Ejector device
An ejector device that includes one or more ejectors comprises an ejector layer that spans at least one hollow area. The ejector layer has a first surface and an opposing second surface arranged to receive a viscous material with viscosity between 20 and 50,000 centipoise. The ejector layer includes a radiation absorber material configured to thermally expand without phase transition in response to heating by activation radiation transmitted to the first surface. Thermal expansion of the ejector layer causes displacement of the ejector layer and ejection of the material from the second surface of the ejector layer.
1. An ejector device for ejecting droplets of viscous fluids, comprising:
one or more ejectors comprising an ejector layer that spans a hollow area, the ejector layer having a first surface and an opposing second surface arranged to receive a viscous material with viscosity between 20 and 50,000 centipoise, the ejector layer comprising a radiation absorber material configured to thermally expand without phase transition in response to heating by activation radiation transmitted to the first surface, the ejector layer comprises multiple layers including a first layer having a first coefficient of thermal expansion, CTE1, and a second layer having a second coefficient of thermal expansion, CTE2, wherein CTE2>CTE1, wherein thermal expansion of the ejector layer causes displacement of the ejector layer and ejection of the material from the second surface of the ejector layer.
2. The device of claim 1 , wherein the one or more ejectors comprise an array of ejectors.
3. The device of claim 2 , wherein the array is a one dimensional array that includes one or more hollow mesas.
4. The device of claim 2 , wherein the array is a two dimensional array that includes one or more hollow islands.
5. The device of claim 1 , further comprising:
a substrate;
one or more mesas disposed on the substrate, at least one of the mesas being an ejector mesa comprising the ejector layer that spans the hollow area; and
at least one channel disposed adjacent to at least one of the one or more mesas, the channel configured to carry the material to the ejectors.
6. The device of claim 5 , wherein the substrate comprises at least one of:
a material that is transparent at wavelengths of the activation radiation; and
one or more vias through the substrate.
7. The device of claim 5 , wherein the one or more ejectors comprise one or more hollow mesas, each of the one or more hollow mesas disposed between and bonded to solid mesas.
8. The device of claim 7 , wherein the ejector layer includes at least one layer that conforms to the channel and walls of the solid mesas.
9. The device of claim 5 , further comprising a thermally conductive layer disposed at least partially along the channel.
10. The device of claim 5 , wherein the substrate includes vias fluidically coupled to the channel.
11. The device of claim 5 , further comprising an aperture layer disposed at least partially over the channel.
12. The device of claim 1 , wherein the absorption of the activation radiation in the second layer causes buckling of the ejector layer.
13. The device of claim 1 , wherein the second layer comprises amorphous Ge or amorphous Si.
14. The device of claim 1 , wherein at least one layer of the ejector layer comprises a binding material configured to provide a predetermined surface energy.
15. The device of claim 1 , wherein a portion of the ejector layer, when unheated, is convex and bends toward the substrate.
16. The device of claim 1 , wherein the ejector layer has a built in stress gradient.