Abstract: An SiNx film is formed on partial side surfaces and an electrode forming surface excluding an n-side electrode of a first contact layer, the side surfaces of each layer, the upper surface of a second cladding layer and the side surfaces of a ridge portion. An SiOy film is formed on the SiNx film. The SiNx film and the SiOy film form a dielectric film.

Abstract: The present invention provides a wave plate capable of obtaining preferable phase conversion characteristic over a wide wavelength range. The wave plate includes an aluminum oxide film having linear grating groove patterns. The period L (?m) and the duty ratio De of the grating groove patterns are set at values within the first range specified by the following four formulas: L?0.65 L?2×10?14e31.263De L?6.0317De2?10.352De+5.0516 (De?0.85)2/0.442+(L?0.41)2/0.

Abstract: A light-emitting device, having high light extraction efficiency, capable of obtaining diffused light is obtained. This light-emitting device comprises a light-emitting diode, a portion, formed on a plane substantially parallel to a light-emitting surface of the light-emitting diode, having a dielectric constant periodically modulated with respect to the in-plane direction of the plane substantially parallel to the light-emitting surface and a member provided on the side of the light-emitting surface of the light-emitting diode for diffusing light emitted from the light-emitting diode.

Abstract: In an organic electroluminescent device constructed by providing at least an emitting layer and a carrier transport layer using an organic material between a hole injection electrode and an electron injection electrode, at least one of the emitting layer and the carrier transport layer contains a chelate compound of a chromone derivative with zinc or aluminum, a chelate compound of a 3-hydroxyflavone derivative with a metal, a chelate compound composed of an 8-quinolinol derivative dimer and another ligant which are coordinated to a metal, or a chelate compound composed of two 8-quinolinol derivatives coordinated to a metal and one halogen bonded thereto.

Abstract: A light-emitting device with a built-in microlens having a microlens integrated with a semiconductor light-emitting device causing no misalignment of an optical axis is provided. This light-emitting device with a built-in microlens comprises a semiconductor light-emitting device and a microlens, integrated with the semiconductor light-emitting device, formed through light emitted from the semiconductor light-emitting device. Thus, the optical axis of the microlens is automatically aligned in formation of the microlens.

Abstract: In an organic electroluminescent device constructed by providing at least an emitting layer and a carrier transport layer using an organic material between a hole injection electrode and an electron injection electrode, at least one of the emitting layer and the carrier transport layer contains a chelate compound of a chromone derivative with zinc or aluminum, a chelate compound of a 3-hydroxyflavone derivative with a metal, a chelate compound composed of an 8-quinolinol derivative dimer and another ligant which are coordinated to a metal, or a chelate compound composed of two 8-quinolinol derivatives coordinated to a metal and one halogen bonded thereto.

Abstract: In an organic electroluminescent device constructed by providing at least an emitting layer and a carrier transport layer using an organic material between a hole injection electrode and an electron injection electrode, at least one of the emitting layer and the carrier transport layer contains a chelate compound of a chromone derivative with zinc or aluminum, a chelate compound of a 3-hydroxyflavone derivative with a metal, a chelate compound composed of an 8-quinolinol derivative dimer and another ligant which are coordinated to a metal, or a chelate compound composed of two 8-quinolinol derivatives coordinated to a metal and one halogen bonded thereto.

Abstract: In an organic electroluminescent device constructed by providing at least an emitting layer and a carrier transport layer using an organic material between a hole injection electrode and an electron injection electrode, at least one of the emitting layer and the carrier transport layer contains a chelate compound of a chromone derivative with zinc or aluminum, a chelate compound of a 3-hydroxyflavone derivative with a metal, a chelate compound composed of an 8-quinolinol derivative dimer and another ligant which are coordinated to a metal, or a chelate compound composed of two 8-quinolinol derivatives coordinated to a metal and one halogen bonded thereto.

Abstract: A six-segment holographic surface is divided into regions by dividing lines. A four-segment photodetection part is divided into four photodetection parts equal in area by a section line substantially parallel to the radial direction of an optical disk and a section line orthogonal thereto. A main light beam diffracted in the regions of the six-segment holographic surface are condensed as spots at positions apart from each other on opposite sides on a section line of the four photodetection parts, and the main beam diffracted in the regions is condensed as spots in the center of the photodetection parts of the four-segment photodetection part.

Abstract: A transmission-type holographic optical element has a four-segment holographic surface divided into four regions of equal areas by virtual dividing lines which are perpendicular to each other. The first dividing line is at an angle with respect to the track direction of an optical disk and the second dividing line is at an angle with respect to the radial direction of the optical disk before tracking phase adjustment. The first dividing line coincides with the track direction of the optical disk and the second dividing line coincides with the radial direction of the optical disk after tracking phase adjustment. A four-segment photodetection part is divided into four photodetection parts of equal areas by a dividing line substantially parallel to the radial direction of the optical disk and a dividing line perpendicular thereto.

Abstract: A semiconductor laser device comprises an n-type cladding layer, an active layer formed on the n-type cladding layer and having a quantum well structure including one or a plurality of quantum well layers, a p-type cladding layer comprising a flat portion formed on the active layer and a stripe-shaped ridge portion on the flat portion, and a current blocking layer formed on the flat portion so as to cover the side surface of the ridge portion and formed on a region on the upper surface of the ridge portion from one of facets of a cavity to a position at a predetermined distance therefrom.

Abstract: A semiconductor laser device including an n-type cladding layer, an active layer, a p-type cladding layer having a ridge portion, an n-type optical confinement layer formed on the flat portion and side surfaces of the ridge portion of the p-type cladding layer, and an n-type current blocking layer formed on the n-type optical confinement layer in this order. The optical confinement layer is composed of a low resistivity layer doped with n-type impurity, which has a smaller refractive index than the p-type cladding layer and a bandgap energy greater than the energy of lasing light. The optical confinement layer has an impurity concentration of 5.times.10.sup.7 cm.sup.-3 or less. The n-type current blocking layer has a thickness of 0.4 .mu.m or less.

Abstract: A semiconductor laser device of an AlGaInP system includes a GaAs substrate and a surface of the substrate is inclined by 5.degree. or more from a {100} plane in a <011> direction.

Abstract: A semiconductor laser with a self-sustained pulsation is disclosed in which a first cladding layer of first conductive type, an active layer and a second cladding layer of second conductive type having a striped ridge are formed in that order on a semiconductor substrate of first conductive type. The first and second cladding layers have a refractive index smaller than and a band gap larger than the active layer. A saturable optical absorbing layer having a band gap of energy substantially equal to the energy corresponding to lasing wavelength is formed in both the first and second cladding layers. Further, a barrier layer having a refractive index smaller than and a band gap larger than the first and second cladding layers is formed between the first cladding layer and the active layer and/or between the active layer and the second cladding layer.

Abstract: A semiconductor laser device according to the present invention comprises a GaAs substrate of a first conductivity type, a cladding layer of the first conductivity type formed on one main surface of the substrate, an active layer having a quantum well structure in which a tensile strain quantum well layer and a quantum barrier layer which are formed on the cladding layer of the first conductivity type are alternately laminated, and a cladding layer of a second conductivity type formed on the active layer. The one main surface of the substrate is a surface misoriented by 9.degree. to 17.degree. from a {100} plane of the substrate in a <011> direction, and the cavity length is not less than 150 .mu.m nor more than 300 .mu.m.

Abstract: The present invention is directed to a semiconductor laser device in which an active layer is constituted by a quantum well layer having a structure in which well layers and barrier layers which are formed on a GaAs substrate are alternately layered, cladding layers are provided so as to interpose the active layer, the value of a strain on each of the well layers is -0.8% to -1.5%, the thickness of a well layer is from 80 .ANG. to 180 .ANG., the value of strain on each of the barrier layers is +0.5% to +1.0%, the thickness of the barrier layer is 20 .ANG. to 60 .ANG., and the respective numbers of layered well layers and barrier layers are 2 to 4.

Abstract: On an n-type GaAs semiconductor substrate, an n-type cladding layer formed of AlGaInP system crystal almost in lattice matching with the semiconductor substrate, an active layer and a p-type cladding layer formed of AlGaInP system crystal almost in lattice matching with the semiconductor substrate are formed, and a p-type barrier cladding layer formed of AlGaInP system crystal or AlInP system crystal is provided in the p-type cladding layer. The p-type barrier cladding layer has a thickness through which electrons are almost not transmitted, has tensile strain, and also has band gap energy larger than that of the p-type cladding layer.

Abstract: A semiconductor laser with a self-sustained pulsation is disclosed in which a first cladding layer of first conductive type, an active layer and a second cladding layer of second conductive type having a striped ridge are formed in that order on a semiconductor substrate of first conductive type. The first and second cladding layers have a refractive index smaller than and a band gap larger than the active layer. A saturable optical absorbing layer having a band gap of energy substantially equal to the energy corresponding to lasing wavelength is formed in both the first and second cladding layers. Further, a barrier layer having a refractive index smaller than and a band gap larger than the first and second cladding layers is formed between the first cladding layer and the active layer and/or between the active layer and the second cladding layer.

Abstract: A semiconductor laser with a self-sustained pulsation is disclosed in which a first cladding layer of first conductive type, an active layer and a second cladding layer of second conductive type having a striped ridge are formed in that order on a semiconductor substrate of first conductive type. The first and second cladding layers have a refractive index smaller than and a band gap larger than the active layer. A saturable optical absorbing layer having a band gap of energy substantially equal to the energy corresponding to lasing wavelength is formed in both the first and second cladding layers. Further, a barrier layer having a refractive index smaller than and a band gap larger than the first and second cladding layers is formed between the first cladding layer and the active layer and/or between the active layer and the second cladding layer.

Abstract: A semiconductor laser device of an AlGaInP system includes a GaAs substrate and a surface of the substrate is inclined by 5.degree. or more from a {100} plane in a <011> direction.