Interdigital Electrode Rotation Sensing for Injection Devices
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Solution Overview
Problem
Existing drug delivery devices face challenges in accurately and reliably measuring the rotation of components, particularly in mechanically and electronically implemented injection devices, which is crucial for precise dose setting and dispensing, especially for users with impaired vision or dexterity.
Innovation Solution
A compact and robust rotation sensing arrangement using an interdigital electrode structure that generates an electrical signal when a signal generator passes by a sensor, allowing for contactless measurement of rotation, integrated into injection devices or as an add-on, enabling precise angle calculation and dose measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical rotation sensing methods are used in injection devices, then the device structure is simple, but the measurement precision and reliability are insufficient
Solution Approach 1:
The patent replaces mechanical rotation sensing methods with an electrical sensing system using an interdigital electrode structure. This electrical system generates signals when a signal generator passes by the sensor during rotation, providing more precise and reliable rotation measurement without the limitations of purely mechanical approaches.
Solution Approach 2:
The patent introduces an interdigital electrode structure as an intermediary between the rotating component and the measurement system. This electrode structure generates electrical signals that mediate the detection of rotation, enabling precise measurement while maintaining a relatively simple overall device structure.
2Reliability
If contact-based rotation sensing is used, then the device is compact, but the reliability decreases due to wear and friction
Solution Approach 1:
The patent replaces contact-based mechanical sensing with a contactless electrical sensing system. The interdigital electrode structure detects rotation through electrical signals generated during rotation, eliminating physical contact between sensing components. This removes wear and friction issues while maintaining compact device dimensions.
3Measurement precision
If complex rotation sensing systems are implemented, then measurement precision improves, but the device becomes less suitable for disposable use
Solution Approach 1:
The patent uses an interdigital electrode structure as a compact intermediary sensing element that can be integrated into disposable devices. This electrode-based approach provides precise rotation measurement while occupying minimal space and using materials suitable for single-use manufacturing, making the device economically viable for disposable application.
Solution Approach 2:
The patent transitions from complex multi-component mechanical sensing systems to a planar electrode-based sensing approach. The interdigital electrode structure achieves precise rotation detection in a two-dimensional plane, reducing the need for complex three-dimensional mechanical assemblies and simplifying manufacturing for disposable devices.
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 provides a cost-effective, reliable, and precise method for measuring rotations in drug delivery devices, enhancing user safety and accuracy, and is applicable to both disposable and reusable devices.
Implementation Method 1
The at least one sensor comprises an interdigital electrode structure configured to generate an electrical signal in response to a movement of the at least one signal generator relative to the at least one sensor
Data Source
AI summary
The present disclosure relates to a rotation sensing arrangement for an injection device. The rotation sensing arrangement includes a first member and a second member that are rotatable relative to each other with regard to an axis of rotation, at least one signal generator arranged on the first member, at least one sensor arranged on the second member, and a processor (240) connected to the at least one sensor. The at least one sensor includes an interdigital electrode structure configured to generate an electrical signal in response to a movement of the at least one signal generator relative to the sensor. The processor is operable to calculate an angle of rotation of the first member relative to the second member on the basis of the electrical signal.