| 摘要 |
1525569 Lighting fittings THORN ELECTRICAL INDUSTRIES Ltd 17 Oct 1975 [31 Oct 1974] 47256/74 Heading F4R The central portion of a plastics refractor or diffuser 20 in a lighting fitting is shielded from the full thermal radiation from the light source 14 by a heat distributing member 22 having through apertures or perforations 23. The member 22 may be a metal plate or a wire mesh and is supported transversely from a reflector 12 at a third of the distance from the refractor/ diffuser 20 to the source 14. The lighting fitting also includes a stand-by lamp unit 32, 34 in which a photo-cell 30 senses operation of the main source 14 to energize the stand-by source 34 in the event of failure, or during warm-up of the main source 14. The latter is a high pressure Hg/quartz arc lamp. |
