A Novel Digital Photoelectric Sensor Implemented in GaAs IC using Conversion of Light Intensity to Pulse frequency

Abstract

A photoelectronic GaAs integrated circuit, which converts light intensity to digital pulse frequency, has been made using the MES-FET process. The circuit includes a MSM (Metal-Semiconductor-Metal) photodiode (PD), a preamplifier (PA), a schmitt trigger (ST), a flip-flop (FF) (1 bit digital counter) and a reset (RS) FET. This sensor cell has wide dynamic range over 5 decades of incident light power and a γ characteristic suitable for a visible image device.