Rotationally deployed actuators
View Patent ↗A method for making an actuator includes forming, e.g., using photolithography techniques, a substantially planar actuator device of an electrically conductive material, e.g., a semiconductor, to include an outer frame, a fixed frame coupled to the outer frame for rotational movement relative thereto, a moveable frame coupled to the outer frame for rotational movement relative thereto, and an actuator incorporating a plurality of interdigitated teeth, a fixed portion of which is attached to the fixed frame and a moving portion of which is attached to the moveable frame. The fixed frame is then rotated to a deployed position relative to the outer frame such that the fixed portion of the actuator teeth is disposed at a selected angle relative to the moving portion of the actuator teeth, and the position of the fixed frame relative to the outer frame is then fixed at the deployed position.
1. A method for making a device, the method comprising:
forming a substantially planar actuator device, comprising:
an outer frame;
a fixed frame coupled to the outer frame for rotational movement relative thereto;
a moveable frame coupled to the outer frame for rotational movement relative thereto; and,
an actuator incorporating a plurality of interdigitated teeth, a fixed portion of which is attached to the fixed frame and a moving portion of which is attached to the moveable frame;
rotating the fixed frame from a coplanar position to a deployed position relative to the outer frame such that the fixed portion of the actuator teeth is disposed at a selected angle relative to the moving portion of the actuator teeth; and,
fixing the fixed frame in the deployed position relative to the outer frame.
2. The method of claim 1 , wherein the forming comprises photolithography.
3. The method of claim 2 wherein the photolithography comprises one or more of etching and/or micromachining.
4. The method of claim 3 , wherein the etching comprises deep reactive ion etching (DRIE).
5. The method of claim 3 , wherein the micromachining comprises one or more of ion milling, laser ablation, chemical mechanical polishing (CMP), micro-electrical discharge forming and/or micro-forging.
6. The method of claim 1 , wherein the rotating comprises pressing on an upper surface of the fixed frame until the fixed frame is disposed in the deployed position.
7. The method of claim 1 , wherein the rotating comprises pulling on a lower surface of the fixed frame until the fixed frame is disposed in the deployed position.
8. The method of claim 7 , wherein the pulling comprises applying a vacuum to the lower surface of the fixed frame.
9. The method of claim 1 , further comprising placing the actuator device on a fixture having an outer ledge with an upper surface corresponding to a lower surface of the outer frame and a central recess with an upper surface corresponding to a lower surface of the fixed frame when it has been rotated to the deployed position.
10. The method of claim 1 , further comprising:
placing the actuator between:
a first fixture having an outer ledge with an upper surface corresponding to a lower surface of the outer frame and a central recess with an upper surface corresponding to a lower surface of the fixed frame when it has been rotated to the deployed position; and,
a second fixture having an outer ledge with a lower surface corresponding to an upper surface of the outer frame and a central protrusion with a lower surface corresponding to an upper surface of the fixed frame when it has been rotated to the deployed position; and,
wherein the rotating comprises urging the first and second fixtures toward each other until the fixed frame is disposed in the deployed position.
11. The method of claim 1 , wherein:
the actuator device further comprises a deployment stop attached to the fixed frame and comprising a side wall disposed parallel to and in spaced opposition to a side wall of the outer frame;
the rotating comprises rotating the fixed frame until a lower end of the opposing side wall of the deployment stop is disposed in abutment with the opposing side wall of the outer frame; and,
the fixing comprises one or more of:
bonding the lower end of the opposing side wall of the deployment stop to the opposing side wall of the outer frame with an adhesive;
welding the lower end of the opposing side wall of the deployment stop to the opposing side wall of the outer frame with a weldment;
bonding the opposing side wall of the deployment stop to the opposing side wall of the outer frame with a fillet of an adhesive; and/or,
bonding a wedge between the opposing side wall of the deployment stop and the opposing side wall of the outer frame with an adhesive.
12. The method of claim 11 , wherein the welding comprises one or more of laser welding and/or electron beam welding.
13. The method of claim 1 , further comprising forming a serpentine contact flexure extending between the outer frame and the fixed frame, the serpentine contact flexure being one or more of made of an electrically conductive material and/or having an electrically conductive plating disposed thereon.
14. The method of claim 1 , wherein the actuator device further comprises a platform coupled to the moveable frame for rotational movement relative thereto, and further comprising forming a socket in the platform and a complementary ball disposed concentrically within the socket and connected to the outer frame through a slot in a side of the socket.
15. The method of claim 14 , further comprising:
forming a pair of folding frame portions in the outer frame on opposite sides of a central frame portion of the outer frame to which the ball is connected, each folding frame portion having a pair of hinges respectively disposed at opposite ends thereof, a distally opposite pair of the hinges respectively coupling outer ends of the folding frame portions to the outer frame and a proximally opposite pair of the hinges respectively coupling inner ends of the folding frame portions of the central frame portion;
moving the central frame portion and ball to a deployed position below and substantially parallel to the outer frame; and,
fixing the central frame portion at the deployed position.
16. The method of claim 1 , further comprising forming a lateral snubber assembly in the actuator device, the lateral snubber assembly comprising opposing C-shaped first and second snubber members respectively formed on the fixed and moveable frames and separated from each other by a gap.
17. The method of claim 16 , wherein respective ends of the first and second snubber members are semi-cylindrical in shape.
18. The method of claim 16 , wherein the forming comprises:
forming a trench having side walls and a bottom end in an upper surface of a silicon substrate;
depositing a layer of oxide on at least the upper surface of the substrate, the oxide forming corresponding liners on the side walls and bottom end of the trench;
depositing a layer of polysilicon on at least an upper surface of the layer of oxide on the upper surface of the substrate and the liners of oxide in the trench;
removing a portion of the layer of polysilicon from the upper surface of the layer of oxide on the upper surface of the substrate in an area adjacent to a side wall of the trench and above the corresponding liner of oxide on the side wall of the trench;
removing a lower portion of the substrate, including the bottom end of the trench, such that the liner of oxide on the bottom end of the trench is exposed through a lower surface of the substrate; and,
removing the corresponding liner of oxide on the side wall of the trench, at least a portion of the liner of oxide exposed on the bottom end of the trench, and the layer of oxide on the upper surface of the substrate adjacent to the side wall of the trench.
19. An actuator, comprising:
a substantially planar actuator device, comprising:
an outer frame;
a fixed frame coupled to the outer frame for rotational movement relative thereto;
a moveable frame coupled to the outer frame for rotational movement relative thereto; and,
an actuator incorporating a plurality of interdigitated teeth, a fixed portion of which is attached to the fixed frame and a moving portion of which is attached to the moveable frame,
wherein the fixed frame is adapted to be fixed at a deployed position that is rotated relative to the outer frame such that the fixed portion of the actuator teeth is disposed at a selected angle relative to the moving portion of the actuator teeth.
20. The actuator of claim 19 , wherein:
the actuator device further includes a deployment stop attached to the fixed frame and having a side wall disposed parallel to and in spaced opposition to a side wall of the outer frame;
the fixed frame is rotated relative to the outer frame such that a lower end of the opposing side wall of the deployment stop is disposed in abutment with the opposing side wall of the outer frame; and,
the angular position of the fixed frame is fixed at the deployed position by one or more of:
an adhesive bond between the lower end of the opposing side wall of the deployment stop and the opposing side wall of the outer frame;
a weldment between the lower end of the opposing side wall of the deployment stop and the opposing side wall of the outer frame;
a fillet of an adhesive between the opposing side wall of the deployment stop and the opposing side wall of the outer frame; and/or,
a wedge bonded between the opposing side wall of the deployment stop and the opposing side wall of the outer frame with an adhesive.
21. A camera incorporating the actuator of claim 19 .
22. An electronic device incorporating the camera of claim 21 .
23. The electronic device of claim 22 , wherein the device comprises a cell phone, a smart phone, a personal digital assistant, a surveillance system or a computer.