Decorative Sheet Light Diffusion Layer for Darkness Design

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Solution Overview

Problem

Decorative sheets for vehicles and electric products lack design features in dark environments, as existing technologies only enhance design through decorative layers without illumination effects.

Innovation Solution

A decorative sheet comprising a first refractive index layer, a decorative layer, a second refractive index layer, and a light diffusion layer, where the light diffusion layer is partially in contact with the first refractive index layer to diffuse and release light from the front surface, enhancing design features in darkness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a decorative layer is provided on a resin sheet to form a decorative molded article, then the surface appearance with textured impression is improved, but no design effects are obtained in darkness

Engineering Contradiction:
Improvedesign effect in darknessVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The resin sheet is divided into multiple functional layers: a first refractive index layer, a second refractive index layer with lower refractive index, and a light diffusion layer. This segmentation allows each layer to perform its specific function - the refractive index layers guide and trap light, while the diffusion layer scatters light to create the illumination effect in darkness without requiring a complex separate illumination system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes changes in refractive index parameters between different layers to achieve light control. The first refractive index layer has a higher refractive index than the second refractive index layer, creating optical boundaries that guide light. By adjusting these refractive index parameters, the system achieves effective light trapping and guidance to produce design effects in darkness.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If the entire upper surface of the light guide plate is caused to glow, then illumination with impression of greater depth is achieved, but partial glow of resin layer with high refractive index is not realized

Engineering Contradiction:
Improvepartial glow effectVSAvoidmanufacturing difficulty
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The light diffusion layer is selectively positioned at specific locations on the first refractive index layer rather than covering the entire surface. This local quality approach allows only predetermined areas to glow, creating focused design effects in darkness while maintaining manufacturing simplicity through targeted placement of the diffusion layer in the molding process.

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If multiple layers with different refractive indices are provided, then light diffusion and emission from front surface is achieved, but the number of layers and structure complexity increases

Engineering Contradiction:
Improvelight emission from front surfaceVSAvoidnumber of layers
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent combines multiple functional layers (first refractive index layer, second refractive index layer, and light diffusion layer) into a single integrated decorative sheet structure. These layers are formed together as one component, merging the functions of light guidance, light trapping, and light diffusion into a unified structure that achieves front surface light emission without requiring separate assembly of multiple components.

Inventive Principle:
Principle #5Merging (Combining)

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 the emission of light from the decorative sheet's front surface, creating design effects even in dark environments, thereby improving overall design features and providing an illuminated impression.

Implementation Method 1

The light diffusion layer is provided in partial contact with one surface of the first refractive index layer and diffuses light entering from the first refractive index layer so that light is released from part of the front surface of the decorative sheet

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 2

The second refractive index layer is a resin layer having a second refractive index lower than the first refractive index and provided between the first refractive index layer and the decorative layer

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3437857B1Decorative sheet, decorative molded article and decorative module
Publication Date: 2022.04.06 SEIREN CO LTD
  • EP3437857B1 patent drawingFigure 1~2
  • EP3437857B1 patent drawingFigure 3
  • EP3437857B1 patent drawingFigure 4~5

AI summary

A decorative sheet is caused to emit light from part of the front surface to improve the design features. A decorative sheet 1 according to an embodiment includes a first refractive index layer (high refractive index layer) 11 having a first refractive index, a decorative layer 14, a second refractive index layer (low refractive index resin layer) 12 that has a second refractive index lower than the first refractive index and is provided between the first refractive index layer and the decorative layer, and a light diffusion layer 15 that is provided in partial contact with one surface of the first refractive index layer and diffuses light entering from the first refractive index layer so that light is released from part of the front surface of the decorative sheet. A resin molded body 21 may be integrally laminated on the back surface side of the decorative sheet 1 to form a decorative molded article 2. In addition, the decorative molded article 2 may be provided with a light source 31 that injects light from the side surface of the decorative sheet 1 to form a decorative module 3.