Magnetic Dosage Sensor for Pen-Type Drug Injector Error Detection
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Solution Overview
Problem
Current drug delivery devices lack reliable and cost-effective mechanisms for detecting rotational movements, particularly in drug delivery expelling mechanisms, leading to inaccurate logging of injection data and potential misuse due to manual recording methods.
Innovation Solution
A drug delivery system incorporating sensors to measure magnetic fields corresponding to multiple axes, with a processor determining rotational positions and high-speed conditions, allowing for accurate logging of drug expulsion amounts and error detection, optimized for normal operational conditions to reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensors are used to detect rotational movement in drug delivery devices, then measurement precision and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical sensing mechanisms with magnetic field-based detection. Magnets are attached to rotating components (dose setting element, expelling mechanism), and magnetic sensors detect their position and movement through non-contact measurement, eliminating the need for mechanical encoders or optical systems.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary between the mechanical rotating components and the electronic sensing system. The magnets convert mechanical position into detectable magnetic field variations, which the sensors then translate into digital signals for dosage tracking.
2Measurement precision
If continuous monitoring of rotational position is implemented, then logging accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic sampling of magnetic field positions rather than continuous monitoring. The system takes measurements at key moments (during dose setting, during expelling, at end of expelling) and uses these discrete data points to accurately track dosage, significantly reducing power consumption compared to continuous analog-to-digital conversion.
Solution Approach 2:
The patent pre-identifies critical measurement points in the drug delivery cycle (dose setting completion, expelling start, expelling end) and schedules sensor activation around these events. This allows the system to be in low-power mode between measurements while still capturing all necessary dosage information.
3Reliability
If error detection mechanisms are added to detect high-speed rotation, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent uses magnetic sensors to continuously monitor rotational speed during the expelling phase and compares measurements against predefined thresholds. When abnormal high-speed rotation is detected, the system generates error alerts and can halt operation, providing real-time feedback control that prevents dosing errors.
Solution Approach 2:
The patent replaces complex mechanical speed sensors or encoders with simple magnetic field detection. By measuring the frequency of magnetic field variations as the magnetized component rotates, the system can detect abnormal speeds using the same magnetic sensors already deployed for position tracking, adding error detection capability without additional sensor hardware.
4Measurement precision
If multiple sensors measuring multiple axes are used, then rotational position determination accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs multi-axis magnetic sensors that can detect magnetic field variations in three dimensions simultaneously. These sensors serve multiple functions: determining absolute position, detecting rotational direction, measuring rotational speed, and identifying the orientation of the magnet. This multi-functionality reduces the need for separate sensor systems for each measurement type.
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 system provides reliable and efficient detection of rotational movements, ensuring accurate logging of drug delivery data, reducing errors, and optimizing power usage, thus enhancing the reliability and efficiency of drug administration monitoring.
Implementation Method 1
The indicator element comprises a magnet moving together therewith, the magnet being configured to generate a spatial magnetic field which relative to the sensors varies corresponding to the spatial orientation of the magnet and thus the indicator element
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Add-on module (100) for logging the value of an expelled dose from a pen-type drug injector (200), comprising a magnetic sensor system comprising first and second sensor means (745/746) as well as a mechanical dose setting and expelling mechanism comprising a magnetic clutch element (240/740) which rotates during drug expelling. The system further comprises processor means configured to determine (i) on the basis of measured values from the first sensor means, a rotational position of the clutch element, (ii) on the basis of measured values from the second sensor means, a high-speed condition in which the rotational speed of the clutch element exceeds a given threshold level, and (iii) indicate an error state if the high-speed condition is detected.