Combined eye and environment sensing for a head-mounted device
An eye and environment sensing system for a head-mounted device may be configured to determine changes in an eye orientation and range objects in the environment by sharing a common light source. The eye and environment sensing system includes a light source, a first photodetector, and a second photodetector. The light source is coupled to a frame of a head-mounted device and configured to provide a light beam to illuminate a portion of an eyebox region. The first photodetector is coupled to the frame and is oriented towards the eyebox region to receive reflections of the light beam from the eyebox region. The second photodetector is coupled to the frame and is oriented towards a scene side of the head-mounted device to receive reflections of the light beam from an environment of the head-mounted device. With a shared light source, battery consumption in the head-mounted device may be reduced.
1 . An eye and environment sensing system for a head-mounted device comprising:
a light source coupled to a frame of a head-mounted device and configured to provide a light beam to illuminate a portion of an eyebox region;
a first photodetector coupled to the frame and oriented towards the eyebox region to receive reflections of the light beam from the eyebox region; and
a second photodetector coupled to the frame and oriented towards a scene side of the head-mounted device to receive reflections of the light beam, after reflection of the light beam from the eyebox region, from an environment of the head-mounted device.
2 . The eye and environment sensing system of claim 1 , wherein the second photodetector is configured to detect the light beam along a light path,
wherein the light path includes propagation from the eyebox region to an object in the environment and propagation from the object to the second photodetector.
3 . The eye and environment sensing system of claim 1 further comprising:
a micro-electromechanical systems (MEMS) mirror coupled to the frame and configured to direct the light beam from the light source to the portion of the eyebox region.
4 . The eye and environment sensing system of claim 3 , wherein the MEMS mirror is configured to scan the portion of the eyebox region.
5 . The eye and environment sensing system of claim 4 further comprising:
processing logic coupled to the first photodetector and configured to at least partially generate a three-dimensional (3D) model of the portion of the eyebox region.
6 . The eye and environment sensing system of claim 1 further comprising:
a plurality of first photodetectors coupled to the frame and oriented towards the eyebox region, wherein the first photodetector is one of the plurality of first photodetectors.
7 . The eye and environment sensing system of claim 1 further comprising:
a plurality of second photodetectors coupled to the frame and oriented towards the environment, wherein the second photodetector is one of a plurality of second photodetectors.
8 . The eye and environment sensing system of claim 1 further comprising:
processing logic coupled to the first and second photodetectors, wherein the processing logic is configured to determine eye orientation and range to an object using time-of-flight (ToF) of the light beam.
9 . The eye and environment sensing system of claim 8 , wherein the processing logic is configured to determine the orientation and the range using direct ToF or indirect ToF.
10 . The eye and environment sensing system of claim 1 , wherein the first photodetector is configured to capture reflections from the eyebox region within a first shutter window, wherein the second photodetector is configured to capture reflections from the environment within a second shutter window, wherein the first and second shutter windows are separated by a time delay.