Gradient Thermal Welds for Adhesive Layer Tear Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional on-body medical devices with adhesive layers tend to tear when subjected to lateral forces, such as accidental impacts, due to the weakness of thermal welds, which can lead to detachment from the skin.
Innovation Solution
The implementation of meltable thermal weld features with varying structures, including uniform and gradient meltable materials, and dot thermal weld structures, which are designed to absorb and dissipate lateral forces, thereby preventing tears in the adhesive layer and maintaining secure attachment to the skin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermal welds are used to secure the adhesive layer, then the adhesive layer is attached to the housing surface, but the adhesive layer tears when subjected to lateral forces
Solution Approach 1:
The patent applies parameter changes by varying the amount of meltable material in different weld structures (uniform vs. gradient) to create different strength levels. The gradient weld structures have varying material distribution that allows them to fail at lower forces, protecting the adhesive layer while maintaining secure attachment under normal conditions.
Solution Approach 2:
The patent implements local quality by creating different weld structures at different locations - some areas have uniform weld structures for strong attachment, while other areas have gradient weld structures designed to fail first. This spatial variation in weld quality allows the system to absorb lateral forces selectively without tearing the adhesive layer.
2Strength
If stronger thermal welds are used to prevent adhesive layer tearing, then weld strength increases, but lateral forces cause tears near the welds due to stress concentration
Solution Approach 1:
The patent uses parameter changes by creating gradient weld structures where the amount of meltable material varies continuously from the center to the edges. This gradual transition in material amount reduces stress concentration at weld edges, allowing the weld to flex and absorb lateral forces without creating stress points that would cause tearing.
3Ease of manufacture
If uniform meltable material structures are used for thermal welds, then manufacturing is simplified, but the welds cannot effectively dissipate lateral forces
Solution Approach 1:
The patent applies local quality by creating gradient weld structures with varying material distribution in specific locations. These gradient structures are strategically placed to absorb and dissipate lateral forces, while uniform weld structures are used in areas where simple attachment is sufficient. This localized approach balances manufacturing complexity with force dissipation needs.
4Strength
If gradient meltable material structures are used to absorb lateral forces, then adhesive layer protection improves, but device complexity increases
Solution Approach 1:
The patent uses parameter changes by varying the gradient characteristics of different weld structures - some have steep gradients, others have gradual gradients, and they are distributed differently across the housing surface. This parametric variation allows the system to protect the adhesive layer effectively while using a family of related weld designs rather than entirely different structures, thereby controlling complexity.
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 use of sacrificial thermal weld structures effectively diffuses lateral forces, reducing the risk of adhesive layer tears and ensuring the on-body medical device remains securely attached to the user's skin, even under sudden impacts, without causing discomfort or restricting movement.
Implementation Method 1
Thermal welds formed by melting a meltable material, like a plastic, may be used to secure the adhesive layer to the surface
Implementation Method 2
The meltable thermal weld features include a first meltable structure of a substantially uniform amount of a first meltable material above a melting border along a length of the first structure. A portion of the first meltable material at a height above the melting border is configured to melt
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
The exemplary embodiments provide thermal weld structures that help prevent tearing of the adhesive layer of an on-body medical device when subject to lateral forces. These thermal weld structures help reduce the tearing by providing sacrificial thermal weld structures that will absorb forces and then potentially fail to thereby diffuse some of the lateral forces. The sacrificial thermal weld structures may take different forms. For instance, the sacrificial thermal weld structures may be gradient thermal weld structures where the amount of material melted in the gradient thermal weld structures decreases as a gradient along a dimension of the structures, such as their length. In some alternative embodiments, the width of the gradient thermal weld structure may vary instead of the height, or in conjunction with the height. In other exemplary embodiments, the sacrificial thermal weld structures may be dot thermal weld structures.