US 12,461,370 B2
Lightguide with radial pupil replication and visual display based thereon
Ningfeng Huang, Redmond, WA (US); Alexander Koshelev, Redmond, WA (US); and Giuseppe Calafiore, Redmond, CA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed on Dec. 20, 2021, as Appl. No. 17/556,888.
Claims priority of provisional application 63/242,740, filed on Sep. 10, 2021.
Prior Publication US 2023/0085138 A1, Mar. 16, 2023
Int. Cl. G02B 27/01 (2006.01)
CPC G02B 27/0172 (2013.01) [G02B 2027/0178 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A pupil-replicating lightguide comprising:
a slab of a transparent material for guiding light therein, the slab having length and width dimensions parallel to a slab plane, and a thickness dimension perpendicular to the slab plane;
a first grating supported by the slab for in-coupling the light into the slab; and
a second grating supported by the slab for redirecting the light in the slab;
wherein:
a perimeter grating is supported by the slab and disposed proximate to a perimeter of the slab, such that the perimeter grating is configured to reflect the light redirected by the second grating back toward the second grating; and
an orthogonal projection of the perimeter grating onto the slab plane surrounds the orthogonal projection of the second grating onto the slab plane.