Passive Needle Shield Structure for Stable Ocular Injection

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Solution Overview

Problem

Existing injection devices require clinician intervention to remove and replace needle shields, increasing the risk of needle sticks and complicating precise administration, especially in sensitive areas like the eye, while separate shields can lose sterility and complicate disposal.

Innovation Solution

Injection devices with passive needle shields that automatically collapse to expose the needle tip during use, stabilizing the device on the patient's tissue without manual activation, ensuring sterility and reducing needle stick risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a separate external needle shield is used, then needle tip protection is improved, but clinician time and operational complexity increase

Engineering Contradiction:

Improveneedle stick riskVSAvoidclinician time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The needle shield is merged with the syringe body to form an integral structure, eliminating the need for separate external shields. The shield is built into the syringe housing with the needle translating through it, combining protection and administration functions in one integrated device.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The needle shield automatically translates and positions itself without clinician intervention. As the needle advances during injection, the shield passively moves to expose the needle tip, and upon withdrawal, it automatically covers the needle tip again, eliminating manual shield manipulation.

Inventive Principle:

Principle #25Self-service

2Object-affected harmful factors

If a separate external needle shield is used, then needle tip protection is improved, but sterility maintenance deteriorates

Engineering Contradiction:

Improveneedle stick riskVSAvoidsterility

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integral shield maintains continuous protection of the needle tip throughout the entire use cycle from packaging to disposal. The shield remains in place during storage, transport, and administration, only exposing the needle tip temporarily during injection, thereby maintaining sterility continuously without removal and replacement cycles.

Inventive Principle:

Principle #20Continuity of useful action

3Ease of operation

If the needle tip is freestanding and unsupported, then injection flexibility is improved, but alignment precision and stability deteriorate

Engineering Contradiction:

Improveinjection flexibilityVSAvoidalignment precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The shield provides localized support and stabilization at the needle tip region while leaving the rest of the needle free for injection. The shield includes a distal face that contacts the injection site to stabilize the needle tip, and a proximal region that allows freedom of movement for the syringe body, providing support only where needed.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The shield extends beyond the needle tip in the axial dimension to provide stabilization, creating a reference plane (distal face) that contacts the injection site. This adds a dimensional element for alignment and stability without constraining the needle's injection function.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Ease of operation

If an integral needle shield is used, then operational simplicity is improved, but device complexity increases

Engineering Contradiction:

Improveoperational simplicityVSAvoidsyringe structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The shield is constructed as a thin-walled hollow cylindrical structure that is flexible and collapsible. This thin-film construction provides the necessary protection and stabilization functions while minimizing added structural complexity and material usage.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The shield is designed to be dynamically collapsible rather than rigid. As the needle advances, the shield passively collapses inward to expose the needle tip, and upon withdrawal, it returns to its expanded protective state. This dynamic behavior provides protection and stabilization without requiring complex mechanical actuation mechanisms.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20250360272A1Injection device with stabilizing passive needle shield

Publication Date: 2025.11.27 BECTON DICKINSON & CO

AI summary

Medical injection devices incorporate collapsible, passive needle shields for avoiding inadvertent needle tip contact with objects. The needle shield is coupled to the distal end of the syringe barrel, enveloping the needle in its relaxed, non-compressed state. When the needle shield is in a relaxed, non-collapsed state, its contact surface extends distally longer than the needle tip, so that the tip is enveloped and shielded by the contact surface. Abutment of the contact surface against a desired patient body site stabilizes the syringe orientation. Thereafter, the syringe barrel is advanced, which passively collapses the needle shield, so that the now exposed needle tip pierces the patient's body, allowing injection of medical fluids by advancement of the syringe plunger. Injection device embodiments include ocular injection devices for injecting medication through the sclera of a patient's eye.