Canon Kabushiki Kaisha

Masayuki Tomida

Takeshi Nomura

Kiyoshi Yamamoto

Masashi Mashige

Masaki Omori

Hiroe Tanaka

Shizuo Maruyama

A manufacturing method for an optical glass element having a refractive index equal to a design value after press-molding. A glass material of specified composition is melted and press-molded while it is in the molten state. The refractive index of the glass material is calculated by substracting a change in the refractive index of the glass material resulting from the press-molding from a required refractive index for a molded glass element.

Method of manufacturing optical glass element

A method of molding an optical element numerically analyzes the thermal stress produced on a molded optical element product within a mold in a visco-elastic temperature range or elastic temperature range of an optical element material in a cooling step of the molding process on the basis of a visco-elastic characteristic of the optical element material. A correction for the molding face of the mold is made on the basis of the value obtained by the numerical analysis so that any error between the optical functional face of optical element molded by the mold at room temperature and the optical functional face set on design may fall within a tolerance, thereby determining the molding face adapted to the shape of the optical functional face set on design.

Press-molded optical element

A method of molding an optical element numerically analyzes the thermal stress produced on a molded optical element product within a mold in a visco-elastic temperature range or elastic temperature range of an optical element material in a cooling step of the molding process is on the basis of a visco-elastic characteristic of the optical element material. A correction for the molding face of the mold is made on the basis of the value obtained by the numerical analysis so that any error between the optical functional face of optical element molded by the mold at room temperature and the optical functional face set on design may fall within a tolerance, thereby determining the molding face adapted to the shape of the optical functional face set on design.

Mold for optical element and a method of molding optical element

An improved method of forming an optical element, wherein heated upper and lower molds are used in conjunction with radiation heating glass material placed in an optical forming surface of the lower mold. The molds are heated to a necessary temperature, then the glass material is heated by exposure to heat by radiation. The glass blank then is pressed between the upper and lower molds to transfer the optical forming surfaces of each mold to the glass material, and define the optically functional surfaces of an optical element.

Growing community of inventors

Yokohama, Japan

Masayuki Tomida