PROJECTION LENS UNIT AND MANUFACTURE METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a projection lens unit capable of preventing the occurrence of ghost caused by a lens holding frame for holding a lens constituting a magnifying optical system, and to provide a manufacture method thereof. SOLUTION: A second magnifier lens barrel 34 has double cylinder shape, and a first magnifier lens barrel 33 is fit to the outer cylinder 34a thereof from a rear end. The inner cylinder 34b of the second magnifier lens barrel 34 has a step part, and a second magnifier lens 36 is made to abut on the step part and then fixed. In a manufacture stage, the second magnifier lens 36 is inserted in the inner cylinder 34b of the second magnifier lens barrel 34, and made to abut on the step part thereof. The edge part 34c of the inner cylinder 34b is heated and pressured to be plastically deformed, and the second magnifier lens 36 is fixed. The edge part 34c of the inner cylinder 34b is plastically deformed, whereby its outer periphery has shape chamfered by a curved surface. The radius of curvature R1of the curved surface of the edge part 34c is smaller than the radius of curvature R2of the surface 36a of the second magnifier lens 36. COPYRIGHT: (C)2009,JPO&INPIT