US 11,852,836 B2
Directional illuminator and display device with pupil steering by tiltable reflector
Jacques Gollier, Sammamish, WA (US); Fenglin Peng, Redmond, WA (US); Ying Geng, Bellevue, WA (US); and Anqi Ji, 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 Jul. 13, 2021, as Appl. No. 17/374,888.
Prior Publication US 2023/0014577 A1, Jan. 19, 2023
Int. Cl. G02B 27/01 (2006.01); G02B 26/08 (2006.01); G02B 27/00 (2006.01); G02B 27/28 (2006.01)
CPC G02B 27/0179 (2013.01) [G02B 26/0833 (2013.01); G02B 27/0093 (2013.01); G02B 27/0172 (2013.01); G02B 27/286 (2013.01); G02B 2027/0174 (2013.01); G02B 2027/0187 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A directional illuminator for a display panel, the directional illuminator comprising:
a light source for providing a light beam;
a pupil-replicating lightguide; and
a tiltable reflector for receiving the light beam from the light source and redirecting the light beam towards the pupil-replicating lightguide at a variable incidence angle;
wherein the pupil-replicating lightguide is configured to propagate the light beam therein by reflection from opposed surfaces of the pupil-replicating lightguide;
the pupil-replicating lightguide comprising a polarization-selective out-coupling grating for propagating light at a first polarization therethrough substantially without changing direction of propagation and for out-coupling light at a second, orthogonal polarization state from the pupil-replicating lightguide, such that offset parallel portions of the light beam at the second polarization state are out-coupled along at least one of the opposed surfaces at a variable out-coupling angle corresponding to the variable incidence angle of the light beam;
the directional illuminator further comprising an array of tunable polarization rotators optically coupled to the pupil-replicating lightguide along at least one of its opposed surfaces and configured to tune a polarization state of the light beam propagating in the pupil-replicating lightguide in a spatially-selective manner.