Display Device Buffer Layers Refractive Index Optimization

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Solution Overview

Problem

Display devices face challenges in achieving high light emission efficiency and color reproducibility due to light loss in polarization layers and color filters, particularly in liquid crystal and organic light emitting diode displays.

Innovation Solution

A display device configuration incorporating a color conversion display panel with a substrate, a color conversion layer using semiconductor nanocrystals, and buffer layers with a lower refractive index than the color conversion and transparent layers, along with a light filter layer for enhanced light reflection and emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a color filter and polarization layer are used in the display device, then color reproducibility is achieved, but light loss increases

Engineering Contradiction:
Improvecolor reproducibilityVSAvoidlight loss
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent introduces buffer layers with specifically controlled refractive indices (lower than surrounding layers) to optimize light reflection and transmission parameters. By adjusting the refractive index parameter of the buffer layer, the system achieves both color fidelity and reduced light loss through enhanced optical path control

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The buffer layer acts as an intermediary between the color conversion layer and other optical layers. This intermediate layer with tailored refractive index properties mediates light interaction, improving overall light emission efficiency while maintaining color conversion effectiveness

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a color conversion layer with semiconductor nanocrystal is used, then color reproducibility is improved, but device complexity increases

Engineering Contradiction:
Improvecolor reproducibilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the color conversion function and the optical optimization function into an integrated structure. The buffer layer is positioned adjacent to the color conversion layer, merging the light management function with the color conversion function, thereby improving color reproducibility without proportionally increasing device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The buffer layer with specific refractive index properties is selectively positioned only where needed (adjacent to the color conversion layer), providing localized optical optimization. This targeted approach improves color reproducibility in the critical region without unnecessarily increasing overall device complexity

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 improves light emission efficiency and color reproducibility by optimizing light reflection and conversion using semiconductor nanocrystals and buffer layers, increasing the amount of red and green light emitted while reducing blue light loss.

Implementation Method 1

at least one of the first buffer layer and the second buffer layer includes a porous layer... with a lower refractive index than a refractive index of the color conversion layer and the transparent layer

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a color conversion layer positioned between the substrate and the thin film transistor array panel and including a semiconductor nanocrystal

Methodology Applied
Scientific EffectLight conversion: Photoluminescence

Data Source

PatentEP3447572B1Display device
Publication Date: 2022.12.07 SAMSUNG DISPLAY CO LTD
  • EP3447572B1 patent drawingFigure 1
  • EP3447572B1 patent drawingFigure 2
  • EP3447572B1 patent drawingFigure 3

AI summary

A display device according to an exemplary embodiment includes: a thin film transistor array panel (100); and a color conversion display panel (30) overlapping the thin film transistor array panel, the color conversion display panel including: a substrate (310); a color conversion layer (330R, 330G) positioned between the substrate and the thin film transistor array panel and including a semiconductor nanocrystal (331R, 331G); a transparent layer (330B) positioned between the substrate and the thin film transistor array panel; and at least one of a first buffer layer (327) positioned between the color conversion layer and the substrate and between the transparent layer and the substrate, and a second buffer layer (347) positioned between the color conversion layer and the thin film transistor array panel and between the transparent layer and the thin film transistor array panel, wherein the first buffer layer and/or second buffer layer have a lower refractive index than a refractive index of the color conversion layer and the transparent layer, so that total internal reflection of light is generated at the respective interfaces between the color conversion layer and the first and/or second buffer layers.