Hoya Corporation

Hoya Glass Works, Ltd.

Other

Tetsuro Izumitani

Yoshiyuki Asahara

Toshiharu Yamashita

Shinichiro Hirota

Hidemi Tajima

Niro Tarumi

Takeyuki Sawamoto

Kishio Sugawara

Kenji Nakagawa

Kiyotaka Miura

Chiemi Hata

Michimasa Matsukawa

Hiroyuki Sakai

Yuji Nakajima

Isao Masuda

Sho Amano

Hisayoshi Toratani

Shigeo Komiya

Shin Nakayama

Shigeaki Omi

Hiroji Sagara

Kouichi Hara

Seiichi Shingaki

Kunio Takeuchi

Minoru Tokida

Helmuth E Meissner

Yoshijuki Asahara

Yasuo Fukuoka

Michitaka Tsutome

Michitaka Tsuru

Eimei Miyade

Iwao Kinjo

Toshi Takajoh

Koichi Ishida

Teiichi Suzuki

Optical glass of cubic, spherical or polygonal shape is fire polished on a graphite or Cr.sub.2 O.sub.3, concave surface with a surface roughness of 100 Angstroms or less. The optical glass having a surface roughness of 400 Angstroms or less is placed on the concave surface and fire polished by heating the optical glass between the yield point and softening point of the glass in a reducing atmosphere if the concave surface is made of graphite. A Cr.sub.2 O.sub.3 concave surface is required for Pb.sup.+2 containing glasses. The molded preform obtained has a surface roughness of 100 Angstroms or less.

Method for fabricating preforms for molded lenses

A process of removing platinum inclusions from laser glass is disclosed, comprising bubbling the laser glass in a molten state with PCl.sub.3 or POCl.sub.3.

Process of removing platinum inclusions from laser glass

A contact lens is made hydrophilic by contacting the lens with a treating solution containing a hydrophilic monomer, at least one photosensitizer selected from aromatic ketones or quinones, and a sovlent, and thereafter irradiating the contact lens with ultraviolet light.

Method for making contact lens hydrophilic

A single mode laser glass fiber showing excellent laser oscillation characteristics even at a short fiber length can be efficiently obtained using a phosphate laser glass with excellent laser characteristics.

Single mode phosphate laser glass fiber

A silicophosphate laser glass having a composition comprising, in % by mole,

Silicophosphate laser glass

A process of surface-treating a laser glass is disclosed which comprises coating a specific sol solution obtained by hydrolysis and partial polycondensation of a mixture containing a metal alcoholate on the glass surface and heating the coated glass to form a glassy coating, wherein the glass surface may be treated, prior to the coating, with an alkali aqueous solution and with an aqueous solution of phosphoric acid in sequence, or the coating and the heating may repeated to form a double- or multilayer of the same or different kind of glassy coatings. The thus treated laser glass has increased thermal shock resistance and water resistance.

Process of surface treating laser glass

A high quality fluorophosphate laser glass free from bubbles, inclusions and coloring can be obtained by melting a fluorophosphate glass having a total oxide content of 5 to 30% in terms of cationic %, in a carbon container under a non-oxygen gas atmosphere.

Method for melting fluorophosphate glass

According to a method of molding a glass body, a glass preform is placed between upper and lower molds of a mold assembly. The mold assembly is then heated to a predetermined heating temperature falling within a heating temperature range corresponding to a glass viscosity range of the glass preform of 10.sup.8 to 10.sup.10.5 poise. A pressure high enough to mold the glass preform is applied between the upper and lower molds when the glass preform is at the predetermined heating temperature, so that an unfinished glass molded body is formed. The pressure is released, and the unfinished glass molded body and the mold assembly are gradually cooled to a temperature within a glass viscosity range of 10.sup.11.5 to 10.sup.14 poise while the unfinished glass molded body is held in the mold assembly. A glass molded body is then released from the mold assembly.

Method of molding glass body

A process for producing a transparent glass product having a refractive index gradient by the molecular stuffing method is described. A thallium compound is used as a dopant and, after a concentration gradient of the thallium dopant is formed, the porous glass product is heated up to the temperature region of 350.degree. to 550.degree. C. at a temperature-rising rate of 25.degree. to 150.degree. C./hour in a reducing gas atmosphere and then heat treated above 550.degree. C. in an inert gas atmosphere to collapse micropores in the porous glass product, thereby obtaining a glass product having a refractive index gradient which is transparent and free of light-scattering and coloration. The glass product is suitable as materials (preforms) for optical fibers or materials for rod-shaped lenses, particularly rod-shaped microlenses for microlens arrays and microlenses for coupling an optical fiber and a light source.

Process for producing transparent glass product having refractive index

A fluoride glass comprising AlF.sub.3, ZrF.sub.4 and/or HfF.sub.4, and at least one compound selected from CaF.sub.2, SrF.sub.2 and BaF.sub.2, and a fluoride glass comprising these components and at least one additional component selected from MgF.sub.2, YF.sub.3, NaF and other like compounds have the advantages that there hardly occurs crystallization in the production thereof, and that they are excellent in chemical durability, high in surface hardness, so that they can ideally serve as glass to be used for low loss optical fiber, infrared optical fiber for thermometer, infrared laser window, etc.

Fluoride glass

Optical lenses high in configurational accuracy with smooth surfaces are press molded in a carefully finished, polished and properly dimensioned mold preferably in a non-oxidizing atmosphere. The molding operation includes placing a quantity of glass having an internal viscosity of at least about 10.sup.6 poises in such a mold while maintaining the mold at a temperature at least equal to the glass transition temperature and thereafter passing the glass into a lens of predetermined configuration at a pressure of at least 100 Kg/cm.sup.2. Performing procedures are also disclosed.

Method of molding optical lenses

A method of manufacturing a pressed lens based upon the discovery that a high quality lens may be molded despite the fact that the lens is cooled without pressure being applied to the mold. A lens preform is inserted into the pressing mold and pressure is applied to the mold while the preform and mold are at a temperature corresponding to a viscosity of the preform of 10.sup.8.5 -10.sup.10.5 poise. The pressure is then removed while the resulting molding remains in contact with the mold and the preform and mold are then cooled. When the temperature of the preform has fallen to a value corresponding to a viscosity of the molding of not smaller than 10.sup.11.5, the molding may be removed from the pressing mold. The preform may be inserted into the mold and then the preform and the mold may be heated prior to pressing, or alternately, the preform and the mold may be heated separately and the preform may be transferred into the mold for pressing. In the latter case, the preform is held by a holder which remains in the mold during pressing. To increase the lens production rate, the lens and the mold may be cooled at a location different from the location at which pressing occurred.

Method of manufacturing pressed lenses

A high-hydration contact lens having a high strength is disclosed which is made of a copolymer composed of (i) 40 to 90 wt. % of N,N-dimethyl acrylamide, (ii) 5 to 50 wt. % of a hydrophobic monomer, (iii) 0.1 to 10 wt. % of an unsaturated carboxylic acid having one ethylenically unsaturated bond, and (iv) 0.01 to 5.0 wt. % of a crosslinking agent, wherein the hydrophobic monomer is selected from the group consisting of phenyl acrylates, benzyl acrylates, phenyl methacrylates, benzyl methacrylates, alkyl acrylates, alkyl methacrylates, cyclohexyl acrylates and cyclohexyl methacrylates, and the crosslinking agent is selected from those represented by formula (I), (II), or (III) ##STR1## wherein X represents a hydrogen atom or a methyl group, a is an integer of 2 to 23, and b and c each is an integer of 2 to 14.

High-hydration contact lens

A method of optical pumping of an erbium laser and an apparatus therefor with an erbium laser medium, a light source for side-pumping the erbium laser medium, a neodymium laser medium for emitting a laser beam upon optical pumping by the light source, and an optical system for directing the laser beam from the neodymium laser medium to the erbium laser medium for side-pumping the erbium laser medium. Thus the erbium laser medium is side-pumped by the light source and also end-pumped by the laser beam emitted from the neodymium laser medium side-pumped at the same time by the light source in the same lamp house. Therefore the erbium laser can be optically pumped with high efficiency and offer a low threshold value.

Method of optical pumping of erbium-doped laser material and apparatus

A glass melting apparatus is provided with a melting tank, a refining tank and a working tank wherein the melting tank is operatively connected to the refining tank by a temperature control connecting pipe for intermittently supplying molten glass from the melting tank to the refining tank in dependence upon the level of molten glass within the refining tank. The melting tank may be comprised of a single tank which is considerably larger than the refining tank and the working tank or may be comprised of a plurality of individual, movable tanks each of which may be brought into operative association with the refining tank for melting raw material in the melting tank, the molten glass being supplied to the refining tank and continuously treated and supplied to the working tank.

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Hino, Japan

Tetsuro Izumitani