Imaging pixels with depth sensing capabilities

Abstract

An imager may include depth sensing pixels that receive and convert incident light into image signals. The imager may have an associated imaging lens that focuses the incident light onto the imager. Each of the depth sensing pixels may include a microlens that focuses incident light received from the imaging lens through a color filter onto first and second photosensitive regions of a substrate. The first and second photosensitive regions may provide different and asymmetrical angular responses to incident light. Depth information for each depth sensing pixel may be determined based on the difference between output signals of the first and second photosensitive regions of that depth sensing pixel. Color information for each depth sensing pixel may be determined from a summation of output signals of the first and second photosensitive regions.

What is claimed is: 
     
         1 . An image sensor comprising:
 a first photosensitive region with a first asymmetric response to incident light;   a second photosensitive region with a second asymmetric response to incident light, wherein the first and second photosensitive regions are covered by color filter element material of a single color; and   image processing circuitry that obtains depth sensing information by using subtraction to determine a difference between a first image signal output from the first photosensitive region and a second image signal output from the second photosensitive region.   
     
     
         2 . The image sensor defined in  claim 1 , wherein the image processing circuitry determines the difference between the first image signal output and the second image signal output by subtracting the first image signal output from the second image signal output. 
     
     
         3 . The image sensor defined in  claim 1 , wherein the image processing circuitry determines the difference between the first image signal output and the second image signal output by subtracting the second image signal output from the first image signal output. 
     
     
         4 . The image sensor defined in  claim 1 , wherein the first asymmetric response is the opposite of the second asymmetric response. 
     
     
         5 . The image sensor defined in  claim 1  further comprising:
 a substrate, wherein the first and second photosensitive regions are formed in the substrate. 
 
     
     
         6 . The image sensor defined in  claim 5  wherein the first and second photosensitive regions are separated by a portion of the substrate. 
     
     
         7 . The image sensor defined in  claim 6 , further comprising:
 an opaque layer covering the portion of the substrate that separates the first and second photosensitive regions.   
     
     
         8 . The image sensor defined in  claim 7 , wherein the opaque layer is formed from metal that prevents light from passing through to the substrate. 
     
     
         9 . The image sensor defined in  claim 1 , wherein the first photosensitive region is adjacent to the second photosensitive region. 
     
     
         10 . The image sensor defined in  claim 9 , further comprising:
 a single microlens that covers the first photosensitive region and the second photosensitive region.   
     
     
         11 . An image sensor comprising:
 first and second photosensitive regions having asymmetrical and opposite angular responses to incident light;   a color filter layer, wherein the first and second photosensitive regions are covered by color filter element material of the color filter layer of a single color; and   image processing circuitry that, in a depth sensing image capture mode, obtains depth sensing information by using subtraction to determine a difference between a signal from the first photosensitive region and a signal from the second photosensitive region.   
     
     
         12 . The image sensor defined in  claim 11 , wherein the image processing circuitry determines the difference between the signal from the first photosensitive region and the signal from the second photosensitive region by subtracting the signal from the first photosensitive region from the signal from the second photosensitive region. 
     
     
         13 . The image sensor defined in  claim 11 , wherein the image processing circuitry determines the difference between the signal from the first photosensitive region and the signal from the second photosensitive region by subtracting the signal from the second photosensitive region from the signal from the first photosensitive region. 
     
     
         14 . The image sensor defined in  claim 11 , further comprising:
 a single microlens that covers the first photosensitive region and the second photosensitive region.   
     
     
         15 . The image sensor defined in  claim 11 , wherein the color filter element material of the single color that covers the first and second photosensitive regions comprises green color filter element material. 
     
     
         16 . An image sensor comprising:
 a first photosensitive region with a first asymmetric response to incident light, wherein the first photosensitive region is covered by a first microlens portion and wherein the first photosensitive region is covered by color filter element material of a first color;   a second photosensitive region with a second asymmetric response to incident light, wherein the second photosensitive region is covered by a second microlens portion and wherein the second photosensitive region is covered by color filter element material of the first color; and   image processing circuitry that obtains depth sensing information by using subtraction to determine a difference between a first image signal output from the first photosensitive region and a second image signal output from the second photosensitive region.   
     
     
         17 . The image sensor defined in  claim 16 , wherein the first microlens portion is half of a microlens and wherein the microlens covers two photosensitive regions. 
     
     
         18 . The image sensor defined in  claim 16 , wherein the first asymmetric response of the first photosensitive region is the opposite of the second asymmetric response of the second photosensitive region. 
     
     
         19 . The image sensor defined in  claim 16 , wherein the first microlens portion makes up half of a single microlens. 
     
     
         20 . The image sensor defined in  claim 16 , wherein the first microlens portion comprises a first half of a microlens and the second microlens portion comprises a second half of the microlens.