Abstract: Disclosed herein is a glass whose viscosity index (A) defined as a value obtained by dividing the viscosity of the glass at the liquidus temperature thereof by the liquidus temperature of the glass is in the range of 0.0004 to 1.5. Such a glass is melted in a melting furnace equipped with a nozzle, and the molten glass is dropped from the nozzle intermittently and regularly to obtain glass droplets. The glass droplet naturally dropped from the nozzle is received by a receiving mold to form a glass gob. The glass gob can be used as a preform for reheating molding. Further, it is possible to produce an optical glass element having no plane defect such as a shear mark by press-molding a hot glass gob with an upper mold just after the glass gob is received by the receiving mold.

Abstract: Optical glass for press-molding of the present invention includes the following glass components in % by weight: 10 to 38% of SiO2, 15 to 40% of B2O3, 4 to 14% of Li2O, 0 to 5% (zero inclusive) of Na2O, 0 to 5% (zero inclusive) of K2O, where a total content of Li2O+Na2O+K2O is equal to 4 to 20%, and 0 to 10% (zero inclusive) of MgO, 0 to 10% (zero inclusive) of CaO, 0 to 10% (zero inclusive) of BaO, 0 to 10% (zero inclusive) of SrO, and 15 to 39% of ZnO, where a total content of MgO+CaO+BaO+SrO+ZnO is equal to 15 to 39%. Here, in view of improvement in glass stability and adjustment of optical constants, one or two or more kinds of the following glass components may be further contained in % by weight, 0 to 20% of Al2O3, 0 to 5% of Y2O3, 0 to 5% of La2O3, 0 to 5% of Gd2O3, 0 to 5% TiO2, 0 to 5% of ZrO2, 0 to 5% of Nb2O5, 0 to 5% of Ta2O5, 0 to 10% of WO3, 0 to 2% of Sb2O3, and 0 to 5% of Bi2O3.

Abstract: A glass substrate for use as the substrate of an information recording medium such as a magnetic disk, magneto-optical disk, DVD, or MD or of an optical communication device, and a glass composition for making such a glass substrate, contains the following glass ingredients: 45 to 75% by weight of SiO2; 1 to 20% by weight of Al2O3; 0 to 8% by weight, zero inclusive, of B2O3; SiO2+Al2O3+B2O3 accounting for 60 to 90% by weight; a total of 0 to 20% by weight, zero inclusive, of R2O compounds, where R=Li, Na, and K; and a total of 0 to 15% by weight, zero inclusive, of TiO2+ZrO2+LnxOy, where LnxOy represents at least one compound selected from the group consisting of lanthanoid metal oxides, Y2O3, Nb2O5, and Ta2O5.

Abstract: The optical glass of the invention comprising: SiO2: 10 to 30%, B2O3: 15 to 35%, Li2O: 0 (inclusive) to 10%, Na2O: 0 (inclusive) to 5%, and K2O: 0 (inclusive) to 5% provided that Li2O+Na2O+K2O: 0 to 15%; MgO: 0 (inclusive) to 25%, CaO: 0 (inclusive) to 25%, BaO: 0 (inclusive) to 25%, SrO: 0 (inclusive) to 25%, and ZnO: 18 to 55% provided that MgO+CaO+BaO+SrO+ZnO: 18 to 55%; and La2O3: 5 to 20%. This optical glass does not substantially contain poisonous materials such as lead and arsenic. This optical glass has given optical constants, has a low Tg, a low TL and a good devitrification resistance, and is suitable for press molding.

Abstract: A push switch includes an operating body, a case, a return spring, and a light source. The operating body is controlled by push operation, includes a through-hole in the center and a display portion at the upper edge of the through-hole, and supports a movable contact unit. The case has the insert hole on a bottom surface opposing the through-hole and fixed contact units on an inner surface of the sidewall. The movable contact unit comes into contact with fixed contact units. The return spring is interposed between the case and the operating body and returns the position of the operating body in the reverse direction of the push operation. The light source stored in the insert hole and the through-hole. The through-hole is formed linearly in the direction the operating body is moved during the push operation so that the light source does not interfere with the operating body.

Abstract: A switch device capable of increasing the operation speed at the time of reversion of contacts, thereby suppressing generation of arcs, and capable of increasing the contact pressure between the contacts, thereby reducing the bouncing of the contacts. A first rotor plate and a second rotor plate are operatively coupled with each other with a torsion coil spring and when the first rotor plate is rotated, a reversing force from the torsion coil spring causes the contact driving part to engage with or disengage from the contact plate.

Abstract: A push switch includes an operating body, a case, a return spring, and a light source. The operating body is controlled by push operation, includes a through-hole in the center and a display portion at the upper edge of the through-hole, and supports a movable contact unit. The case has the insert hole on a bottom surface opposing the through-hole and fixed contact units on an inner surface of the sidewall. The movable contact unit comes into contact with fixed contact units. The return spring is interposed between the case and the operating body and returns the position of the operating body in the reverse direction of the push operation. The light source stored in the insert hole and the through-hole. The through-hole is formed linearly in the direction the operating body is moved during the push operation so that the light source does not interfere with the operating body.

Abstract: Molten glass is press-molded by a metallic die in which a cylindrical body is provided in a vertically standing manner at a central part of a bottom surface of a bottomed hole and a molding surface corresponding to a chamfering shape of an outer peripheral edge surface of a glass substrate is consecutively formed in an inner peripheral wall, and a glass substrate precursor provided with the chamfering shape axially consecutive on an outer peripheral surface thereof and a through hole formed at a central part thereof is thereby formed. The glass substrate precursor is cut perpendicular to an axial direction to be separated into respective glass substrates. Next, the respective glass substrates are subjected to a lapping process and a polishing process, if necessary, to produce a glass substrate as a final product. According to the manufacturing method, a glass substrate for information recording medium whose inner and outer peripheral edge surfaces are chamfered can be manufactured with an improved efficiency.

Abstract: There is provided a switch device capable of increasing the operation speed at the time of reversion of contacts, thereby suppressing generation of arcs, and capable of increasing the contact pressure between the contacts, thereby reducing the bouncing of the contacts. When an actuating shaft 16 is actuated, a bimetal piece 13 causes a first rotor plate 17 to rotate through a second rotor plate 18 with the rotation of a rotating shaft 18, to turn on a pair of contact plates 2 and 3. When a heater 14 is heated to a predetermined temperature, the bimetal piece 17 is displaced to cause the first rotor plate 17 to rotate through the second rotor plate 18 to turn off the pair of turned-on contact plates 2 and 3.

Abstract: The optical waveguide includes an optical waveguide layer, and a filter element including an ultraviolet curing liquid crystal layer disposed in a position which divides the optical waveguide layer in a waveguide direction. The ultraviolet curing liquid crystal layer having a twisted structure in which a helical pitch after curing reflects light of a predetermined wavelength.

Abstract: A glass substrate for use as the substrate of an information recording medium such as a magnetic disk, magneto-optical disk, DVD, or MD or of an optical communication device, and a glass composition for making such a glass substrate, contains the following glass ingredients: 45 to 75% by weight of SiO2; 1 to 20% by weight of Al2O3; 0 to 8% by weight, zero inclusive, of B2O3; SiO2+Al2O3+B2O3 accounting for 60 to 90% by weight; a total of 0 to 20% by weight, zero inclusive, of R2O compounds, where R=Li, Na, and K; and a total of 0 to 15% by weight, zero inclusive, of TiO2+ZrO2+LnxOy, where LnxOy represents at least one compound selected from the group consisting of lanthanoid metal oxides, Y2O3, Nb2O5, and Ta2O5.

Abstract: The present invention relates to a glass substrate of which the outer periphery portion is unprocessed. The present invention also relates to a manufacturing method for a glass substrate of which the outer periphery portion is unprocessed, characterized in that a first lapping process, a second lapping process, a polishing process and a washing process are carried out after a press molding process is carried out so as to compress glass between an upper mold and a lower mold without regulating the edge surface of the outer periphery portion of the glass and, then, a crystallization process or an annealing process is carried out.

Abstract: A glass substrate for use as the substrate of an information recording medium such as a magnetic disk, magneto-optical disk, DVD, or MD or of an optical communication device, and a glass composition for making such a glass substrate, contains the following glass ingredients: 45 to 75% by weight of SiO2; 1 to 20% by weight of Al2O3; 0 to 15% by weight, zero inclusive, of B2O3; SiO2+Al2O3+B2O3 accounting for 65 to 90% by weight; a total of 7 to 20% by weight of R2O compounds, where R=Li, Na, and K; and a total of 0 to 12% by weight, zero inclusive, of R′O compounds, where R′=Mg, Ca, Sr, Ba, and Zn. Moreover, the following conditions are fulfilled: B2O3=0% by weight, or Al2O3/B2O3≧1.0; and (SiO2+Al2O3+B2O3)/(the total of R2O compounds+the total of R2O compounds)≧3.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.

Abstract: A polished glass disk medium substrate suitable for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. The substrate containing glass forming raw materials may be formed so as to have a Young's modulus of 110 or higher.