Abstract: In a semiconductor laser element, a lower cladding layer, a lower optical waveguide layer, an InGaAs compressive-strain quantum-well active layer, an upper optical waveguide layer, and an upper cladding layer are formed in this order in a stripe-shaped region on a substrate. A current-blocking layer is formed on both sides of the compressive-strain quantum-well active layer so that the compressive-strain quantum-well active layer is sandwiched between two portions of the current-blocking layer, and trenches extending along the direction of the laser resonator are formed through the current-blocking layer. Instead of providing the trenches, the widths of the layers formed above the substrate are reduced so as to form a ridge structure.

Abstract: In a semiconductor laser element, a lower cladding layer of AlGaInP of the first conductive type, a lower optical waveguide layer of AlGaInP, a quantum-well active layer of InGaP, an upper optical waveguide layer of AlGaInP, and an upper cladding layer of AlGaInP of the second conductive type are formed in this order on a substrate of GaAs of the first conductive type. The degree of mismatch ?a/a with the substrate and the thickness dw of the quantum-well active layer satisfy the conditions, ?0.6%??a/a ??0.3% and 10 nm?dw?20 nm. In addition, the resonator length Lc and the reflectances Rf and Rr of the opposite end facets satisfy the conditions, Lc?400 ?m and Rf×Rr?0.5.

Abstract: Crystallized glass is formed by precipitating &bgr;-spodumene solid solution or &bgr;-quartz solid solution, and contains, by mass percent, 55-72% SiO2, 14-30% Al2O3, 2.9-6.0% Li2O, and 1.0-10.0% K2O, wherein a mass ratio between Li2O and K2O (Li2O/K2O) is 2.2 or less.

Abstract: In a semiconductor laser device, a current confinement structure is realized by p-type and n-type layers formed above an active layer, where the p-type and n-type layers include a current stopping layer which has an opening for allowing current injection into only a predetermined stripe region of the active layer. In addition, a semiconductor layer is formed above the current confinement structure, and a pair of trenches are formed on both sides of the opening along the predetermined stripe region so as to extend from the semiconductor layer through the current stopping layer to at least the active layer. Further, an insulation film is formed on the semiconductor layer except that an area of the semiconductor layer located right above the predetermined stripe region is not covered by the insulation film, and an electrode is formed on the area of the semiconductor layer.

Abstract: A semiconductor laser device is bonded to a heat sink. The semiconductor laser device contains a stripe structure having a width equal to or greater than 10 micrometers, and including a first optical guide layer of a first conductivity type, an active layer, and a second optical guide layer of a second conductivity type. A total thickness of the first and second optical guide layers is equal to or more than 0.5 micrometers. The semiconductor laser device is soldered onto the heat sink at a surface of the semiconductor laser device where the surface located is farther from the active layer than other surfaces of the semiconductor laser device.

Abstract: A second-harmonic generation device includes a semiconductor laser element which has a quantum-well active layer, a wavelength control means which controls the wavelength of the light emitted from an end facet of the semiconductor laser element, an optical system which returns to the semiconductor laser element the light the wavelength of which is controlled by the wavelength control means, and a wavelength conversion element which is directly coupled to the other end facet of the semiconductor laser element, and converts the wavelength of the light controlled by the wavelength control means, to a half wavelength. The semiconductor laser element has a resonator length equal to or greater than 900 micrometers and a mirror loss equal to or greater than 16 cm−1.

Abstract: An optical waveguide member is inserted into a tubular member. The tubular member is elongated with heating and fusion-bonded to the optical waveguide member. Thus, a formed body is obtained. The formed body is cut into a predetermined length to obtain an optical waveguide member. The tubular member is preferably made of a crystallized glass with crystals deposited therein at least in the state of the formed body.

Abstract: A meter such as a speedometer for use in an automobile instrument panel includes a pointer driven by a stepping motor. A pulse voltage having a wider pulse width is supplied to the stepping motor to obtain a higher induced voltage to be compared with a threshold voltage for detecting the pointer-zero-position. After the pointer-zero-position is detected, the stepping motor is driven by a pulse voltage having a narrower pulse width to obtain a quicker response of the pointer. In this manner, the pointer-zero-position is accurately adjusted without sacrificing the quick response of the meter pointer.

Abstract: In a semiconductor laser device, a current confinement structure is realized by p-type and n-type layers formed above an active layer, where the p-type and n-type layers include a current stopping layer which has an opening for allowing current injection into only a predetermined stripe region of the active layer. In addition, a semiconductor layer is formed above the current confinement structure, and a pair of trenches are formed on both sides of the opening along the predetermined stripe region so as to extend from the semiconductor layer through the current stopping layer to at least the active layer. Further, an insulation film is formed on the semiconductor layer except that an area of the semiconductor layer located right above the predetermined stripe region is not covered by the insulation film, and an electrode is formed on the area of the semiconductor layer.

Abstract: An instrument panel for use in an automobile includes a speedometer, an engine rotational speed meter and other indicators. A pointer of each meter is driven by a stepping motor via a reduction gear train made of synthetic resin. Terminals of the stepping motor field coils are soldered on a circuit board. After the heat of the soldering is dissipated, the heat-sensitive gear train is assembled to the circuit board. Thus, the resin gears are protected from being damaged by the soldering heat. The soldering is performed under an automatic refolw-soldering or flow-soldering process. As long as the soldering is performed before assembling the resin gears, all the components of the stepping motor and the reduction gear train may be contained in a casing.

Abstract: A meter such as a speedometer for use in an automobile instrument panel includes a pointer driven by a stepping motor. A pulse voltage having a wider pulse width is supplied to the stepping motor to obtain a higher induced voltage to be compared with a threshold voltage for detecting the pointer-zero-position. After the pointer-zero-position is detected, the stepping motor is driven by a pulse voltage having a narrower pulse width to obtain a quicker response of the pointer. In this manner, the pointer-zero-position is accurately adjusted without sacrificing the quick response of the meter pointer.

Abstract: A semiconductor laser includes a first clad layer having one of p-type conductivity and n-type conductivity, a first optical waveguide layer, a first barrier layer of GaAs1-y2Py2, a quantum-well active layer of Inx3Ga1-x3As1-y3Py3, a second barrier layer of GaAs1-y2Py2, a second optical waveguide layer and a second clad layer having the of p-type conductivity and n-type conductivity formed in this order on a GaAs substrate. Each of the first and second clad layers is of a composition which matches with the GaAs substrate in lattice. Each of the first and second optical waveguide layers is of a InGaAsP composition which matches with the GaAs substrate in lattice. Each of the first and second barrier layers is 10 to 30 nm in thickness and is of a composition which has tensile strain relative to the GaAs substrate, the product of the tensile strain and the thickness of each of the first and second barrier layers being 5 to 20% nm.

Abstract: A semiconductor laser has a first conduction type clad layer, an active layer and a second conduction type clad layer formed on a first conduction type semiconductor substrate in this order. An inverted mesa-shaped ridge is formed on a part of the second conduction type clad layer and a first conduction type current stopping layer is formed on each side of the ridge. Each side of the inverted mesa-shaped ridge is curved into a concave surface in a plane perpendicular to the longitudinal direction of the ridge.

Abstract: A semiconductor laser has a first conduction type clad layer, an active layer and a second conduction type clad layer formed on a first conduction type semiconductor substrate in this order. An inverted mesa-shaped ridge is formed on a part of the second conduction type clad layer and a first conduction type current stopping layer is formed on each side of the ridge. Each side of the inverted mesa-shaped ridge is curved into a concave surface in a plane perpendicular to the longitudinal direction of the ridge.

Abstract: A composition comprising (a) an organopolysiloxane having a unit of the formula: RSiO.sub.3/2 wherein R is a substituted or unsubstituted monovalent C.sub.1-10 hydrocarbon group in its molecule and having at least 0.05 alkenyl groups each directly attached to a silicon atom per silicon atom, (b) an organohydrogenpolysiloxane having at least 2 hydrogen atoms each directly attached to a silicon atom per molecule, and (c) a platinum catalyst, maintains good light transmission in cured form when exposed to humidity or stresses and is thus suitable for forming cores of optical fibers.

Abstract: A polymer having dihydropyridine rings or dihydrotriazine rings as main constitutional units, an ethynyl- or cyanato-terminated Schiff's compound which is a starting material for producing the polymer, and applications of the polymer.

Abstract: A plastic optical fiber comprising a core and a clad, said core being formed by an amorphous and optically transparent polymer and said clad being formed by a polymer having a refractive index lower than that of the core by at least 0.3%, at least one of the core and the clad being formed by an amorphous and optically transparent polymer containing metal elements and halogen atoms, is low in light loss and excellent in heat resistance.

Abstract: An optical part for light transmission comprises a light conductor formed of a core of a transparent material and a clad of a material having a smaller refractive index than that of the core material, and a light emitting and/or receiving element, wherein the light emitting and/or receiving element is integrally combined with the core of the light conductor by a same material as the core material or by a material having a same refractive index as that of the core material and having a greater rigidity than that of the material forming the clad and/or jacket. The optical part can be used in a high temperature environment as well as a room temperature environment without involving any appreciable loss in light transmission.

Abstract: The A phase stator and the A phase stator are opposed each other winding same phase coil thereat. The B phase stator and the B phase stator are opposed each other winding same phase coil thereat. The A phase stator and the A phase stator, and the B phase stator and the B phase stator sandwich the mover, respectively. The mover fixes the permanent magnets having small magnetized pitch on the both surfaces thereof. The permanent magnets on both surfaces of the mover comprises the first permanent magnets and the second permanent magnets. The first permanent magnets having one polarity and a predetermined interval each other along the longitudinal direction of the mover are fixed previously on the mover. The second permanent magnets are inserted to the intervals on the mover.

Abstract: There are disclosed a nitrile-terminated Schiff compound represented by the formula X--Z--Y--C.tbd.N).sub.m (I) wherein n is 1 or 2, Z is --CH.dbd.N-- or --N.dbd.CH-- and Y is a divalent organic group such as phenylene and the like, and X is the same as Y when n=2 or H, lower alkyl group etc. when n=1; polymers obtained by polymerizing said Schiff compound alone or together with other monomers, and a process for preparing such a polymer therefrom.