Photocopying – Projection printing and copying cameras – Illumination systems or details
Patent
1980-01-07
1981-11-03
Wintercorn, Richard A.
Photocopying
Projection printing and copying cameras
Illumination systems or details
350314, 354296, G03B 2772
Patent
active
042982740
ABSTRACT:
In an optical system for a multi-magnification copying device, a relative illumination filter is mounted in a fixed position relative to the projection lens with the center on the lens optical axis. The filter provides a radially varying transmission therethrough which compensates for circularly symmetric nonuniformities in the optical system at any magnification.
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patent: 3981565 (1976-09-01), Karasawa
patent: 4229097 (1980-10-01), Vulmiere et al.
IBM Technical Disclosure Bulletin, "Illumination Compensation for Cos.sup.4.theta. Lens Attenuation," G. W. Hobgood, Jr., vol. 14, No. 11, Apr. 1972, p. 3324.
Lenses in Photography, The Practical Guide to Optics for Photographers, CH. VIII, "Lens Attachments", Kingslake, published for Garden City Books, Garden City, N.Y., 1951, p. 143.
Altfather, Jr. Kenneth W.
Lama William L.
Ozern Donna U.
Rees James D.
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