Patent ID: 7619828
Filing Date: 2009-11-17
Classification: G02B,G03B

Abstract:
1. A projection lens unit for use in a rear projection device having a screen onto which a projection lens system projects a subject image from behind, said projection lens unit comprising: a first lens group disposed at an incident side of said projection lens system; a second lens group disposed optically coaxially with said first lens group at an exit side of said projection lens system; a reflection mirror disposed between said first and said second lens groups for folding an optical axis of said projection lens system; and a frame for fixedly holding said first lens group, said second lens group and said reflection mirror, said frame having a mounting aperture which is greater in outside dimension than said reflection mirror so as to receive said reflection mirror therein with a circumferential clearance left between said reflection mirror and said mounting aperture which is filled with a bonding adhesive from the outside of said frame so as thereby to fix said reflection mirror to said frame.