Zoom lens and image projection apparatus

Details Zoom lens and image projection apparatus Zoom lens and image projection apparatus

2008-03-26

2009-08-18

Choi, William C (Department: 2873)

Optical: systems and elements

Lens

With field curvature shaping

C359S680000

Reexamination Certificate

active

07576921

ABSTRACT:
The zoom lens includes a plurality of lens units. The first lens unit is disposed closest to a magnification side in the plurality of lens units and has a negative optical power, and magnification-varying lens units that are disposed closer to a reduction side than the first lens unit and moves for variation of magnification. The first lens unit includes, in order from the magnification side, a first-A lens sub-unit having a negative optical power and a first-B lens sub-unit having a positive optical power. For focusing from an infinite side to a close side, the first-A and first-B lens sub-units move as a distance therebetween increases, and the first-B lens sub-unit moves toward the reduction side. The zoom lens is capable of correcting well variation of curvature of field due to a projection distance change and has a good optical performance.

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Translation of JP 10-186235.
Communication from EPO dated Aug. 19, 2008 including European Search Report dated Aug. 1, 2008.

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