Projection zoom lens system and projector apparatus
AssigneesNittoh Kogaku K.K., InFocus Corporation
InventorsAkira Yamagishi, Jeffrey A. Gohman
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AssigneesNittoh Kogaku K.K., InFocus Corporation
InventorsAkira Yamagishi, Jeffrey A. Gohman
Estimating the term…
A projection zoom lens system of the present invention having telecentric incident side is suitable for a projector apparatus using LCD or DMD with prism. The projection zoom lens system of this invention comprises five lens groups having, from the screen side, negative, positive, positive, negative and positive power. In addition to this arrangement, since the lens located closest to the screen is a screen side convex negative meniscus lens, wide-angled and bright zoom lens system can be realized. Further, by designing the distribution of power of the first lens group located closest to the screen, the projection zoom lens provides further improved aberration correction. As the condition for realizing the aforementioned projection zoom lens system, it is preferable that a focal length f1 of the first lens group and a focal length at a wide-angle end fw satisfy the following condition: -1.9<f1/fw<-0.9 (A).
A projection zoom lens system having a substantially telecentric incidence side, comprising a first lens group having a negative refractive power, a second lens group a positive refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power and a fifth lens group having a positive refractive power, arranged in this order from a screen side, whereby zooming is carried out by fixing said first and fifth lens groups and moving said second, third and fourth lens groups, and
Dependencies are inferred from the claim text.