Iridescent Retroreflective Member with Interference Layer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional retroreflective members fail to display clear and desired colors under diffused light conditions and do not provide sufficient visibility at nighttime, as they produce only single-colored reflected light and lack the necessary safety and reflection performance to enhance visibility for drivers.

Innovation Solution

A retroreflective member with a light-transmissive interference layer of specific optical thickness (100 to 600 nm) is used, incorporating high and low refractive-index metal compounds, which produces iridescent reflected light that changes color with the incident angle, enhancing visibility and safety by adding varying interference colors to the retroreflected light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a light interference film is bonded to a reflective surface to produce interference color, then reflected light exhibits interference color under retroreflection conditions, but the reflected light cannot display clear and desired colors under diffused light conditions and the base member thickness and texture make it difficult to produce desired design

Engineering Contradiction:
Improveinterference color of reflected lightVSAvoidcolor display under diffused light conditions
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The invention changes the optical parameters of the reflective layer by controlling the thickness (100-600 nm) and refractive index of the metal compound layer, enabling the same layer to produce both diffused light color and retroreflected interference color through parameter optimization

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses composite material structure combining metal compounds (such as zinc sulfide, titanium dioxide) with specific refractive indices to create a reflective layer that simultaneously achieves diffused reflection with desired color and retroreflected interference color

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional retroreflective members are used to provide reflection performance, then they meet basic retroreflection requirements, but they produce only single-colored reflected light and lack sufficient visibility at nighttime

Engineering Contradiction:
Improveretroreflection performanceVSAvoidvisibility at nighttime
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The invention introduces color variation in retroreflected light by utilizing interference color effects from the metal compound layer, causing the retroreflected light to display varying colors (such as yellow, orange, red, purple, blue, green) that enhance visibility and distinguishability at nighttime

Inventive Principle:
Principle #32Color changes

3Ease of manufacture

If the optical layer thickness of the interference layer is not controlled within 100 to 600 nm, then the structure can be simpler or manufacturing easier, but iridescent reflected light cannot be assuredly obtained

Engineering Contradiction:
Improvestructural simplicityVSAvoidoptical layer thickness control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention specifies a precise parameter range (100-600 nm) for the optical layer thickness that balances manufacturing feasibility with optical performance, ensuring iridescent reflected light can be obtained while providing clear manufacturing guidelines

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 solution ensures highly visible iridescent reflected light, allowing for clear and desired color display under diffused light and improved retroreflective performance at nighttime, enhancing visibility and safety by distinguishing the retroreflective member from other light sources.

Implementation Method 1

emphasizing a light component having a visible light wavelength by interference

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

giving a phase difference corresponding to a visible light wavelength to at least a part of incident light and recombining, emphasizing a light component having the visible light wavelength by interference

Methodology Applied
Scientific EffectLight interference: Interference

Implementation Method 3

returning coherent light having a visible light wavelength depending on the incident angle in the traveling direction of the incident light

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Data Source

PatentEP2169434B1Iridescent reflected light emitting retroreflective material
Publication Date: 2016.10.19 MARUJIN
  • EP2169434B1 patent drawingFigure 1
  • EP2169434B1 patent drawingFigure 2
  • EP2169434B1 patent drawingFigure 3(A)~3(C)

AI summary

An object of the present invention is to provide a retroreflective member that can improve the visibility further. The retroreflective member includes a reflective layer and transparent microscopic beads 13. The retroreflective member gives a phase difference corresponding to a visible light wavelength to at least a part of incident light and recombines, emphasizes a light component having the visible light wavelength by interference, and returns coherent light having a visible light wavelength depending on the incident angle in the traveling direction of the incident light. The reflective layer includes a light-transmissive interference layer 14, and the interference layer 14 each has an optical layer thickness of 100 to 600 nm so as to generate an interference color having a visible light wavelength depending on the incident angle of light.