REDUCTION OF CROSSTALK IN ROW-COLUMN ADDRESSED ARRAY PROBES
Techniques for reducing or eliminating cross talk in row-column addressed array (RCA) probes are described. A diode can be connected in series to piezo-composite element in each pixel of the RCA to prevent cross talk. A resistor can also be provided in parallel to the piezo-composite element for discharging purposes and providing DC paths for the forward and backward bias voltages to the diodes. Thus. RCA probes using the techniques disclosed herein can use sub-apertures for, among other things, inspecting longitudinal and transverse flaws, and for more efficient local focusing for an acoustic camera without significant cross talk interference.
1 . An inspection probe comprising:
a row-column array (RCA) including a plurality of pixels arranged in rows and columns, wherein at least one pixel of the plurality of pixels includes:
a piezo-composite element, and
a diode coupled to the piezo-composite element in series; and
a control circuit coupled to the RCA to drive the RCA in a transmission mode and to receive an electrical representation of an ultrasound wave in a reception mode.
2 . The inspection probe of claim 1 , wherein the at least one pixel further includes a resistor coupled to the piezo-composite element in parallel.
3 . The inspection probe of claim 2 , wherein the diode is provided in a diode array layer fabricated using thin-film technology.
4 . The inspection probe of claim 3 , wherein the diode array layer is provided between row electrodes of the RCA and a piezo-composite material including the piezo-composite element.
5 . The inspection probe of claim 4 , wherein the resistor is included in a sputtered resistance layer fabricated on a side surface of poles of the piezo-composite material.
6 . The inspection probe of claim 2 , wherein the diode is provided on a printed circuit board coupled to the RCA.
7 . The inspection probe of claim 6 , wherein the resistor is provided on the printed circuit board coupled to the RCA.
8 . The inspection probe of claim 6 , wherein the printed circuit board includes vertically arranged conductors coupling the RCA to a plurality of diodes and a plurality of resistors.
9 . The inspection probe of claim 1 , wherein the control circuit includes a plurality of column switches coupled to the columns and a plurality of row switches coupled to the rows, wherein the control circuit is configured to operate the RCA in a first and second transmission configuration.
10 . The inspection probe of claim 1 , wherein the control circuit includes a plurality of column switches coupled to the columns and a plurality of row switches coupled to the rows, wherein the control circuit is configured to operate the RCA in a first and second reception configuration.
11 . A method comprising:
driving a first set of columns or a first set of rows in a row-column addressed array (RCA) to transmit at least one ultrasound wave using a transmission aperture, wherein the RCA includes a plurality of pixels and each pixel includes a piezo-composite element and a diode coupled to the piezo-composite element in series; and
receiving an electrical representation of the at least one ultrasound wave using the RCA.
12 . The method of claim 11 , wherein each pixel further includes resistor coupled to the piezo-composite element in parallel.
13 . The method of claim 12 , discharging the piezo-composite element using the resistor.
14 . The method of claim 11 , wherein diode is provided in a diode array layer fabricated using thin-film technology.
15 . The method of claim 11 , wherein the diode is provided on a printed circuit board coupled to the RCA.
16 . A row-column addressed array (RCA) probe assembly, comprising:
a RCA including a plurality of row and column electrodes defining a plurality of pixels to transmit and receive ultrasound waves, wherein each pixel includes:
a piezo-composite element,
a diode coupled to the piezo-composite element in series, and
a resistor coupled to the piezo-composite element in parallel; and
a control circuit configured to operate the RCA array in a transmission mode and a reception mode,
wherein in a transmission mode, the control circuit is configured to place the plurality of row and column electrodes in different states in a first configuration providing a transmission aperture,
wherein in a reception mode, the control circuit is configured to place the plurality of row electrodes and column electrodes in different states in a second configuration providing a reception aperture.
17 . The RCA probe assembly of claim 16 , wherein in the transmission mode, the control circuit is configured to place the plurality of row and column electrodes in different states in a first configuration providing a transmission aperture.
18 . The probe of claim 17 , wherein in the reception mode, the control circuit is configured to place the plurality of row electrodes and column electrodes in different states in a second configuration providing a reception aperture.
19 . The probe of claim 16 , wherein the diode is provided in a diode array layer provided between the plurality of row electrodes and a piezo-composite material including the piezo-composite element.
20 . The probe of claim 16 , wherein the diode is provided on a printed circuit board coupled to the RCA.