Multiplexer for a piezo ceramic identification device

• US 7,514,842 B2
• Filed: 06/27/2006
• Issued: 04/07/2009
• Est. Priority Date: 03/23/2000
• Status: Expired due to Term

• Current Assignee: BRAZOS CAPITAL MANAGEMENT LLC
• Original Assignee: Sonavation, Inc.
• Inventors: Scott, Walter G.
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US11/475,248
• Publication Number:
  US 20070126315A1
• Time in Patent Office: 1,015 Days
• Field of Search: 310/316.01, 310/317, 310/319, 310/334, 310/366, 370/351
• US Class Current: 310/316.01
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

Provided is a multiplexer for a biometric apparatus. The multiplexer includes a plurality of first conductors coupled to the first ends of piezo ceramic elements in corresponding rows and a plurality of first switches each of which is coupled to a respective one of the first conductors and a plurality of second conductors coupled to the second ends of piezo ceramic elements in corresponding columns. The multiplexer also includes a plurality of second switches each of which is coupled to a respective one of the second conductors. The first conductors are approximately orthogonal to the second conductors, and the first switches are controlled to couple a signal output from an output port of the signal generator to a particular piezo ceramic element of the at least twenty five thousand piezo ceramic elements. The second switches are controlled to couple a signal associated with the particular piezo ceramic element of the at least twenty five thousand piezo ceramic elements to an input port of the processor.

Claims

1. A multiplexer, comprising:

a plurality of first conductors coupled to first ends of piezo ceramic elements in corresponding rows;

a plurality of first switches each of which is coupled to a respective one of the first conductors;

a plurality of second conductors coupled to second ends of piezo ceramic elements in corresponding columns; and

a plurality of second switches each of which is coupled to a respective one of the second conductors,

wherein the first conductors are approximately orthogonal to the second conductors, and

wherein the first switches are controlled to couple a signal output from an output port of the signal generator to a particular piezo ceramic element of the piezo ceramic elements, and

wherein the second switches are controlled to couple a signal associated with the particular piezo ceramic element to an input port of the processor.

2. The multiplexer of claim 1, wherein each of the first switches and the second switches is a three-way switch.

3. The multiplexer of claim 2, wherein each of the first switches connects one of the first conductors to one of an input of the signal generator, a high impedance open node, and a low impedance ground node.

4. The multiplexer of claim 2, wherein each of the second switches connects one of the second conductors to one of a processor, a high impedance open node, and a low impedance ground node.

5. The multiplexer of claim 1, further comprising:

a shift register coupled to the first switches and configured to control the position thereof.

6. The multiplexer of claim 5, further comprising:

a controller coupled to the shift register and configured to control operation of the shift register.

7. The multiplexer of claim 6, further comprising:

another shift register coupled to the second switches and configured to control the position thereof.

8. The multiplexer of claim 7, wherein the controller is coupled to the another shift register and is configured to control the operation thereof.

9. The multiplexer of claim 1, wherein the first conductors and the second conductors are formed using a vacuum deposition process.

10. The multiplexer of claim 1, wherein the first conductors and the second conductors are formed using a lithography process.

11. The multiplexer of claim 1, wherein the first switches comprise at least two separate integrated circuit (IC) chips.

12. The multiplexer of claim 11, wherein the second switches comprise at least two separate IC chips.

13. A multiplexer comprising:

a plurality of first conductors each coupled to a first end of Y of piezo ceramic elements;

a plurality of second conductors each coupled to a second end of X of the piezo ceramic elements;

a plurality of first switches coupled to the first conductors;

a plurality of second switches coupled to the second conductors;

a first shift register coupled to the first switches and configured to control the position thereof;

a second shift register coupled to the second switches and configured to control the position thereof; and

a controller coupled to the first and second shift registers and configured to control the first and second shift registers.

14. The multiplexer of claim 13, wherein each of the first conductors is approximately orthogonal to each of the second conductors.

15. The multiplexer of claim 13, wherein the first switches are controlled to couple an output port of a signal generator to a respective one of the piezo ceramic elements.

16. The multiplexer of claim 15, wherein the second switches are controlled to couple the respective one of the piezo ceramic elements to an input port of a processor.

17. The multiplexer of claim 13, wherein each of the first switches and the second switches is a three-way switch.

18. The multiplexer of claim 17, wherein each of the first switches connects one of the first conductors to one of an input port of a signal generator, a high impedance open node, and a low impedance ground node.

19. The multiplexer of claim 18, wherein each of the second switches connects one of the second conductors to one of an input port of a processor, a high impedance open node, and a low impedance ground node.

20. The multiplexer of claim 13, wherein each of the first conductors and the second conductors has a width of less than about one hundred microns.