Systems and methods for optical systems with exit pupil expander
Architectures are provided for expanding the exit pupil of systems including one or more waveguides. Various embodiments include a display device including one or more waveguides. One or more physical/optical parameters of the one or more waveguides and/or a wavelength of light input to the waveguide can be varied as the angle at which incoming light is incident on the waveguide varies in order to maintain phase correlation between different beamlets of the output light beam emitted from the one or more waveguides.
1. A method comprising:
receiving a beam into a waveguide at an input angle θ, the waveguide comprising a first edge, a second edge and a pair of reflective surfaces disposed between the first and the second edges, the pair of reflective surfaces separated by a gap having a gap height d, the waveguide comprising a material having a refractive index n, and at least one of the pair of reflective surfaces having a reflectivity r; and
varying at least one parameter selected from the group consisting of: a wavelength from the plurality of wavelengths, the gap height d, the refractive index n, and the reflectivity r, wherein the variation of the at least one parameter is correlated with variation of the input angle θ such that a first value of the at least one parameter is associated with a first value of the input angle θ and a second value of the at least one parameter is associated with a second value of the input angle θ and not with the first value of the input angle θ.
2. The method of claim 1 , wherein varying the at least one parameter comprises varying the input angle θ at a scan rate.
3. The method of claim 1 , wherein varying the at least one parameter comprises varying the at least one parameter at a rate substantially equal to a scan rate.
4. The method of claim 1 , wherein the least one parameter is the wavelength from the plurality of wavelengths.
5. The method of claim 1 , wherein the least one parameter is the gap height d.
6. The method of claim 1 , wherein the least one parameter is the refractive index n.
7. The method of claim 1 , wherein the least one parameter is the reflectivity r.
8. The method of claim 1 , wherein the beam is collimated.
9. The method of claim 1 , wherein the waveguide comprises an acousto-optic material.
10. The method of claim 1 , wherein the waveguide comprises a piezo-electric material.
11. The method of claim 1 , wherein the waveguide comprises an electro-optic material.
12. The method of claim 1 , wherein the waveguide comprises a micro-electro mechanical system (MEMS).
13. The method of claim 1 , wherein the waveguide is configured as an exit pupil expander that expands and multiplies the emitted beam.
14. The method of claim 1 , wherein the waveguide is configured to expand the beam to a spot size greater than 1 mm.
15. The method of claim 1 , wherein the waveguide is integrated in an augmented reality (AR) device.
16. The method of claim 1 , wherein the waveguide is integrated in a near-to-eye display device.
17. The method of claim 1 , wherein the waveguide is integrated in a virtual reality (VR) device.
18. The method of claim 1 , wherein the waveguide is integrated in eyewear comprising at least one of: a frame, one or more lenses or ear stems.