Imaging element and imaging device

Abstract

Pixel formation in an imaging element configured to detect image plane phase difference is simplified. The imaging element includes an on-chip lens, a plurality of photoelectric conversion portions, and a plurality of waveguides. The on-chip lens concentrates incident light on a pixel and is placed on each pixel so as to be shifted from a center of the pixel according to an incident angle of the incident light. The plurality of photoelectric conversion portions is arranged in the pixel and performs photoelectric conversion according to the incident light. The plurality of waveguides is arranged for the plurality of respective photoelectric conversion portion in the pixel. The plurality of waveguides guide the incident light concentrated so that the incident light enters each of the plurality of photoelectric conversion portion, and are formed into shapes dissimilar to each other based on the shift of the on-chip lens.

What is claimed is: 
     
         1 . An imaging element, comprising:
 a plurality of pixels formed in a pixel array, one of the plurality of pixels, comprising:
 an on-chip lens that is configured to concentrate incident light on, and is placed on the one of the plurality of pixels so as to be shifted from a center of the one of the plurality of pixels according to an incident angle of the incident light, 
 a plurality of photoelectric conversion portions arranged in the one of the plurality of pixels and configured to perform photoelectric conversion according to the incident light; and 
 a plurality of waveguides arranged for the plurality of respective photoelectric conversion portions in the one of the plurality of pixels, the plurality of waveguides each being configured to guide the incident light concentrated so that the incident light enters each of the plurality of photoelectric conversion portions being formed into shapes dissimilar to each other on a basis of the shift of the on-chip lens, 
 wherein, in a cross-sectional view, a first waveguide of the plurality of waveguides comprises a first core, a first edge of the first core being disposed closer to a center of the pixel array than a second edge of the first core, 
 wherein, in the cross-sectional view, a second waveguide of the plurality of waveguides comprises a second core, a first edge of the second core being disposed closer to the center of the pixel array than a second edge of the second core, and 
 wherein, in the cross-sectional view, a first inclination angle of the first edge of the first core is different than a second inclination angle of the first edge of the second core. 
   
     
     
         2 . The imaging element according to  claim 1 , wherein, in the cross-sectional view, the first inclination angle of the first edge of the first core is different than a third inclination angle of the second edge of the first core. 
     
     
         3 . The imaging element according to  claim 1 , wherein, in the cross-sectional view, the second inclination angle of the first edge of the second core is different than a fourth inclination angle of the second edge of the second core. 
     
     
         4 . The imaging element according to  claim 1 , further comprising:
 a pixel circuit that is placed in each of the plurality of pixels and configured to generate an image signal based on photoelectric conversion in the plurality of photoelectric conversion portions; and   a wiring layer that is placed on a surface different from a surface for receiving the concentrated incident light, of surfaces of a semiconductor substrate in which the photoelectric conversion portions are formed, the wiring layer being configured to transmit the image signal.   
     
     
         5 . The imaging element according to  claim 1 , wherein each of the plurality of pixels includes two photoelectric conversion portions and two waveguides. 
     
     
         6 . The imaging element according to  claim 1 , wherein the plurality of pixels are arranged two-dimensionally in a grid pattern. 
     
     
         7 . The imaging element according to  claim 1 , wherein the imaging element has a back-illuminated configuration. 
     
     
         8 . The imaging element according to  claim 1 , further comprising a color filter provided between the on-chip lens and the plurality of waveguides. 
     
     
         9 . The imaging element according to  claim 8 , further comprising a planarization film provided between the color filter and the plurality of waveguides. 
     
     
         10 . The imaging element according to  claim 1 , wherein a cladding member provided between the first and second cores has a triangular cross-sectional shape. 
     
     
         11 . An imaging device, comprising:
 a plurality of pixels formed in a pixel array, one of the plurality of pixels, comprising:
 an on-chip lens that is configured to concentrate incident light on, and is placed on the one of the plurality of pixels so as to be shifted from a center of the one of the plurality of pixels according to an incident angle of the incident light, 
 a plurality of photoelectric conversion portions arranged in the one of the plurality of pixels and configured to perform photoelectric conversion according to the incident light; 
 a plurality of waveguides arranged for the plurality of respective photoelectric conversion portions in the one of the plurality of pixels, the plurality of waveguides each being configured to guide the incident light concentrated so that the incident light enters each of the plurality of photoelectric conversion portions being formed into shapes dissimilar to each other on a basis of the shift of the on-chip lens, 
 wherein, in a cross-sectional view, a first waveguide of the plurality of waveguides comprises a first core, a first edge of the first core being disposed closer to a center of the pixel array than a second edge of the first core, 
 wherein, in the cross-sectional view, a second waveguide of the plurality of waveguides comprises a second core, a first edge of the second core being disposed closer to the center of the pixel array than a second edge of the second core, and 
 wherein, in the cross-sectional view, a first inclination angle of the first edge of the first core is different than a second inclination angle of the first edge of the second core; 
   a pixel circuit that is placed in each of the plurality of pixels and configured to generate an image signal based on photoelectric conversion in the plurality of photoelectric conversion portions; and   a processing circuit configured to detect a phase difference on a basis of a plurality of image signals based on photoelectric conversion by the plurality of photoelectric conversion portions.   
     
     
         12 . The imaging device according to  claim 11 , wherein, in the cross-sectional view, the first inclination angle of the first edge of the first core is different than a third inclination angle of the second edge of the first core. 
     
     
         13 . The imaging device according to  claim 11 , wherein, in the cross-sectional view, the second inclination angle of the first edge of the second core is different than a fourth inclination angle of the second edge of the second core. 
     
     
         14 . The imaging device according to  claim 11 , wherein each of the plurality of pixels includes two photoelectric conversion portions and two waveguides. 
     
     
         15 . The imaging device according to  claim 11 , wherein the plurality of pixels are arranged two-dimensionally in a grid pattern. 
     
     
         16 . The imaging device according to  claim 11 , wherein the imaging device has a back-illuminated configuration. 
     
     
         17 . The imaging device according to  claim 11 , further comprising a color filter provided between the on-chip lens and the plurality of waveguides. 
     
     
         18 . The imaging device according to  claim 17 , further comprising a planarization film provided between the color filter and the plurality of waveguides. 
     
     
         19 . The imaging device according to  claim 11 , wherein a cladding member provided between the first and second cores has a triangular cross-sectional shape. 
     
     
         20 . The imaging element according to  claim 11 , wherein light enters the first waveguide of the plurality of waveguides at a smaller incident light than that in the second waveguide of the plurality of waveguides.