Aliphatic TPU Protective Coating for UV-Resistant LED Light Sources

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Solution Overview

Problem

Conventional protective materials for LED light sources, such as silicon and epoxy, degrade under UV light and heat, leading to darkening and loss of transparency, which affects the luminescent capability and mechanical durability, especially in high-brightness applications like emergency exit guidance systems.

Innovation Solution

The use of aliphatic thermoplastic polyurethane (TPU) as a transparent protective material that remains clear and flexible, providing mechanical protection and maintaining visibility even under UV light and heat exposure, suitable for both individual LED components and light-source bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional protective materials (silicon, epoxy) are used for LED light sources, then mechanical protection and flexibility are provided, but the materials darken and lose transparency under UV light and heat exposure

Engineering Contradiction:
Improvemechanical protectionVSAvoidtransparency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the chemical composition parameters of the protective material by using aliphatic TPU instead of conventional silicon or epoxy materials. This material substitution maintains mechanical protection properties while resisting UV-induced darkening and transparency loss, directly resolving the contradiction between reliability and illumination intensity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs aliphatic thermoplastic polyurethane as a composite protective material that combines the flexibility and mechanical protection of silicon with UV and heat resistance. This composite approach eliminates the darkening issue while maintaining all necessary protective functions, resolving the transparency-reliability contradiction.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If high-brightness LED light sources are used to improve visibility in emergency situations, then illumination intensity increases, but heat generation accelerates deterioration of protective materials

Engineering Contradiction:
ImprovebrightnessVSAvoidmaterial durability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the thermal stability parameters of the protective material system by selecting aliphatic TPU, which maintains its optical and mechanical properties at higher temperatures. This enables high-brightness LEDs to operate without accelerating material deterioration, resolving the contradiction between illumination intensity and reliability.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If aromatic TPU or other conventional materials are used as protective coating, then application is simple and cost-effective, but UV exposure causes yellowing and transparency deterioration

Engineering Contradiction:
Improveapplication simplicityVSAvoidclarity
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent changes the chemical structure parameters of the TPU material from aromatic to aliphatic configuration. This fundamental parameter change eliminates the yellowing and transparency loss under UV exposure while preserving the ease of application and cost-effectiveness, resolving the contradiction between manufacturing simplicity and optical clarity.

Inventive Principle:
Principle #35Parameter changes

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 aliphatic TPU ensures the clarity and transparency of the protective material are maintained, preventing undesirable dimming and enhancing mechanical durability, thus ensuring effective illumination in critical situations like fire emergencies.

Implementation Method 1

the materials used nowadays, from which elasticity is also required, are sensitive to UV light and/or to heat

Methodology Applied
Scientific EffectUV resistance: Absorption (EM radiation)

Implementation Method 2

the materials used nowadays, from which elasticity is also required, are sensitive to UV light and/or to heat

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Implementation Method 3

from which elasticity is also required

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

Another drawback is also the impurity that gains access to the surface of a LED light source via diffusion for the aforementioned reasons

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion Barrier

Data Source

PatentEP2676525B1Light source and light-source band
Publication Date: 2017.12.27 MARMILS OY
  • EP2676525B1 patent drawingFigure 1~2
  • EP2676525B1 patent drawingFigure 3
  • EP2676525B1 patent drawingFigure 4

AI summary

LED light source (105), which comprises at least one light-emitting component (1 12). The light- emitting component (1 12) is at least partly protected with a transparent protective material (1 13), which contains aliphatic thermoplastic polyurethane (TPU). The invention also relates to a light-source band.