Radiation switch for photoflash unit
AssigneeGTE Sylvania Incorporated
InventorJohn W. Shaffer
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Abstract
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 flash lamps 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 the lamps. 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 particularly resistant to high relative humidity and above normal ambient temperatures. The switch material composition comprises silver carbonate, a binder such as polystyrene resin, and an oxidizer such as barium chromate.
Claims8
A multilamp photoflash unit comprising, in combination,
- a pair of flashlamps,
- an electrical circuit into which said lamps are arranged to fire individually and in sequence, and
- a solid state radiation switch located external of the lamps and forming part of said electrical circuit, said switch being located adjacent one of said flashlamps to receive radiant energy emitted by that flashlamp, said photoflash unit being characterized by said switch being a high relative humidity and temperature resistant mass of material comprising silver carbonate and/or silver oxide, a binder and a chromate salt having a water solubility which is about equal to or less than the water solubility of said silver carbonate and/or silver oxide.
Dependencies are inferred from the claim text.