Wiegand Wire Injection Status Sensing for Start and Hold Detection

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Solution Overview

Problem

Existing injection devices lack the capability to accurately determine the start, end, and hold times of medicament administration, which is crucial for effective self-administration of treatments like diabetes management.

Innovation Solution

A drug delivery device incorporating Wiegand wires affixed to movable components of the injection device, which induce voltage pulses in coils as they move relative to magnets, allowing a processor to determine these times and enter an enabled state to process data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sensor assembly is integrated into the injection needle hub to detect injection status, then the reliability of injection monitoring is improved, but the device complexity increases

Engineering Contradiction:
Improveinjection status detection reliabilityVSAvoidsensor assembly integration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical sensing mechanisms with a magnetic field-based detection system. A magnet is embedded in the plunger, and a magnetic sensor in the hub detects the magnet's position and movement through magnetic field changes, eliminating the need for direct mechanical contact sensors and reducing mechanical complexity while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic field as an intermediary between the plunger and the detection system. The magnet on the plunger creates a magnetic field that penetrates through the housing and plunger body, allowing the magnetic sensor to detect plunger position and injection status without direct physical contact, thereby simplifying the overall device structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple sensors are integrated into the housing to detect plunger position and injection completion, then the measurement precision is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveplunger position detection precisionVSAvoidsensor placement precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent designs a multi-functional magnetic sensor assembly that can detect multiple parameters (plunger position, injection completion, injection rate) using a single integrated sensor system. This universal sensor replaces multiple separate sensors, reducing the need for precise placement of multiple components while maintaining high measurement precision through software-based multi-parameter analysis.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent monitors changes in magnetic field parameters (strength, direction, position) as the plunger moves, rather than requiring precise mechanical positioning of multiple sensors. By detecting dynamic parameter changes in the magnetic field, the system achieves high measurement precision with simpler manufacturing requirements.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a magnet is incorporated into the plunger and a magnetic sensor into the hub, then the ease of operation is improved through wireless detection, but the device complexity increases due to magnetic component integration

Engineering Contradiction:
Improveinjection monitoring convenienceVSAvoidmagnetic component integration complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical linkages and direct-contact sensing mechanisms with a magnetic field-based detection system. The magnet embedded in the plunger and the magnetic sensor in the hub enable wireless, contactless detection of plunger position and injection status, improving ease of operation while the modular magnetic component design keeps integration complexity manageable.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical 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 precise tracking of injection events, reducing user error and enhancing the reliability of self-administered treatments by providing accurate start, end, and hold time data.

Implementation Method 1

a first Weigand wire (224) comprising an inner core and an outer shell, the first Weigand wire having a starting position proximate to the first magnet (402a) and a target position proximate to the second magnet (404a), wherein a magnetization polarity of the inner core of the first Weigand wire (224) is configured to switch as the first Wiegand wire (224) moves to the target position proximate to the second magnet (404a) and this switch is configured to induce a first voltage pulse in a first coil (406a) of a first sensor assembly (304)

Methodology Applied
Scientific EffectWeigand effect: Wiegand Effect

Implementation Method 2

the magnetization polarity of the inner core of the first Weigand wire (224) is configured to switch as the first Wiegand wire (224) moves to the target position proximate to the second magnet (404a) and this switch is configured to induce a first voltage pulse in a first coil (406a)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a first magnet (402a) and a second magnet (404a), wherein the first and second magnets are of opposite polarity

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP4431135B1Determining a status of an injection
Publication Date: 2026.05.13 SANOFI SA(FR)
  • EP4431135B1 patent drawingFigure 1
  • EP4431135B1 patent drawingFigure 2
  • EP4431135B1 patent drawingFigure 3~4

AI summary

A drug delivery device (102) comprising: a housing (203); a first magnet (402a) and a second magnet (404a), wherein the first and second magnets are of opposite polarity and wherein the first and second magnets are incorporated into the housing of the drug delivery device; and a first Weigand wire (224) comprising an inner core and an outer shell, the first Weigand wire having a starting position proximate to the first magnet (402a) and a target position proximate to the second magnet (404a), wherein a magnetization polarity of the inner core of the first Weigand wire (224) is configured to switch as the first Wiegand wire (224) moves to the target position proximate to the second magnet (404a) and this switch is configured to induce a first voltage pulse in a first coil (406a) of a first sensor assembly (304).