| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection lens for a front projector in which an image circle can be widely taken, the whole length is short and back focus can be made long, and further, which is compact and has reduced pieces while maintaining high performance, and is suitable for a long focal point. SOLUTION: In the projection lens, the rear group subsequent to a diaphragm is composed of six pieces, and is composed of: a negative simple lens; a three piece-cemented lens obtained by cementing the negative-positive-negative ones and having a negative focal length as the whole; a positive simple lens; and a positive simple lens. COPYRIGHT: (C)2010,JPO&INPIT
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