Apparatus and method for sensing change in environmental conditions

• US 7,785,001 B2
• Filed: 11/15/2007
• Issued: 08/31/2010
• Est. Priority Date: 05/10/2004
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Tsow, Francis, Tao, Nongjian
• Primary Examiner(s): Caputo; Lisa M
• Assistant Examiner(s): Jagan; Mirellys
• Application Number:
  US11/940,953
• Publication Number:
  US 20080205479A1
• Time in Patent Office: 1,020 Days
• Field of Search: 374/117, 374/45, 735/79
• US Class Current: 374/117
• CPC Class Codes: G01K 7/32 using change of resonant frequency of a crystal

Abstract

An apparatus for sensing a change in environmental conditions is disclosed. The apparatus includes a coating or a wire between two surfaces that has a mechanical property changed as a result of a change in the environmental conditions. The change in the mechanical property of the coating or wire results in a change in a vibration characteristic of the apparatus, such as the frequency, phase, amplitude or quality factor. The change in the vibration characteristic can be used to determine the change in the environmental condition.

Claims

1. A method of detecting a change in environmental conditions, the method comprising:

providing a structure configured to vibrate in response to an input;

coupling an infrared sensitive material to the structure;

providing the input to the structure and measuring a vibration response;

changing an environmental condition proximal to the structure, wherein the environmental condition is incident infrared radiation; and

measuring a change in the vibration response.

2. The method of claim 1 wherein the infrared sensitive material comprises a thermal responsive polymer.

3. The method of claim 1 wherein the structure comprises a tuning fork with a first prong comprising the first surface and a second prong comprising the second surface.

4. The method of claim 3 wherein the tuning fork is comprised of quartz.

5. The method of claim 3 wherein the tuning fork is approximately 2 millimeters long, approximately 200 micrometers wide and approximately 100 micrometers thick.

6. The method of claim 3, further comprising coupling an electronic circuit to the tuning fork, wherein the electronic circuit is configured to measure the resonant frequency, phase, amplitude or quality factor of the tuning fork.