Projecting zoom lens system and projector apparatus
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United States of America Patent
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-
Jun 13, 2000
Grant Date -
N/A
app pub date -
May 29, 1998
filing date -
Sep 16, 1997
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A projecting zoom lens system whose incidence side is telecentric of this invention is formed by the first to fourth lens groups arranged sequentially from the screen side and having negative, positive, negative and positive refractive powers, respectively. The employment of the negative refractive power lens group on the screen side allows a wider angle and a smaller lens aperture of the first lens group, thereby realizing a compact lens with a larger aperture as a whole. Furthermore, if a positive lens is employed on the screen side in the first lens group of the projecting zoom lens, the balance of refractive power can be improved.
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