Holograghic waveguide eye tracker

• US 10,712,571 B2
• Filed: 02/15/2019
• Issued: 07/14/2020
• Est. Priority Date: 05/20/2013
• Status: Active Grant

• Current Assignee: DigiLens Inc
• Original Assignee: DigiLens Inc
• Inventors: Popovich, Milan Momcilo, Waldern, Jonathan David, Grant, Alastair John
• Primary Examiner(s): Lepisto, Ryan A
• Assistant Examiner(s): Chiem, Erin D
• Application Number:
  US16/277,390
• Publication Number:
  US 20190179153A1
• Time in Patent Office: 515 Days
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 2027/0187 slaved to motion of at least a part of the body of the user, e.g. head, eye
• 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 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02F 1/292 by controlled diffraction or phased-array beam steering controlled diffraction for optical switching G02F1/31
• CPC Class Codes: G02F 1/311 Cascade arrangement of plural switches
• CPC Class Codes: G02F 1/3132 of directional coupler type
• CPC Class Codes: G06F 18/214 Generating training patterns; Bootstrap methods, e.g. bagging or boosting
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

An eye tracker having a first waveguide for propagating illumination light along a first waveguide path and propagating image light reflected from at least one surface of an eye along a second waveguide path. At least one grating lamina for deflecting the illumination light out of the first waveguide path towards the eye and deflecting the image light into the second waveguide path towards a detector is disposed adjacent an optical surface of the waveguide.

Claims

1. An apparatus for tracking the movement of an eye, comprising:

a first waveguide;

a light source for illuminating said eye;

at least one detector optically coupled to said waveguide; and

disposed within said waveguide, at least one grating layer comprising a first plurality of grating elements with a first prescription for diffracting a first characteristic of light reflected from said eye into a first total internal reflection (TIR) path to said detector and a second plurality of grating elements with a second prescription for diffracting a second characteristic of light reflected from said eye into a second TIR path to said detector.

2. The apparatus of claim 1, wherein said first characteristic provides an image of said eye at said detector.

3. The apparatus of claim 1, wherein said second characteristic provides an optical signature formed by at least one of reflection or scatter from at least one of an optical surface or ocular medium of said eye at said detector.

4. The apparatus of claim 3, wherein said signature is one of speckle or glint.

5. The apparatus of claim 1, wherein said first waveguide contains a grating or prism for coupling illumination from said source into an illumination TIR path in said first waveguide and a grating for coupling light out of said illumination TIR path onto said eye.

6. The apparatus of claim 1, further comprising a second waveguide supporting a grating or prism for coupling illumination from said source into an illumination TIR path in said second waveguide and a grating for coupling light out of said illumination TIR path onto said eye.

7. The apparatus of claim 1, wherein at least one of said first plurality of grating elements or said second plurality of grating elements comprises at least one switchable grating element having a diffracting state and a non-diffracting state.

8. The apparatus of claim 1, wherein at least one of said first plurality of grating elements or said second plurality of grating elements comprises at least one switchable grating element having a diffracting state and a non-diffracting state, wherein said element in said diffracting state deflects light reflected from said eye into at least one of said first or second TIR paths.

9. The apparatus of claim 1, wherein at least one of said first plurality of grating elements or said second plurality of grating elements comprises an array of elongate elements.

10. The apparatus of claim 1, wherein at least one of said first plurality of grating elements or said second plurality of grating elements is a two-dimensional array.

11. The apparatus of claim 1, wherein said grating layer comprises at least one of a switchable Bragg grating, a switchable grating recorded in a reverse mode holographic polymer dispersed liquid crystal, a switchable grating recorded in a reverse mode holographic polymer dispersed liquid crystal, a surface relief grating or a non-switching Bragg grating.

12. The apparatus of claim 1, wherein said eye surface is at least one of a cornea, front or rear lens surface, iris, sclera or retina.

13. The apparatus of claim 1, wherein said detector is a two-dimensional array.

14. The apparatus of claim 1, further comprising at least one grating with at least one of optical power or diffusing properties.

15. The apparatus of claim 1, wherein said detector is connected to at least one of an image processing apparatus for determining at least one spatio-temporal characteristic of an eye movement or an image processing system including a neural network.

16. The apparatus of claim 1, wherein said detector is coupled to said waveguide by a grating or a prism.

17. The apparatus of claim 1, integrated within a HMD or HUD.

18. The apparatus of claim 1, further comprising a turning grating.

19. The apparatus of claim 1, wherein said source is a laser or a light emitting diode.

20. The apparatus of claim 1, wherein said at least one detector comprises a first detector for recording said first characteristic of light and a second detector for recording said second characteristic of light.