Piezoelectric Dose Detection for Injection Pen Rotation Sensing

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Solution Overview

Problem

Existing medication delivery devices lack an automated system to accurately detect and record the amount of medication delivered during an injection event, requiring manual tracking by patients, and there is a need for a dose detection device that is either removable and reusable or integral with the delivery device.

Innovation Solution

A medication delivery device equipped with a dose detection system that utilizes piezoelectric sensing to measure relative rotation between components, such as a dose setting member and an actuator, to determine the amount of medication delivered, which can be either modular or integral to the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If manual tracking is used to record injection amounts, then device complexity is reduced, but measurement precision and reliability of dose detection deteriorate

Engineering Contradiction:
Improvedevice complexityVSAvoiddose detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces manual tracking with an automated sensor system that uses magnetic fields to detect the position of the piston and calculate the delivered dose. This mechanical-to-automated substitution resolves the contradiction by providing accurate dose detection without requiring complex manual recording systems.

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

Solution Approach 2:

The sensor system automatically detects and records the delivered dose without user intervention. The system self-monitors the piston position and calculates the dose amount, eliminating the need for manual tracking while maintaining simplicity in operation.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If automated sensor systems are added to detect dose delivered, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvedose detection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor system serves multiple functions: it detects piston position, calculates delivered dose, and can trigger alerts or notifications. This multi-functionality justifies the added complexity by providing comprehensive monitoring capabilities within a single integrated system.

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

Solution Approach 2:

The patent uses a magnetic field as an intermediary between the piston and the sensor, allowing non-contact detection. This intermediary approach simplifies the overall system design by eliminating the need for direct mechanical contact sensors, reducing wear and complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If reusable dose detection devices are designed, then adaptability improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improvereusability with multiple devicesVSAvoidmanufacturing precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The sensor device is designed with universal interfaces and standardized mounting mechanisms that allow it to be attached to different injection devices. This universality enables reusability across multiple devices while maintaining consistent manufacturing specifications through modular design.

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

Solution Approach 2:

The system is divided into separate modules: a reusable sensor component and device-specific mounting components. This segmentation allows the sensor to be manufactured once with high precision and then reused, while each injection device can have simpler, device-specific attachment mechanisms.

Inventive Principle:
Principle #1Segmentation

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 accurately measures the dose delivered, providing automated detection and recording, enhancing user convenience and accuracy without the need for manual tracking.

Implementation Method 1

The relative rotation may occur between a dose setting member and an actuator and/or housing of the medication delivery device. The rotation sensing may involve piezoelectric sensing, more specifically repeatedly deforming a piezoelectric sensor with a mechanical force.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4299091B1Dose detection with piezoelectric sensing for a medication delivery device
Publication Date: 2026.02.04 ELI LILLY & CO
  • EP4299091B1 patent drawingFigure 1
  • EP4299091B1 patent drawingFigure 2
  • EP4299091B1 patent drawingFigure 3~4

AI summary

The present disclosure relates to a medication delivery device having a dose detection system and an associated control system configured to determine an amount of medication delivered from the medication delivery device based on the sensing of relative rotation within the medication delivery device. The relative rotation may occur between a dose setting member and an actuator and/or housing of the medication delivery device. The rotation sensing may involve piezoelectric sensing, more specifically repeatedly deforming a piezoelectric sensor with a mechanical force. The dose detection system may be a modular or integral component of the medication delivery device.