Patent ID: 7053947
Filing Date: 2006-05-30
Classification: H01L,H04N

Abstract:
1. A method of increasing voltage readout sensitivity of a CMOS active pixel sensor, said sensor including a first photodiode having leakage current flow, a first reset transistor for resetting photodiode voltage and a first sense transistor connected to said photodiode, the method comprising the steps of: commonly connecting a second sense transistor at a drain and a source of said first sense transistor, said second sense transistor is of a type complementary to said first sense transistor; commonly connecting a second reset transistor to said first reset transistor for activating both first and second reset transistors by a reset signal; shielding a second photodiode from light incident on said first photodiode and connecting said second photodiode to said second reset transistor and second sense transistor; and reading out voltage upon illumination of incident light on said first photodiode by activating a select transistor connected to said first and second sense transistors.