Color Conversion Panel with Low Refractive Index Layer

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Solution Overview

Problem

Current display devices, particularly OLEDs, face challenges in enhancing display quality due to limitations in color conversion efficiency and external light management, leading to issues like color purity and contrast ratio.

Innovation Solution

A color conversion panel is designed with a substrate having light blocking and transmission areas, featuring a low refractive index layer, multiple color filters, and color conversion layers with specific refractive indices and scattering elements, along with a light transmitting layer, which improves color conversion efficiency and reduces external light reflectance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional OLED display structure is used, then the manufacturing process is relatively simple, but the color purity and contrast ratio are insufficient

Engineering Contradiction:

Improvecolor purityVSAvoidpanel structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the color filter layer and color conversion layer into a single integrated panel structure. The color filter layer (with red, green, blue filters) and color conversion layer (with phosphor particles) are disposed on the same substrate, allowing both color purification and conversion functions to be achieved in one layer system, thereby improving color purity while managing structural complexity

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A low refractive index layer is introduced as an intermediary between the color filter layer and color conversion layer. This layer serves as an optical mediator that reduces light reflection and improves light extraction efficiency, thereby enhancing color purity and contrast ratio without requiring complex additional structures

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If multiple layers with high refractive indices are used, then light extraction efficiency may improve, but external light reflectance increases

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidexternal light reflectance

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a low refractive index layer (with refractive index of 1.3-1.6) between layers with higher refractive indices. This parameter change in refractive index creates an optical gradient that reduces Fresnel reflection at interfaces, thereby reducing external light reflectance while maintaining efficient light extraction through the color conversion layer

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the potentially harmful effect of light reflection at high refractive index interfaces into a beneficial optical management system. The low refractive index layer acts as an anti-reflection coating that transforms reflected light into transmitted light, improving overall light extraction efficiency while minimizing harmful reflections

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Illumination intensity

If a separate blue color filter is added, then blue light transmission may improve, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveblue light transmissionVSAvoidmanufacturing process

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent merges the blue color filter function with the color conversion layer by incorporating blue phosphor particles into the color conversion layer. This allows the blue light transmission function to be achieved through the same layer structure that provides color conversion, eliminating the need for a separate blue color filter layer and simplifying the manufacturing process

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 enhances display quality by improving color purity and reducing external light impact, thereby increasing the contrast ratio and simplifying the manufacturing process without the need for a separate blue color filter.

Implementation Method 1

The low refractive index layer has a refractive index less than a refractive index of the first color conversion layer and a refractive index of the second color conversion layer

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

each of the first and second color conversion layers may include phosphors and scattering elements

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS10872931B2Color conversion panel and display device including the same

Publication Date: 2020.12.22 SAMSUNG DISPLAY CO LTD

AI summary

A color conversion panel includes: a substrate including a light blocking area and first, second, and third transmission areas; a first color filter disposed on the substrate at the first transmission area; a second color filter disposed on the substrate at the second transmission area; a low refractive index layer disposed on the substrate at the light blocking area and the first, second, and third transmission areas; a first color conversion layer disposed on the first color filter and the low refractive index layer; a second color conversion layer disposed on the second color filter and the low refractive index layer; and a light transmitting layer disposed on the low refractive index layer at the third transmission area. The low refractive index layer has a refractive index lower than a refractive index of the first color conversion layer and a refractive index of the second color conversion layer.