Method of actuating MEMS switches

• US 6,388,359 B1
• Filed: 03/03/2000
• Issued: 05/14/2002
• Est. Priority Date: 03/03/2000
• Status: Expired due to Term

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: Optical Coating Laboratory, Inc. (Lumentum Holdings Inc.)
• Inventors: Duelli, Markus, Friedrich, Donald M., Hichwa, Bryant P.
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/517,913
• Time in Patent Office: 802 Days
• Field of Search: 310/309
• US Class Current: 310/309
• CPC Class Codes: G02B 6/3514 the reflective optical element moving along a line so as to translate into and out of the beam path, i.e. across the beam path
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: H01H 2001/0042 Bistable switches, i.e. having two stable positions requiring only actuating energy for switching between them, e.g. with snap membrane or by permanent magnet
• CPC Class Codes: H01H 59/0009 making use of micromechanics

Abstract

A switching signal having multiple sequential pulses is applied to a MEMS switch. A first pulse moves the switch from a first switch position toward a second switch position. After a selected dwell period, a second pulse is applied to dampen ringing or overshoot of the movable portions of the switch. In a further embodiment, non-symmetrical switching signals are used to cycle the switch from the first state to the second state, and back to the first.

Claims

1. A method of operating a micro-electro-mechanical system (“

MEMS”

) switch, the method comprising;

providing the MEMS switch in a first switch position;

applying an electronic signal to the MEMS switch;

accelerating a movable portion of the MEMS switch with the electronic signal from the first switch position toward a second switch position; and

decelerating the movable portion of the MEMS switch with the electronic signal before the movable portion of the MEMS switch reaches the second switch position.

2. The method of claim 1 wherein the MEMS switch includes an electrostatic comb drive actuator.

3. The method of claim 1 wherein the electronic signal includes a first electronic pulse with a first maximum voltage and a second electronic pulse with a second maximum voltage, the first maximum voltage being greater than the second maximum voltage.

4. The method of claim 3 wherein the first maximum voltage is approximately twice the second maximum voltage.

5. The method of claim 1 wherein the electronic signal is essentially a square-wave pulse.

6. The method of claim 1 wherein the MEMS switch has a spring arm attached to the movable portion of the MEMS switch and to a static portion of the MEMS switch.

7. The method of claim 1 wherein the movable portion of the MEMS switch has an intermediate point between the first switch position and the second switch position corresponding to a maximum potential point, the step of accelerating occurring while the movable portion is between the first switch position and the intermediate point, and the step of decelerating occurring while the movable portion is between the intermediate point and the second switch position.

8. The method of claim 1 further comprising steps of:

applying a second electronic signal to the MEMS switch; and

accelerating the movable portion of the MEMS switch with the second electronic signal from the second switch position toward the first switch position.

9. The method of claim 8 wherein the electronic signal has a first energy and the second electronic signal has a second energy, the first energy being greater than the second energy.

10. The method of claim 8 further comprising a step, after the step of accelerating the movable portion of the MEMS switch with the second electronic signal of:

decelerating the movable portion of the MEMS switch with the second electronic signal.

11. The method of claim 9 further comprising a step, after the step of accelerating the movable portion of the MEMS switch with the second electronic signal, of:

decelerating the movable portion of the MEMS switch with the second electronic signal.

12. The method of claim 1 wherein the MEMS switch is a latching switch.

13. A method of operating a micro-electro-mechanical system (“

MEMS”

) switch, the method comprising;

providing the MEMS switch in a first switch position;

applying a first electronic pulse to a first portion of an electrostatic comb drive actuator of the MEMS switch to accelerate a center body of the MEMS switch from the first switch position toward a second switch position;

waiting a selected period of time; and

applying a second electronic pulse to a second portion of the electrostatic comb drive actuator to decelerate the center body before the MEMS switch reaches the second switch position.

14. The method of claim 13 wherein the MEMS switch is a bi-stable switch, the center body traveling through an intermediate point between the first switch position and the second switch position, the intermediate point corresponding to a maximum potential energy position of the center body.

15. A method of cycling a micro-electro-mechanical system (“

MEMS”

) switch, the method comprising;

providing the MEMS switch in a first switch position;

applying a first electronic signal to the MEMS switch to accelerate a movable portion of the MEMS switch from the first switch position toward a second switch position;

waiting a first selected period of time;

applying a second electronic signal to the MEMS switch to retard motion of the movable portion;

applying a third electronic signal to the MEMS switch to accelerate the movable portion of the MEMS switch from the second switch position toward the first switch position;

waiting a second selected period of time; and

applying a fourth electronic signal to the MEMS switch to retard motion of the movable portion.

16. The method of claim 15 wherein the first electronic signal is capable of delivering a first energy to the MEMS switch and the third electronic signal is capable of delivering a second energy to the MEMS switch, the first energy being greater than the second energy.