US 11,940,632 B2
Virtual image display device
Daiki Matsumoto, Suwa (JP); Masatoshi Yonekubo, Nagano-ken (JP); and Takashi Takeda, Suwa (JP)
Assigned to SEIKO EPSON CORPORATION, Tokyo (JP)
Filed by SEIKO EPSON CORPORATION, Tokyo (JP)
Filed on Mar. 31, 2021, as Appl. No. 17/218,200.
Claims priority of application No. 2020-062280 (JP), filed on Mar. 31, 2020.
Prior Publication US 2021/0302754 A1, Sep. 30, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. G02B 27/14 (2006.01); G02B 26/08 (2006.01); G02B 27/01 (2006.01)
CPC G02B 27/144 (2013.01) [G02B 26/0816 (2013.01); G02B 27/0172 (2013.01); G02B 2027/0178 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A virtual image display device comprising:
an image light generating device;
a projection optical system comprising at least one lens and configured to project image light emitted from the image light generating device;
a folding mirror configured to reflect the image light such that an optical path of the image light from the projection optical system is bent toward a non-vertical and twisted direction with respect to an optical axis of the projection optical system;
a semi-transmissive mirror configured to reflect a portion of the image light from the folding mirror; and
a concave surface mirror configured to reflect, toward the semi-transmissive mirror, the image light reflected at the semi-transmissive mirror to form an exit pupil, wherein
an entrance pupil is formed between the projection optical system and the semi-transmissive mirror, and
the folding mirror is not transmissive and is disposed between the semi-transmissive mirror and the concave surface mirror when being viewed from a direction along the optical axis of the projection optical system, wherein the folding mirror includes a first mirror and a second mirror in an order of an optical path from the image light generating device.