US Patent 11579444 Infrared microled based invisible illumination for eye tracking

Eye-tracking systems and methods utilize transparent illumination structures having a plurality of IR μLEDs distributed within the transparent viewing area of illumination structures. The μLEDs are small enough (<100 μm) that they are not visible by a user during use of an HMD or other mixed-reality device, for example, such that they can be positioned within the line-of-sight of the user through the illumination structure and without visibly obscuring or interfering with the user's view of the mixed-reality environment by the mixed-reality device.