Patent ID: 7461918

Claim:
A micro-electromechanical integrated circuit device which comprises a substrate that defines a plurality of fluid inlet channels; drive circuitry positioned on the substrate; a plurality of fixed nozzle chamber walls positioned on the substrate about respective fluid inlet channels; a plurality of movable nozzle chamber structures positioned over respective nozzle chamber walls so that nozzle chambers are defined by the nozzle chamber walls and the nozzle chamber structures, the nozzle chambers being in fluid communication with respective fluid inlet channels and the nozzle chamber structures each defining a fluid ejection port; a plurality of elongate actuators, each elongate actuator being fast at one end with the substrate to receive electrical signals from the drive circuitry and fast at an opposite end with a respective nozzle chamber structure so that, on receipt of an electrical signal, the actuators are operable to displace the movable nozzle chamber structures towards and away from the substrate so that fluid is ejected from the fluid ejection ports; and a nozzle guard mounted on the substrate in spaced relationship to the substrate, the nozzle guard defining a plurality of fluid passages that are substantially aligned with respective fluid ejection ports so that fluid ejected from the fluid ejection ports can pass through the nozzle guard, and wherein the nozzle guard and the substrate have a substantially matching coefficient of thermal expansion.