System for providing illumination of the eye
A thin transparent layer can be integrated in a head mounted display device and disposed in front of the eye of a wearer. The thin transparent layer may be configured to output light such that light is directed onto the eye to create reflections therefrom that can be used, for example, for glint based tracking. The thin transparent layer can be configured to reduced obstructions in the field of the view of the user.
1. A head-mounted display system configured to project light to an eye of a user to display augmented reality image content in a vision field of said user, said head-mounted display system comprising:
a frame configured to be supported on a head of said user;
an image projector configured to project images into said user's eye to display image content in said vision field of said user;
an eyepiece disposed on said frame, said eyepiece configured to direct light into said user's eye to display augmented reality image content to said user's vision field;
a transparent layer supported on said frame and disposed at a location between said eyepiece and said user's eye when said user wears said head-mounted display system such that said transparent layer transmits light from an environment in front of said user to said user's eye to provide a view of said environment in front of said user, said transparent layer comprising front and rear major surfaces surrounded by a plurality of edges, said transparent layer further comprising at least one tilted surface, said tilted surface angled such that light guided within said transparent layer is reflected from said tilted surface and directed through said rear major surface out of said transparent layer to said eye; and
at least one camera disposed to receive at least a portion of said light reflected from said user's eye to capture images using light reflected from said user's eye,
wherein said light reflected from said user's eye is received by said transparent layer and reflected off of said at least one tilted surface towards said at least one camera.
2. The system of claim 1 , wherein said tilted surface comprises one or more of metallization or IR reflective coating.
3. The system of claim 1 , wherein said tilted surface is angled from 35° to 55° with respect to front and/or rear major surface of said transparent layer.
4. The system of claim 1 , further comprising at least one light source disposed with respect to said transparent layer such that light from said at least one light source is injected into said transparent layer, is incident on said tilted surface, and reflected therefrom toward said eye of said user.
5. The system of claim 1 , further comprising at least one light source disposed with respect to at least one edge of said transparent layer such that light from said at least one light source is injected into said transparent layer, is incident on said tilted surface and reflected therefrom toward said eye of said user.
6. The system of claim 5 , wherein said at least one light source comprises a plurality of spaced apart light sources or one or more infrared light sources.
7. The system of claim 5 , wherein said at least one light source creates a point source illuminating said eye of said user.
8. The system of claim 5 , wherein said light source comprises one or more light emitting diodes (LEDs) or lasers.
9. The system of claim 5 , wherein said light from said light source is guided within said transparent layer by total internal reflection off said front and rear major surfaces of said transparent layer.
10. The system of claim 1 , wherein said transparent layer comprises plastic.
11. The system of claim 1 , wherein at least a portion of said eyepiece being transparent and disposed at a location in front of said user's eye when said user wears said head-mounted display system such that said transparent portion transmits light from said environment in front of said user to said user's eye to provide a view of said environment in front of said user.
12. The system of claim 11 , wherein said eyepiece is configured to receive light from said image projector and to direct said light into said user's eye to display augmented reality image content to said user's vision field.
13. The system of claim 11 , wherein said eyepiece comprises at least one waveguide.
14. The system of claim 13 , wherein said image projector is configured to direct light into said at least one waveguide.
15. The system of claim 13 , wherein said at least one waveguide comprises a stack of waveguides.
16. The system of claim 15 , wherein different waveguides of said stack of waveguides are configured to output light with different wavefront divergence as if projected from different distances from said user's eye.
17. The system of claim 15 , wherein different waveguides of said stack of waveguides are configured to output light with different colors.
18. The system of claim 15 , wherein said transparent layer comprises a layer in said eyepiece.
19. The system of claim 1 , further comprising:
at least one waveguide;
at least one coupling optical element configured such that light output from said transparent layer that is reflected from said eye is coupled into said waveguide and guided therein; and
at least one out-coupling element configured to couple light guided within said waveguide out of said waveguide and direct said light to said camera to capture images of said eye.
20. The system of claim 1 , wherein said system is configured to perform eye tracking based on images of said eye captured by said camera.