Photography – Exposure control circuit – With exposure filter
Patent
1997-02-18
1998-08-18
Perkey, W. B.
Photography
Exposure control circuit
With exposure filter
396262, 250205, 349 2, 349 25, 349104, 349113, 359241, 359601, G03B 708, G01J 132, G02F 101, G02F 135
Patent
active
057970505
ABSTRACT:
A real-time, optical, nonlinear attenuator device situated in the image plane of an ocular of special construction provides a highly sensitive, broad spectral band, selective, glare reduction ocular. This system is suitable for the eye or camera which is directed at scenery with illumination ranging from that of a room interior to outside daylight. Special adaptations from spatial light modulator technology and modifications of optical power limiter art increase the nonlinear attenuator device sensitivity to bright light by orders of magnitude over that in current systems using known passive, optical, nonlinear materials. The ocular concept includes an input lens which gathers more light rays than can pass to the eye in order to further enhance nonlinear sensitivity, contains places for filters, operates with either an absorption-promoting or scattering nonlinear device in the intermediate image plane, corrects image inversion and provides embodiments for transmissive or reflective operation.
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