Nippon Sheet Glass Company, Limited

Noboru Akazawa

Shigeo Kittaka

Minoru Toyama

Yoshihiro Matsuno

Hiroshi Koshi

Atsunori Matsuda

Shinya Katayama

Yoshikazu Kaite

Yukio Noguchi

Toshio Tsuno

Manabu Takami

Masakiyo Tachibana

The optical parts according to the invention have a feature of having smoothly coated surfaces for incident and emergent lights covered thereover with a light transmitting solid coating layer, and can be manufactured by a simplified process at least without needing polishing, together with the advantages of being weatherproof in atmosphere of high temperature and high humidity and antiozonant.

Optical part

This invention relates to a method of performing an ion exchange of optical glass to produce an axial gradient index material having a good linear distributiion by bringing a glass body containing a monovalent cation component into contact with a medium containing a monovalent cation component and exchanging these cation components under a predetermined condition.

Method of performing an ion exchange of optical glass

A cesium-containing optical glass comprising, by weight, 32-56% of SiO.sub.2, 6-25% of K.sub.2 O, 6-32% of Cs.sub.2 O, 0-30% of BaO, 0-2.5% of MgO, 5-34% of ZnO, 0-3% of ZrO.sub.2 and 0-5% of SnO.sub.2, provided that the total proportion of BaO, MgO and ZnO is 8-40% and the total proportion of ZrO.sub.2 and SnO.sub.2 is 0.2-6%. When this cesium-containing optical glass is treated in a molten bath containing potassium nitrate, the cesium ion in the glass is easily exchanged with a potassium ion and therefore, the cesium ion concentration gradually decreases radially outwardly from the central axis and the potassium ion concentration gradually increases in that direction. Thus, there is obtained a light converge-type lens in which the refractive index gradually decreases in the same direction.

Cesium-containing optical glass

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Kanagawa, Japan

Noboru Akazawa