| 摘要 |
A snap-through thermal actuator for a micro-electromechanical device such as a liquid drop emitter or a fluid control microvalve is disclosed. The snap-through actuator is comprised of a base element formed with a depression having opposing anchor edges which define a central plane. A deformable element, attached to the base element at the opposing anchor edges, is constructed as a planar lamination including a first layer of a first material having a low coefficient of thermal expansion and a second layer of a second material having a high coefficient of thermal expansion. The deformable element is formed to have a residual shape bowing outward from the central plane in a first direction away from the second layer. The snap-through thermal actuator further comprises apparatus adapted to apply a heat pulse to the deformable element which causes a sudden rise in the temperature of the deformable element. The deformable element initially bows farther outward in the first direction, then, due to thermomechanical torque's acting at the opposing anchor edges, reverses and snaps through the central plane to bow outward in a second direction toward the second layer, and then relaxes to the residual shape as the temperature decreases. The snap-through thermal actuator is configured with a liquid chamber having a nozzle, a fluid flow port to form a liquid drop emitter or a fluid control microvalve, or to activate an electrical microswitch. Heat pulses are applied to the deformable element by resistive heating or by light energy pulses.
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