Patent ID: 6870689

Claim:
A projection zoom lens system that projects, onto a screen, projection light from a light modulator, which includes a plurality of elements and forms an image by changing directions of reflection of illuminating light from an illuminating optical system using the plurality of elements, the projection zoom lens system including first, second, third, fourth, and fifth lens groups arranged in this order from the screen side, the fifth lens group being a common lens group that is disposed on the front side of the light modulator, transmits the illuminating light and the projection light, and does not move during zooming, the first lens group being a focusing lens group that moves in order to adjust a focus and does not move during zooming, the third lens group being a zooming lens group and zooming effect is mainly produced by movement of this group, and the second and fourth lens groups being compensating lens groups that mainly compensate aberrations by moving when zooming is carried out, wherein at least one of the first, second, and fourth lens groups includes an aspherical lens.