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US 4,045,156 AGranted
Photoflash lamp
AssigneeGTE Sylvania Incorporated
InventorsGordon P. K. Chu, Dennis B. Shinn, John F. Waymouth
Life of this patent
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Abstract
A photoflash lamp having an envelope composed of a crystallized glass which exhibits high refractoriness and mechanical strength and minimizes the propagation of flaws. The thermal expansion coefficient of the glass permits a match seal to commonly employed dumet wire leads.
Claims11
A photoflash lamp comprising:
- an hermetically sealed, light-transmitting envelope;
- a quantity of combustible material located in said envelope;
- a combustion-supporting gas in said envelope;
- and
- ignition means attached to said envelope and disposed in operative relationship to said combustible material;
- said envelope comprising a light-transmitting wall of uniformly crystallized glass having a mean coefficient of thermal expansion in the range of about 80 to 95 .times. 10.sup.-7 in./in./.degree. C between 0.degree. C and 300.degree. C, whereby
- the relatively high refractoriness and strength of said crystallized glass wall render said envelope and the internal surface of said envelope particularly resistant to the thermal shock and mechanical stress resulting from the impingement of hot combustion residues upon flashing of said lamp, and the glass-crystal interfacial grain boundaries in said crystallized glass minimize the propagation of cracks through the thickness of said envelope.
4 more elements
Dependencies are inferred from the claim text.