Large-area ultrasound contact imaging

Patent metadata

Field	Value
Publication number	US-9259961-B2
Application number	US-96579310-A
Country	US
Kind code	B2
Filing date	Dec 10, 2010
Priority date	Dec 10, 2010
Publication date	Feb 16, 2016
Grant date	Feb 16, 2016

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.

First claim

What is claimed is:

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

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

8. The apparatus of claim 1 wherein the contact layer 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.

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.

14. The method of claim 13 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 13 wherein generating comprises generating the transmit signal in a quasi continuous wave (CW) mode.

16. The method of claim 13 wherein the contact layer has a thickness less than a wavelength of the ultrasonic frequency.

17. The method of claim 13 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.

18. The method of claim 13 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.

19. The method of claim 13 further comprising:
insulating the transmitter from the receiver by an insulator deposited between the receiver and the transmitter.

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

21. The method of claim 13 wherein the substrate is glass, quartz, plastic, or steel.

22. The method of claim 13 wherein the contact layer is made of one of mylar, epoxy, silicone, poly(methyl methacrylate) (PMMA), or polydimethylsiloxane (PDMS).

23. The method of claim 13 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.

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.

Assignees

• Wong Serena Han Ying
• Lu Jeng Ping
• Apte Raj B
• Palo Alto Res Ct Inc

Inventors

• Wong Serena Han Ying
• Lu Jeng Ping
• Apte Raj B

Classifications

• B06B1/02 Primary

  making use of electrical energy (B06B1/18, B06B1/20 take precedence) · CPC title

• G06K9/0002

  Physics · mapped topic

• G01S7/56

  Display arrangements {(short-range imaging G01S7/52053)} · CPC title

• A61B5/1172

  using fingerprinting · CPC title

• A61B8/08

  Clinical applications (A61B8/02, A61B8/04, A61B8/06 take precedence) · CPC title