Freeform-prism eyepiece with illumination waveguide
An imaging panel includes a light source, a reflective image-forming array, and a freeform-prism eyepiece. The light source includes a light emitter and a waveguide having a grating. The waveguide is configured to confine the light from the light emitter and to release the light through the grating. The reflective image-forming array is configured to form a display image using light from the light source and to reflect the display image back through the waveguide. The freeform-prism eyepiece configured to receive the display image and to present the display image for viewing, together with an external image transmitted through the eyepiece.
1. An imaging panel comprising:
a light source including a light emitter and a waveguide having a grating, the waveguide configured to confine the light from the light emitter and to release the light through the grating;
a reflective image-forming array configured to form a display image using light from the light source and to reflect the display image back through the waveguide; and
a freeform-prism eyepiece configured to receive the display image and to present the display image for viewing, together with an external image transmitted through the eyepiece.
2. The imaging panel of claim 1 wherein the waveguide is substantially transparent to the display image reflected therethrough.
3. The imaging panel of claim 1 wherein the light emitter is among a plurality of light emitters arranged within the light source, and wherein the plurality of light emitters includes a red-emitting laser, a blue-emitting laser, and a green-emitting laser.
4. The imaging panel of claim 3 wherein the waveguide is one of a plurality of waveguides stacked within the light source, and wherein each waveguide has a grating configured to diffract emission from the red-emitting laser, the blue-emitting laser, or the green-emitting laser.
5. The imaging panel of claim 4 wherein each grating is a Bragg grating.
6. The imaging panel of claim 5 wherein the red-emitting laser, the blue-emitting laser, and the green-emitting laser are configured to emit in sequence.
7. The imaging panel of claim 6 wherein each Bragg grating is electronically switchable between a passive, transparent state and an active, diffractive state, and is maintained in the passive state except during firing of the laser whose emission it is configured to diffract.
8. The imaging panel of claim 1 wherein the grating is configured to uniformly illuminate the reflective image-forming array.
9. The imaging panel of claim 1 wherein the waveguide is arranged parallel to and stacked upon the reflective image-forming array.
10. The imaging panel of claim 1 wherein the reflective image-forming array is a liquid-crystal-on-silicon array.
11. The imaging panel of claim 1 wherein the reflective image-forming array is a digital micromirror array.
12. The imaging panel of claim 1 wherein the grating is a surface-relief type grating.
13. The imaging panel of claim 1 wherein the light emitter is a non-lasing light-emitting diode.
14. A head-mounted display device comprising:
a light source including a light emitter and a waveguide having a grating, the waveguide configured to confine the light from the light emitter and to release the light through the grating;
a reflective image-forming array configured to form a display image using light from the light source and to reflect the display image back through the waveguide;
a freeform-prism eyepiece configured to receive the display image and to present the display image for viewing, together with an external image transmitted through the eyepiece; and
a controller configured to provide control signals to the reflective image-forming array, the control signals configured to cause the reflective image-forming array to form the display image.
15. The head-mounted display device of claim 14 wherein the external image originates from real-world imagery external to the head-mounted display device.