Imaging device and electronic device

Abstract

Provided are a first photoelectric conversion unit, a second photoelectric conversion unit having a smaller electric charge amount to be converted per unit time than the first photoelectric conversion unit, a charge accumulation unit that accumulates an electric charge generated by the second photoelectric conversion unit, a charge voltage conversion unit, a first transfer gate unit that transfers an electric charge from the first photoelectric conversion unit to the charge voltage conversion unit, a second transfer gate unit that couples potentials of the charge voltage conversion unit and the charge accumulation unit, a third transfer gate unit that transfers an electric charge from the second photoelectric conversion unit to the charge accumulation unit, an overflow path formed under a gate electrode of the third transfer gate unit, where the overflow path transfers an electric charge overflowing from the second photoelectric conversion unit to the charge accumulation unit, and a light reducing unit that reduces light to enter the second photoelectric conversion unit.

1 . An imaging device, comprising:
 a first photoelectric conversion unit configured to generate a first electric charge;   a second photoelectric conversion unit configured to generate a second electric charge;   a charge voltage conversion unit configured to accumulate the first electric charge generated by the first photoelectric conversion unit;   a charge accumulation unit configured to accumulate the second electric charge generated by the second photoelectric conversion unit;   a first transfer gate unit configured to transfer the first electric charge from the first photoelectric conversion unit to the charge voltage conversion unit;   a second transfer gate unit configured to couple a potential of the charge voltage conversion unit and a potential of the charge accumulation unit;   a third transfer gate unit configured to transfer the second electric charge from the second photoelectric conversion unit to the charge accumulation unit;   an overflow path configured to transfer an overflowing electric charge from the second photoelectric conversion unit to the charge accumulation unit, wherein the overflow path is under a gate electrode of the third transfer gate unit;   a color filter on each of the first photoelectric conversion unit and the second photoelectric conversion unit; and   a light reducing unit between the color filter and the second photoelectric conversion unit, wherein the light reducing unit is configured to reduce light that enters the second photoelectric conversion unit.   
     
     
         2 . The imaging device according to  claim 1 , further comprising an inter-pixel light shielding unit between the first photoelectric conversion unit and the second photoelectric conversion unit, wherein
 the inter-pixel light shielding unit is below the color filter,   the light reducing unit is above the second photoelectric conversion unit, and   the light reducing unit is between the color filter and the inter-pixel light shielding unit.   
     
     
         3 . The imaging device according to  claim 2 , further comprising an insulating film below the color filter, wherein the inter-pixel light shielding unit and the light reducing unit are in the insulating film. 
     
     
         4 . The imaging device according to  claim 2 , further comprising a pinning film between the color filter and the second photoelectric conversion unit, wherein the inter-pixel light shielding unit and the light reducing unit are between the pinning film and the color filter. 
     
     
         5 . The imaging device according to  claim 2 , wherein a part of the inter-pixel light shielding unit corresponds to an optical diaphragm that is between the color filter and the second photoelectric conversion unit. 
     
     
         6 . The imaging device according to  claim 5 , wherein an opening area of the optical diaphragm is less than a plane area of the second photoelectric conversion unit. 
     
     
         7 . The imaging device according to  claim 5 , wherein an opening shape of the optical diaphragm corresponds to a circular shape. 
     
     
         8 . The imaging device according to  claim 5 , wherein an opening shape of the optical diaphragm corresponds to a quadrangular shape. 
     
     
         9 . The imaging device according to  claim 2 , further comprising:
 a first on-chip lens on the first photoelectric conversion unit; and   a second on-chip lens on the second photoelectric conversion unit, wherein each of the color filter, the light reducing unit, and the inter-pixel light shielding unit is between the second on-chip lens and the second photoelectric conversion unit.   
     
     
         10 . The imaging device according to  claim 9 , wherein
 the inter-pixel light shielding unit includes a center in a width direction of the inter-pixel light shielding unit, and   in a portion where the first on-chip lens and the second on-chip lens are adjacent, the light reducing unit extends in a direction of the first photoelectric conversion unit with respect to the center of the inter-pixel light shielding unit.   
     
     
         11 . The imaging device according to  claim 9 , wherein
 a shape of the light reducing unit corresponds to a quadrangular shape, and   a vertex portion of the quadrangular shape is in a portion where the first on-chip lens and the second on-chip lens are adjacent.   
     
     
         12 . The imaging device according to  claim 1 , wherein
 a shape of the light reducing unit corresponds to a quadrangular shape, and   a shape of a vertex portion of the quadrangular shape corresponds to an arc shape.   
     
     
         13 . The imaging device according to  claim 1 , wherein a shape of the light reducing unit corresponds to a circular shape. 
     
     
         14 . The imaging device according to  claim 1 , wherein the light reducing unit is an achromatic optical filter. 
     
     
         15 . The imaging device according to  claim 1 , wherein the light reducing unit includes a passage area through which light transmitted through an on-chip lens passes. 
     
     
         16 . The imaging device according to  claim 1 , wherein the first transfer gate unit, the second transfer gate unit, and the third transfer gate unit are connected in series between the first photoelectric conversion unit and the second photoelectric conversion unit. 
     
     
         17 . The imaging device according to  claim 1 , wherein a light receiving area of the second photoelectric conversion unit is less than a light receiving area of the first photoelectric conversion unit. 
     
     
         18 . An electronic device, comprising:
 an imaging device that includes:
 a first photoelectric conversion unit configured to generate a first electric charge; 
 a second photoelectric conversion unit configured to generate a second electric charge; 
 a charge voltage conversion unit configured to accumulate the first electric charge generated by the first photoelectric conversion unit; 
 a charge accumulation unit configured to accumulate the second electric charge generated by the second photoelectric conversion unit; 
 a first transfer gate unit configured to transfer the first electric charge from the first photoelectric conversion unit to the charge voltage conversion unit; 
 a second transfer gate unit configured to couple a potential of the charge voltage conversion unit and a potential of the charge accumulation unit; 
 a third transfer gate unit configured to transfer the second electric charge from the second photoelectric conversion unit to the charge accumulation unit; 
 an overflow path configured to transfer an overflowing electric charge from the second photoelectric conversion unit to the charge accumulation unit, wherein the overflow path is under a gate electrode of the third transfer gate unit; 
 a color filter on each of the first photoelectric conversion unit and the second photoelectric conversion unit; and 
 a light reducing unit between the color filter and the second photoelectric conversion unit, wherein the light reducing unit is configured to reduce light that enters the second photoelectric conversion unit. 
   
     
     
         19 . An imaging device, comprising:
 a first photoelectric conversion unit;   a second photoelectric conversion unit different from the first photoelectric conversion unit;   a color filter on each of the first photoelectric conversion unit and the second photoelectric conversion unit; and   a light reducing unit between the color filter and the second photoelectric conversion unit, wherein the light reducing unit is configured to reduce light that enters the second photoelectric conversion unit.   
     
     
         20 . The imaging device according to  claim 19 , further comprising an inter-pixel light shielding unit between the first photoelectric conversion unit and the second photoelectric conversion unit, wherein
 the inter-pixel light shielding unit is below the color filter,   the light reducing unit is above the second photoelectric conversion unit, and   the light reducing unit is between the color filter and the inter-pixel light shielding unit.