US 11,703,622 B2
Polarization-based filters with angle-sensitive transmission having circular polarizers
Gary D. Sharp, Boulder, CO (US); and Anthony D. McGettigan, Santa Rosa, CA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by META PLATFORMS TECHNOLOGIES, LLC, Menlo Park, CA (US)
Filed on Oct. 12, 2019, as Appl. No. 16/600,471.
Claims priority of provisional application 62/745,060, filed on Oct. 12, 2018.
Prior Publication US 2020/0116912 A1, Apr. 16, 2020
Int. Cl. G02F 1/1335 (2006.01); G02B 5/30 (2006.01); G02B 27/28 (2006.01)
CPC G02B 5/3083 (2013.01) [G02B 5/3066 (2013.01); G02F 1/133528 (2013.01); G02B 27/286 (2013.01); G02F 1/133541 (2021.01)] 30 Claims
OG exemplary drawing
 
1. An angle-filter, comprising:
exactly two polarizers that function as circular polarizers along a same light beam path, comprising:
an input circular polarizer; and
an analyzing circular polarizer; and
a retarder positioned between the circular polarizers, the retarder having a thickness-direction retardation;
wherein the thickness-direction retardation of the retarder (R1h) is selected to produce a prescribed angle-of-incidence dependent transmission function, and
wherein the circular polarizers reduce the amount of azimuth-dependence in the transmission function.