What is the role of acoustic lenses or curved matching layers in curved array transducers?

• A. To increase the electrical impedance
• B. To tailor the beam to a focal depth
• C. To decrease the mechanical longevity
• D. To reduce the sampling rate

Answer: (B)

The main idea is focusing the ultrasound beam at a specific depth. Acoustic lenses or curved matching layers bend the waves as they leave the curved transducer so they converge at a chosen focal point. This shaping concentrates energy where you want it, improving lateral resolution and brightness at the focal zone. On curved arrays, the curvature helps maintain that focused beam across the surface, ensuring a consistent focal region. They aren’t about changing electrical impedance, sampling rate, or mechanical longevity, so those aspects aren’t what these lenses are for.