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 the user;
an image projector configured to project images into the user's eye to display image content in the vision field of the user;
a transparent layer supported on said frame and disposed at a location in front of the user's eye when the user wears said head-mounted display system such that said transparent layer transmits light from an environment in front of the user to the user's eye to provide a view of the environment in front of the user;
an elongate light guide having a first end and a second end, said first end disposed within said transparent layer, said first end of said elongate light guide having an output for emitting light such that said light is directed to said eye, wherein the transparent layer comprises a channel configured to accept the elongate light guide; and
at least one camera disposed to receive at least a portion of the light reflected from the eye to capture images using light reflected from the user's eye.
2. The system of claim 1 , wherein said first end of said elongate light guide includes an angled reflector configured to couple light through said output of said elongate light guide.
3. The system of claim 2 , wherein said angled reflector comprises a beveled surface at said first end of said elongate light guide.
4. The system of claim 2 , wherein said angled reflector comprises a cleaved surface at said first end of said elongate light guide.
5. The system of claim 2 , wherein said angled reflector comprises metallization.
6. The system of claim 2 , wherein said angled reflector comprises IR reflective coating.
7. The system of claim 2 , wherein said angled reflector is polished.
8. The system of claim 1 , wherein said elongate light guide is disposed within a channel of the transparent layer.
9. The system of claim 1 , wherein said second end of said elongate light guide has an input for receiving light, said elongate light guide configured such that light received by said input of said elongate light guide at said second end is guided within said elongate light guide to said output at said first end of said elongate light guide.
10. The system of claim 1 , wherein said elongate light guide comprises an optical fiber comprising a core and a cladding and said core is between 8 μm and 110 μm across.
11. The system of claim 1 , wherein said elongate light guide comprises an optical fiber comprising a core and a cladding and said cladding is between 100 μm and 150 μm across.
12. The system of claim 1 , wherein said second end of said elongate light guide has an input for receiving light, wherein said second end of said elongate light guide extends outside of said transparent layer such that said input for receiving light is outside said transparent layer.
13. The system of claim 1 , further comprising:
at least one waveguide;
at least one coupling optical element configured such that light from said output of said elongate light guide 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 at least one camera to capture images of said eye.
14. The system of claim 1 , wherein said system is configured to perform eye tracking based on images of said eye captured by said camera.
15. The system of claim 1 , further comprising a diffuser at said output of said elongate light guide at said first end of said elongate light guide.
16. The system of claim 1 , wherein said elongate light guide has a length to thickness ratio of at least 10.
17. The system of claim 1 , wherein said elongate light guide comprises at least one optical fiber.
18. The system of claim 1 , wherein said elongate light guide comprises at least one optical rod.