GB1159144A - Light Source - Google Patents

Abstract

1,159,144. Flash-bulbs. J. DEMENT. July 20, 1966 [July 20, 1965], No. 30793/65. Heading G2L. [Also in Division H1] A light source for producing a flash of visible, infrared or ultraviolet light which may be used for pumping a laser or for irradiating some other photo-sensitive target, comprises a conductor embedded in a solid member of non-conducting material and having leads to at least two spaced points on the conductor to apply electrical energy thereto, part at least of the member being light transmitting. The conductor may be in the form of a wire, tube, hollow filament, film or foil, or may consist of twisted or braided filaments or of stacked film. A fine wire enclosed within a conducting tube may also be used. The Specification lists elements from the groups of the Periodic Table which are stated to be suitable. Additives, particularly materials described as "candoluminescent" and "cathodoluminescent" which have the property respectively of emitting more radiation at a given wavelength than the corresponding black body and of transducing energy in unwanted form (.e.g ultraviolet, thermal and plasma energy) into electromagnetic radiation of a desired wavelength, may be applied as coatings or additives to the conductor or suspended within the non- conducting member. The latter may be of glass, fused silica, quartz, sapphire or ceramics, or composite materials including laminates of glass and plastics, wound glass fibres or tapes, and plastics reinforced with glass or silica fibres. Plastics may also be used without reinforcement. The shock wave resulting from the sudden dissipation of a large amount of energy in the conductor may be dissipated by shaping the non-conducting member e.g. by surface grooving, by including a core of yieldable plastic around the conductor or by providing slots or holes. Alternatively, a series of explodable elements may be passed across the target area (e.g. a laser device) so as to produce the flash opposite the target and to move out of the target area before the shock wave is released. In another arrangement, a part of the non-conductor may be of yieldable material e.g. a strip of light-transmitting plastics may replace a section of the enclosing body. A similar arrangement using a main body of opaque reinforced plastics with an inserted window of e.g. glass or sapphire may be used to produce an element with a light-transmitting portion. For producing a succession of flashes, a rod or belt of non-conducting material enclosing a series of conductors with separate contact electrodes may be provided or a number of blocks or spheroids of non-conducting material, each containing a conductor with contact electrodes, may be formed as a unit, which is moved in steps past a pair of firing electrodes. In one arrangement, Fig. 15 (not shown) a plurality of bulletshaped elements are contained in a magazine whence they are loaded individually into the breech portion of a barrel from which they may be fired as from a gun. In passing down the barrel contacts on the element co-operate with corresponding contacts on the barrel to cause a flash of light to be emitted through an appropriately positioned transparent window in the barrel. Each element emerges from the nozzle end of the barrel before its corresponding shock wave can affect the surrounding equipment. Alternative arrangements are described in which more than one conductor can be exploded at a time or successive explosions can take place in overlapping sequence.