Patent ID: 7733576
Filing Date: 2010-06-08
Classification: G02B

Abstract:
1. A two-group zoom projection lens comprising: in order from a magnification side, a first lens group having a negative refractive power; and a second lens group having a positive refractive power, the second lens group comprising a front group and a rear group in order from the magnification side, the front group comprising a group having at least two positive lenses and a group having at least one negative lens in order from the magnification side, the rear group comprising a group having at least one negative lens and a group having at least two positive lenses in order from the magnification side, wherein the at least one negative lens in the front group comprises a lens having a concave surface directed toward the magnification side, the at least one negative lens in the rear group comprises a lens having a concave surface directed toward a reduction side, and the two-group zoom projection lens satisfies conditional expressions (1) to (4): wherein f n D f f