Provided is a method that can manufacture a glass material having excellent homogeneity by containerless levitation. A block (12) of glass raw material is heated and melted by irradiation with a plurality of laser beams with the block (12) of glass raw material held levitated, thus obtaining a molten glass, and the molten glass is then cooled to obtain a glass material. The plurality of laser beams include a first laser beam (13A) and a second laser beam (13B). A size () of an angle formed between the first laser beam (13A) and the second laser beam (13B) is 0 or more but less than 180. A center (C1) of a spot (S1) of the first laser beam (13A) on the surface of the block (12) of glass raw material and a center (C2) of a spot (S2) of the second laser beam (13B) on the surface of the block 12 of glass raw material are different from each other.

A molten glass gob delivery guide is disclosed that includes a chute having an upstream end, a downstream end, a rear surface, and a front surface. The chute is comprised of a gas permeable material and is able to accommodate the permeable flow of a permeating gas from the rear surface to the front surface of the chute. When a molten glass gob is conveyed along the chute over the front surface of the chute, the permeating gas flows permeably through the chute to establish a gas cushion that displaces the glass gob away from the front surface of the chute, which creates a thermal break between the glass gob and the chute. In this way, heat loss from the molten glass gob to the chute can be minimized as the gob travels along the chute.

A method for manufacturing an optical element, the method including: heating an optical element material by suspending it in a gas; supplying the heated optical element material from a direction which intersects a central axis interconnecting centers of a first mold and a second mold to a space between molds in a non-contact state, the space between molds being a space between the first mold and the second mold; pressurizing the optical element material supplied to the space between molds by the first mold and the second mold; and cooling the pressurized optical element material.

A method for manufacturing an optical element, the method including: heating an optical element material by suspending it in a gas; supplying the heated optical element material from a direction which intersects a central axis interconnecting centers of a first mold and a second mold to a space between molds in a non-contact state, the space between molds being a space between the first mold and the second mold; pressurizing the optical element material supplied to the space between molds by the first mold and the second mold; and cooling the pressurized optical element material.

A process using a three-piece mold for making a three-dimensionally shaped glass article having a flat area and a curved/bend area is disclosed. The process includes placing a glass sheet on a mold having a shaping surface with a desired surface profile for the shaped glass article including a flat area and a bend area, moving a flat area plunger toward the glass sheet to compress the glass sheet, heating a portion of the glass sheet corresponding to an area above the bend area of the mold to a temperature above a forming temperature, and moving a bend area plunger toward the heated glass sheet to compress the heated glass sheet. A temperature of the glass sheet in the area above the bend area of the mold is higher than a temperature of the glass sheet in the area above the flat area of the mold when compressing the heated glass sheet with the bend area plunger.

A process using a three-piece mold for making a three-dimensionally shaped glass article having a flat area and a curved/bend area is disclosed. The process includes placing a glass sheet on a mold having a shaping surface with a desired surface profile for the shaped glass article including a flat area and a bend area, moving a flat area plunger toward the glass sheet to compress the glass sheet, heating a portion of the glass sheet corresponding to an area above the bend area of the mold to a temperature above a forming temperature, and moving a bend area plunger toward the heated glass sheet to compress the heated glass sheet. A temperature of the glass sheet in the area above the bend area of the mold is higher than a temperature of the glass sheet in the area above the flat area of the mold when compressing the heated glass sheet with the bend area plunger.

A molten glass delivery funnel includes a gas permeable conduit. The gas permeable conduit is comprised of a gas permeable material such that a centering gas can flow permeably through the conduit and into an interior passage of the conduit. The permeable flow of the centering gas is able to displace a molten glass charge falling through the conduit away from an interior surface of the conduit and to create a gas cushion between the glass charge and the conduit.

An ionically conductive glass (or glassy) monolithic preform having a certain shape, size, and dimension may be made from a monolithic precursor material (e.g., an ingot or boule of ion conductive glass), generally of a different shape and size.

An optical glass includes, in terms of mol % of cations, a total amount of La.sup.3+, Y.sup.3+, and Gd.sup.3+ components falling within a range of from 5% to 65% and a total amount of Zr.sup.4+, Hf.sup.4+, and Ta.sup.5+ components falling within a range of from 5% to 65%, and a relationship expressed in Expression (1) given below is satisfied. (La.sup.3++Y.sup.3++Gd.sup.3+)(Zr.sup.4++Hf.sup.4++Ta.sup.5+)400(%).sup.2.