Ophthalmic Surgical Control Apparatus Beat Frequency Emulsification
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Solution Overview
Problem
Current ophthalmic surgical handpieces used for phacoemulsification face challenges in maintaining precise ultrasonic vibrations due to shifts in resonant frequency caused by changes in mechanical load and heating, leading to inefficient emulsification and potential corneal burns, requiring complex regulation and periodic interruption of piezoceramic element actuation.
Innovation Solution
An ophthalmic surgical control apparatus that generates a first vibration signal at a frequency lower than and a second vibration signal at a frequency higher than the ultrasonic resonant frequency, which are combined to produce a beat frequency with varying amplitude, allowing for automatic energy interruption and reduced power requirements, eliminating the need for active regulation and periodic interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the piezoceramic elements are operated at high amplitudes in the resonant frequency region to achieve complete emulsification in shortest time, then productivity is improved, but the resonant frequency shifts due to mass change and heating causing loss of precision
Solution Approach 1:
The control apparatus continuously detects the voltage and current profiles of the piezoceramic elements to determine the phase angle, and automatically adjusts the excitation frequency to maintain resonance. This closed-loop feedback system compensates for frequency shifts caused by heating and mass changes, allowing sustained high-power operation without precision loss.
Solution Approach 2:
The system dynamically changes the excitation frequency parameter in response to detected phase angle variations. By continuously adapting the frequency parameter based on real-time feedback, the system maintains optimal resonant conditions despite changes in mechanical load, temperature, and aging effects.
2Manufacturing precision
If constant updating of resonant frequency is performed to maintain precise vibrations, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The control apparatus uses a feedback mechanism that automatically detects phase angle changes and adjusts excitation frequency accordingly. This self-regulating feedback loop maintains vibration precision without requiring complex external regulation systems or manual intervention.
3Manufacturing precision
If multiple successive measurement points are detected over time to determine phase angle, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The control apparatus performs continuous detection of voltage and current profiles without interruption during the emulsification process. This continuous measurement approach maintains precise phase angle determination and frequency adjustment without causing time delays or stopping the useful emulsification action.
4Object-affected harmful factors
If periodic interruption of piezoceramic element actuation is implemented to prevent corneal burns, then object-affected harmful factors are reduced, but productivity decreases
Solution Approach 1:
The control apparatus continuously monitors the phase angle and power delivery, automatically adjusting the excitation frequency to maintain optimal resonant conditions. This prevents excessive heating and corneal burns while maintaining continuous operation, eliminating the need for periodic interruptions.
5Manufacturing precision
If excitation frequency is regulated to correspond to natural frequency, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The control apparatus uses phase angle detection as a feedback signal to automatically regulate the excitation frequency. When the phase angle indicates deviation from resonance, the system automatically adjusts the frequency to restore optimal conditions, achieving precise frequency matching through simple phase-based feedback.
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 efficient emulsification with reduced control complexity, minimizing energy delivery to the eye and preventing overheating, while allowing for reliable shattering of lens fragments with varying hardness and size without precise resonant frequency measurement.
Implementation Method 1
The required ultrasonic vibrations for shattering the clouded eye lens can be produced in such a way that the handpiece is provided with piezoceramic elements. If a voltage is applied to these piezoceramic elements, a change in length can be caused due to the piezoelectric effect, and so a needle connected to the piezoceramic elements can be deflected in the longitudinal direction.
Implementation Method 2
In order to achieve complete emulsification of the eye lens and hence a high effectiveness in the shortest possible time, it is useful to move the hollow needle with the largest possible amplitudes. This can be performed in such a way that the piezoelectric elements are operated in the region of the resonant frequency of the handpiece.
Implementation Method 3
a first frequency module (3) configured to produce a first vibration signal at a first frequency, wherein the first frequency is lower than an ultrasonic resonant frequency of an ophthalmic surgical piezo handpiece (6), for emulsifying an eye lens
Data Source
AI summary
An ophthalmic surgical control apparatus is configured to be connectable to a piezo handpiece for emulsifying an eye lens. The control apparatus includes a frequency generator having a first and a second frequency module. The first frequency module generates a first oscillation signal having a first frequency lower than the ultrasonic resonant frequency of the piezo handpiece. The second frequency module generates a second oscillation signal having a second frequency greater than the ultrasonic resonant frequency of the piezo handpiece. A frequency generator control module controls the first and the second frequency modules.