AUGMENTED REALITY SYSTEMS AND METHODS WITH VARIABLE FOCUS LENS ELEMENTS

• US 20170293145A1
• Filed: 04/06/2017
• Published: 10/12/2017
• Est. Priority Date: 04/08/2016
• Status: Active Grant

• Current Assignee: Magic Leap, Inc.
• Original Assignee: Magic Leap, Inc.
• Inventors: Miller, Samuel A., Greco, Paul M., Schowengerdt, Brian T.
• Granted Patent: US 10,459,231 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0093 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02C 11/10 Electronic devices other than hearing aids
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/294 Variable focal length devices
• CPC Class Codes: G02F 2202/09 inorganic glass
• CPC Class Codes: G06F 1/163 Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042

Abstract

An augmented reality display system includes a pair of variable focus lens elements that sandwich a waveguide stack. One of the lens elements is positioned between the waveguide stack and a user'"'"'s eye to correct for refractive errors in the focusing of light projected from the waveguide stack to that eye. The lens elements may also be configured to provide appropriate optical power to place displayed virtual content on a desired depth plane. The other lens element is between the ambient environment and the waveguide stack, and is configured to provide optical power to compensate for aberrations in the transmission of ambient light through the waveguide stack and the lens element closest to the eye. In addition, an eye-tracking system monitors the vergence of the user'"'"'s eyes and automatically and continuously adjusts the optical powers of the pair of lens elements based on the determined vergence of those eyes.

Claims

1. A display system comprising:

a head-mountable display configured to project light to a viewer to display image information on one or more depth planes, the display comprising;

one or more waveguides configured to project the light to the viewer, wherein the one or more waveguides are further configured to transmit light from objects in a surrounding environment to the viewer;

a first variable focus lens element between the one or more waveguides and a first eye of the viewer; and

a second variable focus lens element between the one or more waveguides and the surrounding environment; and

an eye tracking system configured to determine vergence of the viewer'"'"'s eyes,

wherein the display system is configured to correct a refractive error of the user'"'"'s eyes by adjusting an optical power of the first and second variable focus lens elements based on the determined vergence of the viewer'"'"'s eyes.

2. The display system of claim 1, wherein the display system is configured to modify the optical power of the first and second variable focus lens elements depending on a depth plane for displaying the image information.

3. The display system of claim 1 wherein the display system is configured to adjust an optical power of the second variable focus lens element in response to an optical power of the first variable focus lens element.

4. The display system of claim 1, wherein the one or more waveguides are configured to project divergent light to the viewer to display the image information.

5. The display system of claim 1, wherein each of the one or more waveguides has a fixed optical power.

6. The display system of claim 1, further comprising a third variable focus element between the one or more waveguides and a second eye of the viewer.

7. The display system of claim 6, further comprising a fourth variable focus element between the one or more waveguides and the surrounding environment.

8. The display system of claim 6, wherein the system is configured to adjust an optical power of the third variable focus lens element to vary the wavefront of the projected light based on the determined vergence.

9. The display system of claim 8, wherein the system is configured to adjust an optical power of the fourth variable focus lens element to vary the wavefront of incoming light from the object in the surrounding environment based on the determined vergence.

10. The display system of claim 1, wherein eye tracking system comprises one or more cameras.

11. The display system of claim 1, wherein an optical power of the first and/or second variable focus lens element is adjusted in accordance with a prescription for correcting the viewer'"'"'s vision at two or more distances.

12. The display system of claim 1, wherein the system has three or more preset prescription optical powers for each of the first and second variable focus lens elements.

13. The display system of claim 1, wherein a number of available prescription optical powers is equal to at least a total number of depth planes for the display.

14. The display system of claim 1, wherein the first and/or second variable focus lens elements comprises a layer of liquid crystal sandwiched between two substrates.

15. The display system of claim 14, wherein the first and/or second variable focus lens elements comprise electrodes for altering a refractive index of the liquid crystal layer upon application of a voltage.

16. The display system of claim 14, wherein the substrates comprise glass.

17. The display system of claim 1, further comprising an electronic hardware control system configured to vary the refractive index of the first and/or second variable focus lens element by application of an electrical current or voltage.

18. The display system of claim 17, wherein the eye tracking system forms a feedback loop to the electronic hardware control system to vary the refractive index of the first and/or second variable focus lens element in accordance with the determined vergence of the viewer'"'"'s eyes.

19. A method for displaying image information on a head-mountable display, the method comprising:

providing the display mounted on a head of a viewer, the display configured to display image information on one or more depth planes and comprising;

one or more waveguides configured to project light to the viewer to display the image information,

wherein the one or more waveguides are further configured to transmit light from objects in a surrounding environment to the viewer;

determining a vergence point of eyes of the viewer; and

correcting a refractive error of an eye of the viewer by;

varying optical power of a first variable focus lens element disposed between the one or more waveguides and an eye of the viewer based on the determined vergence point; and

varying optical power of a second variable focus lens element disposed between the one or more waveguides and an environment surrounding the viewer based on the determined vergence point.

20. The method of claim 19, further comprising:

a third variable focus lens element and a fourth variable focus lens element, wherein the third variable focus lens element is between the one or more waveguides and an other eye of the viewer, and wherein the fourth variable focus lens element is directly forward of the third variable focus lens and between the one or more waveguides and the surrounding environment; and

correcting a refractive error of the other eye by varying an optical power of the third and fourth variable focus lens elements based on the determined vergence point.

21. The method of claim 20, wherein determining the vergence point comprises tracking a vergence of the eye and the other eye of the viewer using one or more cameras.

22. The method of claim 19, wherein the optical power of the first variable focus lens element is varied simultaneously with the optical power of the second variable focus lens element.

23. The method of claim 19, wherein the one or more waveguides each comprises diffractive optical elements configured to output divergent light from the waveguides.