US 11,698,539 B2Granted

Short distance illumination of a spatial light modulator using a pancake lens assembly

AssigneeMeta Platforms Technologies, LLC

InventorsYing Geng, Jacques Gollier, Weichuan Gao, Babak Amirsolaimani

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Abstract

A display device includes a light source, a spatial light modulator (SLM), and an optical assembly that includes a first reflective surface and a second reflective surface that is opposite to the first reflective surface. The light source is configured to provide illumination light. The optical assembly is configured to receive the illumination light. At least a first portion of the illumination light received by the optical assembly is transmitted through the first reflective surface toward the second reflective surface, is reflected by the second reflective surface toward the first reflective surface, is reflected by the first reflective surface toward the second reflective surface, and is transmitted through the second reflective surface. The SLM is configured to receive and modulate the portion of the illumination light transmitted through the optical assembly, and to output the modulated light. A method performed by the display device is also disclosed.

Claims18

Dependent claims

A display device, comprising:

a light source configured to provide illumination light;
a spatial light modulator positioned to receive the illumination light;
and
an optical assembly including a first reflective surface and a second reflective surface opposite to the first reflective surface, the optical assembly being positioned relative to the light source so that at least a first portion of the illumination light received by the optical assembly is transmitted through the first reflective surface toward the second reflective surface, is reflected by the second reflective surface toward the first reflective surface, is reflected by the first reflective surface toward the second reflective surface, and is transmitted through the second reflective surface, wherein:
the optical assembly further includes a third reflective surface;
and
the first reflective surface is disposed between the second reflective surface and the third reflective surface so that the optical assembly:
transmits the at least a first portion of the illumination light through the third reflective surface toward the first reflective surface;
and
receives a second portion of the illumination light, distinct from the at least a first portion of the illumination light, such that the second portion of the illumination light is transmitted through the third reflective surface toward the first reflective surface, is reflected by the first reflective surface toward the third reflective surface, is reflected by the third reflective surface toward the first reflective surface, and is transmitted through the first reflective surface and the second reflective surface.

7 more elements

A method, comprising:

outputting illumination light from a light source;
receiving the illumination light at a first reflective surface of an optical assembly, the optical assembly having a second reflective surface located opposite to the first reflective surface, wherein the optical assembly further includes a third reflective surface;
transmitting a first portion of the illumination light through the first reflective surface toward the second reflective surface;
reflecting, at the second reflective surface, the first portion of the illumination light transmitted through the first reflective surface toward the first reflective surface;
reflecting, at the first reflective surface, the first portion of the illumination light reflected by the second reflective surface toward the second reflective surface;
transmitting, through the second reflective surface, the first portion of the illumination light reflected by the first reflective surface;
and
receiving the first portion of the illumination light at a spatial light modulator, wherein the method further comprises:
transmitting, through the third reflective surface, the first portion of the illumination light and a second portion of the illumination light toward the first reflective surface, the second portion of the illumination light being distinct from the first portion of the illumination light;
reflecting the second portion of the illumination light at the first reflective surface toward the third reflective surface;
reflecting, at the third reflective surface, the second portion of the illumination light reflected at the first reflective surface toward the third reflective surface;
transmitting, through the first reflective surface and the second reflective surface, the second portion of the illumination light reflected by the third reflective surface;
and
receiving the second portion of the illumination light at the spatial light modulator.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/858,331Filed 24 Apr 2020 · us provisional application
Priority: 13 Sep 2019
Published: US 2021/0080739 A118 Mar 2021
Granted: 11 Jul 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

G02B 27/283
For polarising: used for beam splitting or combining
G02B 6/005
Means for improving the coupling-out of light from the light guide: provided by one optical element, or plurality thereof, placed on the light…
G02B 6/0058
Means for improving the coupling-out of light from the light guide: varying in density, size, shape or depth along the light guide
G02B 6/0061
Varying in density, size, shape or depth along the light guide: to provide homogeneous light output intensity