Electromagnetic energy controlled low actuation voltage microelectromechanical switch

• US 20030090350A1
• Filed: 11/13/2001
• Published: 05/15/2003
• Est. Priority Date: 11/13/2001
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Feng, Milton, Shen, Shyh-Chiang
• Granted Patent: US 6,717,496 B2
• Time in Patent Office: Days
• US Class Current: 335/78
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

The present invention is an electromagnetic energy, e.g., visible light, controlled low actuation voltage MEMS switch. Stimulation of photovoltaic diodes causes a switching that controls the flow of a signal. A metal or other suitable conductive pad moves freely up and down within brackets, without the need for deformation, in response to the diodes to either ground a signal or permit it to pass. The low activation voltage of the bracketed pad structure permits the use of a reasonable number of photovoltaic diodes to develop sufficient voltage for actuation of the switch, allowing the realization of the present electromagnetic energy, e.g., visible light, controlled MEMS switch in a minimized chip area. The photovoltaic diodes do not require an independent DC power source to operate the switch of the invention. Use of different wavelengths to excite different sets of diodes allows turning on and off of the switch of the invention.

Claims

1. A microelectromechanical switch that controls a flow of signals, the switch comprising:

a ground plane;

a signal line;

a conductive pad responsive to an actuation voltage for controlling the flow of signals in said signal line by selectively making and breaking electrical contact between said conductive pad and said ground and said signal line, without substantially deforming said conductive pad;

brackets to guide said conductive pad when said conductive pad makes and breaks electrical contact;

an electrode for attracting said conductive pad when said actuation voltage is applied to said electrode; and

a photovoltaic source electrically connected to said electrode to supply said actuation voltage in response to electromagnetic energy.

2. The microelectromechanical switch according to claim 1, wherein said actuation voltage is 3 Volts or less.

3. The microelectromechanical switch according to claim 1, wherein said conductive pad further includes access holes for said brackets to fit through to keep said conductive pad properly aligned when making and breaking contact.

4. A microelectromechanical switch that controls a flow of signals, the switch comprising:

waveguides including a signal line and at least one ground plane;

a conductive pad responsive to an actuation voltage, said conductive pad electrically connecting said signal line and said ground plane when located in a relaxed position to send signals from said signal line to ground, and when actuated, allowing signals to flow through said signal line;

an electrode for attracting said conductive pad to said stimulated position when said actuation voltage is applied to said electrode;

brackets for guiding said conductive pad when said conductive pad moves between said relaxed position and a stimulated position due to said actuation voltage;

a photovoltaic source electrically connected to said electrode to supply said actuation voltage in response in response to electromagnetic energy.

5. The microelectromechanical switch according to claim 4, wherein said signal line includes an input port and an output port, the signal being grounded before reaching said output port when said conductive pad is in said relaxed position.

6. The microelectromechanical switch according to claim 4, further including a second electrode for attracting said conductive pad to said relaxed and position;

and

a second photovoltaic source for supplying an attractive voltage to said second electrode.

7. The microelectromechanical switch according to claim 6, further including dielectric suspensions to support said electrodes above said conductive pad and waveguides.

8. The microelectromechanical switch according to claim 6, wherein said second electrode is positioned between said conductive pad and said ground plane to enhance contact of said conductive pad to said ground plane and said signal line.

9. The microelectromechanical switch according to claim 4, wherein said actuation voltage is less than or equal to 3 Volts.

10. The microelectromechanical switch according to claim 4, further including a dielectric layer positioned on said signal line.

11. The microelectromechanical switch according to claim 4, wherein said electrical connection is a capacitive connection.

12. The microelectromechanical switch according to claim 4, wherein said electrical connection is a physical short circuit.

13. The microelectromechanical switch according to claim 5, wherein said input port is electrically connected to said output port by separating said conductive pad from said signal line.

14. A microelectromechanical switch that controls a flow of signals, the switch comprising:

a substrate base;

a ground plane formed on said substrate base;

a signal line formed on said substrate base;

a set of brackets on said substrate base;

a conductive pad moveably positioned within said brackets to contact both of said signal line and ground plane when in a first position and to contact neither said signal line or said ground plane when in a second position;

a first electrode disposed to attract said conductive pad to said first position when a voltage is applied to said first electrode;

a second electrode disposed to attract said conductive pad to said second position when a voltage is applied to said first electrode;

a first set of photovoltaic diodes disposed on said substrate and in electrical contact with said first electrode; and

a second set of photovoltaic diodes disposed on said substrate in electrical contact with said second electrode.