Patent Number: 6,252,702

Title: Infra red filter

Abstract: A phosphate glass doped with copper in an amount of less than 2% by weight is formed to produce a lens for use on external aircraft lights. The glass attenuates infra red radiation to a degree where it does not pose a danger of temporarily blinding a pilot wearing night vision goggles yet remains visible. The glass has little appreciable effect on light transmission in the visible spectrum. Conveniently, the glass can be formed by slumping at a softening temperature against a mold to produce intricate lens shapes. In addition, the glass is able to withstand conventional toughening processes.

Inventors: Cook; Trevor (Devon, GB), Saunders; Adrian (Somerset, GB)

Assignee: Avimo Limited

International Classification: C03C 3/17 (20060101); C03C 3/12 (20060101); C03C 3/062 (20060101); G02B 5/22 (20060101); G02B 013/14 ()

Expiration Date: 06/26/2018