Piezo-Electric Pump Voltage Feedback for Low-Hysteresis Dispensing
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Solution Overview
Problem
Piezo-electric pumps used in semiconductor and medical applications face performance degradation due to temperature changes, leading to increased hysteresis and inconsistent liquid dispensing, especially when cooling devices are employed, which can result in process failures and reduced pump performance.
Innovation Solution
A low hysteresis piezo-electric pump design incorporating a pair of piezo-electric actuators with displacement detection sensors and a control unit that adjusts the applied voltage to maintain consistent operating displacements, ensuring precise and continuous liquid dispensing despite temperature-induced changes in actuator characteristics, without the need for cooling devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a piezo-electric actuator cooling device is added to maintain temperature, then temperature stability is improved, but device volume increases and complexity increases
Solution Approach 1:
The patent implements a feedback control system where a temperature sensor continuously monitors the piezo-electric actuator temperature and feeds this information to a control unit. The control unit adjusts the driving voltage in real-time to compensate for temperature-induced hysteresis changes, maintaining consistent pump performance without requiring physical cooling devices.
Solution Approach 2:
The patent dynamically changes the electrical parameters (voltage magnitude and waveform) of the piezo-electric actuator based on detected temperature or displacement feedback. By adjusting these parameters, the system compensates for temperature effects on hysteresis behavior, maintaining accurate control of the pump's discharge characteristics across varying temperatures.
2Temperature
If cooling device is used to maintain temperature, then temperature control is improved, but reliability decreases due to risk of cooling liquid leakage
Solution Approach 1:
The patent replaces the mechanical cooling system (which uses liquid cooling channels and circulating coolant) with an electrical control system. The temperature sensor and control unit form an all-electrical feedback loop that adjusts actuator driving parameters to compensate for thermal effects, eliminating the reliability issues associated with liquid cooling systems.
3Object-affected harmful factors
If piezo-electric actuator temperature increases, then hysteresis phenomenon increases, but adding cooling device increases device volume
Solution Approach 1:
The patent uses a feedback control mechanism where a displacement sensor monitors the actual position of the piezo-electric actuator and compares it with the commanded position. The control unit adjusts the driving voltage to minimize the hysteresis error, maintaining accurate position control without requiring volume-consuming cooling infrastructure.
4Manufacturing precision
If displacement detection sensor and control unit are added to adjust voltage, then dispensing precision is improved, but device complexity increases
Solution Approach 1:
The patent incorporates a displacement detection sensor that provides real-time feedback on the piezo-electric actuator's actual displacement. The control unit processes this feedback signal and adjusts the driving voltage to compensate for hysteresis effects, achieving high dispensing precision through intelligent control rather than mechanical complexity.
Solution Approach 2:
The patent replaces potential mechanical complexity (such as mechanical pre-compression mechanisms or complex valve systems) with an electrical feedback control system. The displacement sensor and voltage control unit form an electrical system that achieves precise dispensing control without mechanical complexity.
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 solution effectively maintains the dispensing performance of viscous liquids by compensating for temperature-related changes in piezo-electric actuator characteristics, ensuring consistent and accurate liquid discharge, thus improving the reliability and efficiency of the dispensing process.
Implementation Method 1
Each of the pair of piezo-electric actuators is composed of a piezo-electric element whose length increases or decreases depending on a potential of an applied voltage
Data Source
AI summary
A low hysteresis piezo-electric pump using a piezo-electric element as an actuator to dispense a liquid may maintain accurate viscous liquid discharge characteristics by adjusting an applied voltage in response to changes in behavioral characteristics of a piezo-electric actuator depending on causes such as temperature change.