Optical element for reducing stray infrared light

An optical element for a head mounted display (HMD), the optical element comprising:

• an illumination layer configured to emit infrared light towards an eyeward side of the optical element;
• an optical combiner disposed between the illumination layer and a back side of the optical element, wherein the optical combiner is configured to receive reflected infrared light that is reflected by an eye of a user of the HMD and to direct the reflected infrared light towards an infrared camera of the HMD;
• an optically transparent layer disposed between the illumination layer and the eyeward side of the optical element to pass the infrared light;
• and
• a confinement layer disposed on a surface of the optically transparent layer to induce waveguiding of confined infrared light propagating within the optically transparent layer.

An optical element for a head mounted display (HMD), the optical element comprising:

• an illumination layer configured to emit infrared light towards an eyeward side of the optical element;
• an optical combiner disposed between the illumination layer and a back side of the optical element, wherein the optical combiner is configured to receive reflected infrared light that is reflected by an eye of a user of the HMD and to direct the reflected infrared light towards an infrared camera of the HMD;
• an optically transparent layer disposed between the illumination layer and the eyeward side of the optical element to pass the infrared light;
• and
• an infrared extractor disposed on a side-edge of the optically transparent layer to absorb or frustrate confined infrared light propagating within the optically transparent layer.