Patent ID: 7525168

Claim:
A MOS or CMOS based active pixel sensor comprising: A) a substrate; B) an array of pixels fabricated in or on said substrate, each pixel comprising: 1) a pixel electrode and 2) integrated pixel circuits, C) a photodiode structure located above said pixel circuits for converting electromagnetic radiation into charges during charge integration cycles, said photodiode structure defining a photodiode region for each of said pixels, said photodiode structure comprising: 1) at least one layer of charge generating material to generate charges upon the absorption of electromagnetic radiation, and 2) a surface electrode in the form of a thin transparent layer or grid located above said layers of charge generating material; wherein each of said integrated pixel circuits: i) defines: a) a charge collection node on which charges generated inside the photodiode are collected, b) a charge integration node, at which charges generated in said pixel are integrated to produce pixel signals, c) a charge sensing node from which reset signals or the pixel signals are sensed; and ii) is adapted to maintain voltage potential drop across said electromagnetic radiation detection structure at less than 1.0 volts and substantially constant during charge integration cycles.