Switching devices for photoflash unit
AssigneeGeneral Electric Company
InventorsFred F. Holub, Nicholas Roman, Harold F. Webster
Life of this patent
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Abstract
A photoflash unit is designed to have a plurality of lamps fired individually and in sequence and includes a plurality of switching devices capable of being easily activated by radiant energy generated during flashing of the lamps. Initially, the switches have a high resistance ("off" condition) and after being activated by radiation, they undergo a chemical change to a conductive state ("on" condition). The switches are prepared from compositions which impart improved shelf life to the switches under conditions of high relative humidity.
Claims22
A photoflash lamp unit comprising
- a. a pair of flash lamps,
- b. an electrical circuit into which said lamps are arranged to fire individually and in sequence, and
- c. a solid state, radiant energy switching device located external of the lamps and forming part of the electrical circuit, said switching device being located adjacent one of said lamps and disposed to receive radiant energy emitted by that lamp, said photoflash unit being characterized by said switching device being a high relative humidity resistant mass of a composition comprising a metallic silver source and a humidity resistant, organic polymer binder selected from the group consisting of cellulose esters, cellulose ethers, polyalkylacrylates, polyalkylmethacrylates, polymethylmethacrylate, polymethylacrylate, polystyrene and polycarbonate, said silver source consisting of at least 70% by weight of a carbon-containing silver salt and further consisting of silver oxide.
A radiation switching device capable of changing from a high electrical resistance to a very low electrical resistance, said device being a high relative humidity resistant mass of a composition comprising a metallic silver source and a water-insoluble organic polymer binder selected from the group consisting of cellulose esters, cellulose ethers, polyalkylacrylates, polyalkylmethacrylates, polymethylmethacrylate, polymethylacrylate, polystyrene and polycarbonate, said silver source consisting of at least 70% by weight of a carbon-containing silver salt and further consisting of silver oxide.
A radiation switch for use with a photoflash unit and capable of changing from a high electrical resistance to a lower electrical resistance when exposed to radiant energy, said switch being a composition comprising a source of metallic silver and a water-insoluble organic polymer binder, said silver source comprising a mixture of
- a. at least 70% by weight of a carbon-containing silver salt and
- b. at least some and up to 30% by weight silver oxide.
Dependencies are inferred from the claim text.