Light field generation system including directionally-sensitive optical element for improved contrast

Patent metadata

Field	Value
Publication number	US-11009770-B2
Application number	US-201916540650-A
Country	US
Kind code	B2
Filing date	Aug 14, 2019
Priority date	Aug 14, 2018
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A light field generation system includes a two dimensional emitter array for projecting light and a directionally-sensitive optical element in front of the emitter array but before a directional diffuser. Certain classes of emitters are intended to project information principally along one axis (e.g. amplitude modulated in the horizontal plane, i.e. so that each eye sees a potentially different image) and are the basis of horizontal-parallax-only (HPO) displays. Examples include surface acoustic wave (SAW) modulators, such as edge-emitting or surface-emitting modulators. They often project undesired or stray light along directions along a different axis (e.g. vertically) and the diffuser will also spread the visibility of the stray light field components. Thus, the directionally-sensitive optical element will improve contrast in this scenario.

First claim

What is claimed is:

1. A method for improving contrast in a light field generation system, comprising:
projecting light with a two dimensional emitter array;
blocking stray light with a directionally-sensitive optical element in front of the emitter array; and
placing a directional diffuser after the directionally-sensitive optical element.

2. A light field generation system, including:
a two dimensional emitter array for projecting light;
a directionally-sensitive optical element in front of the emitter array; and
a directional diffuser after the directionally-sensitive optical element.

3. A light field generation system, including:
a two dimensional emitter array for projecting light;
a directionally-sensitive optical element in front of the emitter array; and
wherein the two dimensional emitter array comprises a two dimensional array of surface acoustic wave (SAW) modulators.

4. A system as claimed in claim 3 , wherein the SAW modulators are surface-emitting.

5. A system as claimed in claim 3 , wherein the SAW modulators are edge-emitting.

6. A light field generation system, including:
a two dimensional emitter array for projecting light, wherein each emitter of the two dimensional emitter array projects light with controllable amplitudes in an x-z plane; and
a directionally-sensitive optical element in front of the emitter array that blocks stray light along a y-axis direction from the emitter array.

7. A system as claimed in claim 6 , wherein the directionally-sensitive optical element comprises an aperture grille.

8. A system as claimed in claim 7 , wherein a pitch between apertures of the aperture grille matches a pitch between rows of emitters of the emitter array.

9. A system as claimed in claim 6 , wherein the directionally-sensitive optical element comprises microlouver material.

10. A system as claimed in claim 6 , wherein the directionally-sensitive optical element comprises arrays of diffractive optical elements, a reflective element, or a holographic optical element.

11. A system as claimed in claim 6 , wherein the light field generation system is a horizontal parallax only system.

12. A method for improving contrast in a light field generation system, comprising:
projecting light with a two dimensional emitter array, with each emitter of the two dimensional emitter array projecting light with controllable amplitudes in an x-z plane; and
blocking stray light along y-axis direction from the emitter array with a directionally-sensitive optical element in front of the emitter array.

13. A method as claimed in claim 12 , wherein the light field generation system is a horizontal parallax only system.

14. A method as claimed in claim 12 , wherein the two dimensional emitter array comprises a two dimensional array of surface acoustic wave (SAW) modulators.

15. A method as claimed in claim 14 , wherein the SAW modulators are edge-emitting.

16. A method as claimed in claim 14 , wherein the SAW modulators are surface-emitting.

17. A method as claimed in claim 12 , wherein the directionally-sensitive optical element comprises an aperture grille.

18. A method as claimed in claim 17 , wherein a pitch between apertures of the aperture grille matches a pitch between rows of emitters of the emitter array.

19. A method as claimed in claim 12 , wherein the directionally-sensitive optical element comprises microlouver material.

20. A method as claimed in claim 12 , wherein the directionally-sensitive optical element comprises arrays of diffractive optical elements, a reflective element, or a holographic optical element.

Assignees

• Charles Stark Draper Laboratory Inc

Inventors

• Favalora Gregg E

Classifications

• G02F2201/302

  grating coupler · CPC title

• G02F1/335 Primary

  having an optical waveguide structure · CPC title

• G02F2203/22

  diffractive · CPC title