| 摘要 |
A device uses a divergent lens (7) having a concave surface with a central region (12) and a peripheral region (13) of lower curvature than the central region. The light beam (16) crossing the central region is spread over the entire surface of the image frame (10), thereby avoiding a concentration of light in the central portion thereof, and ensuring a more uniform illumination. The device is useful for large size slide projectors using a xenon arc lamp.
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