| 摘要 |
A projection zoom lens includes, from a screen side to an image source side, a first lens group having a negative refractive power, a second lens group having 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. Zooming the projection zoom lens from the wide-angle end to the telephoto end causes the second, third and fourth lens groups to move toward the screen side, and the first and fifth lens groups are kept stationary. The projection zoom lens may further include an auto iris being axially movable with the fourth lens group, a composite prism and a cover glass. The projection zoom lens satisfies several conditions so that it can effectively eliminate aberrations and improve the projection image quality.
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