Surface acoustic wave sensor methods and systems

• US 20060130585A1
• Filed: 12/18/2004
• Published: 06/22/2006
• Est. Priority Date: 12/18/2004
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Liu, James Z., Cook, James D., Magee, Steven J.
• Granted Patent: US 7,165,455 B2
• Time in Patent Office: Days
• US Class Current: 73/570
• CPC Class Codes: G01L 1/165 with acoustic surface waves
• CPC Class Codes: G01L 3/10 involving electric or magnetic means for indicating
• CPC Class Codes: G01L 9/0025 with acoustic surface waves

Abstract

Sensor systems and methods are disclosed herein, including a sensor chip, upon which at least two surface acoustic wave (SAW) sensing elements are centrally located on a first side (e.g., front side) of the sensor chip. The SAW sensing elements occupy a common area on the first side of the sensor chip. An etched diaphragm is located centrally on the second side (i.e., back side) of the sensor chip opposite the first side in association with the two SAW sensing elements in order to concentrate the mechanical strain of the sensor system or sensor device in the etched diagram, thereby providing high strength, high sensitivity and ease of manufacturing thereof.

Claims

1. A sensor system, comprising:

a sensor chip;

at least two surface acoustic wave (SAW) sensing elements located centrally on a first side of said sensor chip, wherein said at least two SAW sensing elements occupy a common area on said first side of said sensor chip;

an etched diaphragm located centrally on a second side of said sensor chip opposite said first side in association with said at least two SAW sensing elements in order to concentrate a mechanical strain in said etched diagram, thereby providing a high strength, high sensitivity and ease of manufacturing thereof.

2. The system of claim 1 wherein said sensor chip comprises swept quartz.

3. The system of claim 1 wherein said at least two SAW sensing elements comprise interdigital transducers thereof.

4. The system of claim 1 wherein said sensor chip comprises a delay line configuration.

5. The system of claim 1 wherein said sensor chip comprises a resonator configuration.

6. The system of claim 1 wherein said etched diaphragm is etched utilizing a wet etchant.

7. The system of claim 1 wherein said etched diaphragm is etched utilizing a dry etchant.

8. The system of claim 1 wherein said etched diaphragm is mechanically etched.

9. The system of claim 1 wherein changes in frequency associated with said sensor chip correlate with said mechanical strain.

10. The system of claim 1 wherein changes in phase associated with said sensor chip correlate with said mechanical strain.

11. The system of claim 1 wherein changes in delay time associated with said sensor chip correlate with said mechanical strain.

12. The system of claim 1 wherein said at least two SAW sensing elements comprises a first SAW sensor and a second SAW sensor.

13. The system of claim 12 further comprising a first set of reflectors associated with said first SAW sensor and a second set of reflectors associated with said second SAW sensor on said first side of said sensor chip.

14. A sensor system, comprising:

a sensor chip, wherein said sensor chip comprises swept quartz;

at least two surface acoustic wave (SAW) sensing elements located centrally on a first side of said sensor chip, wherein said at least two SAW sensing elements comprise interdigital transducers thereof and occupy a common area on said first side of said sensor chip;

an etched diaphragm located centrally on a second side of said sensor chip opposite said first side in association with said at least two SAW sensing elements in order to concentrate a mechanical strain in said etched diagram, thereby providing a high strength, high sensitivity and ease of manufacturing thereof.

herein said first set of reflectors runs opposite said second set of reflectors.

15. The system of claim 14 where said sensor chip comprises a delay line configuration.

16. The system of claim 14 wherein said sensor chip comprises a resonator configuration.

17. A sensor method, comprising the steps of:

providing a sensor chip comprising swept quartz;

locating at least two surface acoustic wave (SAW) sensing elements located centrally on a first side of said sensor chip, wherein said at least two SAW sensing elements occupy a common area on said first side of said sensor chip and wherein said at least two SAW sensing elements comprise interdigital transducers thereof;

etching a diaphragm centrally on a second side of said sensor chip opposite said first side in association with said at least two SAW sensing elements in order to concentrate a mechanical strain in said etched diagram, thereby providing a high strength, high sensitivity and ease of manufacturing thereof.

18. The method of claim 17 further comprising the step of arranging said sensor chip in a delay line configuration.

19. The method of claim 17 further comprising the step of arranging said sensor chip in a resonator configuration.

20. The method of claim 17 further comprising the step of etching said diaphragm on said second side of said sensor chip utilizing a wet etchant.

21. The method of claim 17 further comprising the step of etching said diaphragm on said second side of said sensor chip utilizing a dry etchant.

22. The method of claim 17 further comprising the step of mechanically etching said diaphragm on said second side of said sensor chip.

23. The method of claim 17 further comprising the steps of:

configuring said at least two SAW sensing elements to comprise a first SAW sensor and a second SAW sensor; and

associating a first set of reflectors with said first SAW sensor and a second set of reflectors with said second SAW sensor on said first side of said sensor chip