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US 5,204,578 AGranted
Heat sink means for metal halide lamp
AssigneeGeneral Electric Company
InventorsTimothy P. Dever, Gary R. Allen, John M. Davenport, Gerald E. Duffy
Life of this patent
Estimating the term…
Abstract
Heat sink means are provided for a metal halide lamp to enable more light output during lamp start-up. A xenon-metal halide lamp employing the heat sink means is disclosed along an with automotive headlamp having this lamp for its light source.
Claims18
A metal halide lamp experiencing low light loss during lamp start-up comprising in combination:
- (a) a fused quartz arc tube having a hollow cavity formed with walls hermetically sealing spaced-apart discharge electrodes therein and further containing a fill of mercury, a metal halide and an inert gas,
- (b) external heat sink means physically engaging the exterior surface of one arc tube wall,
- (c) the heat sink means being disposed intermediate the discharge electrodes adjacent the hot spot region of the arc tube for selective condensation of mercury vapor on the inner surface of the arc tube wall at such location;
- and,
- (d) said heat sink means being of a reduced size relative to the surface area of said arc tube and being disposed on a portion of the equatorial surface of said arc tube so as to reduce light blockage by said heat sink means and further being effective during a restarting operation following a recent extinguishment of the arc discharge within said arc tube for preventing condensation of said mercury near said discharge electrodes which would otherwise block light generated immediately upon occurrence of such restarting operation.
2 more elements
A xenon-metal halide lamp experiencing low light loss during lamp start-up comprising in combination:
- (a) a fused quartz arc tube having a hollow cavity formed with walls hermetically sealing a pair of spaced-apart discharge electrodes therein and further containing a fill of mercury, a metal halide and xenon gas at a relatively high pressure,
- (b) an external heat sink member physically engaging the top wall surface of the arc tube,
- (c) the heat sink member being disposed intermediate the discharge electrodes adjacent the hot spot region of the arc tube for selective condensation of mercury vapor on the inner surface of the arc tube wall at such location;
- and,
- (d) said heat sink means being of a reduced size relative to the surface area of said arc tube and being disposed on a portion of the equatorial surface of said arc tube so as to reduce light blockage by said heat sink means and further being effective during a restarting operation following a recent extinguishment of the arc discharge within said arc tube for preventing condensation of said mercury near said discharge electrodes which would otherwise block light generated immediately upon occurrence of such restarting operation.
2 more elements
An automotive headlamp which comprises:
- (a) a reflector member for connection to a power source, the reflector member having a predetermined focal length and focal point,
- (b) a lens member joined to the front section of the reflector,
- (c) a fused quartz arc tube predeterminently positioned within the reflector so as to be approximately disposed adjacent the focal point of the reflector and experiencing low light loss during lamp start-up, the fused quartz arc tube having a hollow cavity formed with walls hermetically sealing a pair of discharge electrodes therein and containing a fill of mercury, a metal halide and an inert gas, the arc tube further having an external heat sink means physically engaging the exterior surface of one arc tube wall, the heat sink means being disposed intermediate the discharge electrodes adjacent the hot spot region of the arc tube for selective condensation of mercury vapor on the inner surface of the arc tube at such location;
- and,
- (d) said heat sink means being of a reduced size relative to the surface area of said arc tube and being disposed on a portion of the equatorial surface of said arc tube so as to reduce light blockage by said heat sink means and further being effective during a restarting operation following a recent extinguishment of the arc discharge within said arc tube for preventing condensation of said mercury near said discharge electrodes which would otherwise block light generated immediately upon occurrence of such restarting operation.
2 more elements
Dependencies are inferred from the claim text.