| 摘要 |
<p>A microfilm camera (7) is fitted with a suction plate (13) to hold a film strip (16). During the exposure process a sealed support of the strip on the frame window is ensured on all sides by a second suction device. The first suction plate has holes (17) and is connected t a vacuum pump (15). When it is lowered against the frame window (9), a spring (27) is compressed and the valve (23) connects the vacuum pump to a suction chamber (20) between the film and the objective (8). This ensures a tight seal of the film on the faces (18). The film can then be exposed by turning a shutter (24) around the spindle (25). When the suction plate (13) is lifted for the next sideways movement, the chamber (20) is automatically cut off from the vacuum pump by the valve (23). The degree of vacuum can be controlled by a needle valve (22).</p> |
