Projection zoom lens and projection type display device
AssigneeFUJIFILM Corporation
InventorsTomoyuki Baba, Masaru Amano, Akiko Nagahara
Life of this patent
Estimating the term…
Abstract
A negative first lens group, a positive second lens group, a negative third lens group, a positive fourth lens group, a negative fifth lens group, and a positive sixth lens group are disposed in this order from the magnification side. The reduction side is made telecentric. While changing magnification, the second lens group through the fifth lens group are moved, and the first lens group and the sixth lens group are fixed. Predetermined conditional expressions are satisfied.
Claims13
A projection zoom lens that substantially consists of six lens groups in which a first lens group having negative refractive power, a second lens group having positive refractive power, a third lens group having negative refractive power, a fourth lens group having positive refractive power, a fifth lens group having negative refractive power, and a sixth lens group having positive refractive power are disposed in this order from a magnification side;
- wherein the reduction side is made telecentric,
- wherein the second lens group, the third lens group, the fourth lens group, and the fifth lens group are moved and the first lens group and the sixth lens group are fixed while changing magnification, and
- wherein conditional expressions (1) and (2) below are satisfied:
- 1.5<ft/fw (1), and
- 0.5<f5/f3<10.0 (2), where
- ft:
- the focal length of the entire system at the telephoto end
- fw:
- the focal length of the entire system at the wide angle end
- f5:
- the focal length of the fifth lens group, and
- f3:
- the focal length of the third lens group.
Dependencies are inferred from the claim text.