OPTICAL SYSTEM FOR PROJECTION, AND PROJECTION-TYPE DISPLAY DEVICE

WIPO Patent Application WO/2013/118471

A1

[Problem] To satisfactorily correct the displacement of the point of focus due to temperature variations in an optical system for projection, and to maintain the excellent optical properties of the system, even after correction, without requiring an increase in the size of the device. [Solution] An optical system which is for projection and in which the reduction side is telecentric, wherein a correction lens group (Gp) comprising a portion of the lens groups of the optical system for projection is configured so as to be mobile along the optical axis in order to correct the displacement of the point of focus due to temperature variations. The following conditional expressions (1) and (2) are satisfied.　In the expressions: ΔBf represents the amount the point of focus on the reduction side is moved when the correction lens group is moved fw/100; fw represents the focal length of the entire system; ΔAt represents the amount the tangential component of the astigmatism of the maximum angle is varied when the correction lens group is moved fw/100; and Imφ represents the maximum effective image circle diameter on the reduction side. (1) 0.5<|ΔBf/(fw/100)|<5.0 (2) |(ΔAt×fw)/(ΔBf×Imφ)|<0.12

NAGATOSHI YUKIKO (JP)

PCT/JP2013/000520

August 15, 2013

January 31, 2013

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FUJIFILM CORP (JP)

G02B15/167; G02B13/04; G02B15/20; G03B21/00; G03B21/14

JP2011039352A	2011-02-24
JP2008026864A	2008-02-07
JP2008536175A	2008-09-04
JP2002341243A	2002-11-27
JP2004264570A	2004-09-24
JP2012032717A	2012-02-16

YANAGIDA, Masashi et al. (JP)
Seiji Yanagida (JP)

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