Lead-Free Piezoelectric Actuator for Liquid Medicine Discharge
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Solution Overview
Problem
The environmental impact of disposable liquid medicine discharge devices used in medical and biological fields is significant due to the use of lead-containing materials, leading to excessive waste and contamination risks, as these devices are frequently replaced during dose-response experiments.
Innovation Solution
A liquid medicine discharge device featuring a lead-free piezoelectric actuator, which includes a piezoelectric film made of a lead-free material such as KNN (a compound of KNbO3 and NaNbO3), reduces environmental burden by minimizing lead content and allowing for safe disposal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lead-containing piezoelectric material (PZT) is used in the actuator of disposable liquid medicine discharge devices, then the device can be frequently replaced for dose-response experiments, but the environmental load and contamination risk increase significantly
Solution Approach 1:
The patent changes the material composition parameter of the piezoelectric element from lead-containing PZT to lead-free materials (such as KNN - potassium sodium niobate). This parameter change maintains the piezoelectric functionality needed for liquid discharge while eliminating the harmful lead component, thereby resolving the contradiction between frequent device replacement and environmental pollution from lead waste.
Solution Approach 2:
The patent designs the liquid medicine discharge device as a disposable unit with a lead-free actuator. By using lead-free materials, the disposable device can be safely discarded after use without causing significant environmental pollution, thus enabling frequent replacement (high productivity) while minimizing environmental harm.
2Reliability
If disposable liquid medicine discharge devices are used to prevent contamination, then contamination risk is reduced, but a large number of devices are wasted
Solution Approach 1:
The patent changes the material parameter of the piezoelectric element from lead-containing to lead-free composition. This enables the disposable devices to be environmentally safe for disposal, thus supporting the disposable design (which prevents contamination) while reducing the environmental impact of the large number of devices that must be discarded.
3Object-generated harmful factors
If lead-free piezoelectric material is used in the actuator, then environmental burden is reduced, but the device must still maintain precise liquid dispensing performance
Solution Approach 1:
The patent changes the piezoelectric material composition from lead-based to lead-free while optimizing other parameters (such as material structure, electrode configuration, and actuator geometry) to maintain the necessary piezoelectric coefficients and mechanical properties. This ensures that precise liquid dispensing performance is preserved despite the material substitution.
Solution Approach 2:
The patent employs composite material structures in the lead-free piezoelectric actuator, such as combining potassium sodium niobate (KNN) with other ceramics or using layered composite structures. These composite materials achieve the required piezoelectric performance for precise liquid dispensing while maintaining lead-free composition for environmental safety.
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 lead-free piezoelectric actuator enables precise liquid medicine dispensing while reducing environmental contamination and waste, as the device is designed for repeated use and eventual safe disposal, meeting performance requirements for disposable applications in medical and biological settings.
Implementation Method 1
an actuator configured to cause the liquid medicine to be ejected from the nozzle by changing pressure in the pressure chamber and including a piezoelectric element formed of a lead-free material
Data Source
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AI summary
According to one embodiment, a liquid medicine discharge device includes a nozzle plate including a nozzle from which a liquid medicine can be discharged, a pressure chamber structure having an outlet on a first surface side and an inlet on a second surface side and a pressure chamber in fluid communication with the nozzle via the outlet on the first side, a liquid holding container on the second surface and in fluid communication with the pressure chamber via the inlet on the second surface, and an actuator configured to cause the liquid medicine to be ejected from the nozzle by changing a pressure in the pressure chamber and including a piezoelectric element formed of a lead-free material.