Phased array principle

Increased productivity and inspection capabilities

The Phased Array concept concerns multielement transducers. Each element of these transducers is connected to a different electronic channel, either directly or through multiplexors, according to electronic device performances.

Each element can be activated or not for each shot. The size and the location of the active aperture of a phased array transducer depends on the activated elements.

An electronic delay can be applied to each electronic channel when emitting and receiving the signal to/from the transducer elements. The setup corresponding to all the delays of a given shot is called Delay Law. Each delay law defines a different acoustic beam with particular direction, focusing distance and lateral resolution.

This technique requires probes with very low acoustic and electric cross coupling  between the elements, so that all the elements could be fired independently. Thanks to their 1-3 structure, Imasonic piezocomposite materials are completely adapted to this feature. More >>

Electronic Scanning

The beam is electronically translated by alternatively firing a given number of elements of a linear or circular array phased array transducer

This technique is an alternative to mechanical translation of a single element probe

The advantages are
- Faster inspection
- No mechanical movement required, or reduction of scanline number
- Possibility of combining with electronic focusing and beam steering (see below)

The beam is electronically focused by applying symmetrical delay laws to the different elements of a linear or annular phased array transducer.

This technique is an alternative to using several transducers to focus at different depths

The advantages are
- Only one probe can focus at each depth
- Faster inspection of complete volume of thick pieces with dynamic focusing
- Electronic focusing can compensate focusing aberrations due to cylindrical interfaces

Electronic Steering

The beam is electronically deflected by applying delay laws to different elements of a linear, circular or matrix array. Linear and circular arrays allow for 2D beam steering, while matrix arrays allow for 3D beam steering.

This technique is an alternative to using different angled transducers

The advantages are
- Only one transducer required for inspection at variable angle
- Faster inspection of complex geometry pieces
- The advantage of this technique can be combined with the advantages of electronic focusing

Note : To optimise beam characteristics, electronic deflection can be used in addition to a mechanical pre-deflection with a wedge