Infrared eye-tracking in high ambient light conditions
An eye-tracking system comprises one or more optical sources configured to emit infrared light with a narrow spectral linewidth toward an eye of a user and one or more shuttered optical sensors configured to receive infrared light reflected off the eye of the user. A controller is configured to pulse the one or more optical sources on and off, such that a pulse-on duration is less than a duration needed to fully thermalize each optical source. The controller is also configured to open the shuttered optical sensor for a detection duration based on the pulse-on duration. A conformation of the user's eye may be indicated based on infrared light received at the shuttered optical sensor during the detection duration.
1. An eye-tracking system, comprising:
one or more optical sources configured to emit infrared light with a narrow spectral linewidth toward an eye of a user;
one or more shuttered optical sensors configured to receive infrared light reflected off the eye of the user; and
a controller configured to:
pulse the one or more optical sources on and off, such that a pulse-on duration is less than a duration needed to fully thermalize each of the one or more optical sources;
open the one or more shuttered optical sensors for a detection duration based on the pulse-on duration; and
indicate a conformation of the user's eye based on infrared light received at the one or more shuttered optical sensors during the detection duration.
2. The eye-tracking system of claim 1 , wherein the one or more optical sources are configured to emit infrared light that includes 940 nm light.
3. The eye-tracking system of claim 1 , wherein the one or more optical sources are configured to emit infrared light with a full width at half-maximum ≤5 nm.
4. The eye-tracking system of claim 1 , wherein the one or more optical sources are laser diodes.
5. The eye-tracking system of claim 4 , wherein the laser diodes are vertical-cavity surface-emitting lasers.
6. The eye-tracking system of claim 1 , wherein each of the one or more shuttered optical sensors includes a plurality of deep well P-type intrinsic N-type diode (PIN) photodiodes.
7. The eye-tracking system of claim 1 , wherein each of the one or more shuttered optical sensors includes a plurality of quantum film photodetectors sensitive to infrared light at 940 nm.
8. The eye tracking system of claim 7 , wherein the quantum film photodetectors are ZnS quantum film photodetectors.
9. The eye-tracking system of claim 1 , further comprising one or more narrow linewidth IR bandpass filters optically coupled between the one or more optical sources and the one or more shuttered optical sensors.
10. The eye-tracking system of claim 9 , wherein the one or more narrow linewidth IR bandpass filters have a spectral linewidth ≤30 nm.