Improvements in and relating to methods of coating articles with highly reflecting surfaces

Abstract

Abstract 492,928. Coating with metals. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 6, 1937, No. 27086. Convention date, Oct. 6, 1936. [Class 82 (ii)] A reflecting surface is formed on glass, metal, &c. surfaces by vaporization of a coating metal such as aluminium, iron, nickel, chromium, copper, magnesium, or alloys thereof such as aluminium-magnesium alloy, in a vacuum of 5-10 microns, and subsequently heating the coated article under open air conditions to increase the adherence of the coating. Glass coated with aluminium is heated to 400-600‹ C. Fig. 1 shows the coating of the reflector 10 of an electric projection lamp of the type described in Specification 479,258. A cup 14, which can be connected at 27 to a vacuum pump and has metal posts 16 to which are attached the leads 18 of a heater 17, rests on rubber gaskets 20 and is held in position by another gasket 22 clamped between rings 21 and 23. The member 10 to be coated rests on the gasket 22 and hair-pin loops 28 of the coating metal are hung on the heater 17, which is preferably made of tungsten wire. Fig. 2 shows the coating of the interior of an electric lamp bulb, a collapsable masking device, comprising a fan-like arrangement of overlapping vanes 32 mounted on a tube 31 having a rubber gasket 34 to hold it in place, being provided to limit the area on which metal is deposited. Specifications 343,424, 459,231 ; and 471,301, [Group XXXVI], also are referred to.

Inventors

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