Multiplexer for a piezo ceramic identification device

• US 9,056,082 B2
• Filed: 03/23/2010
• Issued: 06/16/2015
• Est. Priority Date: 03/23/2009
• Status: Active Grant

• Current Assignee: Sonavation, Inc.
• Original Assignee: Sonavation, Inc.
• Inventors: Liautaud, Christian, Schmitt, Rainer M.
• Primary Examiner(s): LE, BRIAN Q
• Application Number:
  US12/729,609
• Publication Number:
  US 20100237992A1
• Time in Patent Office: 1,911 Days
• Field of Search: 310/311, 310/312, 310/313.R, 310/313.A, 310/313.B, 310/327, 367/180, 367/155, 367/157, 73/351.1, 73/351.2, 73/351.3, 382124-127, 382312-315
• US Class Current: 1/1
• CPC Class Codes: A61K 38/1808 Epidermal growth factor [EGF] urogastrone
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00

Abstract

Provided is a Fingerprint sensor using Acoustic Impediography. The sensor includes an Application Specific Integrated Circuit (ASIC or IC) and an array of mechanical resonator used as sensing elements. The array of sensing elements contains multiple sensing elements arranged in rows and columns.

Claims

1. A sensing device, comprising:

an array of sensing elements, and

wherein said sensing elements operate based upon acoustic impediography principles; and

wherein said sensing device is configured to measure an acoustic impedance associated with at least one of said sensing elements, said acoustic impedance being measured in proportion to a measured electrical impedance of one or more electrical signals that are passed through said at least one of said sensing elements;

a first electrical signal having a first frequency, is passed by said sensor device through said at least one of said sensing elements, said first frequency being equal to a serial resonant frequency of a circuit including said at least one of said sensing elements, and

a second electrical signal having a second frequency, is passed by said sensor device through said at least one of said sensing elements, said second frequency being equal to a parallel resonant frequency of a circuit including said at least one of said sensing elements, and where

said sensing device is configured to measure an amount of current of said first electrical signal to determine a first electrical impedance, and is configured to measure an amount of current of said second electrical signal second electrical signal to determine a second electrical impedance, and where

a said first impedance is lower for a finger valley than a finger ridge, and where

said second impedance is lower for a finger ridge than a finger valley,

in order to determine an acoustical impedance, and to detect a presence of a finger valley or finger ridge in association with said at least one of said sensing elements.

2. The sensing device of claim 1, wherein the sensing elements are arranged in a two dimensional array of rows and columns.

3. The sensing device of claim 1 wherein the sensing device employs an Application Specific Integrated Circuit.

4. The sensing device of claim 2 wherein at least one transmitter transmits said electrical signal through at least one of said rows, and at least one receiver receives said electrical signal from at least one of said columns.

5. The sensing device of claim 4 wherein said at least one transmitter and said at least one receiver reside within one Application Specific Integrated Circuit.

6. The sensing device of claim 1, wherein a sample and hold circuit is employed to process data received from one or more sensing elements.