Active micromechanical air valve for pressure control and method for making same

• US 6,578,816 B1
• Filed: 04/14/2000
• Issued: 06/17/2003
• Est. Priority Date: 04/14/2000
• Status: Expired due to Fees

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: International Business Machines Corporation
• Inventors: Lille, Jeffrey S.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): FRISTOE JR, JOHN K
• Application Number:
  US09/549,259
• Time in Patent Office: 1,159 Days
• Field of Search: 251/11, 251/129.01, 251/129.06
• US Class Current: 251/11
• CPC Class Codes: F15C 5/00 Manufacture of fluid circuit elements; Manufacture of assemblages of such elements integrated circuits
• CPC Class Codes: F16K 2099/008 Multi-layer fabrications
• CPC Class Codes: F16K 2099/0082 Microvalves adapted for a particular use
• 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 99/0044 using thermo-electric means

Abstract

An active micromechanical air valve for pressure control in a disk drive and method for making the same is disclosed. A first layer having a first thermal coefficient of expansion and a second layer having a second thermal coefficient of expansion are formed. The first layer and the second layer are configured to form a membrane. The first and second layer engage in a closed state to prevent air flow there between in a first thermal state and open to allow air flow there between in a second thermal state.

Claims

1. An active micromechanical air valve for providing pressure control, comprising:

a first layer having a first thermal coefficient of expansion;

a second layer having a second thermal coefficient of expansion;

wherein the first layer and the second layer are configured to form a membrane, the first and second layer engaging in a closed state to prevent air flow therebetween in a first thermal state and opening to allow air flow therebetween in a second thermal state.

2. The active micromechanical air valve of claim 1 wherein the first thermal state is achieved by the absence of a control signal.

3. The active micromechanical air valve of claim 2 wherein the control signal is a drive current from a current source.

4. The active micromechanical air valve of claim 1 wherein the second thermal state is achieved by application of a control signal.

5. The active micromechanical air valve of claim 4 wherein the control signal is a drive current from a current source.

6. The active micromechanical air valve of claim 1 wherein the first layer is a conductive layer forming a bridge layer for conducting a drive current applied to the conductive layer.

7. The active micromechanical air valve of claim 6 wherein the first layer further comprises a nickel bridge.

8. The active micromechanical air valve of claim 7 wherein the nickel bridge further comprises a resistive, low stress insulating material sputtered thereon and a doped layer of polycrystalline silicon for providing an electrical resistive layer.

9. The active micromechanical air valve of claim 7 wherein the second layer further comprises a thermal expansive polymer.

10. The active micromechanical air valve of claim 1 wherein the second layer further comprises a first opening and a downward facing member and the first layer comprises a second opening, the second opening of the first layer offset from the first opening in the second layer and the downward facing member plugging the second opening in the first layer when the first and second layer engage in the closed state to prevent air flow therebetween in the first thermal state.