Capacitive Sensor Reservoir Holder Position Detection
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Solution Overview
Problem
Existing injection devices face challenges in reliably and adaptively detecting the position or presence of a reservoir holder or needle cover relative to the housing, especially in environments prone to shocks or with varying reservoir holder sizes.
Innovation Solution
The injection device employs a capacitive sensor with a sensor area that interacts with the reservoir holder or needle cover, providing a capacitive sensor signal dependent on their position. A controller determines the position of these components based on the sensor signal, enabling reliable and adaptive position detection without mechanical switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical switches are used to detect reservoir holder or needle cover position, then the device can detect position changes, but the device becomes vulnerable to shocks and environmental influences
Solution Approach 1:
The patent replaces mechanical switches with a capacitive sensor system that detects position changes through electrical field interactions. The sensor detects changes in capacitance caused by the proximity or contact of the reservoir holder or needle cover, eliminating mechanical contact points that are vulnerable to shocks and environmental damage while maintaining reliable position detection.
2Adaptability or versatility
If fixed position sensors are used, then the detection is simple, but the device cannot adapt to varying reservoir holder sizes and types
Solution Approach 1:
The patent implements a dynamic detection system where the capacitive sensor can detect position changes across a range of movements rather than being fixed at a single position. The sensor monitors capacitance changes as the reservoir holder or needle cover moves through various positions, allowing the system to adapt to different sizes and types of reservoir holders without requiring multiple fixed sensors or complex adjustment mechanisms.
3Extent of automation
If disposable autoinjectors with batteries and electronics are used, then automatic injection is achieved, but disposal becomes complex and resource waste increases
Solution Approach 1:
The patent divides the injection device into separable components: a reusable drive unit containing the motor and electronics, and a disposable syringe unit containing the reservoir and needle. This segmentation allows the complex electronic components to be reused across multiple injections, while only the simple syringe unit is disposed of, simplifying the disposal process and reducing resource waste compared to disposing of entire automatic injectors after single use.
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 solution provides robust and reliable position detection that is customizable and resistant to environmental influences, such as shocks, and can accurately detect the position of reservoir holders and needle covers of different sizes and types.
Implementation Method 1
a capacitive sensor (90) with a sensor area (93) for sensing the reservoir holder (30) or the needle cover (20), wherein the sensor provides a capacitive sensor signal
Data Source
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Figure 3
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AI summary
The invention relates to an injection device (1) for dispensing a liquid drug from a reservoir (15) through a needle (18). The injection device (1) comprises a housing (87), a reservoir holder (30) releasably attachable to the housing (87), a movable needle cover (20), a capacitive sensor comprising a sensor area (93) and providing a capacitive signal and a controller connected to the sensor. The capacitive signal is indicative of a position of the reservoir holder (30) or of the needle cover (20) relative to the sensor area (93) and the controller is configured to determine a position of the reservoir holder (30) or the needle cover (20) relative to the housing (87) based on the capacitive signal.