Liquid Crystal Display Color Conversion Layer Low Refractive Body
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Solution Overview
Problem
Liquid crystal display devices face challenges in improving light extraction efficiency and reducing external light reflection, which affect display quality and color reproducibility.
Innovation Solution
Incorporating a color conversion layer with a low refractive body (1.0 to 1.3 refractive index) and high refractive materials (1.7 to 3.5 refractive index) in a liquid crystal display device, along with light emitters like quantum dots or fluorescent materials, to alter light paths and reduce external light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional color conversion layer with standard refractive index materials is used, then the structure is simple and easy to manufacture, but light extraction efficiency is poor and external light reflection is high
Solution Approach 1:
The color conversion layer employs a composite material system combining quantum dots (light emitters) with resin materials of specifically controlled refractive indices. This composite structure enables both high light extraction efficiency and reduced external light reflection by optimizing the refractive index contrast between different layers, while maintaining a relatively simple single-layer configuration that is manufacturable.
Solution Approach 2:
The patent optimizes the refractive index parameter of the resin material in the color conversion layer, specifying it should be in the range of 1.3 to 1.7. This parameter change is crucial for achieving high light extraction efficiency by matching impedance between the liquid crystal layer and air, while also reducing glare by minimizing reflection at interfaces. The quantum dot concentration and size distribution are also optimized to enhance color purity and extraction efficiency.
2Productivity
If materials with high refractive index are used to improve light extraction, then light extraction efficiency improves, but external light reflection increases causing reduced display quality
Solution Approach 1:
The patent precisely controls the refractive index of the resin material in the color conversion layer within the range of 1.3 to 1.7, which is higher than conventional materials but optimized to balance two opposing effects: enhancing light extraction efficiency by improving impedance matching while simultaneously controlling external light reflection to maintain display quality. This specific parameter range represents an optimal compromise between the two competing requirements.
3Manufacturing precision
If quantum dots are used for color conversion, then color reproducibility improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses quantum dots as light-emitting particles dispersed in a resin material to form the color conversion layer. This composite approach enables superior color reproducibility through the quantum confinement effect of quantum dots, while the resin matrix provides a simple processing medium that facilitates conventional manufacturing techniques such as spin-coating or inkjet printing, thus balancing performance with manufacturability.
Solution Approach 2:
The patent optimizes parameters including quantum dot size (2-50 nm), concentration (1-10 wt%), and resin refractive index (1.3-1.7) to achieve high color reproducibility. By controlling these parameters, the invention enables precise color tuning while maintaining compatibility with existing manufacturing processes, avoiding the need for complex multi-step fabrication procedures.
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 light extraction efficiency and color reproducibility while reducing external light reflectance, thereby improving display quality and contrast ratio under bright ambient conditions.
Implementation Method 1
a color conversion layer disposed between the liquid crystal and the first substrate and including a light emitter and a low refractive body having a reflective index of about 1.0 to about 1.3
Implementation Method 2
a first color conversion portion including a first light emitter that is configured to absorb a first color light provided from the light source member and emit a second color light that is different from the first color light
Data Source
AI summary
A liquid crystal display device includes a light source member and a display panel disposed on the light source member. The display panel includes a first substrate and a second substrate facing each other, a liquid crystal layer, and a color conversion layer that is disposed between the liquid crystal layer and the first substrate. The color conversion layer includes a light emitter and a low refractive body having a refractive index of about 1.0 to about 1.3. The liquid crystal display device exhibits high color reproducibility and improves external light extraction efficiency.