The method for manufacturing a plate glass is a method for manufacturing the plate glass having sides of at least 30 cm or more and a surface thereof on which a predetermined shape is formed. In the manufacturing method, the flat plate glass is heated to a temperature which is lower than a softening point and at which the heated flat plate glass is deformable by being pressed at a predetermined pressure or higher, the heated flat glass, which has been molded by pressing the flat plate glass with a die having a die structure for forming the predetermined shape, is cooled to the strain point while being held with the die. Further, in the manufacturing method, the pressing is performed with the die having a coefficient of thermal expansion whose difference from that of the plate glass is 2.0×10.sup.−6/K or less.

The disclosure concerns to a process for manufacturing an optical element from glass, wherein a blank of glass is tempered, for example in such a way that the blank is cooler in its interior than on its exterior, wherein the tempered blank between a first mold and a second mold, which are moved towards one another to form a closed cavity, is press-molded, for example on both sides, to form the optical element, wherein the first mold and/or the second mold comprises an escape cavity slide which is compressed by the formation of a closed cavity by means of the first mold and the second mold as a function of the volume of the blank, so that, during press-molding, an additional edge which is dependent on the volume of the blank is formed with the optical element.

A mold for molding a glass product is provided. The mold includes a first pressing mold having a first surface and a second pressing mold having a second surface. The first surface is located on a side of the first pressing mold. The second surface is located on a side of the second pressing mold. The first pressing mold includes a first molding portion formed by bending from the first surface. The second pressing mold includes a second molding portion and is formed by bending from the second surface. The first pressing mold further includes a plurality of first hydraulic resistance portions that are spaced apart from each other, close to an outer edge of the first pressing mold, and protrude from the first surface. The disclosure achieves a technical effect of increasing a peripheral molding pressure of the mold and improving yield of products.

The current disclosure relates to highly homogeneous glass sputter targets with a large aspect ratio and a high relative density. The glass sputter targets have properties that are desirable for forming thin films by physical vapor deposition processes such as sputtering.

A curved glass and a preparation method is provided. The preparation method for curved glass includes: melting a glass batch into a glass liquid, and clearing the glass liquid; introducing the cleared glass liquid into a mold cavity with a preset shape, and forming, by using a compression molding process, a glass product with a shape corresponding to that of the curved glass, where a size of the glass product is greater than a size of the curved glass; annealing the molded glass product; and processing the annealed glass product into the curved glass based on the shape and the size of the curved glass.

A method for manufacturing an optical element includes heating an optical material up to a first temperature that is higher than a transition point, pressurizing the optical material using a first mold and a second mold that are situated opposite to each other across the optical material, first cooling the optical material down to a second temperature that is higher than a strain point and lower than the first temperature while pressurizing the optical material with a predetermined load using the first mold and the second mold, releasing the predetermined load at a set speed that is higher than or equal to a speed obtained in advance, at which an elastic deformation occurs preferentially over a viscous deformation in the optical material upon releasing a load, and second cooling the optical material down to a third temperature that is lower than the second temperature.

A method of controlling an optical element manufacturing apparatus includes: heating a cavity formed of a pair of upper and lower dies to a first temperature where an optical element material softens and becomes formable by the pair of dies; heating the cavity to a second temperature where the optical element material is deformed due to a weight of the optical element material in a state of not being in contact with the upper die, the second temperature being higher than the first temperature; and pressing the pair of dies for transfer of forming surfaces of the pair of dies onto the optical element material, the forming surfaces being outside a range where a forming surface of a die has been transferred by the deformation due to the weight in the state where the optical element material is not in contact with the upper die at the second temperature.

The present invention provides a manufacturing method of glass formed body and a forming die which make it possible to sufficiently fill a glass material in the forming die and manufacture a glass formed body having a desired shape. The manufacturing method of glass formed body includes: heating a plate-shaped glass material; pressing the heated plate-shaped glass material by the forming die; and cooling and solidifying the glass material transferred shapes of forming surfaces of the forming die by the pressing, wherein planar-view contour shapes of the forming surfaces are non-circular, a gap formed by the forming surfaces is formed so as to become wider from an inner side toward an outer side of the forming surfaces, and pressure distribution occurring in the plate-shaped glass material in the pressing is uniform in a contour region of each of the forming surfaces.

A method for manufacturing an optical element includes heating an optical material up to a first temperature that is higher than a transition point, pressurizing the optical material using a first mold and a second mold that are situated opposite to each other across the optical material, first cooling the optical material down to a second temperature that is higher than a strain point and lower than the first temperature while pressurizing the optical material with a predetermined load using the first mold and the second mold, releasing the predetermined load at a set speed that is higher than or equal to a speed obtained in advance, at which an elastic deformation occurs preferentially over a viscous deformation in the optical material upon releasing a load, and second cooling the optical material down to a third temperature that is lower than the second temperature.

A method for manufacturing an optical element includes pressing a phosphate-based glass containing Bi.sub.2O.sub.3 in a proportion of 10 mass % or higher and 30 mass % or lower with a hot mold; and then cooling the same, in which pressure equal to or higher than the critical pressure of oxygen and equal to or lower than a strength of glass is continuously applied to the glass from the time of bringing the glass into contact with the pressing surface of the mold at a glass viscosity of log =9 [dPa.Math.sec] or higher and 10 [dPa.Math.sec] or lower until the glass viscosity log increases to 12 [dPa.Math.sec] by cooling.