High performance backlight device using photonic integrated circuits
Embodiments of the present disclosure relate to a high performance backlight device with photonic integrated circuits. The backlight device includes a light source assembly, a multi-mode slab waveguide, and an out-coupling assembly. The light source assembly includes one or more light sources that generate light in accordance with emission instructions, and a de-speckling mechanism that conditions the generated light to mitigate speckle. The multi-mode slab waveguide in-couples the conditioned light and expands the in-coupled conditioned light in two dimensions to form a homogenous area of conditioned light within a region of the multi-mode slab waveguide. The out-coupling assembly out-couples the conditioned light from the region in a direction normal to the two dimensions, wherein a light modulation layer forms an image from the out-coupled conditioned light.
1. A backlight device comprising:
a light source assembly including:
a plurality of light sources configured to generate light in accordance with emission instructions and in a plurality of color channels, and
a de-speckling mechanism configured to condition the generated light to mitigate speckle;
a multi-mode slab waveguide configured to in-couple the conditioned light and expand the in-coupled conditioned light in two dimensions to form a homogenous area of conditioned light within a region of the multi-mode slab waveguide; and
an out-coupling assembly configured to out-couple the conditioned light from the region in a direction normal to the two dimensions, wherein a light modulation layer forms an image from the out-coupled conditioned light.
2. The backlight device of claim 1 , wherein the de-speckling mechanism includes a plurality of phase modulators configured to randomize phases of the generated light.
3. The backlight device of claim 1 , wherein the plurality of light sources comprises at least one of:
one or more lasers,
one or more superluminescent light emitting devices, and
one or more nonlinear light sources configured to generate the light.
4. The backlight device of claim 1 , wherein a single light source of the plurality of light sources is configured to feed with the generated light a plurality of ports of the light source assembly, each port of the plurality of ports comprising a respective phase modulator coupled to the multi-mode slab waveguide.
5. The backlight device of claim 1 , wherein the plurality of light sources comprises a plurality of independent light sources configured to directly guide the generated light of the plurality of color channels into the multimode slab waveguide, and wherein the multimode slab waveguide comprises a light reflector that reflects the light of the plurality of color channels into a folded light path toward the out-coupling assembly.
6. The backlight device of claim 1 , wherein the multi-mode slab waveguide comprises one or more material layers on a substrate each having a different refractive index, the one or more material layers configured to expand the in-coupled conditioned light.
7. The backlight device of claim 1 , wherein the multi-mode slab waveguide comprises at least one of: a reflector element, a deflector element, and a diffractor element configured to expand the in-coupled conditioned light.
8. The backlight device of claim 1 , wherein the out-coupling assembly comprises one or more grating elements attached to the multi-mode slab waveguide.
9. The backlight device of claim 1 , wherein the out-coupling assembly is etched into the multi-mode slab waveguide.
10. The backlight device of claim 1 , wherein the out-coupling assembly comprises an array of grating couplers.
11. The backlight device of claim 1 , wherein the out-coupling assembly comprises an array of scatterer groups.
12. The backlight device of claim 1 , wherein the out-coupling assembly comprises an anti-reflective coating on a side of the out-coupling assembly that is adjacent to the multi-mode slab waveguide.
13. The backlight device of claim 1 , wherein a size of each out-coupling pixel on the out-coupling assembly is larger than a size of a respective pixel on the light modulation layer.
14. The backlight device of claim 1 , wherein the backlight device is integrated into a display assembly capable of being part of a head-mounted display.
15. A display assembly comprising:
a display panel; and
a backlight device coupled to the display panel, the backlight device comprising:
a light source assembly comprising:
a plurality of light sources configured to generate light in accordance with emission instructions and in a plurality of color channels, and
a de-speckling mechanism configured to condition the generated light to mitigate speckle,
a multi-mode slab waveguide configured to in-couple the conditioned light and expand the in-coupled conditioned light in two dimensions to form a homogenous area of conditioned light within a region of the multimode slab waveguide, and
an out-coupling assembly configured to out-couple the conditioned light from the region in a direction normal to the two dimensions, wherein the display panel forms an image from the out-coupled conditioned light.
16. The display assembly of claim 15 , wherein the light source assembly is further configured to directly guide the generated light of the plurality of color channels into the multimode slab waveguide, wherein the multimode slab waveguide comprises a light reflector that reflects the light of the plurality of color channels into a folded light path toward the out-coupling assembly.
17. The display assembly of claim 15 , wherein:
the plurality of light sources comprises at least one of: one or more lasers, one or more superluminescent light emitting devices, and one or more nonlinear light sources configured to generate the light;
the multi-mode slab waveguide comprises one or more material layers on a substrate each having a different refractive index, the one or more material layers configured to expand the in-coupled conditioned light; and
the out-coupling assembly comprises one or more grating elements attached to the multi-mode slab waveguide.
18. A backlight device comprising:
a light source assembly comprising:
one or more light sources configured to generate light in accordance with emission instructions, and
a plurality of ports, wherein a single light source of the one or more light sources is configured to feed with the generated light the plurality of ports, and each port of the plurality of ports comprises a phase modulator configured to condition the generated light to mitigate speckle;
a multi-mode slab waveguide configured to in-couple the conditioned light from the plurality of ports, wherein each respective phase modulator of each port of the plurality of ports is coupled to the multi-mode slab waveguide, and to expand the in-coupled conditioned light in two dimensions to form a homogenous area of conditioned light within a region of the multi-mode slab waveguide; and
an out-coupling assembly configured to out-couple the conditioned light from the region in a direction normal to the two dimensions, wherein a light modulation layer forms an image from the out-coupled conditioned light.
19. The backlight device of claim 18 , wherein the light source assembly further comprises:
a bus waveguide configured to feed the generated light from the single light source to the plurality of ports.
20. The backlight device of claim 19 , wherein the light source assembly further comprises:
a plurality of tap couplers coupled to the bus waveguide and to the plurality of ports, the plurality of tap couplers configured to feed the generated light from the bus waveguide to the plurality of respective phase modulators in each of the plurality of ports.