Single substrate electromagnetic actuator

• US 20050116798A1
• Filed: 10/31/2003
• Published: 06/02/2005
• Est. Priority Date: 11/01/2002
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Hesketh, Peter J., Bintoro, Jemmy Sutanto
• Granted Patent: US 7,474,180 B2
• Time in Patent Office: Days
• US Class Current: 335/78
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/0069 Bistable microvalves
• CPC Class Codes: F16K 2099/0074 using photolithography, e.g. etching
• CPC Class Codes: F16K 2099/008 Multi-layer fabrications
• CPC Class Codes: F16K 2099/0084 Chemistry or biology, e.g. "lab-on-a-chip" technology
• CPC Class Codes: F16K 2099/0086 Medical applications
• CPC Class Codes: F16K 99/0001 Microvalves microdevices B81B1/00; manufacture or treatment of devices or systems in or on a substrate B81C1/00; microfluidic structures B01L3/5027; micropumps F04B19/006
• CPC Class Codes: F16K 99/0015 Diaphragm or membrane valves
• CPC Class Codes: F16K 99/0046 using magnets

Abstract

A microvalve which utilizes a low temperature (<300° C.) fabrication process on a single substrate. The valve uses buckling and an electromagnetic actuator to provide a relatively large closing force and lower power consumption. A buckling technique of the membrane is used to provide two stable positions for the membrane, and to reduce the power consumption and the overall size of the microvalve. The use of a permanent magnet is an alternative to the buckled membrane, or it can be used in combination with the buckled membrane, or two sets of micro-coils can be used in order to open and close the valve, providing the capability for the valve to operate under normally opened or normally closed conditions. Magnetic analysis using ANSYS 5.7 shows that the addition of Orthonol between the coils increases the electromagnetic force by more than 1.5 times. At a flow rate of 1 mL/m, the pressure drop is <100 Pa. The maximum pressure tested was 57 kPa and the time to open or close the valve in air is under 100 ms. This results in an estimated power consumption of 0.1 mW.

Claims

1. An actuator locatable in a flow path, the actuator comprising:

a single substrate upon which is fabricated a membrane and a membrane activating mechanism;

the membrane capable of moving though a first position and a second position, in the first position, the membrane inhibiting flow through the flow path, and in the second position, the membrane enabling flow through the flow path; and

the membrane activating mechanism to move the membrane between the first position and the second position.

2. The actuator of claim 1, wherein the actuator is a non-electrostatic, non-thermal actuator.

3. The actuator of claim 1, wherein the actuator is an electromagnetic actuator, and the substrate is provided with an orifice.

4. The actuator of claim 1, wherein the membrane is a pre-stressed membrane, and the membrane activating mechanism includes an electromagnetic force generator;

wherein the membrane is positionable into the first position by the pre-stressed nature of the membrane;

wherein when the electromagnetic force generator generates an electromagnetic force in a first direction, the membrane is drawn into the second position; and

wherein when the electromagnetic force generator generates an electromagnetic force in a direction substantially opposite the first direction, the membrane is drawn into the first position.

5. The actuator of claim 4, wherein the membrane is stable in both the first and the second positions without assistance of an electromagnetic force from the electromagnetic force generator.

6. The actuator of claim 1, wherein the membrane is a convex membrane, and the membrane activating mechanism includes an electromagnetic force generator;

wherein the membrane is positionable into the first position by the convex nature of the membrane;

wherein when the electromagnetic force generator generates an electromagnetic force in a first direction, the membrane is drawn into the second position; and

wherein when the electromagnetic force generator generates an electromagnetic force in a direction substantially opposite the first direction, the membrane is into the first position.

7. The actuator of claim 6, wherein the membrane is stable in both the first and the second positions without assistance of an electromagnetic force from the electromagnetic force generator.

8. The actuator of claim 1, wherein the membrane activating mechanism includes a permanent magnet, the membrane located between the electromagnetic force generator and the permanent magnet;

wherein when the electromagnetic force generator generates a force in a direction substantially in the same direction as the force of the permanent magnet, the membrane is drawn into the first position; and

wherein when the electromagnetic force generator generates a force in a direction substantially in an opposite direction as the force of the permanent magnet, the membrane is drawn into the second position.

9. The actuator of claim 8, wherein the membrane is stable in both the first and the second positions without assistance of an electromagnetic force from the electromagnetic force generator.

10. The actuator of claim 1, wherein the actuator has an energy consumption of 400 mW or less to fully actuate.

11. The actuator of claim 1, wherein the actuator fully actuates in less than or equal to 0.36 seconds.

12. An actuator locatable in a flow path, the actuator comprising:

a membrane capable of moving though a first position and a second position, in the first position, the membrane inhibiting flow through the flow path, and in the second position, the membrane enabling flow through the flow path; and

a membrane activating mechanism to move the membrane between the first position and the second position;

the membrane selected from the group consisting of a pre-stressed membrane, a convex membrane, a torsional membrane providing for rotational movement of the membrane between the first and second positions, a membrane having a dome portion, and a membrane having a dome portion and legs.

13. The actuator of claim 12, wherein the actuator is fabricated in a CMOS compatible process.

14. The actuator of claim 12, wherein the actuator is an electromagnetic microvalve;

wherein the microvalve is fabricated upon a single substrate having an orifice;

wherein the membrane activating mechanism includes a magnet and at least one coil;

wherein when the at least one coil generates a force in a direction substantially in the same direction as the force of the magnet, the membrane is drawn into the first position; and

wherein when the at least one coil generates a force in a direction substantially in an opposite direction as the force of the magnet, the membrane is drawn into the second position.

15. The actuator of claim 14, wherein the membrane is stable in both the first and the second positions without assistance of an electromagnetic force from the at least one coil.

16. The actuator of claim 15, wherein the substrate has a first face and a second face;

and

wherein the magnet is a permanent magnet in communication with the first face of the substrate.

17. The actuator of claim 16, wherein a high permeability material with a high magnetic field saturation is provided between at least one coil turn of the at least one coil.

18. A method of fabricating an actuator on a single substrate comprising the steps of:

electroplating a high permeability material into a mould;

electroplating an electrical conductor into a mould; and

stacking the layers to make an actuator on a single substrate.

19. The method according to claim 18, wherein the steps are conducted at temperatures of approximately 300°

C. or less.

20. The method according to claim 18, wherein the actuator is an electromagnetic microvalve including a membrane and a membrane activating mechanism to move the membrane.