PROJECTION LENS SYSTEM

WIPO Patent Application WO/2019/052156

A1

Disclosed in the present invention is a projection lens system. The projection lens system comprises, from an object side to an image side in sequence along an optical axis: a first lens having positive focal power, an object side surface thereof being a convex surface; a second lens having negative focal power; a third lens having positive focal power, an image side surface thereof being a convex surface; and a diaphragm. The optical centers of all the lenses are located on one straight line. The projection lens system meets the following conditions: f12>f3, (dn/dt)1<-50×10-6/°C, (dn/dt)2<-50×10-6/°C, and (dn/dt)3>-10×10-6/°C, wherein f12 represents a combined focal length of the first and second lenses, f3 represents the focal length of the third lens, and (dn/dt)1, (dn/dt)2, and (dn/dt)3 respectively represent rates of change of the refractive indexes of the first, second and third lenses with temperature. The projection lens system can counteract the impact on the focal length caused by thermal expansion of lenses and a structural part because of the reasonable distribution of the rates of change of the refractive indexes of the lenses with temperature, so that the projection lens system can achieve a stable focal length and is applicable to different temperature occasions.

LIU XUMING (CN)
WANG KEMIN (CN)
ZENG JIYONG (CN)
ZENG HAOJIE (CN)
BAO YUMIN (CN)
CHEN WEIJIAN (CN)

PCT/CN2018/081615

March 21, 2019

April 02, 2018

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JIANGXI LIANCHUANG ELECT CO LTD (CN)

G02B13/00; G02B1/00; G02B1/04; G02B7/02; G02B13/18

CN107505689A	2017-12-22
CN1760709A	2006-04-19
US20090153982A1	2009-06-18
CN203759344U	2014-08-06

TSINGYIHUA INTELLECTUAL PROPERTY LLC. (CN)

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