Photographic film projection dissolve system for arc lamp projectors
AssigneeBergen Expo Systems, Inc.
InventorsEugene Demick, Adrian J. Van Haasteren, Jr.
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Abstract
A photographic film projection system includes a plurality of projectors, one of which is an arc lamp projector, and a dissolver instrument whose controlled output power to the arc lamp projector is a phase controlled average a.c. power. The arc lamp projector has a light valve comprising a motor means linearly responsive to average power, for example, a moving iron galvanometer, and a movable means, such as a louvre, positioned between the arc lamp and the film gate.
Claims11
A system for the projection of photographic film comprising:
- a plurality of photographic film projectors;
- a dissolver instrument connected to said projectors and to a source of a.c. power, said dissolver instrument including power control means to regulate by phase control its average output power to said projectors;
- at least one of said projectors having an arc lamp light source and a film gate and a light valve means positioned between said arc lamp and said film gate;
- said light valve means attenuating the arc lamp light reaching the film from zero to full intensity and changing such intensity at a controlled rate of speed, said light valve means comprising a motor means connected to said dissolver instrument, said motor means being a rotational motor having a servo feed back loop, the extent of rotation, as distinct from the speed of rotation, of said rotational motor being a function of said average output power, and movement means connected to said motor means and moved thereby at a controlled rate of speed to relatively open, closed and intermediate positions dependent upon the angular position of said rotor means.
A high lumen output photographic film slide projector adapted to be connected along with other slide projectors to a dissolver instrument, the output of said dissolver instrument being a phase control of average output power, said projector comprising:
- an arc lamp light source;
- a motor driven slide transport mechanism;
- a film gate in proximity to the slide in said transport mechanism to be projected;
- a light valve means comprising a motor means connected to said dissolver instrument, said motor means being a rotational motor having a servo feedback loop, the amount of rotation, as distinct from the speed of rotation, of said rotational motor being a function of said average output power, and a movement means connected to said motor means and positioned between said arc lamp and said film gate and moved by said motor means to relatively open, closed and intermediate positions to control the amount of light reaching the film gate from the arc lamp.
Dependencies are inferred from the claim text.