Invention Grant
- Patent Title: Projection-type video display device
- Patent Title (中): 投影式视频显示装置
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Application No.: US14786944Application Date: 2013-04-24
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Publication No.: US09581795B2Publication Date: 2017-02-28
- Inventor: Masahiko Yatsu
- Applicant: Hitachi Maxell, Ltd.
- Applicant Address: JP Osaka
- Assignee: HITACHI MAXELL, LTD.
- Current Assignee: HITACHI MAXELL, LTD.
- Current Assignee Address: JP Osaka
- Agency: McDermott Will & Emery LLP
- International Application: PCT/JP2013/061967 WO 20130424
- International Announcement: WO2014/174600 WO 20141030
- Main IPC: G03B21/28
- IPC: G03B21/28 ; G02B17/08 ; G02B13/04 ; G02B13/00 ; G03B9/64 ; G03B21/14 ; G02B13/16 ; G02B13/18 ; H04N9/31

Abstract:
Provided is a projection-type video display device implementing further reduction of a projection distance and further miniaturization of a projection optical system. The projection-type video display device includes a lens group which includes a plurality of lenses, a free-form-surface lens, and a free-form-surface mirror which projects light from the free-form-surface lens on a screen, wherein the lens group includes a third lens which has a bi-convex shape, a fourth lens which has a bi-concave shape, a fifth lens which has a bi-convex shape, the third to fifth lenses constitute a triplet lens, and wherein the free-form-surface lens has a meniscus lens shape of which a convex surface is oriented toward the magnification side.
Public/Granted literature
- US20160077319A1 PROJECTION-TYPE VIDEO DISPLAY DEVICE Public/Granted day:2016-03-17
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