ULTRA SHORT-THROW PROJECTION LENS UNIT

摘要

An ultra short-throw projection lens unit is disclosed, which is adapted to image a first image displayed on a display into an amplified second image. The ultra short-throw projection lens unit includes the following components that are arranged sequentially along an optical path: a first lens assembly, being adapted to image the first image into a first intermediate image; an aperture stop disposed at an imaging position of the first intermediate image; a second lens assembly, being adapted to image the first intermediate image into a second intermediate image; and a reflecting mirror, being adapted to reflect the second intermediate image to form the amplified second image. The first lens assembly, the aperture stop and the second lens assembly have a same principal optical axis. The ultra short-throw projection lens unit has a transmittance of 0.2˜0.25 and a focus of −2.9 mm˜−3.2 mm, and an offset of the first image relative to the principal optical axis is greater than 120%. The present disclosure can project a large-sized image at a short distance and with a high imaging quality.

主权项

1. An ultra short-throw projection lens unit, being adapted to image a first image displayed on a display into an amplified second image, the ultra short-throw projection lens unit comprising following components that are arranged sequentially along an optical path:
a first lens assembly, being adapted to image the first image into a first intermediate image; an aperture stop disposed at an imaging position of the first intermediate image; a second lens assembly, being adapted to image the first intermediate image into a second intermediate image; and a reflecting mirror disposed behind the second lens assembly, being adapted to reflect the second intermediate image to form the amplified second image; wherein the first lens assembly, the aperture stop and the second lens assembly have a same principal optical axis; and the ultra short-throw projection lens unit has a transmittance of 0.20˜.25 and a focus of −2.9 mm˜3.2 mm, and an offset of the first image relative to the principal optical axis is greater than 120%.