Fully-Addressable Sensor Array for Acoustic Imaging Systems

• US 20160092714A1
• Filed: 08/10/2015
• Published: 03/31/2016
• Est. Priority Date: 09/30/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Yazdandoost, Mohammad Yeke, Bussat, Jean-Marie
• Granted Patent: US 10,133,904 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/1626 with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs]
• CPC Class Codes: G06F 1/1684 Constructional details or arrangements related to integrated I/O peripherals not covered by groups G06F1/1635 - G06F1/1675
• CPC Class Codes: G06F 21/00 Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

An acoustic imaging system can contain a plurality of individual acoustic elements that each contain an acoustic transducer, drive circuitry, and low voltage sense and/or read circuitry. In many embodiments both the drive circuitry and the read circuitry can be independently addressable. For example, if the individual acoustic elements are arranged into rows and columns, each acoustic element can include row/column drive circuit enable switches and row/column read circuit enable switches.

Claims

1. A fingerprint imaging system comprising:

a drive voltage node;

a sense voltage node;

a plurality of acoustic elements electrically arranged into a plurality of rows and a plurality of columns, each acoustic element comprising;

an acoustic transducer comprising;

a drive mode in which the acoustic transducer produces an acoustic pulse in response to a first electronic signal; and

a sense mode in which the acoustic transducer produces a second electronic signal in response to receiving an acoustic pulse;

a first pair of switches configured to couple the acoustic transducer in the drive mode to the drive voltage node through a row selected from the plurality of rows and a column selected from the plurality of columns; and

a second pair of switches configured to couple the acoustic transducer in the sense mode to the sense voltage node through the selected row the selected column;

an addressing controller configured to selectively enable the first pair or the second pair of switches associated with an acoustic element selected from the plurality of acoustic elements.

2. The fingerprint imaging system of claim 1, wherein each of the plurality of acoustic elements are coupled to a bottom surface of a substrate.

3. The fingerprint imaging system of claim 2, wherein the substrate is formed from one of the group consisting of glass, sapphire, and metal.

4. The fingerprint imaging system of claim 1, wherein the acoustic transducer is formed from a material configured to expand and contract in response to a voltage signal.

5. The fingerprint imaging system of claim 1, wherein the drive voltage node is coupled to a voltage source configured to output 100 volts.

6. The fingerprint imaging system of claim 5, wherein the sense voltage node is coupled to a low voltage source configured output less than 10 volts.

7. The fingerprint imaging system of claim 1, wherein the drive voltage node comprises a common electrode coupled to each acoustic element of the plurality of acoustic elements.

8. The fingerprint imaging system of claim 1, wherein the sense voltage node comprises a common electrode coupled to each acoustic element of the plurality of acoustic elements.

9. The fingerprint imaging system of claim 7, wherein the common electrode comprises a conductive plate.

10. A method of driving an acoustic element of a fingerprint imaging sensor comprising a drive circuit and a read circuit, the method comprising:

enabling each of a row and column select switch associated with a drive mode of the acoustic element to couple the drive circuit to a voltage source; and

driving the acoustic element with a voltage signal.

11. The method of claim 10, wherein the acoustic element comprises an acoustic transducer formed from a material configured to expand and contract in response to the voltage signal.

12. The method of claim 10, wherein the voltage source is configured to output 100 volts.

13. The method of claim 12, wherein acoustic element further comprises a read circuit coupled to a low voltage source configured to output approximately 3.3 volts.

14. The method of claim 10, wherein the acoustic elements is coupled to a bottom surface of a substrate.

15. The method of claim 14, wherein the substrate is formed from one of the group consisting of glass, sapphire, and metal.

16. The method of claim 10, wherein the acoustic element further comprises at least one acoustic transducer formed from a material configured to expand in response to a voltage signal.

17. A method of reading an acoustic element of a fingerprint imaging sensor comprising an addressable read circuit and an addressable drive circuit, the method comprising:

enabling each of a row and column select switch associated with a read mode of the acoustic element to couple the read circuit to a low voltage source; and

obtaining an electrical signal from the acoustic element.

18. The method of claim 17, wherein the acoustic element comprises an acoustic transducer formed from a material configured to generate an electrical signal in response to mechanical pressure.

19. The method of claim 17, wherein the drive circuit is coupled to a voltage source configured to output 100 volts.

20. The method of claim 17, wherein the read circuit is coupled to a low voltage source configured to output approximately 3.3 volts.