Title:
PROJECTION-TYPE VIDEO DISPLAY DEVICE
Document Type and Number:
WIPO Patent Application WO/2014/174600
Kind Code:
A1
Abstract:
Provided is a projection-type video display device in which further reduction in size of a projection optical system and further reduction of projection distance are realized. This projection-type video display device is provided with a lens group including a plurality of lenses, a free-form surface lens, and a free-form surface mirror for projecting light from the free-form surface lens onto a screen. The lens group is provided with: a biconvex first lens, a smaller curvature radius of which is oriented toward a video display element side; an aspherical second lens; a biconvex third lens; a biconcave fourth lens; a biconvex fifth lens; a biconvex sixth lens, a smaller curvature radius of which is oriented toward a magnification side; a meniscus-shaped seventh lens, a convex face of which is oriented toward a reduction side; a biconcave eighth lens; a biconvex ninth lens, a smaller curvature radius of which is oriented toward the magnification side; and a meniscus-shaped tenth lens, a convex face of which is oriented toward the magnification side. The third through fifth lenses constitute a triplet lens, and the free-form surface lens is meniscus-shaped, a convex face of which is oriented toward the magnification side.
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Inventors:
YATSU MASAHIKO (JP)
Application Number:
PCT/JP2013/061967
Publication Date:
October 30, 2014
Filing Date:
April 24, 2013
Export Citation:
Assignee:
HITACHI MAXELL (JP)
International Classes:
G02B17/08
Foreign References:
| JP2007334052A | 2007-12-27 | |||
| JP2008009223A | 2008-01-17 | |||
| JP2010181672A | 2010-08-19 | |||
| JP2012108267A | 2012-06-07 | |||
| JP2013029788A | 2013-02-07 |
Attorney, Agent or Firm:
SEIRYO I. P. C. (JP)
青稜 patent business corporation (JP)
青稜 patent business corporation (JP)
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