Radiation activated micro-fluid ejection devices and methods for ejecting fluids

A micro-fluid ejection device comprising:

• a passageway plate;
• a fluid chamber defined in the passageway plate operable for containing a fluid filled through a fluid channel also defined in the passageway plate;
• a fluid ejection hole defined through a top plate corresponding to the fluid chamber, the passageway plate having a thickness from a bottom of the fluid channel in the fluid chamber to an underside of the top plate;
• a lens provided adjacent to the fluid chamber;
• and
• an irradiator, wherein the irradiator provides radiation through the lens and into the fluid contained in the fluid chamber, the fluid is nucleated by the radiation such that a vapor bubble is formed and directly adjacently displaces the fluid as a droplet of fluid ejected through the fluid ejection hole, the thickness of the passageway plate being sufficiently thin to enable the formed bubble to directly eject the droplet through the top plate, the fluid chamber having a coating on a fluid side surface thereof to protect the passageway plate against cavitation effects from collapse of the vapor bubble.