Abstract: The present invention relates to a glass in which: the glass is a crystallized glass; the glass has a difference log ??log ?0 (dPa·s) between a logarithm log ? (dPa·s) of bulk viscosity ? (dPa·s) and a logarithm log ?0 (dPa·s) of local viscosity ?0 (dPa·s) of larger than 0 and 1.8 or smaller, in a temperature range in which the logarithm log ?0 (dPa·s) of the bulk viscosity ? (dPa·s) is 11.4 or larger and 12.7 or smaller.

Abstract: A glass substrate molding method includes: preparing a rotatable or wheelable molding die having a die surface and contacting the die surface with one of a pair of principal surfaces of a glass substrate made of a glass material containing an alkali metal oxide, the die having conductivity; keeping the one of principal surfaces contacted with the die surface at a temperature over 100° C. and equal to or lower than Tg+50° C.; applying direct-current voltage to the substrate to be higher voltage on the contacted one of principal surfaces than voltage on an opposite surface of the contacted one of principal surfaces; and rotating or wheeling the die and simultaneously moving the die or the substrate in a direction parallel to the contacted one of principal surfaces in conformity with rotation or wheeling speed of the die, to mold the contacted one of principal surfaces of the substrate.

Abstract: 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.

Abstract: A glass substrate molding method includes: preparing a rotatable or wheelable molding die having a die surface and contacting the die surface with one of a pair of principal surfaces of a glass substrate made of a glass material containing an alkali metal oxide, the die having conductivity; keeping the one of principal surfaces contacted with the die surface at a temperature over 100° C. and equal to or lower than Tg+50° C.; applying direct-current voltage to the substrate to be higher voltage on the contacted one of principal surfaces than voltage on an opposite surface of the contacted one of principal surfaces; and rotating or wheeling the die and simultaneously moving the die or the substrate in a direction parallel to the contacted one of principal surfaces in conformity with rotation or wheeling speed of the die, to mold the contacted one of principal surfaces of the substrate.

Abstract: 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.

Abstract: A method capable of forming a sufficiently thick low alkali concentration region without heating glass to a high temperature and even in an atmosphere which is not an atmosphere of plasma formation gas such as helium and argon, is provided. A glass substrate having a pair of main surfaces and being made of glass containing an alkali oxide in its composition, is disposed between a first electrode and a second electrode so that one main surface is separated from the first electrode and the other main surface is brought into contact with the second electrode, and a corona discharge is generated by applying a direct-current voltage to the first electrode as a positive electrode and the second electrode as a negative electrode, in a positive-electrode-side surface layer portion of the glass substrate, at least one positive ion including an alkali ion migrate toward the negative-electrode-side.

Abstract: A glass melting apparatus is provided with a clarifier tank adapted to clarify melted glass which is obtained by melting a raw glass material. Partition walls are provided in the clarifier tank so as to define a meandering flow passage through which the melted glass flows. A bottom of the clarifier tank is sloped so that the flow passage ascends from an upstream side thereof to a downstream side thereof.

Abstract: A method for producing an optical element by bonding a plurality of optical member with an adhesive, which is capable of providing the optical element with sufficient optical performance and with such a sufficient bonding strength to prevent separation from being made at bonded portions, and of making alignment easily, is provided. The method for producing an optical element, which comprises bonding two or more optical members with an adhesive, is characterized in that at least one of confronting bonded surfaces on at least one pair of contact surfaces of the optical members is subjected to dry cleaning in such a state that at least a surface connecting to a bonded surface is masked, followed by applying a liquid adhesive as the adhesive on the cleaned surface and curing the liquid adhesive to bond the optical members.