Hoya Corporation

Nissan Chemical Industries Limited

Tetsunori Matsukura

Yoshitane Watanabe

Keitaro Suzuki

Eiichi Yajima

An optional element having a cured coating film on optical base material wherein the cured coating film is prepared with a coating composition comprising an organosilicon compound and modified stannic oxide-zirconium oxide composite colloidal particles which are obtained by partially or fully coating the surface of stannic oxide-zirconium oxide composite colloidal particles with tungstic oxide-stannic oxide composite colloidal particles. The formed cured coating film is excellent in hot water resistance, and light-resistance and weathering resistance are not impaired even when the antireflection film made by vepor deposition of inorganic oxides is applied on the cured coating film.

Optical elements having cured coating film

A stable sol which comprises colloidal particles of modified stannic oxide-zirconium oxide composite having a particle size of from 4.5 to 60 nm, said colloidal particles consisting essentially of, as nuclei, colloidal particles of stannic oxide-zirconium oxide composite having a particle size of from 4 to 50 nm and having a structure in which colloidal particles of stannic oxide and colloidal particles of zirconium oxide are bonded to each other in a ratio, by weight of these oxides, of from 0.02 to 1.0 as ZrO.sub.2 /SnO.sub.2, and, as a coating on the surface of the nuclei, colloidal particles of tungstic oxide-stannic oxide composite having a particles size of from 2 to 7 nm and a WO.sub.3 /SnO.sub.2 weight ratio of from 0.5 to 100, and which has a total content of metal oxides of from 2 to 50 wt %.

Modified stannic oxide-zirconium oxide composite sol and process for

A coating composition comprising an organosilicon compound and modified stannic oxide - zirconium oxide composite colloidal particles which are obtained by partially or fully coating the surface of stannic oxide - zirconium oxide composite colloidal particles with tungstic oxide - stannic oxide composite colloidal particles. The formed cured coating film is excellent in hot water resistance, and light-resistance and weathering resistance are not impaired even when the antireflection film made by vepor deposition of inorganic oxides is applied on the cured coating film.

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Sodegaura, Japan

Tetsunori Matsukura