Langevin Transducer Split Electrodes for Transverse Motion
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Solution Overview
Problem
Existing phacoemulsification techniques face challenges in inducing transverse motion at the tip of a needle attached to a Langevin transducer horn without increasing costs or requiring significant changes to the handpiece design, as previous methods introduce mechanical losses and necessitate the use of bent needles or special stack configurations.
Innovation Solution
The implementation of split electrodes on ceramic elements, where out-of-phase voltage signals induce out-of-phase strain, creating flexural motion and thus transverse motion at the needle tip, while in-phase signals produce longitudinal motion, allowing for adjustable ratios of flexural to longitudinal motion without altering the transducer stack geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If torsional motion is created through a separate ceramic stack or special stack configuration to achieve transverse motion, then transverse motion is generated, but mechanical loss increases and device complexity increases
Solution Approach 1:
The electrodes on the ceramic stack are divided into multiple segmented electrodes (e.g., first and second segmented electrodes) that can be independently controlled. This segmentation allows different phases of voltage signals to be applied to different segments, creating differential expansion and contraction that generates transverse motion directly without requiring separate stacks or mechanical conversion mechanisms, thereby reducing mechanical loss.
Solution Approach 2:
The same ceramic stack that generates longitudinal motion is made capable of generating transverse motion through phase-controlled segmented electrodes. By adjusting the phase relationship between voltages applied to different segments, the transducer can produce both longitudinal and transverse motions using the same physical structure, eliminating the need for separate dedicated transducers or complex mechanical conversion systems.
2Ease of operation
If torsional motion is converted to transverse motion via a bent needle, then transverse motion is achieved, but device complexity increases and manufacturing precision requirements increase
Solution Approach 1:
The electrodes are segmented into multiple independently controllable sections. By applying voltages with different phases to these segments, the patent creates differential strain that directly produces transverse motion at the needle tip, eliminating the need for bent needles or complex mechanical conversion mechanisms.
Solution Approach 2:
The patent replaces the mechanical conversion system (bent needle converting torsional motion to transverse motion) with a direct electro-mechanical approach. Phase-controlled voltages applied to segmented electrodes create transverse motion through differential piezoelectric expansion and contraction, substituting mechanical complexity with electrical control.
3Ease of operation
If special stack configurations are used to create transverse motion, then transverse motion is generated, but manufacturing precision requirements increase and device complexity increases
Solution Approach 1:
The electrodes are divided into multiple segmented electrodes that can be independently controlled. This segmentation allows transverse motion to be generated through phase-controlled electrical signals rather than requiring special geometric configurations of the stack, thereby reducing manufacturing precision requirements for the transducer geometry itself.
Solution Approach 2:
The patent controls the phase and amplitude of voltages applied to segmented electrodes to dynamically adjust the motion characteristics. By changing electrical parameters (voltage phase and magnitude) rather than relying on fixed geometric configurations, the system achieves transverse motion with standard transducer geometries, reducing manufacturing precision requirements.
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 approach enables the generation of both longitudinal and transverse motion in the needle tip using a conventional handpiece and needle, reducing mechanical losses and costs, while providing adjustable motion control for improved surgical efficacy.
Implementation Method 1
When the piezoelectric stack is subjected to an oscillating voltage, the ceramic piezoelectric elements expand and contract, thereby causing rapid longitudinal movement (i.e. longitudinal vibration at ultrasonic frequencies) in the horn and thereby in a needle which is attached at a distal end of the horn
Implementation Method 2
out of phase voltage signals are applied to the split electrodes, inducing out of phase strain in the material. This out of phase strain creates flexural motion in the horn
Data Source
AI summary
A Langevin transducer horn uses split electroding or selective electroding of transducer elements and phase relationships of the voltages applied thereto to determine the relative longitudinal and flexural/transverse motion induced in the tip of the horn.