Abstract: An object of the present invention is to provide a press-forming method for glass capable of uniformly heating press dies and a preform and preventing oxidation of the press dies. According to the press-forming method for glass of the present invention, a preform is placed between a pair of press dies in a press-forming chamber and the preform and the press dies are heated in an inert gas atmosphere. After the temperature of the press dies reaches a predetermined value, evacuation of the press-forming chamber is initiated. After the pressure of the press-forming chamber reaches a predetermined value and the temperature of the press-forming chamber are stabilized at a second predetermined value, the preform is press-formed. Preferably, an exhaust rate for evacuating the chamber is limited to a predetermined value or less.

Abstract: The forming apparatus has top and bottom die assemblies which form a heated silica glass material by press forming. These top and bottom die assemblies include, respectively, mold dies, which are made of isotropic carbon, and core molds, which are made of vitrified carbon. The heating and pressing time of a silica glass element, which requires a high forming temperature, is shortened by pinching the silica glass material between top and bottom core molds by controlling a torque so as to produce a close contact condition which permits heat transfer from the top and bottom core molds to the silica glass material between the top and bottom core molds.

Abstract: Provided is an apparatus for forming glass elements, which includes top and bottom die assemblies, each of the die assemblies comprising a core mold, a mold die which supports the core mold, and a die plate, and a glass material being interposed between the top and bottom core molds, a first fastening member, which fastens the mold die and bottom die plate of the bottom die assembly together, a second fastening member, which fastens the die plate of the bottom die assembly and the heat insulating cylinder together, a third fastening member, which fastens the mold die and die plate of the top die assembly together, and a fourth fastening member, which fastens the die plate of the top die assembly and the heat insulating cylinder together. Each of the first to fourth fastening members is made of a material selected from the group consisting of carbon and molybdenum.

Abstract: An optical element molding apparatus according to the present invention comprises a sealed molding chamber, a pair of molds arranged in the molding chamber, and a vacuum-pump means which vacuum-pumps an inside of the molding chamber. The vacuum-pump means includes a twist-groove-vacuum pump having a twisted groove on a surface of a rotor which is rotated at a high speed, and a rotary pump. The pair of molds are adapted to mold an optical element by press-molding an optical element material which is heated to a temperature higher than a transition point.

Abstract: An object of the present invention is to provide a press-forming method for glass capable of uniformly heating press dies and a preform and preventing oxidation of the press dies. According to the press-forming method for glass of the present invention, a preform is placed between a pair of press dies in a press-forming chamber and the preform and the press dies are heated in an inert gas atmosphere. After the temperature of the press dies reaches a predetermined value, evacuation of the press-forming chamber is initiated. After the pressure of the press-forming chamber reaches a predetermined value and the temperature of the press-forming chamber are stabilized at a second predetermined value, the preform is press-formed. Preferably, an exhaust rate for evacuating the chamber is limited to a predetermined value or less.

Abstract: The forming apparatus has top and bottom die assemblies which form a heated silica glass material by press forming. These top and bottom die assemblies include, respectively, mold dies, which are made of isotropic carbon, and core molds, which are made of vitrified carbon. The heating and pressing time of a silica glass element, which requires a high forming temperature, is shortened by pinching the silica glass material between top and bottom core molds by controlling a torque so as to produce a close contact condition which permits heat transfer from the top and bottom core molds to the silica glass material between the top and bottom core molds.

Abstract: Provided is an apparatus for forming glass elements, which includes top and bottom die assemblies, each of the die assemblies comprising a core mold, a mold die which supports the core mold, and a die plate, and a glass material being interposed between the top and bottom core molds, a first fastening member, which fastens the mold die and bottom die plate of the bottom die assembly together, a second fastening member, which fastens the die plate of the bottom die assembly and the heat insulating cylinder together, a third fastening member, which fastens the mold die and die plate of the top die assembly together, and a fourth fastening member, which fastens the die plate of the top die assembly and the heat insulating cylinder together. Each of the first to fourth fastening members is made of a material selected from the group consisting of carbon and molybdenum.