HOLOGRAPHIC WAVEGUIDE EYE TRACKER

• US 20160209657A1
• Filed: 05/19/2014
• Published: 07/21/2016
• Est. Priority Date: 05/20/2013
• Status: Active Grant

• Current Assignee: DigiLens Inc
• Original Assignee: DigiLens Inc
• Inventors: WALDERN, Jonathan David, POPOVICH, Milan Momcilo, GRANT, Alastair John
• Granted Patent: US 10,209,517 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 eye tracker comprising:

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;

a source of said illumination light optically coupled to said waveguide;

a detector optically coupled to said waveguide; and

disposed adjacent an optical surface of said waveguide at least one grating lamina for deflecting said illumination light out of said first waveguide path towards said eye and deflecting said image light into said second waveguide path towards said detector.

2. The apparatus of claim 1 wherein said grating lamina comprises an output grating for deflecting said illumination light out of said first waveguide path towards eye and an input grating for deflecting said image light into said second waveguide path towards detector.

3. The apparatus of claim 2 wherein at least one of said input and output gratings comprises at least one switchable grating element having a diffracting state and a non diffracting state.

4. The apparatus of claim 1 wherein said grating lamina comprises at least one switchable grating element having a diffracting state and a non diffracting state wherein said element in said diffracting state deflects said illumination light out of said first waveguide path towards said eye and deflects said image light into said second waveguide path towards said detector.

5. The apparatus of claim 4 wherein said switchable grating elements are elongate with longer dimension aligned perpendicular to at least one of said first and second waveguide paths.

6. The apparatus of claim 1 wherein said first and second waveguide paths are parallel.

7. The apparatus of claim 1 wherein said at least one grating lamina further comprises at least one of:

an input grating for deflecting said illumination light from said source into said first waveguide path; and

an output grating for deflecting said image light out of said second waveguide path towards said detector.

8. The apparatus of claim 7 further comprising a second waveguide containing a linear array of switchable grating elements optically coupled to said detector and overlaying said output grating, each said element when in its diffracting state sampling a portion of said light in said first waveguide and deflecting it along said second waveguide towards said detector.

9. The apparatus of claim 7 further comprising third waveguide containing a linear array of switchable grating elements optically coupled to said light source and overlaying said input grating, each said element when in its diffracting state deflecting light from said third waveguide into said first waveguide.

10. The apparatus of claim 2 wherein said output grating abuts an upper or lower edge of said second grating along said first waveguide path.

11. The apparatus of claim 2 wherein said output grating comprises upper and lower gratings disposed adjacent upper and lower edges of the output grating along said first waveguide path.

12. The apparatus of claim 7 wherein said input grating comprises a first array of switchable elongate beam deflection grating elements and an overlapping second array of switchable elongate beam deflection grating elements, said elements of said first and second arrays being disposed with their longer dimensions orthogonal.

13. The apparatus of claim 7 wherein at least one of said input and output gratings is a linear array of elongate switchable beam deflection elements with longer dimension aligned perpendicular to said first and second waveguide path.

14. The apparatus of claim 1 wherein said optical surface of said waveguide is at least one of an internal surface or an external surface of said waveguide.

15. The apparatus of claim 1 wherein said at least one grating lamina is 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 and a non switching Bragg grating.

16. The apparatus of claim 1 wherein said image light is speckle.

17. The apparatus of claim 1 wherein said eye surface is at least one of the cornea, lens, iris, sclera and retina.

18. The apparatus of claim 1 wherein said detector is a two dimensional array.

19. The apparatus of claim 1 wherein said at least one grating lamina encodes at least one of optical power and diffusing properties.

20. The apparatus of claim 1 wherein said detector is connected to an image processing apparatus for determining at least one spatio-temporal characteristic of an eye movement.

21. The apparatus of claim 1 wherein said at least one of the grating lamina includes at least one turning grating.

22. The apparatus of claim 1 wherein said the eye tracker image processing system includes a neural network.

23. An eye tracker comprising:

a waveguide for propagating illumination light reflected from at least one surface of an eye along a waveguide path;

a source of said illumination light;

a detector optically coupled to said waveguide; and

disposed in said waveguide at least one grating lamina for deflecting said reflected illumination light into said second waveguide path towards said detector.