| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection zoom lens which satisfies the conditions that it has a relatively wide angle of view, it is a bright optical system with a small F number, has a simple lens configuration, and is inexpensive. SOLUTION: The projection zoom lens 40 achieves high resolving power, a small F number, and an increase in the amount of ambient light by shifting second, third, and fourth lens groups G2, G3, G4. Moreover, in the projection zoom lens 40, a fifth lens group G5 acts as a lens group for obtaining good telecentricity. Accordingly, the occurrence of color unevenness in a cross dichroic prism 67, which is a color combining prism, can be suppressed. The projection zoom lens 40 satisfies the conditions that it has a relatively wide angle of view, it is a bright optical system with a small F number, has the simple lens configuration, and is inexpensive. COPYRIGHT: (C)2010,JPO&INPIT
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