatus including: a light source allowing light to illuminate a hologram-recording medium having a recording layer, where information is recorded by an interference fringe of a signal light and a reference light, and a cover layer on an upper-layer side thereof; a spatial light-modulator performing spatial light-modulation on the light from the light source to generate the signal light and/or the reference light; and a light illuminating unit allowing the light, which is subject to the spatial light-modulation by the spatial light-modulator, as a recording/reproduced light to illuminate the hologram-recording medium through an objective lens, wherein a focus position of the recording/reproduced light is set so that a distance from a surface of the hologram-recording medium to the focus position of the recording/reproduced light is smaller than a distance from the surface to a lower-layer side surface of the recording layer.

Abstract: A recording/reproduction method of performing recording/reproduction of a hologram by illuminating a hologram recording medium, which has a recording layer in which information is recorded by interference fringes between signal light and reference light, with the signal light and/or the reference light as recording/reproduction light through an objective lens includes the step of: setting a focal position of the recording/reproduction light such that a distance from a surface of the hologram recording medium to the focal position of the recording/reproduction light is larger than a distance from the surface to a lower-layer-side surface of the recording layer and illuminating the hologram recording medium including an angle-selective reflective layer, which is formed below the recording layer and has a selective light reflection/transmission characteristic depending on a light incidence angle, with the recording/reproduction light the focal position of which has been set.

Abstract: An optical pickup apparatus includes: a light source to irradiate light onto a hologram recording medium onto which information is recorded by interference fringes of signal light and reference light; a spatial light modulation portion to generate the reference light by performing a spatial light modulation on the light from the light source; and an optical system to irradiate the reference light onto the hologram recording medium via a relay lens system and an objective lens and guide reproduction light obtained from the hologram recording medium in accordance with the irradiation of the reference light to an image pickup device via the objective lens and the relay lens system, the optical system being provided with, in an optical path between the relay lens system and the image pickup device, an angle permselective device that selectively transmits light with an incidence angle of a predetermined angle or less.

Abstract: A skew of an optical pickup device can be adjusted by a movable-side member itself which holds thereon an objective lens. A holder which holds an objective lens is supported by four spring wires such that it can be moved in the focusing direction and the tracking direction of an optical disk. A center of a magnetic circuit which drives the holder is shifted in the outer peripheral side relative to the optical disk. Elastic force of the spring wires of the inner peripheral side is suppressed by increasing the amount of a gel material bonded to the spring wires located on the inner peripheral side of the optical disk as a damping material as compared with the amount of the gel material bonded to the spring wires located on the outer peripheral side.

Abstract: A skew of an optical pickup device can be adjusted by a movable-side member itself which holds thereon an objective lens, A holder which holds an objective lens is supported by four spring wires such that it can be moved in the focusing direction and the tracking direction of an optical disk. A center of a magnetic circuit which drives the holder is shifted in the outer peripheral side relative to the optical disk. Elastic force of the spring wires of the inner peripheral side is suppressed by increasing the amount of a gel material bonded to the spring wires located on the inner peripheral side of the optical disk as a damping material as compared with the amount of the gel material bonded to the spring wires located on the outer peripheral side.

Abstract: An optical pickup including a light source for radiating a light beam, a diffraction element for separating a light beam radiated from the light source into at least three beams, namely a main beam and two side beams, an objective lens for converging the light beams separated by the diffraction element on a signal recording surface of the optical recording medium, a light receiving unit having a four-segment first light receiving portion for receiving the main beam reflected by the recording surface of the optical recording medium and second and third light receiving portions arranged on both sides of the first light receiving portion for receiving the side beams reflected by the recording surface of the optical recording medium, and a calculation unit for generating a first tracking signal based on respective outputs of the first light receiving portion and for generating a second tracking signal based on outputs of the second and third light receiving portions.

Abstract: A laser diode applies a laser beam through a grating, a beam splitter, and an objective to a compact disc. A laser beam reflected by the compact disc is applied through the objective and the beam splitter to a photodiode. The objective has a large numerical aperture of 0.6 in order to be able of play back a digital video disc that has a thin substrate and contains information recorded at a high density. To prevent the photodiode from suffering aberrations caused due to the large numerical aperture of the objective, the photodiode has a relatively small photodetector unit having a normalized detector size ranging from 3 &mgr;m to 16 &mgr;m, for detecting only returning light up to a numerical aperture of 0.3 and not detecting light of greater numerical aperture values.