Method of spray-reflectorizing electric lamp envelopes
AssigneeWestinghouse Electric Corp.
InventorsAristide R. DeCaro, Eugene F. Murphy, Billy A. Maynard
Life of this patent
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Abstract
A selected part of the envelope of a fabricated electric lamp is made light-reflecting by spraying it with a coating composition that contains aluminum flakes of such minute size that they inherently arrange themselves in planar relationship and form a specular film which provides a mirror-like reflector surface as the composition dries. A protective coating of a suitable heat-resistant material, such as silicone plastic, is then sprayed over the reflective film and cured. The protective coating can also contain aluminum particles in order to fill voids that may be left in the thin specular film and to make the latter more opaque.
Claims6
In the manufacture of electric lamps having envelopes composed of vitreous light-transmitting material, the method of providing selected outer surface portions of the lamp envelopes with reflector coatings of mirror-like quality efficiently and in mass-production quantities, which method comprises;
- dispersing a predetermined amount of aluminum flakes of selected minute size in a vaporizable liquid vehicle to form a reflector-coating composition, said aluminum flakes having a particle size in the range of from about 10 200 microns so that the composition can readily be dispensed by spraying means, and the amount of aluminum flakes in the reflector-coating composition relative to the vaporizable liquid vehicle being so correlated that the composition is of a type which permits the aluminum flakes to automatically orient themselves in substantially side-by-side planar relationship and inherently form a thin adherent film of aluminum when said composition is sprayed onto the lamp envelopes,
- depositing, by means of a single spraying operation, a layer of the reflector-coating composition on the selected outer surface portions of each of the lamp envelopes, said spraying operation being done in a manner such that the deposited layer of the reflector-coating composition contains a sufficient number of aluminum flakes to form an aluminum film having a thickness of from about 10 to about 630 microns, when the flakes orient themselves in substantially planar relationship,
- allowing the aluminum flakes in the wet spray-deposited layer of reflector-coating composition to arrange themselves in said planar relationship and thus form, in situ, a thin adherent film of aluminum that has a thickness of from about 10 to about 630 microns and is also specular at the envelope-film interface and thus provides a brilliant mirror-like reflector at said interface,
- drying the spray-reflectorized portions of the lamp envelopes to set the aluminum reflector films, and then
- coating the mirror-like films of aluminum flakes with a protective layer of a material that holds the flakes in their film-forming relationship on the respective lamp envelopes without impairing the light-reflective capability of the aluminum films.
Dependencies are inferred from the claim text.