Retroreflective Material with Segmented Interference Layers
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Solution Overview
Problem
Conventional retroreflective materials exhibit uneven color hue when incident light hits them from the same angle, failing to meet consumer demands for high chroma and diverse color tones, and often require thick interference layers that increase production costs.
Innovation Solution
An open-type retroreflective material structure with a transparent resin layer and a reflective layer formed of a transparent metal compound thin film, where the layer thicknesses are specifically set to achieve high chroma and angle-dependent color tone changes with reduced color unevenness, using a transparent microsphere embedded in a fixing resin layer with a portion exposed, and a transparent resin layer between the microsphere and the reflective layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-layer interference layer is directly deposited on transparent microspheres to produce multicolored interference colors, then color tone diversity is improved, but the layer thickness must be increased to approximately 400 nm leading to very high vapor deposition cost
Solution Approach 1:
The patent divides the single-layer interference structure into two separate layers: a first interference layer with a specific metal compound (e.g., zinc sulfide) and a second interference layer with a different specific metal compound (e.g., zinc selenide). This segmentation allows each layer to contribute different interference colors, achieving multicolored effects while using thinner layers that are more cost-effective to deposit.
Solution Approach 2:
The patent uses composite materials by combining two different specific metal compounds in separate layers. The first interference layer uses one specific metal compound and the second interference layer uses another specific metal compound, creating a composite structure that produces diverse color tones through optical interference without requiring excessive thickness.
2Adaptability or versatility
If a single-layer interference layer is used to achieve multicolored interference colors, then color diversity is improved, but hue unevenness occurs depending on the region of the retroreflective material
Solution Approach 1:
The patent segments the interference color generation into two separate layers, each with controlled thickness and material composition. The first interference layer and second interference layer work together to produce consistent hue across different regions, eliminating the unevenness problem that occurs with single-layer designs.
Solution Approach 2:
The patent applies local quality by giving each interference layer specific material properties and thickness parameters tailored to its function. The first interference layer has a specific metal compound and thickness range, while the second interference layer has a different specific metal compound and thickness range, optimizing local optical properties to achieve uniform overall color distribution.
3Adaptability or versatility
If the layer thickness of the interference layer is increased to obtain more multicolored interference colors, then color diversity is improved, but production cost increases very high
Solution Approach 1:
The patent segments the color generation function across two layers, allowing each layer to be thinner than a single thick layer would need to be. This reduces the total quantity of specific metal compound materials required while still achieving multicolored interference effects.
Solution Approach 2:
The patent changes the parameters by using two different specific metal compounds with different optical properties instead of increasing the thickness of a single layer. By adjusting the material composition and thickness of each layer within specific ranges, diverse color tones are achieved with reduced material quantity.
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 material achieves high chroma with a wide angle of incidence and changes color tone effectively based on the incident angle, while minimizing color unevenness, enhancing both visibility and decorativeness for various applications.
Implementation Method 1
A typical retroreflective material has a structure in which transparent microspheres are provided on a reflective layer, whereby light incident through the transparent microspheres is reflected at the reflective layer, and light is emitted through the transparent microspheres, so that light is retroreflected.
Implementation Method 2
light incident through the transparent microspheres is reflected at the reflective layer, and light is emitted through the transparent microspheres
Implementation Method 3
a transparent resin layer may be provided between the reflective layer and the transparent microspheres to adjust the reflective luminance or the color tone of the reflected light
Implementation Method 4
a reflective layer (3) formed of a transparent metal compound thin film... can change the color tone of reflected light depending on the incident angle of the incident light
Data Source
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AI summary
An object of the present invention is to provide a retroreflective material that shows high chroma for incident light with a wide angle, and can change the color tone of reflected light depending on the incident angle of the incident light, and also has reduced unevenness in the color of the reflected light. An open-type retroreflective material in which a transparent resin layer and a reflective layer formed of a transparent metal compound thin film are laminated between a transparent microsphere and a fixing resin layer, and the layer thickness of the transparent resin layer is set to satisfy predetermined conditions, can show high chroma for incident light with a wide angle, and can change the color tone of reflected light depending on the incident angle of the incident light, and can also have reduced color unevenness.