Abstract: An information reproducing method for reproducing information recorded on a medium by irradiating a laser beam and detecting a reflected light beam from the medium. The method includes detecting a plurality of reflected light beams in which the polarities of variations in reflected light beam intensity distributions are substantially inverted to each other, the distribution variation being produced when a light spot of the laser beam crosses a track on the medium, adding focus error signals for the plurality of reflected light beams to generate a focus error signal, and taking a difference between tracking error signals of the plurality of reflected light beams to generate a tracking error signal.

Abstract: A semiconductor device having a stack structure comprises: a single-piece substrate having a chip support surface serving as a main surface, a back surface, a plurality of connection terminals provided on the chip support surface and a plurality of solder balls provided on the back surface; a first semiconductor chip having a main surface, aback surface, a plurality of semiconductor devices on the main surface of the first semiconductor chip and a plurality of pads provided on the main surface of the first semiconductor chip; a second semiconductor chip having a main surface, a back surface, a plurality of semiconductor devices provided on the main surface of the second semiconductor chip and a plurality of pads provided on the main surface of the second semiconductor chip; and a resin sealing body formed on the chip support surface of the single-piece substrate and used for sealing the first semiconductor chip and the second semiconductor chip; and a plurality of wires for connecting the pads of the second s

Abstract: An optical detector for detecting at least three optical beams reflected by an optical information recording medium and outputting an electric signal, the optical detector having three light receiving areas each of which receives a respective one of the three optical beams and each of which has four light receiving surfaces, twelve signal lines to transmit an electric signal obtained on respective ones of the four light receiving surfaces of the three light receiving areas, selected ones of the twelve signal lines connected to the four light receiving surfaces of different ones of the three light receiving areas being joined together within the optical detector, and less than nine signal output lines formed by joining the selected ones of the twelve signal lines extend from the optical detector to a signal processing circuit.

Abstract: A method of manufacturing an electronic device including a first electronic component mounted on one main surface of a wiring board by being thermo-compression bonded by means of a thermo-compression bonding tool with an adhesive resin interposed between a first area of the one main surface of the wiring board and the first electronic component, and a second electronic component mounted on a second area different from the first area of the one main surface of the wiring board by melting a soldering paste material and higher than the first electronic component in post-mounting height, and wherein the first electronic component is mounted before the mounting of the second electronic component.

Abstract: This invention relates to a process for forming a multi-layer coating film by applying, to a substrate, intermediate paint, metallic paint and clear paint by 3C1B method, which process is characterized in that said intermediate paint contains 0.5 to 5 phr of flat talc powder of a size of 0.5 to 10 &mgr;m in longer direction and 0.01 to 1 &mgr;m in thickness, and has a total pigment content of 40 to 100 phr.

Abstract: An optical information reproducing method for reproducing information recorded at at least one mark on an optical information medium. The method includes irradiating a laser to the optical information medium, detecting a reflected beam reflected from the optical information medium, and reproducing information recorded on the optical information medium from an output signal of a detector which detects the reflected beam. The step of reproducing information is changed in dependence upon a length of the mark of the optical information medium.

Abstract: An information recording/reproducing apparatus includes a detector circuit for detecting a state of reflection light from the recording medium, a control circuit for calculating a radiation power used for writing the information in the recording medium, in accordance with the reflection light state, a pulse generator circuit for generating record pulse information in accordance with the radiation power, and an optical driver circuit for converting the record pulse information into optical information in accordance with the radiation power and driving the optical head to record the light information into the recording medium. Accordingly, the apparatus records information by applying light from an optical head to a record area of a recording medium and changing a state of the record area and reads the information recorded in the record area.

Abstract: Information recorded on an optical disk in accordance with a mark edge recording scheme is detected by a center detection circuit which includes a bisected beam detector to obtain a mark center position signal. In succession, the mark center position signal is converted to a mark edge position signal by an edge signal generating circuit. An information reproducing device is implemented which is capable of performing reproducing operation on an information medium conforming to a high-density mark edge recording scheme and which is stable against changes of recording paper, recording sensitivity and reflectivity.

Abstract: An optical head eliminates an disturbance which occurs in a focus error signal in association with the decentering of an optical disk when an optical spot crosses a track on a storage film surface, and in addition the optical head cancels an off-set which occurs in a tracking error signal in association with the movement of an objective lens. In the constitution of the optical head, phases of wave surfaces of ±1st order diffracted lights are shifted by an amount of &lgr;/2 with a common period by using a phase-inverted diffraction grating the phase of which is inverted with a period of D &lgr;/(2P . NA) in a radial direction of the optical disk, thus causing, on the optical disk, sub-spots to be located on the same track as a main-spot. Taking advantage of this location, focal point shift error signals of the main-spot and the sub-spots are added to each other with an appropriate gain ratio, thereby making it possible to cancel the disturbance which occurs in the focus error signal.

Abstract: An optical head having a plurality of laser light source and a plurality of photodetectors corresponding to the plurality of laser light sources. The plurality of laser light sources have at least three wavelengths with frequencies which are different from one another, a first laser module includes at least two laser light sources with two frequencies which are in close proximity and two photodetectors corresponding to the at least two laser light sources, and a second laser module includes another laser light source and another photodetector corresponding to the another laser light source.

Abstract: The present invention provides a thermocurable resin composition for coating with good storage stability and capable of forming a coating film excellent in low temperature curability, acid resistance, scratch resistance etc., containing a polymer obtained by half-esterifying with a monohydric alcohol the acid anhydride group of an acid anhydride group-containing polymer, obtained by copolymerizing a polymerizable, unsaturated, half-esterified product obtained by half-esterification of a hydroxyl group-containing, polymerizable unsaturated monomer and an acid anhydride group-containing compound in the proportion of 1-1.5 moles of the acid anhydride group per 1 mole of the hydroxyl group, an acid anhydride group-containing, polymerizable unsaturated monomer and another polymerizable unsaturated monomer; and a polymer having both hydroxyl group and epoxy group in the molecule.

Abstract: A method of manufacturing an electronic device including a first electronic component mounted on one main surface of a wiring board by being thermo-compression bonded by means of a thermo-compression bonding tool with an adhesive resin interposed between a first area of the one main surface of the wiring board and the first electronic component, and a second electronic component mounted on a second area different from the first area of the one main surface of the wiring board by melting a soldering paste material and higher than the first electronic component in post-mounting height, and wherein the first electronic component is mounted before the mounting of the second electronic component.

Abstract: An information recording/reproducing apparatus includes a detector circuit for detecting a state of reflection light from the recording medium, a control circuit for calculating a radiation power used for writing the information in the recording medium, in accordance with the reflection light state, a pulse generator circuit for generating record pulse information in accordance with the radiation power, and an optical driver circuit for converting the record pulse information into optical information in accordance with the radiation power and driving the optical head to record the light information into the recording medium. Accordingly, the apparatus records information by applying light from an optical head to a record area of a recording medium and changing a state of the record area and reads the information recorded in the record area.

Abstract: An optical head having a plurality of laser light source and a plurality of photodetectors corresponding to the plurality of laser light sources. The plurality of laser light sources have at least three wavelengths with frequencies which are different from one another, a first laser module includes at least two laser light sources with two frequencies which are in close proximity and two photodetectors corresponding to the at least two laser light sources, and a second laser module includes another laser light source and another photodetector corresponding to the another laser light source.

Abstract: An optical head for an optical disc drive is provided with a first laser diode that emits a shorter wavelength laser beam, a second laser diode that emits a longer wavelength laser beam, and an objective lens for converging the beams emitted by the laser diodes on the data recording surface of the optical disc. Each of first and second surfaces of the objective lens is rotationally symmetrical, and a rotational axis of the first surface and a rotational axis of the second surface are arranged to be deviated from each other.

Abstract: An optical disc drive using either one of a first disc (e.g., DVD) and a second disc (e.g., CD), is provided with a first laser diode that emits a shorter wavelength beam, a second laser diode that emits a longer wavelength beam, an objective lens, and a driving unit that holds and rotates the optical disc. The optical axis of the objective lens is inclined relative to a normal to the optical disc. The first laser diode is located at a first position so that the coma, which is caused when the first laser beam is converged on a data recording surface of the first disc, is minimized, and the second laser diode is located at a second position so that the coma, which is caused when the second laser beam is converged on a data recording surface of the second disc, is minimized.

Abstract: An information recording/reproducing apparatus includes a detector circuit for detecting a state of reflection light from the recording medium, a control circuit for calculating a radiation power used for writing the information in the recording medium, in accordance with the reflection light state, a pulse generator circuit for generating record pulse information in accordance with the radiation power, and an optical driver circuit for converting the record pulse information into optical information in accordance with the radiation power and driving the optical head to record the light information into the recording medium. Accordingly, the apparatus records information by applying light from an optical head to a record area of a recording medium and changing a state of the record area and reads the information recorded in the record area.

Abstract: An objective lens converges a shorter wavelength laser beam on a DVD having a protective layer, which is 0.6 mm thick, and a longer wavelength laser beam on a CD having a protective layer, which is 1.2 mm thick. A common region is defined on the objective lens. The common region provides a numerical aperture appropriate for converging the longer wavelength laser beam on the CD. Coma of the objective lens in the first region is compensated better in a case where the longer wavelength laser beam is converged on the CD than a case where the shorter wavelength laser beam is converged on the DVD.

Abstract: In an optical head for recording on or reproducing from a plurality of kinds of optical information recording media corresponding to a plurality of kinds of different wavelengths, coma aberration is prevented, and low price and high reliability are realized. To that end, in an optical head constituted by laser light sources of three wavelengths and photodetectors corresponding to the laser light sources of the three wavelengths, a two-laser module including laser light sources of two adjacent wavelengths and photodetectors corresponding to the laser light sources, a laser module including a laser light source of the rest one wavelength and a photodetector corresponding to the laser light source, and a dichroic mirror bonded with a rising mirror are combined.

Abstract: In optical heads with multiple semiconductor laser chips with different wavelengths, coma aberrations generated by laser beams projected at an angle relative to the entry axis of a focus lens is reduced.