| 摘要 |
<p>A tungsten halogen lamp producing infra red radiation, for example for cooking or heating, has an envelope of high silica content material sealed at each end by a pinch seal (8). A gas fill is at a room temperature pressure of 250-750 mm Hg. A portion of the envelope at each end (2) is clear and the rest (1) contains an opacifier which reduces transmission of visible light. A suitable opacifier is red, being produced by the reduction of copper oxide dispersed in the high silica content material. The envelope is produced by butt joining clear end sections (2) and a tube (1) of material containing opacifier.</p> |
