ACTUATOR CHIP FOR INKJET PRINTHEAD WITH ELECTROSTATIC DISCHARGE PROTECTION

摘要

An inkjet printhead chip includes electrostatic discharge (ESD) circuits to protect the chip during ESD events, such as one especially to prevent a thin dielectric layer on a substrate from breakdown. In one embodiment, the chip includes an ESD circuit essentially dedicate per each actuator. In another, ESD circuits alternate connection between power and ground. In still another, actuators are approximately equidistantly spaced with respect to respective ESD circuits. Exemplary ESD circuits include a ballast resistor in series with a diode. In turn, diodes are either forward biased toward power or away from ground. In a thermal inkjet embodiment, a cavitation layer above a resistor and dielectric layer have pluralities of fingers connecting the cavitation layer to a metal buss. The metal buss attaches to the ballast resistors. Protection typically embodies the safe distribution of ESD current to ground during both chip manufacture and user printhead installation.