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US 6,211,618 B1Granted
Arc discharge lamp with bimetal strip for fast passive lamp failure
AssigneePhilips Electronics North America Corporation
InventorsStephen C. Fancher, Thomas O. Leyh
Life of this patent
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Abstract
Fluorescent tube type discharge lamp has end sealed in base with terminal pins connected to lead wires passing through stem press and supporting an electrode in the form of a coil having an emitter. Bimetal strip has a first end welded to one of the leads and a second end proximate to a thin walled portion of the stem. When electrode fails and an arc discharge operates directly off the leads, the bimetal strip heats up so that second end contacts thin walled portion and arcs through to admit air for passive failure of lamp.
Claims4
A discharge lamp comprising
- a base having an insulator therein,
- a pair of terminals fixed in said insulator and passing through said base,
- a light transmissive arc tube having an end fixed in said base,
- a glass stem in said end, said stem comprising a stem press and a thin walled portion attached to said arc tube,
- a pair of leads connected to respective terminals and extending through said stem press into said arc tube,
- an electrode connected between said leads, and
- a bimetal strip having a first end welded to one of said leads and a second end proximate said thin walled portion of said stem, said bimetal strip being arranged so that said second end bends toward said thin walled portion when it is heated by an arc discharge which occurs on said leads when said electrode fails.
4 more elements
Dependencies are inferred from the claim text.