SWITCHING DEVICES FOR PHOTOFLASH UNIT

摘要

A multiple flashlamp array has a plurality of flashlamps which are arranged to be fired individually and in sequence. The array includes a plurality of static solid switching devices, each device being located adjacent an associated flashlamp. Actuation of a switching device by radiant energy generated during flashing of the adjacent flashlamp causes the next-to-flash lamp to be connected into the circuit. Initially, the switching devices have a high electrical resistance ("off" condition). After actuation by radiation, they undergo chemical conversion and have a low electrical resistance ("on" condition). The switches are prepared from compositions which impart improved shelf life under conditions of relatively high humidity at above normal ambient temperature.