Patent ID: 7440203

Claim:
A projection lens, comprising: a front sleeve having a plurality of grooves and a first guiding part, wherein the grooves and the first guiding part are located on an outer surface of the front sleeve; a rear sleeve; a main sleeve covering the front sleeve and the rear sleeve, wherein the main sleeve has a plurality of first threads and a second guiding part, the first threads are located on an outer surface of the main sleeve and the second guiding part is located on an inner surface of the main sleeve, and the second guiding part engages with the first guiding part, the front sleeve reciprocates along an axis of the main sleeve without rotation; a driving ring covering the front sleeve and the main sleeve, wherein the driving ring has a plurality of second threads, and the second threads are located on an inner surface of the driving ring for meshing with the first threads; a plurality of sliding components assembled to the driving ring, wherein the sliding components protrude from the driving ring into the grooves so that the sliding components slide inside the grooves of the front sleeve and push the front sleeve along the axis to reciprocate when the driving ring rotates; and a plurality of lenses, disposed inside the front sleeve and the rear sleeve.