Optics: image projectors – Epidiascope
Patent
1992-12-21
1994-03-22
Cuchlinski, Jr., William A.
Optics: image projectors
Epidiascope
353 38, 353 98, 353DIG3, G03B 2128, G03B 21132
Patent
active
052968820
ABSTRACT:
A low-profile transmissive overhead projector employs a folded optical path and an off-axis Fresnel lens condensing system which includes a catadioptric lens element. This lens provides a fast condensing system which allows collimation, dispersion, or concentration of light striking the lens at a high angle of incidence, with efficient transmission to the far edge of the lens. This also enables additional reduction in the OHP base height by allowing the single mirror to be mounted at a flatter angle, with the light source still maintained at a position below (and adjacent) the stage. A novel catadioptric lens design further imparts achromaticity to the element, so that it may be constructed of any material, regardless of its index of refraction. The condensing system may have a single or doublet catadioptric lens.
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Fesler Robert M.
Nelson John C.
Vanderwerf Dennis F.
Cuchlinski Jr. William A.
Dowling William C.
Griswold Gary L.
Kirn Walter N.
Minnesota Mining and Manufacturing Company
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