Drive scheme for ultrasonic transducer pixel readout

Patent metadata

Field	Value
Publication number	US-10503309-B2
Application number	US-201715474084-A
Country	US
Kind code	B2
Filing date	Mar 30, 2017
Priority date	Apr 4, 2016
Publication date	Dec 10, 2019
Grant date	Dec 10, 2019

Abstract

This disclosure provides some implementations of systems, methods and apparatus associated with a drive scheme for ultrasonic transducer pixel readout. In some implementations, a piezoelectric ultrasonic transducer has a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes. The second electrode is coupled with a sampling node. A sampling diode has an input and an output. The input is coupled to receive a diode bias signal. The output is coupled with the sampling node. Controller circuitry is configured to control the diode bias signal to at least partially drive a voltage at the sampling node. Read circuitry is coupled with the sampling node to read the voltage.

First claim

What is claimed is:

1. An apparatus comprising:
a piezoelectric ultrasonic transducer having a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the second electrode being coupled with a sampling node, wherein the first electrode is configured to receive a receive bias signal;
a sampling diode having an input and an output, the input coupled to receive a diode bias signal, the output coupled with the sampling node;
controller circuitry configured to control the diode bias signal to at least partially drive a voltage at the sampling node; and
read circuitry coupled with the sampling node to read the voltage,
wherein the controller circuitry is configured to control the diode bias signal to switch between two voltage levels comprising a first level and a second level, the first level being a non-zero voltage level that corresponds to a normal mode of operation of the read circuitry and the second level being a non-zero voltage level that corresponds to a sampling mode of operation of the read circuitry, and wherein the first level is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is different from the first level and from the voltage level of the receive bias signal.

2. The apparatus of claim 1 , wherein the controller circuitry is configured to assert the second level during a sampling window corresponding to activation of the read circuitry.

3. The apparatus of claim 1 , further comprising a substrate disposed adjacent to the second electrode opposite the piezoelectric layer, the substrate being a thin-film transistor (TFT) layer and comprising the sampling diode.

4. The apparatus of claim 3 , further comprising a reset transistor formed in the TFT layer and coupled with the sampling diode to control resetting of the voltage.

5. The apparatus of claim 1 , wherein the first electrode is coupled with one of: a ground terminal, a DC voltage source or a fixed AC voltage source.

6. The apparatus of claim 1 , wherein the first electrode is floating.

7. The apparatus of claim 1 , further comprising a touch controller coupled with the first electrode, the touch controller configured to provide touch control of the piezoelectric layer.

8. The apparatus of claim 1 , further comprising a platen disposed adjacent to the first electrode opposite the piezoelectric layer.

9. A method comprising:
providing a diode bias signal to a sampling diode coupled with a sampling node;
providing a receive bias signal to a first electrode;
initiating transmission of an ultrasonic signal using a piezoelectric ultrasonic transducer having the first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the second electrode being coupled with the sampling node, the piezoelectric ultrasonic transducer capable of receiving a reflected portion of the ultrasonic signal and generating a response characteristic based on the reflected portion of the ultrasonic signal;
controlling the diode bias signal to bias the diode in association with a temporary transition of a mode of operation from a normal mode to a sampling mode, the diode bias signal being driven to a first level corresponding to the normal mode and a second level corresponding to the sampling mode, wherein the first level is a non-zero voltage level that is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is a non-zero voltage level that is different from the first level and from the voltage level of the receive bias signal; and
enabling sampling, during the sampling mode of operation, of an electrical signal at the sampling node.

10. The method of claim 9 , wherein read circuitry is controlled to perform the sampling during the sampling mode of operation.

11. The method of claim 9 , further comprising:
resetting a voltage at the sampling node using a reset switch coupled with the diode.

12. The method of claim 9 , wherein a substrate is disposed adjacent to the second electrode opposite the piezoelectric layer, the substrate being a thin-film transistor (TFT) layer and comprising the sampling diode.

13. A non-transitory computer readable medium storing program code to be executed by one or more processors, the program code comprising instructions configured to cause:
providing a diode bias signal to a sampling diode coupled with a sampling node;
providing a receive bias signal to a first electrode;
initiating transmission of an ultrasonic signal using a piezoelectric ultrasonic transducer having the first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the second electrode being coupled with the sampling node, the piezoelectric ultrasonic transducer capable of receiving a reflected portion of the ultrasonic signal and generating a response characteristic based on the reflected portion of the ultrasonic signal;
controlling the diode bias signal to bias the diode in association with a temporary transition of a mode of operation from a normal mode to a sampling mode, the diode bias signal being driven to a first level corresponding to the normal mode and a second level corresponding to the sampling mode, wherein the first level is a non-zero voltage level that is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is a non-zero voltage level that is different from the first level and from the voltage level of the receive bias signal; and
enabling sampling, during the sampling mode of operation, of an electrical signal at the sampling node.

14. The computer readable medium of claim 13 , the instructions further configured to cause:
resetting a voltage at the sampling node using a reset switch coupled to the diode.

15. An apparatus comprising:
transducer means for generating an ultrasonic wave and receiving a reflected portion of the wave, the transducer means having a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the first electrode configured to receive a receive bias signal, the second electrode being coupled with a sampling node;
diode bias means for at least partially driving an electrical signal at the sampling node, the diode bias means coupled with the sampling node, the diode bias means providing a diode bias signal to a sampling diode at a first level corresponding to a normal mode of operation and a second level corresponding to a sampling mode of operation, wherein the first level is a non-zero voltage level that is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is a non-zero voltage level that is different from the first level and from the voltage level of the receive bias signal; and
reading means for reading the electrical signal, the reading means coupled with the sampling node.

Assignees

• Qualcomm Inc

Inventors

• Hinger Ashish

Classifications

• A61B5/1172

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• G06F3/03547

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• H04R17/10

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• G01N29/26

  Arrangements for orientation or scanning {by relative movement of the head and the sensor (mechanical steering of sound transducers or their beams G10K11/35)} · CPC title

• G06F2203/0338

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