US 11,709,308 B2
Optical waveguide beam splitter for directional illumination of display
Ying Geng, Bellevue, WA (US); Jacques Gollier, Sammamish, WA (US); Fenglin Peng, Redmond, WA (US); and Weichuan Gao, Redmond, WA (US)
Assigned to META PLATFORMS TECHNOLOGIES, LLC, Menlo Park, CA (US)
Filed by META PLATFORMS TECHNOLOGIES, LLC, Menlo Park, CA (US)
Filed on Apr. 29, 2020, as Appl. No. 16/862,403.
Claims priority of provisional application 62/850,521, filed on May 20, 2019.
Prior Publication US 2020/0371389 A1, Nov. 26, 2020
Int. Cl. F21V 8/00 (2006.01); G02B 5/30 (2006.01); G02B 6/10 (2006.01); G02B 27/00 (2006.01); G02B 27/01 (2006.01); G02B 27/14 (2006.01); G02B 27/28 (2006.01); G02F 1/13 (2006.01); G02B 6/12 (2006.01)
CPC G02B 6/0056 (2013.01) [G02B 5/3025 (2013.01); G02B 6/0028 (2013.01); G02B 6/0031 (2013.01); G02B 6/105 (2013.01); G02B 27/0093 (2013.01); G02B 27/0172 (2013.01); G02B 27/145 (2013.01); G02B 27/283 (2013.01); G02B 6/0025 (2013.01); G02B 2006/12116 (2013.01); G02B 2027/0125 (2013.01); G02B 2027/0138 (2013.01); G02B 2027/0174 (2013.01); G02B 2027/0178 (2013.01); G02F 1/1326 (2013.01)] 19 Claims
OG exemplary drawing
 
1. An optical device, comprising:
a light source configured to provide illumination light;
a waveguide having:
an input surface;
an output surface distinct from and non-parallel to the input surface; and
an output coupler, wherein:
the waveguide is configured to:
receive, at the input surface, the illumination light provided by the light source;
propagate the illumination light via total internal reflection; and
redirect, by the output coupler, the illumination light so that the illumination light is output from the output surface for illuminating a spatial light modulator; and
the output coupler is configured to:
receive the illumination light at a first location on the output coupler;
redirect from the first location on the output coupler a first portion of the illumination light in a first direction and redirect from the first location on the output coupler a second portion of the illumination light that is mutually exclusive to the first portion of the illumination light in a second direction that is distinct from the first direction;
receive the second portion of the illumination light at a second location on the output coupler distinct and separate from the first location on the output coupler; and
redirect from the second location on the output coupler a third portion of the illumination light that is a subset of the second portion of the illumination light in the first direction and redirect from the second location on the output coupler a fourth portion of the illumination light that is a subset of the second portion of the illumination light and mutually exclusive to the third portion of the illumination light in the second direction;
a reflective polarizer disposed on a first side of the waveguide and configured to transmit light having a first polarization and reflect light having a second polarization different from the first polarization;
a flat reflector disposed on a second side of the waveguide, that is opposite to the first side of the waveguide, to receive the light reflected by the reflective polarizer and reflect the received light toward the reflective polarizer; and
an optical retarder disposed between the reflective polarizer and the flat reflector.