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 wearable heads-up display (“WHUD”) comprising:
a support structure that in use is worn on a head of a user;
a projector to generate light signals, the projector comprising at least one light source;
an optical waveguide comprising:
a volume of optically transparent material;
a first volume of liquid crystal carried by the volume of optically transparent material;
an in-coupler positioned to in-couple the light signals into the volume of transparent material; and
an out-coupler positioned to out-couple the light signals from the volume of transparent material; and
a controller communicatively coupled to the first volume of liquid crystal, wherein a refractive index of the first volume of liquid crystal is modulatable in response to signals from the controller, and wherein light signals that enter the optical waveguide propagate along at least a portion of a length of the optical waveguide by total internal reflection and an optical path of the light signals within the optical waveguide depends on the refractive index of the first volume of liquid crystal.
2 . The WHUD of claim 1 wherein the first volume of liquid crystal comprises a single modulatable region.
3 . The WHUD of claim 1 wherein the first volume of liquid crystal comprises at least two distinct, independently modulatable regions.
4 . The WHUD of claim 1 further comprising at least a second volume of liquid crystal carried by the volume of optically transparent material, wherein the path of the light signals is steered by the second volume of liquid crystal, and wherein the controller is communicatively coupled to the second volume of liquid crystal and a refractive index of the second volume is modulatable in response to signals from the controller.
5 . The WHUD of claim 4 wherein the second volume of liquid crystal comprises a single modulatable region.
6 . The WHUD of claim 4 wherein the second volume of liquid crystal comprises at least two distinct, independently modulatable regions.
7 . The WHUD of claim 1 further comprising a processor communicatively coupled to the controller to modulate the output of signals from the controller.
8 . The WHUD of claim 1 further comprising a processor communicatively coupled to the projector to modulate the generation of light signals.
9 . The WHUD of claim 1 wherein the support structure has the shape and appearance of an eyeglass frame and wherein the WHUD further comprises an eyeglass lens carried by the support structure.
10 . The WHUD of claim 9 wherein the waveguide is carried by the eyeglass lens.