Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Sumita Optical Glass, Inc.

Panasonic Corporaton

Shoji Nakamura

Masaaki Sunohara

Makoto Umetani

Hidenao Kataoka

Yoshinari Kashiwagi

Kenji Inoue

Satoru Morimoto

Tadao Shioyama

Takashi Inoue

Kazuhiko Ishimaru

Jun Murata

Toshiaki Takano

Minoru Onoda

Tadayoshi Yonemoto

Takahisa Kondou

Takasi Inoue

Masaki Aoki

Yoshiyuki Shimizu

Hideo Torii

Hideyuki Okinaka

Satoru Yuhaku

Takayuki Kimoto

Kazuaki Takagi

Noriyuki Kawata

Daijirou Yonetani

Chizuo Izumino

An optical glass composition contains, in % by mole, 14.0% or more and 31.0% or less of SiO, 19.0% or more and 40.0% or less of BO, 0% or more and 5.0% or less of LiO, 0% or more and 12.0% or less of ZnO, 0% or more and 12.0% or less of ZrO, 15.0% or more and 26.0% or less of LaO, 22.0% or more and 38.0% or less of LaO+ZrO, 2.0% or more and 5.0% or less of TaOand 4.0% or more and 16.0% or less of GdO, and has nd of 1.83 or higher and 1.87 or lower and &#x3bd;d of 43 or higher and 47 or lower, and a preform and an optical element are formed from the optical glass composition.

Optical glass composition, preform and optical element

An optical glass composition contains, in % by weight, 1.0% or more and 12.0% or less of SiO, 8.0% or more and 18.0% or less of BO, 0% or more and 6.0% or less of ZnO, 1.0% or more and 10.0% or less of ZrO, 25.0% or more and 47.0% or less of LaO, 0% or more and 5.0% or less of RO (here, R is at least one of Li, Na and K), 0% or more and 15.0% or less of NbO, 0% or more and 7.0% or less of TiO, 0% or more and 15.0% or less of TaO, 1.0% or more of NbO+TiO+TaO, 0% or more and 25.5% or less of GdO, 0.5% or more and 15.0% or less of WOand 0.5% or more and 26.0% or less of GdO+WO, and has nd of 1.88 or higher and 1.92 or lower and &#x3bd;d of 33 or higher and 37 or lower, and a preform and an optical element are formed from the optical glass composition.

A die for press-molding glass optical elements comprising (a) a base material having heat resistance and sufficient strength to withstand press-molding of optical glass elements; (b) a film on said base material comprising an alloy film containing B and one metal selected from the group consisting of Ni, Co, and Fe, and one metal selected from the group consisting of Si, Ti, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W, Re, Os, and Ir, to form a cutting layer; and (c) a surface protective layer on top of said cutting layer made of an alloy film comprising at least one metal selected from the group consisting of Pt, Pd, Ir, Rh, Os, Ru, Re, W, and Ta.

Die for press-molding optical elements

A die for press-molding glass optical elements which can press-mold glass optical elements having high melting points and various shapes repeatedly, which includes a base material having high strength on which a cutting layer having heat resistance and free cutting machinability is formed. After cutting the cutting layer into the desired shape with high accuracy, the die is coated with a surface protective film.

Method of manufacturing a die for press-molding optical elements

A method for making optical preforms of optical elements without residual stress or distortion is provided. In this method, an optical material is supplied between upper and lower molds. The upper mold has a plurality of recesses arranged in a predetermined pitch, and each recess corresponds to a first surface shape of the optical element. The lower mold has a plurality of recesses facing the recesses of the upper mold and each recess of the lower mold corresponds to a second surface shape of the optical element. The supplied optical material is pressed between the upper and lower molds to be a set of optical preforms. The set of optical preforms is processed by die punching or tool cutting to separate each optical preform from the set of optical preforms. Each optical preform is used for producing an optical element by further pressing. Alternatively, optical element can be formed directly by the press molding process.

Method for making optical preforms and optical elements by press

A method for press molding preforms to obtain optical articles in which each preform is prepared beforehand to have a diameter larger than that of an optically functional area of the optical article and edges of the preform to be press mold contact with molding surfaces of a pair of molds outside an area of each molding surface corresponding to the optically functional area of the optical article, thereby elongating the lifetime of molds.

Method of molding optical articles

A method and an apparatus for producing an optical element capable of performing a molding temperature control required for a plurality of independent molding blocks in a short period of time, and continuously and simultaneously producing a plurality of different optical elements having a high degree of accuracy at a low cost is provided.

Method and apparatus for producing an optical element using a molding

A method of press-molding glass optical elements by press-molding glass, having a high melting point, at a temperature of 650.degree. C. and higher using a die for press-molding glass optical elements which includes a base material having a heat resistance and sufficient strength to withstand press-molding of optical glass elements, a cutting layer on the base material, and a surface protective layer on the cutting layer. The cutting layer is formed of an alloy film containing P and one metal selected from the group Ni, Co, and Fe, and one metal from the group Si, Ti, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W, Re, Os, and Ir, or an alloy film containing Cu and 20 to 80 atom % of one metal selected from the group Ni, Co, Fe, Si, Ti, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W, Re, Os, and Ir, or an alloy film containing Si and 20 to 80 atom % of one metal selected from the group Ni, Co, Fe, Cu, Ti, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, W, Re, Os, and Ir. The surface protective layer is formed of an alloy film of at least one metal selected from the group Pt, Pd, Ir, Rh, Os, Ru, Re, W, and Ta.

Method of press molding glass optical elements

Optical material, which was already roughly molded, is deposited into a space defined by a top mold, a bottom mold and a drum mold, and is then heated, pressed and molded, thus providing an optical element. By controlling the rate of plastic deformation of the optical material so as to prevent the material from entering clearance sections between the outside diameter of the top mold or of the bottom mold and the inside diameter of the drum mold, an optical element of high precision with no burr nor strain is provided at low cost.

Method and device for manufacturing optical elements

A method of producing a glass blank, comprising the steps of: supplying a desired weight of molten glass material to a bearer heated to a temperature of not more than a softening point of the glass material; performing and cancelling, at a temperature of not less than the softening point, pressing of the glass material supplied to the bearer so as to adjust a thickness of the glass material; and cooling the glass material to a temperature of not more than the softening point.

Method of producing glass blank

A machine is provided for molding an optical element by using a molding block having upper and lower molding dies, a sleeve die and a glass blank combined integrally with each other. The machine includes a chamber which accommodates a heating zone having a plurality of sections for heating the molding block from above and below, a deformation zone for pressing the molding dies and a cooling zone having a plurality of sections for cooling the molding block. The chamber is formed with an inlet and an outlet for the molding block. The sections of the heating zone, the deformation zone and the sections of the cooling zone are provided independently of one another. A transport member is provided for sequentially transporting the molding block through the heating zone, the deformation zone and the cooling zone, and first and second shutters are provided for opening gas supply member is provided for introducing nonoxidizing gas into the chamber.

Method of producing the optical element

Machine for molding optical element

A mold arranged between a pair of heater blocks for molding an optical element comprises a pair of first and second elements each having a molding surface for defining a cavity and an outer surface opposite to the molding surface and in contact with a corresponding heater block, and a ring member for guiding the first and second elements. The rear surface of at least one of the first and second elements has a part which is not in contact with the corresponding heater block. Also, another mold comprises a pair of first and second elements each having a molding surface for defining a cavity and an outer surface opposite to the molding surface, a first ring member for guiding the first and second elements, and a second outer ring member made of a material with a lower thermal conductivity than that of the first ring member. A molding method for optical elements is such that a glass with a viscosity of 10.sup.12 poise or more is fed to a mold with a temperature at or below the glass transition point, heated to a temperature corresponding to the glass viscosity of 10.sup.8 to 10.sup.10 poise and pressed for 3 to 90 seconds. The glass is then cooled at a rate of 1.5.degree. to 2.5.degree. C./sec to a viscosity of 10.sup.10 to 10.sup.11 poise and thereafter at a rate of 0.2.degree. to 1.5.degree. C./sec with the glass pressurized, and removed as an optical element at or below the glass transition point.

Mold for molding optical elements

A mold used for manufacturing optical glass parts by the direct press molding of lumps of raw optical glass. The pressing surface of the mold is made of a material comprising .alpha. type SiC or amorphous SiC or a mixture of both. The pressing surface may be a coated film on a base body of hard alloy or high density carbon.

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Hirakata, Japan

Shoji Nakamura