Compact rim-mounted curved optical see-through lightguide based eyewear as mobile augmented reality display
An optical device includes a lightguide and a display at a top of a head mountable frame. The display is oriented toward an eye-side of the optical device. A reflector is positioned at an eye-side of the optical device and directs light into the lightguide. This orientation and arrangement of components reduces light leaking out of the optical device. The lightguide includes curved first and second surfaces. The device reflects light through the curved first surface to a user eye for augmented reality vision. A head mountable frame supports the display, the reflector, and the lightguide.
1. An optical device comprising:
a display oriented toward an eye-side of the optical device and configured to emit light toward the eye-side of the optical device based on an input signal;
a lightguide having:
a curved first surface at the eye-side of the optical device; and
a curved second surface for reflecting the light through the curved first surface to a user eye;
a reflector having a reflective surface positioned at the eye-side relative to the display above at least one of the curved first surface and the curved second surface of the lightguide, wherein the reflector is positioned to reflect light from the display into the lightguide; and
a head mountable frame supporting the display, the reflective surface, and the lightguide, wherein the display is positioned at a top of the head mountable frame.
2. The optical device of claim 1 , further comprising:
a field lens having a first surface to receive light from the reflector and a second surface oriented toward an interior of the lightguide, wherein the field lens is positioned at a top side of the lightguide.
3. The optical device of claim 2 , wherein a second surface of the field lens, oriented toward the lightguide, is spherical in shape.
4. The optical device of claim 2 , wherein a surface of the field lens, the lightguide, or both the field lens and the lightguide is shaped to correct an astigmatism of a computer-generated image of the light from the display in at least one of a first dimension and a second dimension as the light progresses from the display toward the user eye.
5. The optical device of claim 1 , wherein the display, the lightguide, and the reflector are positioned so as to reflect light at least two times from at least one of the curved first surface and the curved second surface of the lightguide before the light from the display reaches the user eye.
6. The optical device of claim 1 , wherein the lightguide includes a third surface at a top of the lightguide for receiving light from the reflector.
7. The optical device of claim 1 , wherein the display, the reflector, and the lightguide are arranged in the optical device to provide at least a 10 degree diagonal field of view with respect to a resulting image from the display.
8. The optical device of claim 1 , wherein the display, the reflector, and the lightguide are arranged in the optical device to provide at least a 3:1 horizontal-to-vertical aspect ratio with respect to a resulting image from the display.
9. The optical device of claim 1 , wherein an eye relief distance from the curved first surface of the lightguide to the user eye is 26 millimeters or less.
10. The optical device of claim 1 , wherein a top edge of a resulting image is located at least 2 degrees below a center axis of a pupil of the user eye.
11. The optical device of claim 1 , wherein a resulting image from the display is oriented with at least 2 degrees of pantoscopic tilt relative to the user eye.
12. The optical device of claim 1 , wherein a fourth surface of the lightguide is spherical having a spherical dimension between 80 mm and 100 mm of curvature.
13. The optical device of claim 1 , wherein the curved second surface of the lightguide includes a combiner for a resulting image from the display, and wherein a resulting image from the display and a world view form a combined view to the user eye.
14. The optical device of claim 1 , further comprising:
a filler piece having a first surface shaped to conform to a world-side fourth surface of the lightguide and shaped to fit into a recess in the lightguide, wherein the filler piece has a second surface shaped to conform to the curved second surface of the lightguide.
15. The optical device of claim 1 , wherein the first and second curved surfaces are transparent and the lightguide further includes:
a transparent third surface oriented toward the top of the head mountable frame for receiving display light, the display light reflecting inside the lightguide via total internal reflection; and
a transparent curved fourth surface shaped to reflect light from the display through the transparent curved first surface to a user eye and to combine the display light with ambient light entering from a world-side through the transparent curved second surface of the lightguide,
wherein the reflector is positioned on the eye-side of the optical device and oriented to direct light from the display into the lightguide through the transparent third surface.
16. The optical device of claim 15 , further comprising a display lens positioned at the top of the lightguide, wherein a first surface of the display lens is oriented toward the third surface of the lightguide, and wherein the first surface of the display lens is curved in a freeform manner along a first axis and the first surface of the display lens is curved along a second axis perpendicular to the first axis thereby augmenting a resultant image area in at least one dimension at the transparent curved fourth surface of the lightguide.
17. The optical device of claim 16 , wherein a curvature of the transparent curved fourth surface of the lightguide is freeform along at least one axis, and wherein light from the display is reflected at least two times by internal reflection from each of the curved first and second surfaces of the lightguide before reflecting from the transparent curved fourth surface and being transmitted through the transparent curved first surface on the eye-side of the lightguide toward a user eye.
18. The optical device of claim 16 , wherein a curvature of the transparent curved third surface of the lightguide is freeform along at least one axis thereby augmenting a resultant image area in at least one dimension at the transparent curved fourth surface of the lightguide.
19. An apparatus comprising:
a display positioned at a top of a head wearable frame and oriented toward an eye-side of the apparatus;
a lightguide to direct light from the display toward an eye-direction, the lightguide including:
a transparent curved first surface on the eye-side of the lightguide;
a transparent curved second surface on a world-side of the lightguide;
a transparent third surface oriented toward the top of the head wearable frame for receiving display light, the display light reflecting inside the lightguide via total internal reflection; and
a transparent curved fourth surface shaped to reflect light from the display through the transparent curved first surface to a user eye and to combine the display light with ambient light entering from the world-side through the transparent curved second surface of the lightguide; and
a reflector positioned on the eye-side of the apparatus and oriented to direct light from the display into the lightguide through the transparent third surface.
20. The apparatus of claim 19 , further comprising a display lens positioned at the top of the lightguide, wherein a first surface of the display lens is oriented toward the third surface of the lightguide, and wherein the first surface of the display lens is curved in a freeform manner along a first axis and the first surface of the display lens is curved along a second axis perpendicular to the first axis thereby augmenting a resultant image area in at least one dimension at the transparent curved fourth surface of the lightguide.
21. The apparatus of claim 20 , wherein a curvature of the transparent curved fourth surface of the lightguide is freeform along at least one axis, and wherein light from the display is reflected at least two times by internal reflection from each of the curved first and second surfaces of the lightguide before reflecting from the transparent curved fourth surface and being transmitted through the transparent curved first surface on the eye-side of the lightguide toward a user eye.
22. The apparatus of claim 20 , wherein a curvature of the transparent curved third surface of the lightguide is freeform along at least one axis thereby augmenting a resultant image area in at least one dimension at the transparent curved fourth surface of the lightguide.
23. The apparatus of claim 19 , wherein the display and the reflector are mounted inside of a generally pentahedral-shaped compartment of a top portion of the head wearable frame above an optical axis of the apparatus.