Electronic Devices With Ambient Light Sensors and Emissive Displays

Abstract

An electronic device may have a display with an array of pixels that display images for a user. The electronic device may have an ambient light sensor for gathering ambient light information. A subset of the pixels in the array of pixels may overlap the ambient light sensor so that ambient light passing through the subset of pixels may be measured. Each pixel may have an emission enable transistor coupled in series with a light-emitting diode. Control circuitry in the electronic device may disable the subset of pixels to reduce stray light during ambient light measurements while enabling remaining pixels in the array of pixels to display an image. Ambient light sensor circuitry may gather ambient light sensor measurements over one or more periods by using transfer transistors to transfer change from the photodetectors to charge storage capacitors formed from floating diffusions in a common substrate.

What is claimed is: 
     
         1 . An electronic device comprising:
 a display having an array of pixels;   light measurement circuitry having photodetectors formed in a semiconductor substrate, wherein the photodetectors are configured to gather light measurements on light passing through a subset of the array of pixels overlapping the photodetectors; and   control circuitry configured to take action in response to the light measurements gathered by the light measurement circuitry.   
     
     
         2 . The electronic device of  claim 1 , wherein the control circuitry is configured to adjust a content output by the display based on the light measurements gathered by the light measurement circuitry. 
     
     
         3 . The electronic device of  claim 1 , wherein the light measurement circuitry comprises:
 floating diffusion regions formed in the semiconductor substrate.   
     
     
         4 . The electronic device of  claim 3 , wherein the light measurement circuitry comprises:
 transistors that are each respectively formed in the semiconductor substrate between one of the photodetectors and one of the floating diffusion regions.   
     
     
         5 . The electronic device of  claim 1 , further comprising:
 a tablet computer housing that houses the display, the light measurement circuitry, and the control circuitry.   
     
     
         6 . The electronic device of  claim 1 , further comprising:
 cellular telephone communications circuitry coupled to the control circuitry.   
     
     
         7 . The electronic device of  claim 1 , wherein the light measurement circuitry comprises non-camera image sensing circuitry. 
     
     
         8 . The electronic device of  claim 7 , wherein the non-camera image sensing circuitry comprises an ambient light sensor. 
     
     
         9 . An electronic device comprising:
 a display having an array of pixels; and   light measurement circuitry comprising:
 photodiodes formed in a semiconductor substrate, wherein the photodiodes are configured to gather light measurements on light passing through a subset of the array of pixels overlapping the photodiodes; 
 storage capacitors formed in the semiconductor substrate; and 
 transistors that are each respectively formed in the semiconductor substrate between one of the photodiodes and one of the storage capacitors. 
   
     
     
         10 . The electronic device of  claim 9 , further comprising:
 control circuitry configured to adjust the display based on the light measurements gathered by the light measurement circuitry.   
     
     
         11 . The electronic device of  claim 10 , wherein the light measurement circuitry comprises non-camera light sensing circuitry. 
     
     
         12 . The electronic device of  claim 11 , wherein the light arriving at the photodiodes passes through the subset of the array of pixels without passing through a lens. 
     
     
         13 . The electronic device of  claim 12 , wherein the non-camera light sensing circuitry comprises ambient light sensing circuitry. 
     
     
         14 . The electronic device of  claim 9 , further comprising a tablet computer housing or a cellular telephone housing that houses the display and the light measurement circuitry. 
     
     
         15 . An electronic device comprising:
 a display having an array of pixels; and   a non-camera optical sensor comprising:
 photodiodes formed in a semiconductor substrate; 
 floating diffusion regions formed in the semiconductor substrate; and 
 transistors formed in the semiconductor substrate and coupled between the photodiodes and the floating diffusion regions. 
   
     
     
         16 . The electronic device of  claim 15 , wherein the photodiodes are configured to gather light measurements on light passing through a subset of the array of pixels overlapping the photodiodes. 
     
     
         17 . The electronic device of  claim 16 , wherein the non-camera optical sensor lacks a lens. 
     
     
         18 . The electronic device of  claim 16 , further comprising:
 control circuitry configured to take action responsive to the light measurements gathered by the photodiodes.   
     
     
         19 . The electronic device of  claim 18 , wherein the action taken by the control circuitry comprises adjusting a content output by the display. 
     
     
         20 . The electronic device of  claim 19 , further comprising a touch sensor configured to gather touch input.