| 摘要 |
1,147,969. Photo-electric lighting control. PHILIPS ELECTRONIC & ASSOCIATION INDUSTRIES Ltd. June 1, 1967 [June 4, 1966], No. 25265/67. Heading G1A. [Also in Division G3] A closed lighting fitting for a tunnel includes a lamp and a photo-electric device for monitoring the intensity of the lamp in the fitting and keeping it constant. The fitting, which is triangular in section to fit into the corner of a rectangular section tunnel has a glass cover 6 and contains a low pressure mercury discharge lamp 9. A photo-resistor 24 receives light from lamp 9 through an optical wedge or striped attenuator 27 which is adjustable for initial calibration. A resistor in series with the photo-resistor may be used instead of the attenuator. The output of photo-resistor 24 is taken by leads 19 through a cable duct 20 in the tunnel roof to means to control the lamp current automatically. The output may be compared with that of a photo-cell responsive to ambient light outside the tunnel to vary the tunnel light accordingly. |
