Patent ID: 8358167
Filing Date: 2013-01-22
Classification: H01L,H04N

Abstract:
1. A photo sensing unit, comprising: a photo sensing transistor, having a first gate, a first source, and a first drain, used to receive a light signal for inducing a photo current correspondingly, wherein the first source is coupled to a first signal source, and the first gate is coupled to a second signal source; a storage capacitor, having a first end and a second end, used to store a plurality of electrical charges induced from the light signal, wherein the first end is coupled to the first drain, and the second end is coupled to a low voltage; and a switching transistor, having a second gate, a second source, and a second drain, controlled by the second signal source, and used to output a readout signal stored in the storage capacitor to a signal readout line, wherein the second source is coupled to the first end, and the second drain is coupled to the signal readout line, and the second gate is coupled to the second signal source; wherein a threshold voltage of the photo sensing transistor is higher than that of the switching transistor.