Architectures and methods for outputting different wavelength light out of waveguides
View Patent ↗Architectures are provided for selectively outputting light for forming images, the light having different wavelengths and being outputted with low levels of crosstalk. In some embodiments, light is incoupled into a waveguide and deflected to propagate in different directions, depending on wavelength. The incoupled light then outcoupled by outcoupling optical elements that outcouple light based on the direction of propagation of the light. In some other embodiments, color filters are between a waveguide and outcoupling elements. The color filters limit the wavelengths of light that interact with and are outcoupled by the outcoupling elements. In yet other embodiments, a different waveguide is provided for each range of wavelengths to be outputted. Incoupling optical elements selectively incouple light of the appropriate range of wavelengths into a corresponding waveguide, from which the light is outcoupled.
1. A display system comprising:
a display comprising a waveguide stack comprising a plurality waveguides, each waveguide comprising a first major surface and a second major surface, wherein the waveguide stack comprises:
a first waveguide;
a first wavelength selective filter proximate to and on the first major surface of the first waveguide;
a first outcoupling optical element comprising diffractive elements proximate to and on the first wavelength selective filter;
a second waveguide over the first outcoupling optical element;
a second wavelength selective filter proximate to and on the first major surface of the second waveguide;
a second outcoupling optical element comprising diffractive elements proximate to and on the second wavelength selective filter of the second waveguide;
a first incoupling optical element configured to incouple incident light into the first waveguide; and
a second incoupling optical element configured to incouple incident light into the second waveguide;
wherein the first wavelength selective filter has a first rearward surface adjacent the first major surface and a first forward surface opposite the first rearward surface, the first wavelength selective filter configured to:
transmit incoupled light at a first plurality of wavelengths through the first rearward surface and reflect a portion of the transmitted light at the first plurality of wavelengths away from the first forward surface; and
wherein the first outcoupling optical element is configured to outcouple the incoupled light of the first plurality of wavelengths transmitted through the first wavelength selective filter.
2. The display system of claim 1 , wherein the first waveguide further comprises:
an additional wavelength selective filter on the second major surface, the additional wavelength selective filter having a second rearward surface adjacent the second major surface and a second forward surface opposite the second rearward surface, the additional wavelength selective filter configured to:
transmit incoupled light at second wavelengths different from the first plurality of wavelengths through the second rearward surface and reflect a portion of the transmitted light at the second wavelengths from the second forward surface; and
an additional outcoupling optical element comprising diffractive elements disposed on the additional wavelength selective filter, the additional outcoupling optical element configured to outcouple the incoupled light at the second wavelengths transmitted through the additional wavelength selective filter.
3. The display system of claim 1 , wherein each waveguide has an associated depth plane, wherein each waveguide is configured to produce an image appearing to originate from that waveguide's associated depth plane.
4. The display system of claim 1 , wherein different waveguides of the waveguide stack have different associated depth planes.
5. The display system of claim 4 , wherein the outcoupling optical elements for different depth planes have different optical power so as to provide different divergence of exiting light for each depth plane.
6. The display system of claim 2 , wherein each waveguide further comprises a light redistributing element configured to:
receive a portion of light at the first plurality of wavelengths and the second wavelengths transmitted through the first and the additional wavelength selective filters; and
distribute the light of the first plurality of wavelengths and the second wavelengths to the first and additional outcoupling optical elements.
7. The display system of claim 2 , wherein the first and the additional wavelength selective filters comprise dichroic filters.
8. The display system of claim 2 , wherein the first and the additional wavelength selective filters are configured to transmit light of the first plurality of wavelengths and the second wavelengths incident at angles between 0 degrees and 20 degrees with respect to a normal to the corresponding first or the second major surface of the first waveguide.
9. The display system of claim 2 , further comprising:
light distributing elements configured to:
receive incoupled light of the first plurality of wavelengths and the second wavelengths from the first incoupling optical element; and
distribute the light of the first plurality of wavelengths and the second wavelengths to the first and additional outcoupling optical elements.
10. The display system of claim 9 , wherein the light distributing elements comprise one or more diffractive optical elements.
11. The display system of claim 9 , wherein the light distributing elements are orthogonal pupil expanders.
12. The display system of claim 2 , wherein the additional wavelength selective filter is configured to transmit incoupled light at the second wavelengths and reflect incoupled light at wavelengths other than the wavelengths.
13. The display system of claim 1 , wherein the first outcoupling optical element comprises a surface relief grating, a hologram, or a switchable diffractive optical element.
14. The display system of claim 13 , wherein the switchable diffractive optical element comprises a switchable Polymer Dispersed Liquid Crystal (PDLC) grating.
15. The display system of claim 13 , wherein the surface relief grating comprises one or more of an analog surface relief grating (ASR) or a binary surface relief structure (BSR).
16. The display system of claim 13 , wherein the one or more gratings of the additional outcoupling optical element comprises one or more of a surface relief grating, a hologram, or a switchable diffractive optical element.
17. The display system of claim 16 , wherein the switchable diffractive optical element comprises a switchable Polymer Dispersed Liquid Crystal (PDLC) grating.
18. The display system of claim 1 , wherein the incoupling optical element includes one or more diffractive optical elements.
19. The display system of claim 18 , wherein the one or more diffractive optical elements comprises a surface relief grating or a hologram.
20. The display system of claim 19 , wherein the surface relief grating comprises one or more of an analog surface relief grating (ASR) or a binary surface relief structure (BSR).
21. The display system of claim 18 , wherein the one or more diffractive optical elements comprises a switchable diffractive optical element, the switchable diffractive optical element being a switchable Polymer Dispersed Liquid Crystal (PDLC) grating.
22. The display system of claim 1 , wherein the first wavelength selective filter is configured to transmit incoupled light at a first plurality of wavelengths and reflect incoupled light at wavelengths other than the first plurality of wavelengths.