| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection lens which is made satisfactorily compact even while keeping an excellent optical performance. SOLUTION: The projection lens is constituted in such a manner that a first lens group 1 having negative power, a second lens group 2 having positive power, a third lens group 3 having positive power and a TIR prism 4 are arranged in order from the screen side which is not illustrated. Therein, the first lens group 1 includes an aspheric lens 12 and the final lens surface (surface of the TIR prism 4 side of a negative lens 32) of the third lens group 3 is formed in a flat surface, which is brought into contact with or is adhered to the surface of the TIR prism 4. COPYRIGHT: (C)2004,JPO&NCIPI
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