Color-corrected curved optical see-through thin lightguide with large field of view in eyewear formfactor

Patent metadata

Field	Value
Publication number	US-11249312-B2
Application number	US-202016864813-A
Country	US
Kind code	B2
Filing date	May 1, 2020
Priority date	May 1, 2020
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

An optical device includes a display that emits light toward a lightguide. Display light reflects from lightguide surfaces by total internal reflection (TIR). The display is mounted proximate to the lightguide. The optical device includes a first surface at an eye-side of the optical device and a second surface at a world-side. The optical device includes a first material having a first Abbe number and a second material having a second Abbe number different from the first Abbe number. The first material and the second material cause a color correction to light from the display or alters a chromatic aberration of the light from the display. A head mountable frame supports the display and the lightguide including the first and second materials.

First claim

What is claimed is:

1. An optical device comprising:
a display to emit light based on an input signal;
a lightguide oriented to receive light from the display, wherein the lightguide includes:
a first surface at an eye-side of the optical device;
a second surface at a world-side for reflecting the light through the first surface to a first user eye, wherein the emitted light from the display is reflected by total internal reflection (TIR) within the lightguide;
a first material having a first Abbe number; and
a second material having a second Abbe number different from the first Abbe number, wherein the first material and the second material alter a chromatic aberration of light from the display; and

a head mountable frame supporting the display and the lightguide.

2. The optical device of claim 1 , wherein the display is positioned at a top of the head mountable frame.

3. The optical device of claim 1 , wherein the first surface, the second surface, or both the first surface and the second surface are curved.

4. The optical device of claim 1 , further comprising:
a field lens having a first surface to receive light from the display and a second surface oriented toward an interior of the lightguide, wherein the field lens is positioned at a top side of the lightguide.

5. The optical device of claim 4 , wherein the second surface of the field lens is spherical in shape.

6. The optical device of claim 4 , wherein the display and the lightguide are positioned relative to one another so as to reflect light at least two times from at least one of the first surface and the second surface of the lightguide before the light from the display reaches the user eye.

7. The optical device of claim 4 , wherein the lightguide includes a third surface as an incoupler surface at a top of the lightguide for receiving light from the display.

8. The optical device of claim 4 , wherein:
the field lens includes the first material having the first Abbe number; and
at least one of the first surface and the second surface includes the second material having the second Abbe number.

9. The optical device of claim 4 , 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 (CGI) 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.

10. The optical device of claim 1 , wherein the lightguide is a compound component having a first component coupled contiguously to a second component, wherein the second component includes a combiner surface that reflects display light toward the user eye.

11. The optical device of claim 1 , wherein the optical device, including the lightguide, has a wrap angle spherically between 5 and 10 degrees in front of both user eyes as measured within a plane that transects both user eyes.

12. The optical device of claim 1 , wherein the optical device, including the lightguide, has a pantoscopic tilt angle of between 5 and 15 degrees in front of the user eye.

13. The optical device of claim 1 , wherein the display 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.

14. The optical device of claim 1 , wherein a distance between the first surface at the eye-side of the optical device and the second surface of the lightguide is 4.5 mm or less along a cross-section of the lightguide.

15. The optical device of claim 1 , wherein an eye relief distance from the first surface of the lightguide to the user eye is 26 mm or less.

16. 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.

17. A method for altering a chromatic aberration, the method comprising:
mounting a display to a head mountable frame, wherein the display emits light based on an electronic input signal; and
mounting a lightguide to the head mountable frame, wherein the lightguide is positioned to receive light from the display, wherein the lightguide includes:
a first surface at an eye-side of the head mountable frame;
a second surface at a world-side of the head mountable frame, wherein the second surface is positioned to reflect the emitted display light through the first surface to a first user eye, and wherein the light from the display is reflected by total internal reflection (TIR) within the lightguide;
a first material having a first Abbe number; and
a second material having a second Abbe number different from the first Abbe number, wherein the first material and the second material alter a chromatic aberration of the emitted light from the display.

18. The method of claim 17 , wherein at least one of the first surface and the second surface is curved along an eye-side of the head mountable frame, and wherein the method further comprises:
mounting a field lens at a top of the head mountable frame in a light path between the display and the lightguide.

19. An apparatus comprising:
a display coupled to a head wearable frame; and
a lightguide coupled to the head wearable frame, wherein the lightguide directs light from the display toward an eye-direction, the lightguide including:
a transparent first surface on an eye-side of the lightguide;
a transparent second surface on a world-side of the lightguide;
a first material having a first Abbe number;
a second material having a second Abbe number different from the first Abbe number, wherein the first material and the second material alter a chromatic aberration of the light from the display; and

a transparent curved surface as a combiner surface shaped to:
reflect the light from the display to a user eye; and
combine the light from the display with ambient light entering from a world-side through the transparent second surface of the lightguide.

20. The apparatus of claim 19 , wherein at least one of the transparent first surface and the transparent second surface of the lightguide is curved toward the eye-side of the lightguide.

Assignees

• Google Llc

Inventors

• Cakmakci Ozan
• Corbalan Daniel
• Gallant Benjamin Mclaughlin
• Vieri Carlin
• Lee Juseok

Classifications

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02C11/10 Primary

  Electronic devices other than hearing aids · CPC title

• G02C7/086

  Auxiliary lenses located directly on a main spectacle lens or in the immediate vicinity of main spectacles · CPC title