Silicone Lens Light Guide for UV-Stable Automotive Trim Lighting
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Solution Overview
Problem
Current automotive lighting components using polycarbonate (PC) or polymethylmethacrylate (PMMA) materials face issues with UV stability, scratch resistance, and increased costs due to the need for UV additives and additional processing steps, which affect the durability and appearance of decorative components.
Innovation Solution
Incorporating a silicone lens as a light guide that is UV resistant and does not require additional UV additives, formed through reactive injection molding, which allows for light transmission and diffusion without the need for a hardcoat, and provides flexibility and sealing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polycarbonate (PC) material is used for the lens, then optical quality and mechanical properties are improved, but UV stability and scratch resistance deteriorate
Solution Approach 1:
The patent applies composite materials by combining silicone resin with UV stabilizers and scratch-resistant additives to create a lens material that integrates both UV protection and mechanical durability properties, resolving the contradiction between PC's mechanical strength and UV instability
2Reliability
If UV additives are added to PC resin to increase UV resistance, then UV stability is improved, but cost and yellowing increase
Solution Approach 1:
The patent changes the fundamental material parameter from PC to silicone resin, which inherently provides UV resistance without requiring additional UV additive formulations, thereby avoiding the cost increase associated with specialized UV-stabilized PC compounds
3Strength
If a silicone hardcoat is applied to enhance scratch resistance, then scratch resistance is improved, but processing complexity and cost increase
Solution Approach 1:
The patent merges the lens substrate and protective coating into a single integrated silicone resin component, eliminating the separate hardcoat application step while maintaining scratch resistance through the inherent properties of the silicone material formulation
4Reliability
If PMMA material is used for the lens, then UV stability is improved, but impact resistance deteriorates
Solution Approach 1:
The patent uses composite silicone resin formulation that combines the UV stability characteristics similar to PMMA with the superior impact resistance and flexibility of silicone elastomers, achieving both requirements simultaneously
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 silicone lens offers improved UV resistance, thermal properties, and impact resistance, reducing costs and complexity while maintaining aesthetic appeal and functionality, without sacrificing durability or appearance.
Implementation Method 1
a transparent or translucent light-transmissive lens mounted to the light source... the lens disperses light and includes a molded silicone body defining a light guide, wherein light generated by the light source is transmitted through the lens
Implementation Method 2
the lens disperses light... the lens includes a light diffusing roughened surface texture on one or both of the inner surface and the outer surface
Data Source
AI summary
A decorative component for an automobile includes a carrier, a light source, a lens, and a cover. The lens is made of silicone material that is UV resistant, and does not include a UV resistant hardcoat. The silicone lens is flexible and covers the light source, and also seals against the carrier structure. The cover is sized to cover a portion of the lens, leaving an uncovered portion of the lens from which light from the light source will be transmitted and made visible. The lens may be formed by reactive injection molding, including a liquid silicone resin with low viscosity, such that the liquid silicone resin reaches small crevices within the mold cavity. A surface of the mold may include fine detail engraving, replicated in the formed solid of the lens, which may provide aesthetic features and/or light diffusion. The silicone resin may also include a diffusion agent.