Patent attributes
A backlight device includes a first surface and a second surface that is opposite to the first surface. The backlight device is configured to emit light in a first optical band through the second surface toward a display panel of a head-mounted display (HMD). The display panel is configured to convert the light from the backlight device to image light. The backlight device is transparent to light in a second optical band that is different than the first optical band. An eye tracking system illuminates an eyebox with light in the second optical band. A camera assembly positioned adjacent to the first surface of the backlight device. The camera assembly is configured to capture images of the eye in the second optical band through the backlight device, the display panel. The eye tracking system determines eye tracking information based at least in part on the captured images.