ULTRA SHORT-THROW PROJECTION LENS UNIT

摘要

Disclosed by the present invention is an ultra-short focus projection lens for forming a first image displayed on a display into an expanded second image. The ultra-short focus projection lens comprises: a first lens group for forming a first image arranged in the front and rear sides along an optical path into a first intermediate phase; an aperture diaphragm which is installed in the forming position of the first intermediate phase; a second lens group for forming the first intermediate phrase into a second intermediate phase; and a reflective mirror which forms an expanded second image by reflecting the second intermediate phase. The first lens group, the aperture diaphragm, and the second lens group have the same main optical axis, the projection rate of the ultra-short focus projection lens is 0.2-0.25, a focus distance is from -2.9 mm to -3.2 mm, and a shift amount for the main optical axis of a first image is equal to or more than 120%. The present invention is able to project a large image in a short range and has excellent quality in forming a phase.