Patent ID: 7403348
Filing Date: 2008-07-22
Classification: G02B,H04N

Abstract:
1. A lens assembly having first and second lens components movable in a direction of an optical axis, said first lens component being constituted by a first lens element, being aspherical and plastic, and disposed on a side of a screen surface, said lens assembly comprising: a first lens barrel for holding said first lens component; a second lens barrel for holding said second lens component; a stationary barrel for movably containing said second lens barrel; a first thread mechanism for helically coupling said first lens barrel with said second lens barrel, and for, in response to rotation of said first lens barrel relative to said second lens barrel, moving said first lens component in said optical axis direction with said first lens barrel, in order to correct image distortion; a second thread mechanism for helically coupling said second lens barrel with said stationary barrel, and for, in response to rotation of said second lens barrel relative to said stationary barrel, moving said first and second lens components in said optical axis direction with said first and second lens barrels, in order to adjust focus; wherein said second lens barrel is rotated with said second thread mechanism to adjust said focus, and thereafter said first lens barrel is rotated with said first thread mechanism to correct said distortion, and also to adjust a rotational position of said first lens element, so as to offset a gate mark on an edge portion of said first lens element from an effective projecting region of image projection.