Nondestructive measurement of oxygen level in a tungsten-halogen incandescent bulb
AssigneeGeneral Motors Corporation
InventorJeffrey A. Sell
Life of this patent
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Abstract
A previously unlit tungsten filament bulb with a fill gas is flashed for about one second to form a dispersion of tungsten oxide particles therein. In a preferred embodiment, a laser beam is passed through the dispersion and the scattered light is detected to provide a measure of the oxygen content of the bulb.
Claims2
A method of determining whether the oxygen content of a fill gas of a tungsten filament-halogen incandescent light bulb with a transparent envelope meets a predetermined standard, comprising
- passing a current through the tungsten filament of a previously unlit bulb for a short period of time to disperse particles of tungsten oxide in the fill gas of the bulb,
- immediately directing a beam of monochromatic light through the dispersed particles whereby some of the light is scattered,
- detecting the amount of light scattered in a particular direction, and
- comparing such value with data obtained in a like manner from bulbs known to have a suitable oxygen content.
A method of determining whether the oxygen content of a tungsten filament, transparent envelope incandescent light bulb containing a gas meets a predetermined standard, comprising
- passing a current through the tungsten filament of a previously unlit bulb for a period of time sufficient to react oxygen in the gas with the tungsten and to disperse particles of tungsten oxide in the gas of the bulb,
- immediately directing a beam of monochromatic light through the dispersed particles whereby some of the light is scattered,
- detecting the amount of light scattered in a particular direction, and
- comparing such value with data obtained in a like manner from bulbs having a suitable oxygen content.
Dependencies are inferred from the claim text.