Lighting Component PUR Coating for Complex Optical Microstructures
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Solution Overview
Problem
Conventional motor vehicle light devices made from injection-molded thermoplastic materials face challenges with high viscosity and injection pressures, limiting geometric complexity and increasing manufacturing costs, while protective varnishes are expensive and have implementation limitations.
Innovation Solution
A motor vehicle light device component featuring a substrate of thermoplastic material coated with polyurethane (PUR) or polyurea (PUA), where the second material is injected after the first material has not cooled, forming a thin, self-healing, and optically transparent coating with microstructures, reducing production costs and enhancing mechanical and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If thermoplastic materials are used for injection-molded optical components, then transparency and cost-effectiveness are improved, but high viscosity requires high injection pressures and limits geometric complexity
Solution Approach 1:
The patent uses a composite structure combining a thermoplastic substrate (PMMA or PC) with a polyurethane or polyurea coating layer. This composite approach allows the bulk material to provide structural integrity and optical transparency, while the coating layer provides the necessary surface properties and enables complex geometries with diffractive structures that would be difficult to achieve with thermoplastics alone due to lower required injection pressures for the coating material.
2Strength
If protective varnishes are deposited on outer lens surfaces, then scratch resistance is improved, but thickness limitations and implementation constraints worsen
Solution Approach 1:
The patent changes the material parameter from conventional varnishes to polyurethane or polyurea coatings, which offer superior mechanical properties including higher scratch resistance and flexibility. These materials can be applied as thin layers through injection molding, avoiding the thickness and implementation limitations of traditional varnishes while providing enhanced protective functions.
Solution Approach 2:
The polyurethane or polyurea coating layer serves multiple functions simultaneously: it provides scratch resistance, enables complex geometric structures, and can be integrated directly into the injection molding process. This self-integrating approach eliminates the need for separate varnishing steps, reducing implementation complexity while maintaining protective properties.
3Shape
If silicone is used for optical components with small-sized structuring, then geometric limitations are overcome, but material cost and implementation cost increase
Solution Approach 1:
The patent employs a composite structure where a thermoplastic substrate provides the main component structure at low cost, while a polyurethane or polyurea coating layer (applied in the same injection molding process) provides the capability to form small-sized structuring and diffractive patterns. This composite approach achieves the geometric complexity of silicone components without the high material and implementation costs, as the coating material requires lower injection pressures and can be applied in a single manufacturing step.
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 solution enables the production of complex, optically and mechanically enhanced light device components with reduced production costs by using low-viscosity PUR or PUA coatings on thermoplastic substrates, allowing for self-repair and fine structural details, while maintaining high transmittance and resistance to scratches.
Implementation Method 1
the second material crosslinking by chemical reaction of a polyol with an isocyanate
Implementation Method 2
the first and second materials have between them, at an interface between said materials, polar bonds
Implementation Method 3
the coating forms an outer surface of said component, capable of self-repair by application of a source of heat to said coating
Data Source
AI summary
A component of a lighting device for a motor vehicle includes a substrate composed of a first thermoplastic material, and a coating arranged on the substrate and composed of a second plastic material. The second plastic material includes polyurethane PUR, polyurea PU A or a combination of PUR and PU A.