Ultrasonic Sensor Top Page > Frequently Asked Questions (FAQs)

Frequently Asked Questions (FAQs)

This page provides frequently asked questions in the form of questions and answers.

About ultrasonic waves

Don't ultrasonic waves scatter?
The likeliness of scattering of ultrasonic waves depends on the size of the sound source and the frequency (wavelength).
In general, ultrasonic waves transmitted from a smaller source are more likely to scatter and those from a larger source less likely to scatter.
Attaching an acoustic lens to the ultrasonic transducer will allow the transducer to focus ultrasonic waves.
To what extent can the lens focus ultrasonic waves?
The focusing effect of an acoustic lens depends on the near field length that is decided by the size of the ultrasonic sensor and the wavelength (radius of the transducer/wavelength) and the curvature of the lens.

About sensor construction

Which part of the sensor uses quartz crystals?
None of the modern ultrasonic sensors mainly used for medicine uses quartz crystals. Because of their low electromechanical coupling factor, quartz crystals are not suitable for using in transducers that convert electric signals into ultrasonic waves (and vice versa) such as ultrasonic sensors.
Instead, ceramic materials are typically used as piezoelectric elements.
How are transducers driven?
When a pulse voltage is applied across the electrodes attached to both poles of the piezoelectric element, the element has mechanical oscillation with its own resonance frequency.
For more information, see "Basic Knowledge: Basic Principle of Operation of Medical Ultrasonic Probes".
How can 3D images be obtained?
3D images can be generated when data in the three-axis (longitudinal, lateral and depth) directions to the sensor (longitudinal, lateral and depth) are available.
NDK uses the technology that mechanically moves a cross-sectional probe (for cross-secrional image) capable of obtaining lateral and depth data in the longitudinal direction to implement 3D imaging.
Abdomen probes are mainly used as 3D imaging sensors for prenatal diagnosis.


What is the product range available?
NDK can provide a variety of sensors including linear and convex types based on our expertise accumulated in the past provision of tailored products.
For more information, see "Product: Ultrasonic probe / Transducer".


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