Self-focusing high-frequency ultrasonic transducers for non-destructive testing applications

Area of Science:

• Materials Science
• Acoustics
• Non-Destructive Testing

Background:

• High-frequency acoustic waves are crucial for industrial non-destructive testing (NDT) due to their high resolution and sensitivity.
• Current focusing methods for high-frequency transducers, such as mechanical pressure and lens focusing, can cause damage and reduce transmission efficiency.

Purpose of the Study:

• To propose and demonstrate an efficient self-focusing approach for high-frequency ultrasonic transducers.
• To overcome the limitations of traditional focusing methods in NDT applications.

Main Methods:

• Utilized half-concave piezoelectric elements to achieve self-focusing at high frequencies.
• Employed precise micro-nano processing technology for transducer design and fabrication.
• Characterized the transducer's performance at a high frequency of 62.7 MHz.

Main Results:

• Successfully designed and fabricated a self-focusing half-concave ultrasonic transducer.
• Achieved excellent lateral resolution of 39 μm and a -6 dB bandwidth of 76.6%.
• Demonstrated outstanding imaging performance on a multilayer circuit board and a chip.

Conclusions:

• The self-focusing half-concave high-frequency ultrasonic transducer shows significant potential for industrial NDT.
• This technology is particularly promising for high-resolution defect detection in chip packaging.