Patent ID: 7960766

Claim:
A light sensor, comprising: a layer of a first conductivity type; a first region of a second conductivity type in the layer of the first conductivity type and forming a first PN junction photodiode with the layer of the first conductivity type; a well of the second conductivity type in the layer of the first conductivity type and forming a second PN junction photodiode with the layer of the first conductivity type; a second region of the second conductivity type in the well of the second conductivity type, wherein the second region of the second conductivity type is more heavily doped than the well of the second conductivity type; wherein carriers are produced in the layer of the first conductivity type when light, including both visible light and infrared (IR) light, is incident on the light sensor; wherein a portion of the carriers produced due to the visible light and the IR light incident on the first region of the second conductivity type are captured by the first region of the second conductivity type and contribute to a first photocurrent that is indicative of both the visible light and the IR light; wherein a further portion of the carriers, produced due to the IR light that passes through the well of the second conductivity type, are captured by the second region of the second conductivity type in the well of the second conductivity type and contribute to a second photocurrent that is indicative of the IR light; and wherein a differential photocurrent, produced by determining a difference between the first and second photocurrents, has a spectral response with a significant portion of the IR light removed.