Projection lens and projection display device using the same

Details Projection lens and projection display device using the same Projection lens and projection display device using the same

2007-10-09

2007-10-09

Ullah, Akm (Department: 2809)

Optical: systems and elements

Lens

With variable magnification

C359S651000, C359S749000

Reexamination Certificate

active

11342858

ABSTRACT:
A projection lens includes three lens groups, arranged as follows from the magnification side: a first lens group of negative refractive power, a second lens group of positive refractive power, and a third lens group of positive refractive power. The first lens group includes three lens elements, each of negative refractive power, and two of these lens elements each have a meniscus shape with its convex surface on the magnification side. The second lens group includes a lens element having positive refractive power, a meniscus shape, and a convex surface on the magnification side. The third lens group includes: a lens element of positive refractive power and a meniscus shape with its convex surface on the reduction side; a cemented lens component; and at least one aspheric surface. The projection lens satisfies specified conditions regarding focal lengths and spacings of lens surfaces. A projection display device uses the projection lens.

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