Shear Piezo Transducer Launching Lamb Waves
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Solution Overview
Problem
Existing ultrasonic transducers for non-invasive liquid measurements face challenges in achieving optimal radiation fields, leading to non-optimum measurements due to undesired wave propagation.
Innovation Solution
A transducer comprising a shear-type piezoelectric element mounted on a host material, configured to launch Lamb waves into a vessel wall with a phase velocity greater than the speed of sound in the liquid, enabling effective excitation of leaky Lamb waves for precise directional ultrasonic beam generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ultrasonic transducers are used for non-invasive measurement, then the measurement can be performed, but the radiation field is not optimal leading to non-optimum measurements
Solution Approach 1:
The patent changes the fundamental wave propagation parameter by using Lamb waves in the vessel wall instead of direct ultrasonic waves in the liquid. By exciting Lamb waves at specific frequencies and controlling their phase velocity to exceed the liquid's sound speed, the transducer achieves optimal radiation field and improved measurement quality.
Solution Approach 2:
The vessel wall acts as an intermediary medium. Instead of directing ultrasonic waves directly into the liquid, the transducer couples to the vessel wall and excites Lamb waves that propagate along the wall, which then interact with the liquid to produce optimal radiation field for measurement.
2Shape
If phase arrays or Y-cut quartz crystals are used to achieve directional ultrasonic beam, then directional beam can be obtained, but the device complexity and cost increase
Solution Approach 1:
The patent extracts and utilizes the natural directional propagation characteristics of Lamb waves in the vessel wall. By coupling a simple piezoelectric element to the wall and exciting specific Lamb wave modes, the system achieves directional beam formation without requiring complex phase arrays or specialized crystal cuts.
Solution Approach 2:
Instead of using complex phase array structures to synthesize directional beams, the patent copies the directional propagation behavior naturally exhibited by Lamb waves in the vessel wall, achieving the same effect with a much simpler transducer structure.
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
This configuration allows for accurate and precise non-invasive measurement of liquid parameters such as level and speed of sound, with a well-defined, directional ultrasonic beam, reducing complexity and cost compared to traditional phase arrays or Y-cut quartz crystals.
Implementation Method 1
a shear-type piezoelectric element; and a host material, wherein the shear-type piezoelectric element is mounted to a first face of the host material
Implementation Method 2
the transducer when activated at an activation frequency is configured to launch a Lamb wave into the wall of the vessel
Data Source
AI summary
A transducer for non-invasive measurement includes: a shear-type piezoelectric element; and a host material. The shear-type piezoelectric element is mounted to a first face of the host material. A second face of the host material is mountable to a wall of a vessel that holds a liquid. When the second face of the host material is mounted to the wall of the vessel, the transducer when activated at an activation frequency launches a Lamb wave into the wall of the vessel. The transducer is designed such that a phase velocity of the Lamb wave in the wall of the vessel is greater than a speed of sound in the liquid held by the vessel.