Focused Diffraction-Grating Transducer for Angled Beam Sensitivity
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Solution Overview
Problem
Conventional ultrasonic diffraction-grating transducers (DGTs) have a broad uniform-width beam that limits their application in producing high-resolution images and sensitivity, especially when used as receivers, due to their inability to detect ultrasound scattered from point scatterers over a wide range of angles.
Innovation Solution
A focused diffraction-grating transducer (F-DGT) is developed by adjusting the spacing and shaping of array elements to form a focused ultrasound beam, allowing for increased sensitivity as a receiver and higher intensity as a transmitter, while maintaining the capability of producing an angled beam from a single cable and signal channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional DGT with uniform-width beam is used, then the transducer can be fabricated simply and operates with a single cable connection, but the beam width is broad which limits imaging resolution and sensitivity
Solution Approach 1:
The transducer face is divided into multiple discrete array elements (e.g., 16 elements) arranged in a diffraction grating pattern. Each element can be independently controlled to contribute to beam formation, enabling focused beam generation while maintaining the single-cable operation through sequential or phased activation of elements.
Solution Approach 2:
The transducer employs dynamic control of array element activation and timing to achieve focusing. By varying the activation sequence and timing of individual elements, the system can dynamically form focused beams at different depths and angles, transforming the static uniform beam into a dynamically controllable focused beam.
2Measurement precision
If a conventional DGT with uniform-width beam is used as a receiver, then the structure is simple, but the sensitivity to ultrasound scattered from point scatterers is limited due to narrow angular detection range
Solution Approach 1:
The receiver array is segmented into multiple discrete elements that can independently detect ultrasound signals. By processing signals from multiple elements with different angular orientations, the system achieves enhanced sensitivity to scattered ultrasound from point scatterers while maintaining structural simplicity through the diffraction grating geometry.
Solution Approach 2:
The same array of elements serves dual functions as both transmitter and receiver. The elements can operate in transmit mode to generate focused beams and in receive mode to detect scattered ultrasound, eliminating the need for separate transmit and receive structures and achieving multi-functionality with a single device configuration.
3Measurement precision
If a phased-array system with multiple transducer elements is used to achieve focusing, then the focusing capability and sensitivity are improved, but the system requires expensive transducers, multiple cables, and complex circuitry
Solution Approach 1:
Multiple transducer elements are electrically merged into a single operational unit controlled by one cable. The diffraction grating geometry and phased activation scheme allow all elements to be driven sequentially or in phases through a single cable connection, combining the functionality of multiple elements while eliminating the need for multiple separate cable connections and associated complex circuitry.
Solution Approach 2:
The array elements serve themselves through diffraction-based beam forming. The geometric arrangement of elements in a diffraction grating pattern naturally produces the desired beam focusing and angular distribution through wave interference, reducing the need for complex external focusing mechanisms and control circuitry.
4Power
If a conventional DGT is used as a transmitter, then the structure is simple with single cable connection, but the beam intensity is dispersed and cannot produce high-resolution images
Solution Approach 1:
The transmitter is segmented into multiple array elements that can be activated in a coordinated sequence. By controlling the timing and phase of each element, the system concentrates acoustic energy into a focused beam, increasing beam intensity at the focal point while maintaining the simple single-cable connection through sequential activation.
Solution Approach 2:
The array elements are pre-positioned in a diffraction grating pattern with specific geometric relationships. This preliminary geometric configuration enables the elements to constructively interfere and focus energy at predetermined locations, allowing focused beam generation without requiring complex real-time adjustment mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The F-DGT achieves greater sensitivity in detecting ultrasound scattered by point scatterers and produces a tightly focused spot, enabling improved measurement of blood velocity and imaging applications with enhanced sensitivity and resolution.
Implementation Method 1
An ultrasonic diffraction-grating transducer (DGT), which can be fabricated from piezoceramic, piezoplastic, or any piezoactive material
Implementation Method 2
an ultrasonic diffraction-grating transducer (DGT)... has the special capability of producing a beam at an angle to its face
Implementation Method 3
A focusing device offers the advantage of greater sensitivity as a receiver (because a lens system gathers energy over range of angles) and greater intensity creation as a transmitter because of its focusing action
Data Source
AI summary
Ultrasound diffraction-grating transducers produce beams at an angle to their face, which makes them useful for Doppler measurement of scattering fluids such as blood. The present invention discloses a diffraction-grating transducer, with the capability to focus transmitting or receiving beams to a desired point in space. This focusing capability leads to greater sensitivity when the diffraction-grating transducer is used as a receiver, and greater concentration of ultrasound energy when used as a transmitter. The focusing is achieved by using curved elements instead of the straight ones in conventional diffraction-grating transducers, and by using non-uniform spacing among these elements rather than the uniform spacing of conventional diffraction-grating transducers. Methods of computing the proper curvature of the elements and their spacing for a desired focal point in space are provided.