Patent ID: 8520315

Claim:
A zoom projection lens comprising a first lens set and a second lens set arranged in sequence from an object side to an image side of said zoom projection lens, wherein said first lens set has a negative optical power, and consists of a first lens; wherein said second lens set has a positive optical power, and consists of a second lens, a third lens on one side of said second lens opposite to said first lens set, a fourth lens on one side of said third lens opposite to said second lens, and an aperture stop disposed between said second lens and said third lens; wherein said first lens is an aspherical plastic lens, one of said third lens and said fourth lens is an aspherical glass lens, and said zoom projection lens satisfies: 1.463 <|tt/lt|< 1.505, in which, tt represents an overall length of said zoom projection lens in a wide-angle mode from an object side of said first lens to an imaging plane, and lt represents a length of said zoom projection lens in the wide-angle mode from said object side of said first lens to an image side of said fourth lens; and wherein said zoom projection lens further satisfies: 1.311 <|ex/bf|< 1.383 in which, ex represents an exit pupil position of an optical system of said zoom projection lens, and bf represents a back focal length of said zoom projection lens.