Apparatus for a near-eye display
An apparatus for providing gaze tracking in a near-eye display. Certain examples provide an apparatus including a light modulator configured to receive light of a first range of wavelengths and generate an image beam therefrom. The light modulator is further configured to receive light of a second range of wavelengths and generate a probe beam therefrom. The apparatus also includes one or more light guides including one or more in-coupling element areas, and one or more out-coupling element areas. The one or more in-coupling element areas are configured to receive and in-couple the image beam and the probe beam into the one or more light guides. The one or more out-coupling element areas are configured to out-couple, from the one or more light guides: the image beam to a user's eye for user viewing, and the probe beam to the user's eye for detection of reflection therefrom.
1. An apparatus comprising:
a light source operable to generate light having first and second ranges of wavelengths;
a light modulator positioned to receive the light of a first range of wavelengths and generate an image beam therefrom, wherein the light modulator is further positioned to receive the light of a second range of wavelengths and, simultaneously with generation of the image beam by the light modulator, generate a probe beam therefrom;
first and second light guides, each respective light guide comprising:
one or more respective in-coupling element areas, and
one or more respective out-coupling element areas;
wherein the one or more in-coupling element areas of the first light guide are configured to receive and in-couple the image beam and the probe beam into the first light guide;
wherein the one or more in-coupling element areas of the second light guide are configured to receive and in-couple the image beam into the second light guide;
wherein the one or more out-coupling element areas of the first light guide are configured to out-couple, from the first light guide the image beam to an eye of a user for user viewing;
wherein the one or more out-coupling element areas of the first light guide are configured to expand the probe beam and out-couple the probe beam to the eye for detection of reflection therefrom; and
wherein the one or more out-coupling element areas of the second light guide are configured to out-couple, from the second light guide the image beam to the eye for user viewing.
2. An apparatus as claimed in claim 1 , wherein the light modulator is further configured to:
control a pattern, shape and/or size of the probe beam; and/or
dynamically vary a pattern of the probe beam.
3. An apparatus as claimed in claim 1 , further comprising a detector configured to detect reflections of the probe beam.
4. An apparatus as claimed of claim 3 , further comprising a controller to modify the probe beam dependent upon the detection of the reflected probe beam.
5. An apparatus as claimed in claim 3 , further comprising a reflector configured to further reflect the reflected probe beam to the detector.
6. An apparatus as claimed in claim 3 , further comprising a controller to determine a user's gaze based on the detected reflected probe beam.
7. An apparatus as claimed in claim 1 , wherein the light of the first range of wavelengths comprises visible light and the light of the second range of wavelengths comprises Infrared light.
8. An apparatus as claimed in claim 1 , wherein the light source is configured to generate simultaneously the light of the first range of wavelengths, and the light of the second range of wavelengths.
9. An apparatus as claimed in claim 1 , further comprising a selectively controllable filter to selectively filter one of: the light of the first range of wavelengths and the light of the second range of wavelengths.
10. An apparatus as claimed in claim 1 , further comprising a light source configured to generate sequentially the light of the first range of wavelengths and the light of the second range of wavelengths.
11. An apparatus as claimed in claim 1 , wherein the one or more in-coupling element areas and one or more out-coupling element areas are comprised in a single light guide.
12. An apparatus as claimed in claim 1 , wherein the one or more light guides is configured as an exit pupil expander.
13. An apparatus as claimed in claim 1 , wherein the apparatus is configured for use as a near eye display and a gaze tracker.
14. A module comprising the apparatus of claim 1 .
15. A device comprising the apparatus of claim 1 , wherein the device is configured for at least one at least one of:
portable use, wearable use, head mountable use, wireless communications.
16. An apparatus as claimed in claim 1 where the one or more in-coupling element areas comprise at least one in-coupling diffractive element area.
17. An apparatus as claimed in claim 1 where the one or more out-coupling element areas comprise at least one out-coupling diffractive element area.
18. An apparatus as claimed in claim 1 wherein the first and second light guides are first and second overlapping light guides.