Electro-optical Switching Element Light Scattering Color Purity

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Solution Overview

Problem

Current electro-optical switching elements face challenges in achieving simple device configurations with better color purity, higher out-coupling efficiency, and reduced color shift and brightness contrast under incident light.

Innovation Solution

An electro-optical switching element comprising a light source and a light converting layer with a light converting material that converts light to longer wavelengths and a coloring agent that absorbs visible light, along with light scattering particles, to enhance color purity and out-coupling efficiency while minimizing color shift and improving brightness contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a light converting layer with coloring agent is used to improve color purity, then color purity is improved, but out-coupling efficiency deteriorates

Engineering Contradiction:
Improvecolor purityVSAvoidout-coupling efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent introduces a light scattering layer as an intermediary component between the light source and the light converting layer. This scattering layer mediates the light path, allowing light to undergo multiple internal reflections and interactions with the light converting material, thereby improving both color purity through enhanced conversion and out-coupling efficiency by redirecting light that would otherwise be trapped by total internal reflection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a microlens array structure that operates in the optical dimension to focus and redirect light rays. By adding this dimensional control element, the system can manipulate light propagation angles and paths, enabling light to escape at optimized angles while maintaining color purity through the light converting layer.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If multiple layers are added to improve color purity and out-coupling efficiency, then color purity and out-coupling efficiency are improved, but device complexity increases

Engineering Contradiction:
Improvecolor purityVSAvoiddevice configuration
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent combines multiple functional layers (light scattering layer, light converting layer, microlens array) into an integrated electro-optical switching element structure. By merging these components into a single cohesive device architecture, the patent achieves improved color purity and out-coupling efficiency while managing device complexity through unified structural design rather than separate discrete components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light scattering layer serves multiple functions simultaneously: it scatters light to improve out-coupling efficiency, enhances the interaction path length for better color conversion, and works synergistically with the microlens array for light extraction. This multi-functionality reduces the need for additional dedicated components, thereby managing device complexity.

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

3Loss of energy

If light scattering particles are added to improve out-coupling efficiency, then out-coupling efficiency is improved, but color shift under incident light increases

Engineering Contradiction:
Improveout-coupling efficiencyVSAvoidcolor shift
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent applies light scattering particles locally in specific regions or with specific size distributions optimized for different functions. By controlling the local properties of the scattering particles (size, concentration, distribution), the patent can optimize out-coupling efficiency in certain areas while minimizing color shift effects in others, particularly by using smaller particle sizes that scatter less wavelength-dependent.

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

The solution effectively improves color purity and out-coupling efficiency while reducing color shift and enhancing brightness contrast, addressing the limitations of existing technologies.

Implementation Method 1

a light converting material (130) that converts light wavelength of the light from the light source (110) into longer light wavelength

Methodology Applied
Scientific EffectLight wavelength conversion: Photoluminescence

Implementation Method 2

a coloring agent (140) that absorbs a visible light

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

the electro optical switching element (100) comprises a plural of light scattering particles (150)

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3254156B1Electro-optical switching element and display device
Publication Date: 2020.11.25 MERCK PATENT GMBH
  • EP3254156B1 patent drawingFigure 1~2
  • EP3254156B1 patent drawingFigure 3~4
  • EP3254156B1 patent drawingFigure 5~6

AI summary

The present invention relates to an electro-optical switching element comprising at least one light source, and a light converting layer, and to a use of the electro-optical switching element in an optical device. The invention further relates to an optical device comprising the electro-optical switching element.