Patent attributes
A projection lens including a front sleeve, a rear sleeve, a main sleeve, a driving ring, sliding components and lenses is provided. The main sleeve covers the front sleeve and the rear sleeve. The driving ring covers the front sleeve and the main sleeve. The sliding component is assembled to the driving ring. The lenses are disposed inside the front sleeve and the rear sleeve. The front sleeve has grooves and a first guiding part outside. The main sleeve has first threads and a second guiding part. Furthermore, the second guiding part engages with the first guiding part and the first threads on the main sleeve mesh with a plurality of second threads on the driving ring. The sliding components protrude from the driving ring into the grooves. When the driving ring rotates, the sliding components slide in the grooves and push the front sleeve along an axis to reciprocate.
