| 摘要 |
1,115,928. Illuminating devices. MINNESOTA MINING & MANUFACTURING CO. 2 June, 1965 [24 June, 1964], No. 23617/66. Heading F4R. [Also in Division G2] A light source for contact printing apparatus comprises a single tubular lamp 14 placed at the junction of two arcuate reflectors 13. The upper part of each reflector is displaced to form a ventilation slot 19. Closely above the lamp is a curved shield 15, which serves to guide cooling air round the lamp. This shield may be transparent, or may be a polished aluminium trough (15<SP>1</SP>, Fig. 6, not shown) having staggered slots (25), which latter produces a more evenly spread illumination. Flat end reflectors (12, Fig. 1, not shown) define the exposure area of the glass plate 16 which forms the work support. Cooling air is forced through the apparatus from an entry opening 18 at one side to an exit opening 18 at the other. In the modification of Fig. 3 (not shown), the inner edges of the reflectors are replaced by a pair of narrow flat specular reflectors (23) of partially silvered glass. These reflect visible light but transmit the infra-red rays, which are then absorbed by a metal radiator (24) just below them. The arrangement is designed to give a very uniform illumination over the whole exposure area of the glass plate 16. |
