3-dimensional electro-optical see-through displays
A display placed in an optical pathway extending from an entrance pupil of a person's eye to a real-world scene beyond the eye. The display includes at least one 2-D added-image source that is addressable to produce a light pattern corresponding to a virtual object. The source is situated to direct the light pattern toward the person's eye to superimpose the virtual object on an image of the real-world scene as perceived by the eye via the optical pathway. An active-optical element is situated between the eye and the added-image source at a location that is optically conjugate to the entrance pupil and at which the active-optical element forms an intermediate image of the light pattern from the added-image source. The active-optical element has variable optical power and is addressable to change its optical power to produce a corresponding change in perceived distance at which the intermediate image is formed, as an added image to the real-world scene, relative to the eye.
1. A stereoscopic headmounted display for creating an image of a virtual 3-D scene containing objects located at differing 3-D depths within the virtual 3-D scene, the headmounted display comprising:
a 2-D display addressable to produce at least two light patterns corresponding to respective virtual objects located at differing 3-D depths within the virtual 3-D scene, each of the respective virtual objects located at a respective virtual distance associated with a respective accommodation cue provided by the 2-D display;
an active-optical element disposed at a location to receive the at least two light patterns emitted by the 2-D display, the active-optical element having an addressable and variable optical power corresponding to the differing 3-D depths of the virtual objects within the virtual 3-D scene; and
a controller in communication with the 2-D display and the active-optical element, and configured to create and update the at least two patterns on the 2-D display and configured to change the variable optical power of the active-optical element synchronously with the update of the at least two patterns to match to the variable optical power to the respective accommodation cues being provided by the 2-D display
wherein the active-optical element is addressable to change the variable optical power at a switching rate, f N , given by
f
N
=
f
min
N
,
where N is the total number of focal planes and f min is a lowest response speed (in Hz) among the 2-D display, the active-optical element, and electronics driving the 2-D display and active-optical element.
2. The stereoscopic headmounted display of claim 1 , wherein the 2-D display comprises a 2-D array of light-producing pixels.
3. The stereoscopic headmounted display of claim 1 , comprising a spherical mirror disposed on the optical axis in optical communication with the active-optical element and at a location such that the active-optical element is disposed between the spherical mirror and the 2-D display.
4. The stereoscopic headmounted display of claim 3 , wherein the active-optical element is offset along the optical axis from the center of a radius of curvature, R, of the spherical mirror.
5. The stereoscopic headmounted display of claim 4 , wherein the active-optical element is offset by Δ, and an exit pupil of the 2-D display is magnified by an amount m p ,
m
p
=
R
R
+
2
Δ
.
6. The stereoscopic headmounted display of claim 1 , wherein the active-optical element comprises a refractive active-optical element.
7. The stereoscopic headmounted display of claim 6 , wherein the refractive active-optical element comprises a liquid lens.
8. The stereoscopic headmounted display of claim 1 , wherein the controller is configured to change the optical power of the active-optical element to produce a corresponding change in perceived distance at which an intermediate image is formed.
9. The stereoscopic headmounted display of claim 8 , wherein the stereoscopic headmounted display is a see-through display and wherein the intermediate image is added to a real-world scene observable through the see-through display.
10. The stereoscopic headmounted display of claim 8 , wherein a distance at which the intermediate image is formed can serve as an accommodation cue for the person with respect to the intermediate image.
11. The stereoscopic headmounted display of claim 8 , wherein the controller is configured to change the optical power of the active-optical element to correspondingly move the intermediate image along an optical pathway relative to a focal plane to produce a corresponding change in distance of the image relative to the person's eye.
12. The stereoscopic headmounted display of claim 1 , wherein the stereoscopic headmounted display is a see-through display.
13. The stereoscopic headmounted display of claim 1 , wherein the active-optical element is configured to change the variable optical power at a rate of at least 60 Hz.