Reflective Element for Bright Image Display via Wavelength Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Image display devices using structural colors face a limitation in brightness due to the reduction in light emission when only red, green, and blue color-emitting elements are arranged in a planar manner, resulting in insufficient screen brightness.

Innovation Solution

A reflective element and filter element configuration that allows for the display of red, green, blue, and composite colors using a single light-emitting portion, utilizing a dielectric multilayer film or rubber-like material with fine particles to achieve color variation through interference, enabling efficient light reflection and transmission characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If elements each of which can emit only light having any one of red, green, and blue colors are arranged in a planar manner, then color display capability is achieved, but the amount of light emission is reduced to one third resulting in insufficient screen brightness

Engineering Contradiction:
Improvescreen brightnessVSAvoidlight emission amount
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The invention divides the light emission function into two separate components: a white light source that emits all wavelengths, and a reflective element that selectively reflects specific wavelength bands (red, green, blue). This segmentation allows the white light source to emit full-spectrum light efficiently while the reflective element directs the appropriate color bands to the viewer, thereby maintaining high brightness without the one-third light loss inherent in using three separate monochromatic light sources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The white light source serves multiple functions simultaneously: it provides the illumination for all three primary colors (red, green, blue) and acts as the foundation for generating composite colors. By using a single white light source instead of three separate monochromatic sources, the system achieves universal color coverage while maximizing light emission efficiency and screen brightness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Illumination intensity

If a single light-emitting portion is used to display red, green, blue, and composite colors, then screen brightness is enhanced, but the complexity of the optical system increases

Engineering Contradiction:
Improvescreen brightnessVSAvoidoptical system complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflective element is designed with a nested multi-layer structure where dielectric layers are stacked in sequence, with each layer having specific optical characteristics. The first reflective element handles red and green wavelength bands, while the second reflective element (nested or adjacent) handles blue wavelength bands. This nested arrangement allows multiple color functions to be integrated within a compact structure, enhancing brightness while controlling system complexity through hierarchical organization.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The reflective element employs composite material structures combining dielectric materials with specific refractive indices and thicknesses. These composite layers create interference effects that selectively reflect different wavelength bands. By using optically optimized composite materials, the system achieves high brightness output from a single light-emitting portion while managing the complexity through material-level solutions rather than requiring complex mechanical or electronic systems.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If dielectric multilayer film or rubber-like material with fine particles is used to achieve color variation through interference, then manufacturing precision is improved, but the physical size changes and wavelength shifts increase

Engineering Contradiction:
Improvecolor variation controlVSAvoidphysical size changes
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

The invention controls color variation by precisely adjusting optical parameters such as the thickness of dielectric layers, their refractive indices, and the size distribution of fine particles in rubber-like materials. By changing these parameters within optimized ranges, the system achieves accurate color control through interference effects while minimizing the physical size changes of the reflective element. The parameter optimization ensures that wavelength shifts remain within acceptable limits for high-quality color display.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The reflective element exhibits local quality variations where different regions or layers have specifically tailored optical properties. The dielectric multilayer film has varying layer thicknesses and material compositions at different depths, while rubber-like materials have controlled fine particle distributions. These local quality differences enable precise color variation control through interference while keeping the overall physical size of the element compact and minimizing wavelength shifts.

Inventive Principle:
Principle #3Local quality

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

Enhances screen brightness by allowing the display of full colors with reduced light emission loss, achieving color variation with minimal physical size changes and wavelength shifts, thereby improving the overall display performance.

Implementation Method 1

utilizing a dielectric multilayer film or rubber-like material with fine particles to achieve color variation through interference

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

A reflective element according to the claimed invention is defined in appended claim 1... an element that, among light L emitted by a light source LS, reflects in an oblique direction or absorbs light in a specific wavelength region and transmits light in the other wavelength region

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3518019B1Reflective element and image display device element comprising the reflective element
Publication Date: 2024.10.23 YAMAMOTO KAZUHIRO
  • EP3518019B1 patent drawingFigure 1
  • EP3518019B1 patent drawingFigure 2
  • EP3518019B1 patent drawingFigure 3

AI summary

The present invention provides a display element, particularly an image display device element, a filter element, and a reflective element, whereby a display screen can be brightened by displaying red, green, blue, and composite colors thereof through use of a single light-emitting portion. The image display device (10) according to the present invention includes a configuration in which an element (1) in which a boundary wavelength between light absorption and light transmission or a boundary wavelength between reflection in an oblique direction and light transmission is variable or the boundary wavelength is fixed and an element (2) in which a wavelength region to be reflected is variable or the wavelength region is fixed are arranged in a combination in which at least either the boundary wavelength of the element (1) and the wavelength region of the element (2) is variable and in a positional relationship in which light transmitted by the element (1) is incident on the element (2) and, by controlling overlap between a light transmission band of the element (1) and a light reflection band of the element (2) through varying at least one of the boundary wavelength of the element (1) and the wavelength region of the element (2), varies a band of light reflected by the element (2) and the amount of the light.