Invention Grant
- Patent Title: Projection-type image display apparatus
- Patent Title (中): 投影式图像显示装置
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Application No.: US11755878Application Date: 2007-05-31
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Publication No.: US07766487B2Publication Date: 2010-08-03
- Inventor: Takanori Hisada , Koji Hirata , Masahiko Yatsu
- Applicant: Takanori Hisada , Koji Hirata , Masahiko Yatsu
- Applicant Address: JP Tokyo
- Assignee: Hitachi, Ltd.
- Current Assignee: Hitachi, Ltd.
- Current Assignee Address: JP Tokyo
- Agency: Antonelli, Terry, Stout & Kraus, LLP.
- Priority: JP2006-153587 20060601
- Main IPC: G03B21/14
- IPC: G03B21/14

Abstract:
A projection-type image display apparatus for projecting an image, enlargedly, onto a projection surface, comprises: an image display element; a lens group, being disposed behind the image display element, comprising therein, a front lens group made up with a plural number of lenses, including, at least, a refractive lens, having a positive power and being rotationally symmetric in a surface configuration thereof, and a rear lens group made up with a plural number of lenses, including, at least, a lens having a free curved surface configuration and being rotationally asymmetric, thereby emitting the image displayed on the image display element; a reflection mirror for reflecting the light from the lens group, thereby projection onto the projection surface, obliquely; and a movement member for moving the plural number of lenses of the rear lens group.
Public/Granted literature
- US20070279598A1 Projection-Type Image Display Apparatus Public/Granted day:2007-12-06
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