MEMBRANE MEMS ACTUATOR INCLUDING FLUIDIC IMPEDANCE STRUCTURE
A liquid dispenser includes a first liquid chamber including a nozzle and a second liquid chamber. A flexible membrane is positioned to separate and fluidically seal the first liquid chamber and the second liquid chamber. A heater is associated with the second liquid chamber. A liquid supply channel is in fluid communication with the second chamber. A liquid return channel is in fluid communication with the second chamber. A liquid supply provides a liquid that flows continuously from the liquid supply through the liquid supply channel through the second liquid chamber through the liquid return channel and back to the liquid supply. A fluidic impedance structure is positioned in the second liquid chamber between the heater and the liquid return channel.
1 . A liquid dispenser comprising:
a first liquid chamber including a nozzle;
a second liquid chamber;
a liquid supply channel in fluid communication with the second chamber;
a liquid return channel in fluid communication with the second chamber;
a heater associated with the second liquid chamber;
a flexible membrane positioned to separate and fluidically seal the first liquid chamber and the second liquid chamber;
a liquid supply that provides a liquid that flows continuously from the liquid supply through the liquid supply channel through the second liquid chamber through the liquid return channel and back to the liquid supply; and
a fluidic impedance structure positioned in the second liquid chamber between the heater and the liquid return channel.
2 . The liquid dispenser of claim 1 , wherein the fluidic impedance structure includes a fluid diode.
3 . The liquid dispenser of claim 1 , wherein the fluidic impedance structure includes a post.
4 . The liquid dispenser of claim 1 , wherein the fluidic impedance structure includes a wall that extends into the second liquid chamber.
5 . The liquid dispenser of claim 1 , wherein the fluidic impedance structure includes a porous member positioned at the interface of the second liquid chamber and the liquid return channel.
6 . The liquid dispenser of claim 1 , the fluidic impedance structure being a first fluidic impedance structure, the liquid dispenser further comprising:
a second fluidic impedance structure positioned in the second chamber between the heater and the liquid supply channel.
7 . The liquid dispenser of claim 1 , wherein the flexible membrane is corrugated.
8 . The liquid dispenser of claim 7 , the nozzle including a center point, the heater including a center point, and the flexible corrugated membrane including a center point, wherein the center points of the nozzle, the heater, and the flexible corrugated membrane are collinear relative to each other.
9 . The liquid dispenser of claim 1 , the first liquid chamber including a first liquid and the second liquid chamber including a second liquid, wherein the first liquid and the second liquid are different liquids.
10 . The liquid of dispenser of claim 9 , wherein the second liquid has a lower boiling point when compared to first liquid.
11 . The liquid of dispenser of claim 9 , wherein the second liquid is a non-corrosive liquid.
12 . The liquid dispenser of claim 1 , wherein the heater is a split heater.
13 . The liquid dispenser of claim 1 , the nozzle including a center point, the heater including a center point, and the flexible membrane including a center point, wherein the center points of the nozzle, the heater, and the flexible membrane are collinear relative to each other.