| 摘要 |
An ambient pressure lamp for automobiles and related conveyances includes a parabolic reflector having an inner reflective surface, an outer surface, a base portion and an outer peripheral edge wherein the base portion includes a centrally located clearance aperture for receipt of a lamp filament socket. The reflector member is enclosed by a lens member which as a stepped inner surface and a surrounding lip portion which is sealingly attached to the outer peripheral edge of the reflector member in order to define an inner chamber wherein a lamp filament is positioned. An expandable membrane is sealingly joined around the outer surface of the reflector member and around the lamp filament socket so as to define an expansion chamber between the outer surface and the membrane. This expansion chamber is completely enclosed except for being in flow communication with the inner chamber so that as pressure increases result due to the heating of the filament and heating of the internal atmosphere within the inner chamber, the expandable membrane stretches outwardly in order to provide an increased volume so that the internal pressure within the lamp remains at an ambient level regardless of the operating status of the lamp. The lamp filament socket includes purge and fill passageways so that the inner chamber and the expansion chamber can be purged of all oxygen and moisture and filled with an inert gas mixture.
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