Capacitance Sensing for Liquid Medicine Injection Dosing
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Solution Overview
Problem
Existing liquid medicine injection devices face challenges in accurately controlling the amount of medication administered, leading to potential side effects due to variations in injection volume, and lack effective leakage detection mechanisms.
Innovation Solution
A liquid medicine injection device featuring a cylinder with a piston, electrodes on its surface, and a circuit unit that calculates displacement information based on capacitance changes between the electrodes to accurately determine the amount of medicine dispensed, incorporating a pump and a conductive member for precise control and leakage sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional injection device is used without sensing structure, then the device structure is simple, but the injection amount cannot be precisely controlled and leakage cannot be detected
Solution Approach 1:
The patent replaces mechanical measurement methods with a capacitance-based sensing system. Two electrodes are positioned on the cylinder surface, and the capacitance change between them is used to detect piston displacement and calculate injection amount, eliminating the need for complex mechanical sensors or gauges.
Solution Approach 2:
The cylinder itself serves as part of the sensing system. The electrodes are mounted directly on the cylinder outer surface, and the cylinder's own dimensional changes during piston movement provide the sensing mechanism, eliminating the need for separate sensing components.
2Measurement precision
If electrodes are mounted on the cylinder surface, then the injection amount can be calculated through capacitance change, but the device structure becomes more complex
Solution Approach 1:
The patent uses capacitance sensing to replace mechanical displacement sensors. The capacitance change between two electrodes mounted on the cylinder surface directly reflects piston displacement, providing precise measurement without mechanical linkages or complex sensor assemblies.
3Reliability
If no leakage detection mechanism is included, then the device structure remains simple, but leakage of liquid medicine cannot be detected
Solution Approach 1:
The capacitance sensing system serves multiple functions: it measures piston displacement for injection amount calculation and simultaneously detects leakage by monitoring changes in the electric field between electrodes. This multi-functional approach adds leakage detection without requiring a separate dedicated sensing system.
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
Enables accurate control of liquid medicine administration and detection of leakage, ensuring precise dosing and minimizing side effects by calculating displacement information and actual discharge amounts through capacitance changes, thereby improving treatment efficacy.
Implementation Method 1
The circuit unit may calculate displacement information of the piston based on a capacitance change between the first electrode and the second electrode.
Data Source
AI summary
A liquid medicine injection device includes: a liquid medicine storage unit including a cylinder including a space configured to store liquid medicine therein and a discharge hole connected to the space, and a piston arranged inside the cylinder and moving toward the discharge hole depending on discharge of the liquid medicine; a first electrode on an outer surface of the cylinder; a second electrode on the outer surface of the cylinder, the second electrode facing the first electrode with the piston therebetween; and a circuit unit including a substrate electrically connected to the first electrode and the second electrode.