Display Systems With Optical Sensing

Abstract

A head-mounted device may have catadioptric lenses that each include a partial mirror, a quarter wave plate, and a polarizer. An optical system in the head-mounted device may have an infrared light-emitting device and an infrared light-sensing device. The optical system may illuminate a user's eyes in eye boxes and may gather measurements from the illuminated eye boxes for eye tracking and other functions. The optical system may operate through the catadioptric lenses. To enhance optical system performance, the polarizers may be wire grid polarizers that are formed from conductive lines that exhibit enhanced infrared transmission and/or the quarter wave plates may be formed from cholesteric liquid crystal layers that serve as quarter wave plates at visible wavelengths and that do not serve as quarter wave plates at infrared wavelengths.

What is claimed is: 
     
         1 . A head-mounted device, comprising:
 a lens that includes a wire grid polarizer that exhibits more infrared light transmission than visible light transmission;   an infrared light-emitting device configured to emit infrared light through the lens; and   an infrared light-sensing device configured to detect infrared light through the lens.   
     
     
         2 . The head-mounted device of  claim 1 , wherein the lens comprises a catadioptric lens. 
     
     
         3 . The head-mounted device of  claim 1 , wherein the wire grid polarizer is formed from parallel lines, and each of the parallel lines comprises first regions of a first material and second regions of a second material that is different from the first material. 
     
     
         4 . The head-mounted device of  claim 3 , wherein the first material comprises a metal. 
     
     
         5 . The head-mounted device of  claim 4 , wherein the second material comprises a non-metal. 
     
     
         6 . The head-mounted device of  claim 3 , wherein the first regions form islands within the second regions. 
     
     
         7 . The head-mounted device of  claim 3 , wherein the first regions are continuous regions and wherein the second regions are continuous regions. 
     
     
         8 . The head-mounted device of  claim 1 , further comprising:
 a display visible through the lens from an eye box.   
     
     
         9 . The head-mounted device of  claim 8 , the infrared light-emitting device is between the wire grid polarizer and the eye box. 
     
     
         10 . The head-mounted device of  claim 1 , wherein the lens comprises a layer that forms a visible-light quarter wave plate that is transparent at infrared wavelengths and does not form a quarter wave plate at infrared wavelengths. 
     
     
         11 . The head-mounted device of  claim 1 , wherein the layer comprises a cholesteric liquid crystal layer. 
     
     
         12 . A head-mounted device, comprising:
 a lens that includes a layer that serves as a quarter wave plate at visible light wavelengths and that does not serve as a quarter wave plate at infrared wavelengths;   a light-emitting device configured to emit infrared light through the lens; and   an infrared image sensor configured to detect infrared light that has passed through the lens.   
     
     
         13 . The head-mounted device of  claim 12 , wherein the lens further includes a polarizer and a partial minor. 
     
     
         14 . The head-mounted device of  claim 12 , wherein the layer comprises a cholesteric liquid crystal layer. 
     
     
         15 . The head-mounted device of  claim 12 , wherein the lens further includes a wire grid polarizer that exhibits more infrared light transmission than visible light transmission. 
     
     
         16 . The head-mounted device of  claim 15 , wherein the wire grid polarizer comprises parallel lines, and each of the parallel lines includes first regions of a first material and second regions of a second material. 
     
     
         17 . An electronic device, comprising:
 a transparent structure that includes a polarizer configured exhibit a first transmission at infrared light wavelengths and a second transmission at visible light wavelengths that is less than the first transmission;   an infrared light-emitting device configured to emit infrared light through the transparent structure; and   an infrared light-sensing device configured to detect infrared light through the transparent structure.   
     
     
         18 . The electronic device of  claim 17 , wherein the transparent structure is a catadioptric lens. 
     
     
         19 . The electronic device of  claim 17 , wherein the polarizer is formed from parallel lines, and each of the parallel lines comprises first regions of a first material and second regions of a second material that is different from the first material. 
     
     
         20 . The electronic device of  claim 17 , wherein the transparent structure comprises a layer that forms a quarter wave plate at the visible light wavelengths and does not form a quarter wave plate at the infrared light wavelengths.