Auto-Injector Plunger Tracking With Cyclical Delivery Indication
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Solution Overview
Problem
Existing auto-injectors often result in sub-optimal or incomplete delivery of medicament due to users prematurely removing the device before the full dose is administered, despite holding the needle in place during the delivery process.
Innovation Solution
An auto-injector equipped with a detector arrangement to track the plunger's movement and provide visual, haptic, or audible cyclical indications until the delivery is complete, ensuring the user knows the process is ongoing, and optionally includes a holding period after full dose delivery to allow for bung expansion and medicament dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a static visual indication is provided during delivery, then the device shows it is active, but the user cannot distinguish whether delivery is actually ongoing or simply switched on
Solution Approach 1:
The patent applies periodic action by implementing a cyclical visual indication pattern where display elements illuminate and extinguish in a repeating sequence during medicament delivery. This periodic illumination pattern provides dynamic feedback that clearly distinguishes active delivery from a static powered-on state, resolving the information ambiguity without requiring complex additional components.
2Reliability
If the user holds the auto-injector against the injection site for the complete delivery sequence, then full-dose delivery is achieved, but users may prematurely remove the device before complete delivery
Solution Approach 1:
The patent implements feedback by providing real-time visual indication during the delivery sequence that confirms the device is functioning correctly and delivery is ongoing. This feedback loop keeps the user informed of the delivery status, reinforcing the need to maintain the device at the injection site until completion, thereby improving both reliability and user compliance simultaneously.
Solution Approach 2:
The cyclical illumination pattern serves as periodic feedback that actively engages the user's attention throughout the delivery process. The repeating pattern creates a clear visual signal that delivery is in progress, making it easier for users to understand when to maintain and when to remove the device, thus improving compliance without compromising delivery completeness.
3Reliability
If cycles of indication are provided to show delivery is ongoing, then premature removal is reduced, but the indicator arrangement requires multiple electrically-operated display elements
Solution Approach 1:
The patent applies universality by designing the indicator arrangement so that the same set of display elements serves multiple functions: indicating power status, showing delivery progress through cyclical patterns, and signaling delivery completion. This multi-functionality allows the system to provide comprehensive feedback while minimizing the number of display elements required, balancing reliability improvement with device complexity constraints.
Data Source
AI summary
The present invention relates to an auto-injector. The auto-injector includes a housing for receiving a syringe having a plunger, a needle, and a barrel containing a dose of medicament; a drive mechanism configured to, when triggered by a user, automatically drive the plunger from a first position to a second position to expel the dose from the barrel of the syringe through the needle at a front end of the auto-injector; a detector arrangement configured to detect a state of the plunger including at least departure from the first position and arrival at the second position; and an indicator arrangement comprising a display having one or more electrically-operated display elements and configured to provide, responsive to the detector arrangement detecting the departure of the plunger from the first position, a visual indication comprising cycles of indications, the cycles of indications repeating until the detector arrangement detects the arrival of the plunger at the second position.