Abstract: An optical pickup device comprises a light source, a beam converting optical system for converting a light beam emitted from the light source to a light beam having substantially circular distribution of quantity of light, an objective optical section for converging the light beam on an optical recording medium, and a signal detecting system for reproducing information recorded on the optical recording medium. The signal detecting system includes a separating optical element for separating a return light beam from a go light beam, and an signal detecting section for detecting an information signal based on the separated return light beam. The beam converting optical system has a first beam converting prism and a second beam converting prism, each of which has two optical surfaces nonparallel to each other. One of them is an entrance surface through which a light beam to be converted enters and the other is an exit surface through which the converted light beam exits.

Abstract: The present invention avoids a loss of information recorded on or information to be recorded onto an optical disk by accepting a state of deterioration of a semiconductor laser in a closed-type optical disk apparatus. The optical disk is rotated in a predetermined direction by a driving of a spindle motor through a motor driver based on an instruction from a control section. Information is recorded onto or reproduced from the optical disk by a semiconductor laser driven through a laser driver based on an instruction from the control section. The state of progress of deterioration of the semiconductor laser is monitored by a monitoring section, and this state is displayed by a light display section according to a deterioration state.

Abstract: A laser beam emitted from a laser source provided at a silicon substrate passes through a hologram element formed of a translucent flat plate and a grating, thereby being Subjected to NA conversion executed by an NA converting lens, passing through a polarizing film of a polarization beam splitter, and converging onto a magneto-optical disk via a collimator lens and an objective. A part of back-reflection from the magneto-optical disk, which is reflected by a polarizing film of the polarization beam splitter, is reflected by a reflection surface of the splitter, then branched into two polarized light beams by a Wollaston prism, and guided to one light receiving element group. On the other hand, another part of the back-reflection, which passes through the polarization beam splitter, is branched into two beams by the hologram element and guided to the other light receiving element groups.

Abstract: An optical head for recording and reproducing information on and from an opto-magnetic record medium by projecting a light beam onto the record medium and introducing a return light beam reflected by the record medium onto photodetectors, including a light source for emitting a linearly polarized light beam, an objective lens for projection the light beam onto the record medium, and an optical element having a surface on which a beam splitting surface is provided in the diverging or converging return beam. Said beam splitting surface is curved such that light rays of the return light beam are made incident upon the beam splitting surface at substantially the same incident angle, so that the return light beam can be split accurately into P-polarized and S-polarized light beams.

Abstract: An optical pick-up apparatus for reproducing information recorded on a magneto-optical record medium including a semiconductor laser emitting a linearly polarized laser beam, and a polarizing film provided between a glass prism and a uniaxial birefringent crystal prism. The laser beam emitted by the semiconductor laser is made incident upon the polarizing film via the glass prism and is reflected thereby. The apparatus further includes an objective lens projecting the laser beam reflected by the polarizing film onto the magneto-optical record medium as a fine spot and converging a return laser beam reflected by the record medium toward the polarizing film. The return beam transmitted through the polarizing film is refracted by the uniaxial birefringent crystal prism and is divided into ordinary light and extraordinary light, which are received by a first photodetector to produce a reproduced information signal.

Abstract: A beam shaping and beam splitting device for converting a cross sectional shape of a polarized parallel incident light beam into a light beam having a corrected cross sectional shape, emanating the light beam toward a reflection surface and emanating a return light beam reflected by said reflection surface in a direction which is different from an incident direction of said incident light beam, including a prism made of an anisotropic material and having a first surface upon which said incident light beam is made incident from an incident direction which is inclined with respect to said first surface and a second surface from which the incident light beam emanates from the prism, in which said return light beam is refracted by said first surface and emanates from the first surface in a direction which is different from said incident direction.

Abstract: The present invention is directed to an apparatus using an integrated type pickup as an optical head for writing and reading optical information and capabling of writing data at high speeds. The apparatus includes a laser diode having an active layer at its intermediate position and having one area side held over a surface of a semiconductor substrate with an insulating layer interposed between the semiconductor substrate and the laser diode relative to the active layer. The laser diode has two areas with the active layer as a boundary and a constant potential is applied from a power supply to the insulating layer side of the laser diode and a transistor (laser diode drive unit) is provided to apply a modulation signal to the other area of the laser diode so that the laser diode is driven to modulate its output.

Abstract: An optical head has a semiconductor laser for emitting light, a collimator lens for converting the light from the laser into a parallel light beam, a semiconductor substrate for reflecting the light beam, and an objective lens for focussing the light beam reflected from the substrate on the optical disk. A 1/4 wavelength plate is situated between the substrate and the objective lens. A beam splitter which transmits the light from the laser and reflects the light returning from the disk is provided between the collimator lens and the substrate. Following the beam splitter, a collective lens, a cylindrical lens and an optical detector are arranged in this order on an optical path for the returning light. A light receiving element for outputting a signal corresponding to the intensity of the light received is formed on the semiconductor substrate, and a polarizing film is formed on the surface thereof.

Abstract: An optical head for reading and/or writing information from and/or from a magneto-optical record medium including a semiconductor laser, a composite prism having a glass prism, a birefringent prism and a dielectric multilayer film interposed between the glass prism and birefringent prism, an objective lens and fist and second photodetectors. A laser beam emitted by the semiconductor laser impinging upon the glass prims is reflected by the dielectric film and is projected onto the record medium by the objective lens. A return beam reflected by the record medium is incident upon the dielectric film via the objective lens, and a part of the return beam transmitted through the dielectric film is separated by the birefringent prism into a first ordinary beam and a second extraordinary beam which are received by the first and second photodectors, respectively.

Abstract: An optical head for recording and reproducing information on and from an opto-magnetic record medium by projecting a light beam onto the record medium and introducing a return light beam reflected by the record medium onto photodetectors, including a light source for emitting a linearly polarized light beam, an objective lens for projection the light beam onto the record medium, and an optical element having a surface on which a beam splitting surface is provided in the diverging or converging return beam. Said beam splitting surface is curved such that light rays of the return light beam are made incident upon the beam splitting surface at substantially the same incident angle, so that the return light beam can be split accurately into P-polarized and S-polarized light beams.

Abstract: An optical head for recording and/or reproducing information on and/or from an opto-magnetic record medium including an optical member formed by first and second prisms having parallel opposing surfaces and being joined with each other and having an incident angle on which a beam splitting surface is provided and a polarizing beam splitting plane formed between contact surfaces of the first and second prisms, a laser light source for emitting a laser beam which is made incident upon said beam splitting surface of the optical member, an objective lens for projecting said incident laser beam reflected by said beam splitting surface onto the opto-magnetic record medium and introducing a return laser beam reflected by the opto-magnetic record medium onto the beam splitting surface, and first and second photodetectors for receiving first and second laser beams having mutually orthogonal polarizing directions transmitted through and reflected by said polarizing beam splitting plane, respectively.

Abstract: An optical head for writing and/or reading information on and/or from an optical record medium such as a magneto-optical record medium including a semiconductor substrate, a semiconductor laser mounted on a surface of the semiconductor substrate for emitting a laser beam, an objective lens for projecting the laser beam onto the optical record medium as a fine spot, a plurality of photodetectors firmed in the surface of the semiconductor substrate, and an optical block arranged on said semiconductor substrate to form an integral unit together with said semiconductor substrate. The optical block includes a hologram for diffracting a return beam reflected by said magneto-optical record medium and a polarization beam splitting plane arranged in substantially parallel with an optical axis of a zero order beam emanating from the hologram for splitting a pupil of the hologram.

Abstract: A fine surface profile meter includes an X-Y stage, supported by a leaf spring, for supporting a sample thereon, a piezoelectric actuator for two-dimensionally scanning the X-Y stage, a positioning table, disposed below the X-Y stage, for positioning the X-Y stage at an arbitrary position, an objective lens disposed above the X-Y stage, an observation optical system for allowing an operator to observe an enlarged sample image, a measurement optical system, an optical axis of which is aligned with an optical path of the objective lens through a beam splitter, the measurement optical system for emitting a laser beam onto the sample through the objective lens and to receive the laser beam reflected by the sample, a calculator circuit for calculating height information of the sample using an output from the measurement optical system and for obtaining a two-dimensional distribution of the height information, a cover for shielding the X-Y stage, the positioning means, the objective lens, the beam splitter, the obs

Abstract: A means receiving a light returning from an optical recording medium and detecting the beam distribution in the tangential direction of the track of the recording medium is provided. The offset of at least one controlling signal of a focusing controlling signal and tracking controlling signal is eliminated by the output signal of this beam distribution detecting means.

Abstract: In an optical measuring device including a laser ray source, a polarization prism, an objective lens to condensing parallel ray to the surface of a substance to be measured, and divided photo-sensor means to detect reflected ray, the divided photo-sensor means is two divided photo-sensors, to eliminate noise effect caused by the laser ray source.

Abstract: This invention relates to an improved process for preparing N-carboxylic anhydrides of amino acids, and N-carboxylic anhydrides of derivatives of amino acids by reacting an amino acid, a derivative of amino acid or a salt thereof with trichloromethylchloroformate in an organic solvent, preferably a mixture of an ether or ester with one or more other organic solvents and adding to the reaction mixture carbon, basic aluminum chloride or aluminum oxide just before or immediately after completion of the initial reaction.