Flexible Thermoplastic Resin Light Guide with Anti-Yellowing Clad
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Solution Overview
Problem
Conventional light guiding rods made from transparent resins are too rigid for practical use due to high flexural modulus of elasticity, limiting their ability to be bent for decorative purposes, and they suffer from luminescent color yellowing at distances away from the light source.
Innovation Solution
A thermoplastic resin molded body with a core layer made from acryl-based thermoplastic elastomer and a clad layer with added light diffusing agents, where the total light transmittance of the clad layer is less than 70%, and a second clad layer without diffusing agents is interposed between the core and first clad layers, along with a bluing agent to prevent color yellowing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a transparent resin with high flexural modulus of elasticity is used for the core layer, then the light guiding rod maintains structural integrity, but it becomes too rigid to be bent for practical decorative use
Solution Approach 1:
The patent changes the material parameter of the core layer from conventional transparent resins to thermoplastic elastomers, which have different mechanical properties including lower flexural modulus of elasticity, enabling flexibility while maintaining light guiding functionality
Solution Approach 2:
The patent uses a composite structure with a core layer made of thermoplastic elastomer and a clad layer made of transparent resin, combining the flexibility of the elastomer core with the optical clarity and strength of the resin clad to achieve both bendability and structural integrity
2Adaptability or versatility
If an acryl based thermoplastic elastomer is used for the core layer to achieve flexibility, then the rod can be bent, but the light emitting performance is insufficient and luminescent color yellowing occurs at distal locations
Solution Approach 1:
The patent applies different properties to different parts of the light guiding rod: the core layer contains a light diffusing agent for uniform light distribution, the clad layer has specific refractive index properties for light guidance, and a bluing agent is added to counteract yellowing, with each layer optimized for its specific function
Solution Approach 2:
The patent introduces a light diffusing agent as an intermediary substance in the core layer to scatter and distribute light uniformly, and a bluing agent as another intermediary to optically compensate for yellowing, thereby improving light emitting performance without sacrificing flexibility
3Reliability
If a small amount of bluing agent is added to suppress yellowing, then the luminescent color remains stable, but the overall light transmittance and luminance are reduced
Solution Approach 1:
The patent optimizes the concentration parameter of the bluing agent within a specific range (0.01-10 ppm) to achieve the minimum effective amount for suppressing yellowing while minimizing the negative impact on light transmittance and overall luminance
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 allows for a flexible light guiding rod that can be bent and formed into decorative shapes, improving light emitting performance and preventing luminescent color yellowing, enhancing its industrial applicability.
Implementation Method 1
a light diffusing agent is added to the thermoplastic elastomer from which the core layer 1 is made and the thermoplastic resin from which the first clad layer 2 is made respectively
Implementation Method 2
a first clad layer 2 made from a thermoplastic resin whose refractive index is smaller than that of the thermoplastic elastomer from which the core layer is made
Implementation Method 3
a small amount of bluing agent being added to the resin materials from which the core layer and the clad layer are made so as to make the light emitted from such rod somewhat bluish
Data Source
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AI summary
To provide a circumferentially light-emitting type thermoplastic resin molded body which can be flexibly bent for use according to the type of optical ornaments or the shape of an object to be decorated and which allows the overall luminance of the emitted light to improve and restrains the luminescent color from being yellowed at the distal locations of such body with regard to the light source. The thermoplastic resin molded body at least comprises a core layer 1 made from a thermoplastic elastomer; and a first clad layer 2 made from a thermoplastic resin whose refractive index is smaller than that of the thermoplastic elastomer from which the core layer 1 is made, in which a light diffusing agent is added to the thermoplastic elastomer from which the core layer (1) is made and the thermoplastic resin from which the first clad layer (2) is made respectively; and the total light transmittance of the first clad layer 2 is defined as less than 70%.