Method and structure for an out-of plane compliant micro actuator
View Patent ↗This present invention relates generally to manufacturing objects. More particularly, the invention relates to a method and structure for fabricating an out-of-plane compliant micro actuator. The compliant actuator has large actuation range in both vertical and horizontal planes without physical contact to the substrate. Due to fringe field actuation, the compliant actuator has no pull-in phenomenon and requires low voltage by a ‘zipping’ movement compared to conventional parallel plate electrostatic actuators. The method and device can be applied to micro actuators as well as other devices, for example, micro-electromechanical sensors, detectors, fluidic, and optical systems.
1. An actuator device, the actuator device comprising:
a substrate member, the substrate member comprising a surface region;
a movable compliant actuator member having a fixed end, a free end, and a length formed between the fixed end and the free end, the fixed end being coupled to a portion of the surface region, the actuator member having at least a first state at a first spatial position and a second state at a second spatial position, the free end being at the first spatial position during the first state, the first spatial position being a first predetermined height normal to the surface region and the second spatial position being a second predetermined height normal to the surface region;
an arc region defining a path between the first spatial position and the second spatial position, the actuator member being in a stressed state at the second spatial position, the stressed state being in a direction toward the first spatial position;
a plurality of electrode members spatially disposed along a first region of the surface region and a second region of the surface region, the first region being within a vicinity of the portion of the surface region coupled to the fixed end of the movable compliant actuator member;
whereupon one or more of the electrodes is capable of being biased relative to the movable compliant actuator to cause the movable compliant actuator member to move along the arc region from the first spatial position to the second spatial position; and
wherein the actuator member comprises a plurality of openings therein, the plurality of openings being provided to form a pair of electrodes with the plurality of fixed electrode within the surface region.
2. The device of claim 1 wherein each of the electrodes is actuated to cause the movable compliant actuator member to be in the second spatial position.
3. The device of claim 1 wherein the actuator member, except for the fixed end, is free from physical contact with the surface region.
4. The device of claim 1 wherein each of the plurality of electrode members is characterized by a length and a width, the length being provided in a direction normal to the length of the actuator member.
5. The device of claim 1 wherein each of the plurality of electrode members is embedded within the surface region.
6. The device of claim 1 wherein the substrate comprises a silicon wafer including one or more integrated circuits.
7. The device of claim 1 wherein the substrate is a TFT glass substrate.
8. The device of claim 1 wherein the movable compliant actuator member is made of a stressed film selected from: Aluminum, Titanium, TiN, Copper, amorphous Silicon, poly Silicon, single crystal Silicon, SiO2, Si3N4, or metal alloy.
9. The device of claim 1 wherein the movable compliant actuator is a stack of films the stack of films selected from films of different Coefficient of Thermal Expansion (CTE) including Aluminum/Ti, Aluminum/TiN, TiN/amorphous silicon.