Apparatus for eye tracking

• US 10,437,051 B2
• Filed: 10/27/2017
• Issued: 10/08/2019
• Est. Priority Date: 05/11/2012
• Status: Active Grant

• Current Assignee: DigiLens Inc
• Original Assignee: DigiLens Inc
• Inventors: Popovich, Milan Momcilo, Waldern, Jonathan David, Grant, Alastair John
• Primary Examiner(s): Dang, Hung X
• Application Number:
  US15/796,169
• Publication Number:
  US 20180113303A1
• Time in Patent Office: 711 Days
• Field of Search: 351221, 351209, 351210
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• 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 2027/0174 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 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02B 6/4287 Optical modules with tapping or launching means through the surface of the waveguide G02B6/2852, G02B6/4286 take precedence
• CPC Class Codes: G02F 1/13342 Holographic polymer dispersed liquid crystals
• 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 1/294 Variable focal length devices
• CPC Class Codes: G02F 1/2955 by controlled diffraction or phased-array beam steering controlled diffraction for optical waveguide switching G02F1/313
• CPC Class Codes: G02F 1/3132 of directional coupler type
• CPC Class Codes: G02F 2201/16 series; tandem
• CPC Class Codes: G02F 2201/30 grating
• CPC Class Codes: G02F 2201/302 grating coupler
• CPC Class Codes: G02F 2201/305 : diffraction grating
• CPC Class Codes: G02F 2201/307 : Reflective grating, i.e. Bragg grating
• CPC Class Codes: G02F 2203/24 : beam steering
• CPC Class Codes: G02F 2203/28 : focussing or defocussing
• CPC Class Codes: G02F 2203/62 : Switchable arrangements whereby the element being usually not switchable
• CPC Class Codes: G06V 40/193 : Preprocessing; Feature extraction
• CPC Class Codes: H04N 5/33 : Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

An eye tracker comprises a light source; a detector; and first and second waveguides. The first waveguide comprises an input coupler for coupling source light into a waveguide path and a first grating for coupling light out of the waveguide path onto an eye. The second waveguide comprises a second grating for coupling light reflected from the eye into a waveguide path and an output coupler for coupling light out of the waveguide path onto the detector. The second grating is optically configured for imaging the eye onto the detector.

Claims

1. An eye tracker comprising:

a light source;

a detector;

a first waveguide comprising an input coupler for coupling illumination from said source into a TIR waveguide path in said first waveguide and a first grating for coupling light out of said TIR waveguide path onto an eye; and

a second waveguide comprising a second grating for coupling light reflected from said eye into a TIR waveguide path in said second waveguide and an output coupler for coupling light out of said TIR path onto said detector, wherein said second grating is optically configured for forming an image of said eye on said detector.

2. The apparatus of claim 1, wherein said second grating comprises a plurality of grating elements with optical power.

3. The apparatus of claim 1, wherein said second grating comprises a plurality of grating elements each having an optical power prescription selected from a set of at least two different optical prescriptions.

4. The apparatus of claim 1, wherein said second grating comprises a plurality of variable focal length grating elements.

5. The apparatus of claim 1, wherein said second grating comprises a plurality of variable focal length grating elements each comprising a fixed focal length diffractive optical element in contact with a variable refractive index layer.

6. The apparatus of claim 1, wherein said second grating comprises a plurality of electrically switchable elements each having a diffracting state for coupling light from said eye into said waveguide and a non-diffracting state.

7. The apparatus of claim 1, wherein said second grating is a linear array of elongate grating elements with optical power, each said element having a longer dimension aligned perpendicular to a principal optical path in said second waveguide.

8. The apparatus of claim 1, wherein said second grating is one of a switchable Bragg grating, a switchable grating recorded in a reverse mode holographic polymer dispersed liquid crystal, or a non-switching Bragg grating.

9. The apparatus of claim 1, wherein said second grating comprises more than one grating layer.

10. The apparatus of claim 1, wherein said output coupler comprises at least one grating element with optical power.

11. The apparatus of claim 1, wherein said output coupler comprises at least one grating.

12. The apparatus of claim 1, wherein said output coupler comprises at least one switchable grating.

13. The apparatus of claim 1, wherein said output coupler is a grating formed in a common layer with said second grating.

14. The apparatus of claim 1, wherein said first and second waveguide are configured as separate overlapping waveguide layers wherein said first grating at least partially overlaps said second grating.

15. The apparatus of claim 1, wherein said light reflected from said eye is provided by at least one of the cornea, lens, iris, sclera or retina of said eye.

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

17. The apparatus of claim 1, wherein said first grating encodes at least one of optical power or diffusion.

18. 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.

19. The apparatus of claim 1, wherein said source is in the infrared band.

20. The apparatus of claim 1, provided for left and right eyes.