| 摘要 |
<p>A filter for use in an incandescent lamp utilizing a transparent heat mirror coating on the lamp envelope for transmitting radiation in a selected portion of the visible range to produce a desired color and reflecting infra-red radiation back to the filament for increasing its temperature and thereby increasing its efficiency. The coating is preferably of the insulator/metal/inculator type having a layer of a metal sandwiched between two layers of an insulating material.</p> |
