Abstract: A glass-coated light-emitting element 10 of the invention has a semiconductor light-emitting element 2 having a surface on which no electrode is formed is coated with a glass 1, in which a surface of the glass 1 constitutes a part of a spherical surface broader than a hemispherical surface, the refractive index of the glass 1 at an emission peak wavelength of the semiconductor light-emitting element 2 is 1.7 or more, and the ratio of the diameter of the above-mentioned spherical surface to the maximum diameter of a surface of the semiconductor light-emitting element 2 on which electrodes are formed is 1.8 to 3.5, whereby light emitted from the light-emitting element can be efficiently introduced into a light control unit, and alignment with a lens or a light pipe, which has hitherto been made, becomes unnecessary.

Abstract: An optical glass which has an internal transmittance to a light having a wavelength of 400 nm being at least 90% as calculated in a thickness of 1 mm and which contains at least 25 mol % of B2O3 and from 0.1 to 20 mol % of TeO2. The above optical glass which contains La2O3. The above optical glass wherein the glass transition point ?650° C. and the refractive index at 633 nm?1.70. A process for producing an optical element made of the above optical glass, which comprises dropping the optical glass in a molten state from a flow outlet of a flow out pipe made of a platinum alloy to form a preform and subjecting it to precision press-molding.

Abstract: To provide an alkali-free glass substrate, which has a high Young's modulus, a low linear expansion coefficient, a high strain point and a low density, does not devitrify in the float forming process and is excellent in acid resistance. An alkali-free glass substrate, which contains neither alkali component nor BaO and consists essentially of, as represented by mol % based on oxide, from 57.0 to 65.0% of SiO2, from 10.0 to 12.0% of Al2O3, from 6.0 to 9.0% of B2O3, from 5.0 to 10.0% of MgO, from 5.0 to 10.0% of CaO and from 2.5 to 5.5% of SrO, provided that MgO+CaO+SrO is from 16.0 to 19.0%, MgO/(MgO+CaO+SrO)?0.40, and B2O3/(SiO2+Al2O3+B2O3)?0.12; wherein Young's modulus ?75 GPa; the linear expansion coefficient at from 50 to 350° C. is from 30×10?7/° C. to 40×10?7/° C.; the strain point ?640° C.; the temperature T2 (the viscosity ? satisfies log ?=2)?1,620° C.; the temperature T4 (the viscosity ? satisfies log ?=4)?1,245° C.; the devitrification temperature ?T4; and weight loss per unit area is at most 0.

Abstract: To provide an optical glass which has a high transmittance and a high refractive index and shows little decrease in the transmitted light intensity when continuously irradiated with a blue-violet laser diode light, and which is less prone to a higher melting temperature and exhibits chemical durability being not low. An optical glass consisting essentially of, as represented by mol %, from 35 to 54% of TeO2, from 0 to 10% of GeO2, from 5 to 30% of B2O3, from 0 to 15% of Ga2O3, from 0 to 8% of Bi2O3, from 3 to 20% of ZnO, from 0 to 10% of MgO+CaO+SrO+BaO, from 1 to 10% of Y2O3+La2O3+Gd2O3, from 0 to 5% of Ta2O5+Nb2O5, from 0 to 1.8% of TiO2, and from 0 to 6% of Li2O+Na2O+K2O+Rb2O+Cs2O. A lens made of such an optical glass.

Abstract: The present invention provides a process for producing a light-emitting device capable of achieving high directivity without a cavity, which minimizes occurrence of short circuit at a time of covering a light-emitting element with glass. The present invention further provides a light-emitting device capable of achieving high directivity without a cavity. After a LED mounted on a wiring board is prepared, a glass member having a shape approximated by a rectangular solid or a sphere is placed on the LED. In this step, the glass member is placed so that the central axis of the glass member placed on the LED is present in a region from the central axis of LED to a position inside from the periphery of LED, and that the area of the region is at most 90% of the area of entire surface on which the glass member is placed.

Abstract: The present invention provides a light-emitting device realizing high directivity without using a cavity, which minimizes wire-breakage deformation of electrodes and generation of bubbles. The light-emitting device has a wiring board, a LED electrically connected with the wiring board, and a glass covering the LED. Entirety of the glass is substantially spherical, and the LED is embedded in a part of the glass. Then, a curved surface of the glass preferably contact with side faces of the LED, and the LED is preferably a polygonal semiconductor chip having a rotational center in a front view.

Abstract: A diode chip is sealed by a glass material. There are provided a light emitting diode chip and a glass member in close contact with at least one portion of the surface of the light emitting diode chip. The glass member has a surface shape containing a curved surface at least a portion thereof. The curved surface is preferably a portion of a spherical surface or a spheroidal surface. The glass member has a surface shape containing a spherical portion and a flat portion, and the diode chip is preferably disposed on the flat portion.

Abstract: To provide a process for producing and alkali free glass for effectively suppressing bubbles, and an alkali free glass produced by the process, which is suitable as a glass substrate for flat panel displays and has few bubbles. A process for producing an alkali free glass containing substantially no alkali metal oxide, which comprises melting a glass starting material having a matrix composition of the following composition, and subjecting the molten glass to a treatment process of removing bubbles under reduced pressure, stirring or transferring under a condition where the molten glass is in contact with a platinum member, wherein the starting material is prepared so as to contain SnO2 in an amount of from 0.01 to 2.0% per 100% of the total amount of the above matrix composition; the starting material is melted under heating at from 1,500 to 1,650° C.

Abstract: To provide a production process capable of making the transmittance of an optical glass element obtainable by press-molding a TeO2-containing glass high. A process for producing an optical glass element, which comprises press-molding a TeO2-containing glass, wherein the press-molding is carried out in an atmosphere in which the nitrogen partial pressure is at most 102 Pa. The above process for producing an optical glass element, wherein the face of a mold for the press-molding to be in contact with the glass is made of carbon. The above process for producing an optical glass element, wherein the molded glass obtained by the press-molding is held in an oxygen-containing atmosphere at a temperature within a range of at least a temperature lower by 50° C. than the glass transition point of the TeO2-containing glass and at most the softening point of the glass.

Abstract: To provide an optical glass which has a high transmittance and a high refractive index and shows little decrease in the transmitted light intensity when continuously irradiated with a blue-violet laser diode light, and which is less prone to a higher melting temperature and exhibits chemical durability being not low. An optical glass consisting essentially of, as represented by mol %, from 35 to 54% of TeO2, from 0 to 10% of GeO2, from 5 to 30% of B2O3, from 0 to 15% of Ga2O3, from 0 to 8% of Bi2O3, from 3 to 20% of ZnO, from 0 to 10% of MgO+CaO+SrO+BaO, from 1 to 10% of Y2O3+La2O3+Gd2O3, from 0 to 5% of Ta2O5+Nb2O5, from 0 to 1.8% of TiO2, and from 0 to 6% of Li2O+Na2O+K2O+Rb2O+Cs2O. A lens made of such an optical glass.

Abstract: A light emitting diode element having a light emitting diode sealed by glass, wherein the glass consists essentially of, as represented by mol % based on the following oxides, from 30 to 70% of SnO, from 15 to 50% of P2O5, from 0.1 to 20% of ZnO, from 0 to 10% of SiO2+GeO2, from 0 to 30% of Li2O+Na2O+K2O, and from 0 to 20% of MgO+CaO+SrO+BaO. Glass for covering a light emitting diode element, which has an internal transmittance of at least 80% with thickness of 1 mm for a light having a wavelength of 405. nm and which consists essentially of, as represented by mol % based on the following oxides, from 40 to 53% of TeO2, from 0 to 10% of GeO2, from 5 to 30% of B2O3, from 0 to 10% of Ga2O3, from 0 to 10% of Bi2O3, from 3 to 20% of ZnO, from 0 to 3% of Y2O3, from 0 to 3% of La2O3, from 0 to 7% of Gd2O3 and from 0 to 5% of Ta2O5, and TeO2+B2O3 is at most 75 mol %.

Abstract: An optical glass which has an internal transmittance to a light having a wavelength of 400 nm being at least 90% as calculated in a thickness of 1 mm and which contains at least 25 mol % of B2O3 and from 0.1 to 20 mol % of TeO2. The above optical glass.which contains La2O3. The above optical glass wherein the glass transition point ?650° C. and the refractive index at 633 nm ?1.70. A process for producing an optical element made of the above optical glass, which comprises dropping the optical glass in a molten state from a flow outlet of a flow out pipe made of a platinum alloy to form a preform and subjecting it to precision press-molding.

Abstract: An optical glass which contains at least 20 mol % of TeO2 and has an internal transmittance of at least 80% in a thickness of 2 mm to a light having a wavelength of 405 nm and a refractive index of at least 1.85 to the same light, and which contains no alkali metal oxide or contains alkali metal oxides in a total amount of at most 15 mol %.

Abstract: An optical glass which contains at least 20 mol % of TeO2 and has an internal transmittance of at least 80% in a thickness of 2 mm to a light having a wavelength of 405 nm and a refractive index of at least 1.85 to the same light, and which contains no alkali metal oxide or contains alkali metal oxides in a total amount of at most 15 mol %.

Abstract: Voltage is applied between electrodes (14a, 14b) under UV irradiation to perform a UV excitation poling, thereby producing microcrystal particles at a core unit (10a). Accordingly, second-order optical nonlinearity is developed at the core unit (10a) of an optical fiber (10). Under a high-temperature condition, a second-order optical nonlinearity can be imparted by a comparatively low-voltage UV excitation poling when a second-order optical nonlinearity decreases.

Abstract: Voltage is applied between electrodes (14a, 14b) under UV irradiation to perform a UV excitation poling, thereby producing microcrystal particles at a core unit (10a). Accordingly, second-order optical nonlinearity is developed at the core unit (10a) of an optical fiber (10). Under a high-temperature condition, a second-order optical nonlinearity can be imparted by a comparatively low-voltage UV excitation poling when a second-order optical nonlinearity decreases.