Thermal actuator with spatial thermal pattern

A liquid drop emitter comprising:

• (a) a chamber, formed in a substrate, filled with a liquid and having a nozzle for emitting drops of the liquid;
• (b) a thermal actuator having a cantilevered element including a thermo-mechanical bender portion extending from a wall of the chamber and a free end tip residing in a first position proximate to the nozzle, the thermo-mechanical bender portion having a base end adjacent the base element and a free end adjacent the free end tip;
• and
• (c) apparatus adapted to apply a heat pulse having a spatial thermal pattern directly to the thermo-mechanical bender portion causing a rapid deflection of the free end tip and ejection of a liquid drop, and wherein said spatial thermal pattern results in a substantially greater temperature increase of the base end than the free end of the thermo-mechanical bending portion.

A thermal actuator for a micro-electromechanical device comprising:

• (a) a base element;
• (b) a cantilevered element including a thermo-mechanical bender portion extending from the base element to a free end tip residing at a first position, the thermo-mechanical bender portion having a base end adjacent the base element and a free end adjacent the free end tip, the thermo-mechanical bender portion further including a first deflector layer constructed of a first material having a large coefficient of thermal expansion, a second deflector layer, and a barrier layer constructed of a dielectric material having low thermal conductivity wherein the barrier layer is bonded between the first deflector layer and the second deflector layer;
• and
• (c) apparatus adapted to apply a heat pulse having a spatial thermal pattern directly to the first deflector layer, causing the deflection of the free end tip of the cantilevered element to a second position, followed by restoration of the cantilevered element to the first position as heat diffuses through the barrier layer to the second deflector layer and the cantilevered element reaches a uniform temperature, and wherein said spatial thermal pattern results in a substantially greater temperature increase of the base end than the free end of the first deflector layer.

A liquid drop emitter comprising:

• (a) a chamber, formed in a substrate, filled with a liquid and having a nozzle for emitting drops of the liquid;
• (b) a cantilevered element including a thermo-mechanical bender portion extending from a wall of the chamber to a free end tip residing at a first position proximate to the nozzle, the thermo-mechanical bender portion having a base end adjacent the base element and a free end adjacent the free end tip, the thermo-mechanical bender portion further including a first deflector layer constructed of a first material having a large coefficient of thermal expansion, a second deflector layer, and a barrier layer constructed of a dielectric material having low thermal conductivity wherein the barrier layer is bonded between the first deflector layer and the second deflector layer;
• and
• (c) apparatus adapted to apply a heat pulse having a spatial thermal pattern directly to the first deflector layer, causing a rapid deflection of the free end tip and ejection of a liquid drop, followed by restoration of the cantilevered element to the first position as heat diffuses through the barrier layer to the second deflector layer and the cantilevered element reaches a uniform temperature, and wherein said spatial thermal pattern results in a substantially greater temperature increase of the base end than the free end of the first deflector layer.

A thermal actuator for a micro-electromechanical device comprising:

• (a) a base element;
• (b) a cantilevered element including a thermo-mechanical bender portion extending from the base element to a free end tip residing at a first position, the thermo-mechanical bender portion having a base end adjacent the base element and a free end adjacent the free end tip, the thermo-mechanical bender portion further including the cantilevered element including a barrier layer constructed of a dielectric material having low thermal conductivity, a first deflector layer constructed of a first electrically resistive material having a large coefficient of thermal expansion, and a second deflector layer constructed of a second electrically resistive material having a large coefficient of thermal expansion wherein the barrier layer is bonded between the first and second deflector layers;
• (c) a first heater resistor formed in the first deflector layer and adapted to apply heat energy having a first spatial thermal pattern which results in a first deflector layer base end temperature increase, ΔT1b, in the first deflector layer at the base end that is greater than a first deflector layer free end temperature increase, ΔT1f, in the first deflector layer at the free end;
• (d) a second heater resistor formed in the second deflector layer and adapted to apply heat energy having a second spatial thermal pattern which results in a second deflector layer base end temperature increase, ΔT2b, in the second deflector layer at the base end that is greater than a second deflector layer free end temperature increase, ΔT2f, in the second deflector layer at the free end;
• (e) a first pair of electrodes connected to the first heater resistor to apply an electrical pulse to cause resistive heating of the first deflector layer, resulting in a thermal expansion of the first deflector layer relative to the second deflector layer;
• (f) a second pair of electrodes connected to the second heater resistor portion to apply an electrical pulse to cause resistive heating of the second deflector layer, resulting in a thermal expansion of the second deflector layer relative to the first deflector layer, wherein application of an electrical pulse to either the first pair or the second pair of electrodes causes deflection of the cantilevered element away from the first position to a second position, followed by restoration of the cantilevered element to the first position as beat diffuses through the barrier layer and the cantilevered element reaches a uniform temperature.

A liquid drop emitter comprising:

• (a) a chamber, formed in a substrate, filled with a liquid and having a nozzle for emitting drops of the liquid;
• (b) a thermal actuator having a cantilevered element including a thermo-mechanical bender portion extending from a wall of the chamber and a free end tip residing in a first position proximate to the nozzle, the thermo-mechanical bender portion having a base end adjacent the base element and a free end adjacent the free end tip, the thermo-mechanical bender portion further including a barrier layer constructed of a dielectric material having low thermal conductivity, a first deflector layer constructed of a first electrically resistive material having a large coefficient of thermal expansion, and a second deflector layer constructed of a second electrically resistive material having a large coefficient of thermal expansion wherein the barrier layer is bonded between the first and second deflector layers;
• (c) a first heater resistor formed in the first deflector layer and adapted to apply heat energy having a first spatial thermal pattern which results in a first deflector layer base end temperature increase, ΔT1b, in the first deflector layer at the base end that is greater than a first deflector layer free end temperature increase, ΔT1f, in the first deflector layer at the free end;
• (d) a second heater resistor formed in the second deflector layer and adapted to apply heat energy having a second spatial thermal pattern which results in a second deflector layer base end temperature increase, ΔT2b, in the second deflector layer at the base end that is greater than a second deflector layer free end temperature increase, ΔT2f, in the second deflector layer at the free end;
• (e) a first pair of electrodes connected to the first heater resistor to apply an electrical pulse to cause resistive heating of the first deflector layer, resulting in a thermal expansion of the first deflector layer relative to the second deflector layer;
• (f) a second pair of electrodes connected to the second heater resistor portion to apply an electrical pulse to cause resistive heating of the second deflector layer, resulting in a thermal expansion of the second deflector layer relative to the first deflector layer, wherein application of electrical pulses to the first and second pairs of electrodes causes rapid deflection of the cantilevered element, ejecting liquid at the nozzle, followed by restoration of the cantilevered element to the first position as heat diffuses through the barrier layer and the cantilevered element reaches a uniform temperature.