Patent ID: 7532264

Claim:
An on-substrate ESD protection system for use with an image sensor array including a two-dimensional array of pixels formed on a substrate, each of the pixels being connected to a corresponding one of a plurality of gate lines and to a corresponding one of a plurality of data lines, each of the pixels including a photo-sensitive element and a switching transistor, the protection system, comprising: a common ESD bus formed on the substrate, the common ESD bus being perpetually electrically isolated from each of the data lines; and at least one ESD protection circuit formed on the substrate, the circuit including a pair of thin film transistors connected in a back-to-back configuration between one of the gate lines and the common ESD bus, the circuit being configured to switch between high resistance when a voltage across the gate line and the common ESD bus is below a threshold value and low resistance when the voltage across the gate line and the common ESD bus is above the threshold value; whereby upon the occurrence of an electrostatic discharge onto the gate line that causes the voltage across the gate line and the common ESD bus to exceed the threshold value, the ESD protection circuit discharges the electrostatic charge from the gate line to the ESD bus, and whereby the common ESD bus is electrically isolated from the data lines during the occurrence of the electrostatic discharge.