| 摘要 |
988,248. Lens arrangements for light sources. GRETAG A.G. July 28, 1961 [Aug. 8, 1960; July 3, 1961], No. 27540/61. Heading F4R. [Also in Division G2] A light source for projection purposes comprises a gas discharge lamp 12, e.g. a mercury vapour or Xenon lamp, two concave specular reflectors 14, 16 and two condensing lenses 18, 20 disposed around the light emitting part of the lamp and co-operating in pairs to collect substantially all the light emitted from the lamp, a deflecting mirror 22 in at least one of the light paths from the lenses and lenses 34, 36 arranged one in each of the light paths so as to form an image of each condenser lens in the picture field 24. The reflectors are spherical reflectors with their centres of curvature inside the column of gas 10. An additional lens 42 may be arranged in front of the picture field and a projecting objective arranged to throw the projected picture on a screen. The lenses 34, 36 are relatively displaced to allow for the differing lengths of the light paths and may vary in refracting power so as to form co-incident images of equal size in the picture field. In a modification, the deflecting mirror is arranged so that the direct and reflected light paths are parallel, the focusing lenses being arranged with their axes inclined to one another so as to produce co-incident images in the picture field. |
