Ohara, Inc.

Junko Suzuki

Masahiro Onozawa

Michiko Ogino

There is provided an optical glass with a high refractive index and a low dispersion having a refractive index (nd) of not less than 1.75 and an Abbe's number (&#x3bd;d) of not less than 35 where the image formation characteristic is hardly affected by changes in temperature of the using environment. SiO, BOand LaOare contained as essential components and the ratio of the constituting components are adjusted whereby an optical glass in which a product of &#x3b1; and &#x3b2; where &#x3b1; is an average linear expansion coefficient at &#x2212;30 to +70&#xb0; C. and &#x3b2; is an optical elasticity constant at the wavelength of 546.1 nm is not more than 130&#xd7;10&#xb0; C.&#xd7;nm&#xd7;cm&#xd7;Pais able to be achieved.

Optical glass

An optical glass having a refractive index (nd) within a range from 141 to 1.47 and an Abbe number (&#x3bd;d) within a range from 90 to 100 comprises in mass % on element basis: and comprises, as an essential component, one or more elements selected from the group consisting of Ca, Sr and Ba. In this optical glass, the ratio (Si+B+P+Al)/F is within a range from 0.15 to 0.40.

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Sagamihara, Japan

Junko Suzuki