| 摘要 |
A photoflash unit having a plurality of high voltage type flashlamps mounted in a planar array on a printed circuit board containing circuitry for sequentially igniting the flashlamps in response to successive high voltage firing pulses applied thereto. The circuitry includes a plurality of solid state switches capable of being easily activated by radiant energy generated during flashing of lamps located adjacent to respective switches. Initially, the switches have a high resistance, and after being activated by radiation, they undergo chemical conversion to a conductive state. The switches are prepared from compositions which include a comparatively large proportion of nonconductive inert particulate solids to improve switch functioning.
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