| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a compact wide-angle lens with high performance and a small lens aperture for enlarging and projecting an image from a light valve forming the image by varying the reflection direction of light, such as DMD, to a screen, etc. <P>SOLUTION: The wide angle lens system is composed of: a first lens group having negative refractive power as a whole; a second lens group having positive refractive power as a whole; and a third lens group having positive refractive power as a whole, in this order from the enlargement side. In this case, the first lens group is composed by arranging five lenses which are; a lens of a convex meniscus-shape on the enlargement side having negative refractive power (hereafter, negative lens); a lens having positive refractive power (hereafter, positive lens); a negative lens; and a negative lens of a meniscus-shape which is concave on the enlargement side; and a lens having positive refractive power in this order from the enlargement side. The second lens group is composed by arranging four lenses which are: a negative lens; a positive lens; and a negative and positive cemented type, in this order from the enlargement side. The third lens group is composed by arranging one positive lens. <P>COPYRIGHT: (C)2012,JPO&INPIT |
