Retrofocus wide angle lens
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United States of America Patent
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-
Jun 8, 1993
Grant Date -
N/A
app pub date -
Dec 3, 1991
filing date -
Dec 3, 1991
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
A wide angle lens system of the retrofocus type is provided which includes two lens units. The first lens unit is of negative power and includes a combination of a positive element having a high dispersion and a negative element having a low dispersion for correction of lateral color. The second lens unit is of positive power and includes a combination of a positive element having a low dispersion and a negative element having a high dispersion for correction of longitudinal color. The lens units satisfy the relationship that the magnitude of f.sub.1 is less than about 1.15 times f.sub.2 and preferably satisfy the relationship that the magnitude of f.sub.1 is less than f.sub.0. The first and second lens units each preferably include an aspheric surface. Applications of the lens system include rear projection television systems wherein a single lens is used to project light from three LCD light valves onto a viewing screen.
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Cited Art Landscape
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