Light output system with reflector and lens for highly spatially uniform light output
In some embodiments, optical systems with a reflector and a lens proximate a light output opening of the reflector provide light output with high spatial uniformity and high efficiency. The reflectors are shaped to provide substantially angularly uniform light output and the lens is configured to transform this angularly uniform light output into spatially uniform light output. The light output may be directed into a spatial light modulator, which modulates the light to project an image.
1. A head-mounted display system comprising:
a reflector comprising:
an input end;
an output end;
an even number of faceted sides extending between the input end and the output end, wherein two opposing sides of the reflector define a first curved cross-sectional profile and two other opposing sides of the reflector define a second curved cross-sectional profile different from the first cross-sectional profile;
a lens located one focal length of the lens away from the input end of the reflector;
a light modulating device configured to receive and to modulate light passing through the lens to form image light; and
a stack of waveguides, wherein each waveguide of the stack comprises:
a light incoupling optical element configured to incouple image light modulated by the light modulating device; and
a light outcoupling optical element,
wherein light incoupling optical elements of different waveguides, as seen in a top-down plan view, are laterally offset from one another.
2. The head-mounted display system of claim 1 , wherein the reflector is one of an array of reflectors.
3. The head-mounted display system of claim 2 , further comprising a plurality of light emitters, wherein each of the array of reflectors has an associated one of the plurality of light emitters disposed at an input end of the each of the reflectors.
4. The head-mounted display system of claim 3 , wherein some of the plurality of light emitters are configured to emit light of different wavelengths than others of the plurality of light emitters.
5. The head-mounted display system of claim 3 , wherein the light emitters are light emitting diodes.
6. The head-mounted display system of claim 1 , wherein the lens is disposed at the output end of the reflector, wherein the reflector extends one focal length of the reflector.
7. The head-mounted display system of claim 1 , wherein the first cross-sectional profile is a first compound parabolic concentrator (CPC) profile.
8. The head-mounted display system of claim 7 , wherein the second cross-sectional profile is a second compound parabolic concentrator (CPC) profile, wherein the first and the second CPC profiles are different.
9. The head-mounted display system of claim 1 , wherein the light modulating device comprises a spatial light modulator.
10. The head-mounted display system of claim 9 , wherein the spatial light modulator comprises a liquid crystal display (LCD).
11. The head-mounted display system of claim 10 , wherein the liquid crystal display is a liquid crystal on silicon (LCoS) display.
12. The head-mounted display system of claim 9 , further comprising a mask between the reflector and the spatial light modulator, wherein the mask has an opening smaller than the output end.
13. The head-mounted display system of claim 12 , wherein the mask is between the lens and the spatial light modulator.
14. The head-mounted display system of claim 12 , wherein the mask has a mask surface facing the reflector, wherein the mask surface is absorptive.
15. The head-mounted display system of claim 1 , wherein a cross-sectional shape of the input end is different from a cross-sectional shape of the output end.
16. The head-mounted display system of claim 1 , wherein the lens is one of a plurality of lenses, wherein the reflector is one of a plurality of reflectors formed by sidewalls of openings extending through a thickness of a common unitary body, wherein each reflector has an associated lens of the plurality of lenses forward of the output opening of the reflector.
17. The head-mounted display system of claim 16 , wherein the unitary body has a multi-tiered surface, wherein some reflectors have output openings on a different tier than other reflectors.
18. The display system of claim 17 , wherein each reflector has an associated light emitter, wherein some light emitters are configured to emit light of different wavelengths than other light emitters, wherein a height of the tiers varies with a wavelength of light emitted by an associated light emitter.