GB548297A - Improvements in electric flash lamps - Google Patents

Abstract

548,297. Flash-lamps. BRITISH THOMSONHOUSTON CO., Ltd., April 7, 1940. No. 4616. Convention date, April 8, 1940. [Class 9 (ii)] An electric flash lamp comprises a light transmitting container, one or more non-combustible supports within the container, a combustible coating in the form of a bead on the supports for emitting a flash the coating constituting substantially the sole source of active radiation and means in the container for igniting the coating. In one form, the glass container 10 coated with a laquer or varnish to minimize cracking, as described in Specification 538,676, has a re-entrant stem 11 and leading in wires 12, 13. with straight parallel terminations 15, 16 bridged by a small filament 17 The filament is covered by a member 18 formed of combustible light-giving material adapted to be ignited by the filament. The supports may be arranged in groups of four or six arranged parallely and covered with the combustible material in the form of a paste or the ends 15, 16 may terminate in portions 28 bent at right angles to their lengths so that the burnt material flies upwardly instead of horizontally. The transparent globe may be of elliptic section as described in Specification 546,189. Examples of flash compositions are zirconium metal powder with calcium peroxide made into a paste with thin glue and applied in the form of a bead to the supports which are then dipped into a mixture of aluminium powder and calcium peroxide made into a paste with solution of nitrocellulose in amyl acetate finally covered with a lacquer coating. Two other flashing mixtures are given. The colour of the flash may be modified by the' inclusion of salts of metals such as strontium, calcium, sodium or potassium and the like. Specifications 1544/02, [Class 9], and 503,540 also are referred to.