Title:
PROJECTION OPTICAL SYSTEM AND IMAGE PROJECTION DEVICE
Document Type and Number:
WIPO Patent Application WO/2019/082933
Kind Code:
A1
Abstract:
According to an embodiment, a projection optical system for an image projection device, that includes a plurality of lenses. The projection optical system satisfies conditional expression (1): where fw is a focal length of a lens having the weakest refractive power in the lenses and f is a focal length of the whole projection optical system.
Inventors:
KUBOTA TAKASHI (JP)
Application Number:
PCT/JP2018/039510
Publication Date:
May 02, 2019
Filing Date:
October 24, 2018
Export Citation:
Assignee:
RICOH CO LTD (JP)
KUBOTA TAKASHI (JP)
KUBOTA TAKASHI (JP)
International Classes:
G02B9/64; G02B13/16
Foreign References:
| US20090109543A1 | 2009-04-30 | |||
| JP5199148B2 | 2013-05-15 | |||
| JPS5210196B1 | 1977-03-22 | |||
| JP2011170309A | 2011-09-01 | |||
| JP2010249946A | 2010-11-04 | |||
| JP2714687B2 | 1998-02-16 | |||
| JP2014021309A | 2014-02-03 |
Attorney, Agent or Firm:
SAKAI, Hiroaki (JP)
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