LARGE-AREA ULTRASOUND CONTACT IMAGING

• US 20120147698A1
• Filed: 12/10/2010
• Published: 06/14/2012
• Est. Priority Date: 12/10/2010
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: Wong, Serena Han Ying, Lu, Jeng Ping, Apte, Raj B.
• Granted Patent: US 9,259,961 B2
• Time in Patent Office: Days
• US Class Current: 367/7
• CPC Class Codes: A61B 5/1172 using fingerprinting
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• CPC Class Codes: B06B 1/02 making use of electrical energy B06B1/18, B06B1/20 take precedence
• CPC Class Codes: B60B 1/02 Wheels with wire or other tension spokes
• CPC Class Codes: G01S 7/56 Display arrangements short-range imaging G01S7/52053
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing

Abstract

An embodiment is a method and apparatus for ultrasonic contact imaging. A thin-film transistor (TFT) array is deposited on a substrate. A receiver having a plurality of receiver elements is deposited on the TFT array to receive a received signal. A transmitter adjacent to the receiver generates a transmit signal at an ultrasonic frequency. The transmit signal is reflected from a surface to produce a reflected signal. The received signal is a superposition of the transmit signal and the reflected signal as result of interference. The received signal is representative of differences in acoustic impedances across the surface.

Claims

1. An apparatus comprising:

a thin-film transistor (TFT) array deposited on a substrate;

a receiver having a plurality of receiver elements deposited on the TFT array to receive a received signal;

a transmitter adjacent to the receiver to generate a transmit signal at an ultrasonic frequency, the transmit signal being reflected from a surface to produce a reflected signal; and

a contact layer deposited on the transmitter having the surface-and a thickness such that the received signal is a superposition of the transmit signal and the reflected signal as result of interference, the received signal representative of differences in acoustic impedances across the surface.

2. The apparatus of claim 1 wherein each of the plurality of receiver elements comprises:

a range-gated peak collector to collect the received signal to produce a pixel on the TFT array.

3. The apparatus of claim 1 wherein the transmitter generates the transmit signal in a quasi continuous wave (CW) mode.

4. The apparatus of claim 1 wherein the thickness of the contact layer is less than a wavelength of the ultrasonic frequency.

5. The apparatus of claim 1 further comprising:

an insulator deposited between the receiver and the transmitter.

6. The apparatus of claim 1 wherein the substrate is glass, quartz, plastic, or steel.

7. The apparatus of claim 1 wherein the contact layer is made of one of mylar, epoxy, silicone, poly(methyl methacrylate) (PMMA), or polydimethylsiloxane (PDMS).

8. The apparatus of claim 5 wherein the insulator is made of one of mylar, epoxy, silicone, poly(methyl methacrylate) (PMMA), or polydimethylsiloxane (PDMS).

9. The apparatus of claim 1 wherein one of the receiver and the transmitter is made of one of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), piezoelectric transducer (PZT), or electrostatic transducer.

10. The apparatus of claim 1 wherein the thickness is chosen such that the transmit signal and the reflected signal are out of phase when there is no contact from an object on the surface, resulting in the received signal having an approximately zero amplitude.

11. The apparatus of claim 1 wherein the thickness is chosen such that the transmit signal and the reflected signal are in-phase when there is no contact from an object on the surface, resulting in the received signal having an approximately maximum amplitude.

12. The apparatus of claim 1 wherein an effective acoustic length between the surface and the transmitter is approximately an integer multiple of a quarter of operating wavelength.

14. The method of claim 11 further comprising:

collecting the received signal by a range-gated peak collector to produce a pixel on the TFT array.

15. The method of claim 11 wherein generating comprises generating the transmit signal in a quasi continuous wave (CW) mode.

16. The method of claim 11 wherein the contact layer has a thickness less than a wavelength of the ultrasonic frequency.

17. The method of claim 11 further comprising:

insulating the transmitter from the receiver by an insulator deposited between the receiver and the transmitter.

18. The method of claim 11 wherein the substrate is glass, quartz, plastic, or steel.

19. The method of claim 11 wherein the contact layer is made of one of mylar, epoxy, silicone, poly(methyl methacrylate) (PMMA), or polydimethylsiloxane (PDMS).

20. The method of claim 15 wherein the insulator is made of one of mylar, epoxy, silicone, poly(methyl methacrylate) (PMMA), or polydimethylsiloxane (PDMS).

21. The method of claim 11 wherein one of the receiver and the transmitter is made of one of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), piezoelectric transducer (PZT), or electrostatic transducer.

22. The method of claim 16 wherein the thickness is chosen such that the transmit signal and the reflected signal are out of phase when there is no contact from the object on the layer surface, resulting in the received signal having an approximately zero amplitude.

23. The method of claim 16 wherein the thickness is chosen such that the transmit signal and the reflected signal are in-phase when there is no contact from the object on the layer surface, resulting in the received signal having an approximately maximum amplitude.

13. A method comprising:

generating a transmit signal by a transmitter at an ultrasonic frequency through a contact layer deposited on the transmitter, the transmit signal being reflected from a surface of the contact layer to produce a reflected signal; and

receiving a received signal by a receiver on a thin-film transistor (TFT) array deposited on a substrate, the received signal being a superposition of the transmit signal and the reflected signal as result of interference, the received signal representative differences in acoustic impedances across the surface.

24. The method of claim 13 wherein an effective acoustic length between the surface and the transmitter is approximately an integer multiple of a quarter of operating wavelength.

25. A system comprising:

an imaging structure comprising;

a thin-film transistor (TFT) array deposited on a substrate,

a receiver having a plurality of receiver elements deposited on the TFT array to receive a received signal,

a transmitter on the receiver to generate a transmit signal at an ultrasonic frequency, the transmit signal being reflected from a surface to produce a reflected signal, and

a contact layer deposited on the transmitter having the surface and a thickness such that the received signal is a superposition of the transmit signal and the reflected signal as result of interference, the received signal representative of differences in acoustic impedances across the surface; and

a processing circuit coupled to the imaging structure to process the received signal to form an image.