SYSTEMS, DEVICES, AND METHODS FOR OPTICAL WAVEGUIDES
Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical device comprises an optical waveguide including a volume of optically transparent material, an in-coupler, an out-coupler, a volume of liquid crystal carried by the volume of optically transparent material, and a controller to modulate a refractive index of the volume of liquid crystal. Light is in-coupled into the waveguide and is propagated along a length of the waveguide by total internal. As the light crosses a thickness of the waveguide the light passes through or within the volume of liquid crystal and is refracted according to the modulated refractive index of the volume of liquid crystal. In this way, light signals can be steered to create an image and/or to move an exit pupil of an image. WHUDs that employ such optical waveguides are also described.
1 . A method of operating an optical device comprising a waveguide including a volume of optically transparent, a first volume of liquid crystal carried by the volume of optically transparent material, a controller communicatively coupled to the first volume of liquid crystal, an in-coupler, and an out-coupler, the method comprising:
in-coupling a first set of light signals into the waveguide by the in-coupler;
modulating a refractive index of the first volume of liquid crystal to a first refractive index by the controller;
propagating the first set of light signals along at least a portion of a length of the waveguide by total internal reflection;
steering the first set of light signals by the first volume of liquid crystal, wherein a path of the first set of light signals within the waveguide is dependent on the first refractive index of the first volume of liquid crystal; and
out-coupling the first set of light signals by the out-coupler.
2 . The method of claim 1 further comprising:
in-coupling a second set of light signals into the waveguide by the in-coupler;
modulating a refractive index of the first volume of liquid crystal to a second refractive index by the controller;
propagating the second set of light signals along at least a portion of the length of the waveguide by total internal reflection;
steering the second set of light signals by the first volume of liquid crystal, wherein a path of the second set of light signals within the waveguide is dependent on the second refractive index of the first volume of liquid crystal; and
out-coupling the first set of light signals by the out-coupler.
3 . The method of claim 1 wherein the optical device further comprises at least a second volume of liquid crystal carried by the volume of optically transparent material, wherein the second volume of liquid crystal is communicatively coupled to the controller, and wherein the method further comprises:
modulating a refractive index of the second volume of liquid crystal to a third refractive index by the controller; and wherein
steering the first set of light signals further includes:
steering the first set of light signals by the second volume of liquid crystal, wherein a path of the first set of light signals within the waveguide is dependent on the first refractive index of the first volume of liquid crystal and the third refractive index of the second volume of liquid crystal.