Lens and process for the production thereof
AssigneeHoya Corporation
InventorsKazutaka Hayashi, Kouichi Satou, Koichiro Shiraishi
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Abstract
A lens formed of a high-refractivity low-dispersion glass and free of fogging and scorching on its optical-function surface, which is obtained by precision press-molding of an optical glass having a refractive index (nd) of over 1.83, an Abbe's number (νd) of 40 or more and a glass transition temperature (Tg) of 640° C. or lower and containing no Li2O and has one form of a meniscus form, a biconcave form or a plano-concave form.
Claims10
A lens formed of an optical glass having a refractive index (nd) of over 1.83, an Abbe's number (νd) of 40 or more and a glass transition temperature (Tg) of 640° C. or lower and containing no Li2O and obtained by precision press-molding and the lens having one form of a meniscus form, a biconcave form or a plano-concave form.
A process for the production of a lens by heating and precision press-molding a glass material, which comprises introducing a glass material formed of an optical glass having a refractive index (nd) of over 1.83, an Abbe's number (νd) of 40 or more and a glass transition temperature (Tg) of 640° C. or lower and containing no Li2O into a press mold and precision press-molding the glass material to produce a lens having one form of a meniscus form, a biconcave form or a plano-concave form.
Dependencies are inferred from the claim text.