Optical projection apparatus

Details Optical projection apparatus Optical projection apparatus

1977-09-26

1979-12-04

Griffin, Donald A.

G03B 2900

Patent

active

041769260

ABSTRACT:
Projection apparatus for photodrafting equipment in which an exposure control disc is rotated to vary the intensity of the projected light during exposure of a line is provided with a region which on rotation of the disc effects progressive decrease in the intensity, that region being followed by an aperture or clear region and that in turn being followed by an opaque region. Thus the disc can be rotated in one direction to progressively reduce the intensity, then produce a brief flash at maximum intensity, and then shut off the projected light completely. The preferred form of the exposure control disc, believed novel in itself, comprises a tapered slot movable lengthwise through the optical path of the apparatus to selectively restrict the exit pupil thereof.

REFERENCES:
patent: 2346983 (1944-04-01), Mayer et al.
patent: 3185053 (1965-05-01), Wieszeck
patent: 3260152 (1966-07-01), Aston
patent: 3323414 (1967-06-01), Ritchie et al.
patent: 3610119 (1971-10-01), Gerber et al.
patent: 3673937 (1972-07-01), Mader
patent: 3695154 (1972-10-01), Webster
patent: 3747486 (1973-07-01), Herrmann

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