Quantum Dot Light Control Layer for Green Display Efficiency

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Solution Overview

Problem

Existing display devices face challenges in enhancing power conversion efficiency and light transmission efficiency, particularly in light control units using quantum dots, which affect the display quality, especially for green light.

Innovation Solution

Incorporating a light-emitting element with green and blue light-emitting structures and a light control layer containing green quantum dots, such as AgInXGa1-XS2, to convert and emit green light with a power conversion efficiency less than 32%, and a light control panel with separate units for red, green, and blue light-emitting regions to optimize wavelength conversion and transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If quantum dots are used in light control units to convert wavelength, then display quality is improved, but power conversion efficiency decreases

Engineering Contradiction:
Improvedisplay qualityVSAvoidpower conversion efficiency
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by precisely controlling the composition parameters (x value in AgInXGa1-XS2) and physical parameters (diameter 3-10 nm, thickness 50-200 nm) of quantum dots to optimize the balance between wavelength conversion capability and power conversion efficiency. By adjusting these parameters, the quantum dots achieve improved display quality while maintaining acceptable power conversion characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining quantum dots with specific matrix materials and integrating multiple light control units (red, green, blue) with different quantum dot compositions. The AgInXGa1-XS2 quantum dots are embedded in a matrix material, creating a composite structure that enhances overall performance by leveraging the strengths of each component material.

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If quantum dots are used in light control units, then light transmission efficiency is improved, but power conversion efficiency decreases

Engineering Contradiction:
Improvelight transmission efficiencyVSAvoidpower conversion efficiency
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by creating spatially differentiated light control units with specific quantum dot compositions optimized for their respective functions. Each light control unit (red, green, blue) has locally optimized quantum dot properties tailored to its specific wavelength conversion requirements, allowing high light transmission efficiency in each region while managing power conversion characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by adjusting quantum dot composition (x value), size (diameter), and layer thickness to optimize the trade-off between light transmission efficiency and power conversion efficiency. Specific parameter ranges are established to achieve the desired balance for each color channel.

Inventive Principle:
Principle #35Parameter changes

3Illumination intensity

If green quantum dots with high conversion efficiency are used, then green light emission is improved, but overall light extraction efficiency decreases

Engineering Contradiction:
Improvegreen light emissionVSAvoidlight extraction efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent applies partial or excessive action by setting the power conversion efficiency of green light control units to less than 32%, which is intentionally limited rather than maximized. This partial optimization allows other factors (such as blue light transmission and overall spectral balance) to be optimized, ultimately improving total light extraction efficiency while maintaining adequate green light emission.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent inverts the conventional approach by deliberately not maximizing green light conversion efficiency. Instead of making green light control units as efficient as possible, the patent limits their power conversion efficiency to less than 32%, which paradoxically improves overall light extraction efficiency by reducing energy losses in the green channel and allowing better utilization of blue light from the light-emitting element.

Inventive Principle:
Principle #13The other way round (Inversion)

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 light extraction efficiency and improves display quality by optimizing power conversion and transmission efficiency for green light, resulting in improved display performance.

Implementation Method 1

a green light control unit including a green quantum dot that converts the wavelength of light emitted from the light-emitting element and emits green light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP4646084A1Display device and electronic device
Publication Date: 2025.11.05 SAMSUNG DISPLAY CO LTD
  • EP4646084A1 patent drawingFigure 1~2
  • EP4646084A1 patent drawingFigure 3
  • EP4646084A1 patent drawingFigure 4

AI summary

A display device is disclosed. The display device may include a light-emitting element that outputs source light and a light control layer on the light-emitting element, which transmits the source light or converts the wavelength of the source light. The light-emitting element may include a first electrode, a second electrode facing (e.g., opposite to) the first electrode, at least one green light-emitting structure between the first electrode and the second electrode, and at least one blue light-emitting structure between the first electrode and the second electrode. The light control layer may include a green light control part including a green quantum dot that converts the wavelength of light emitted from the light-emitting element and emits green light. The power conversion efficiency of the green light control part may be less than about 32%, thereby being able to exhibit or provide excellent or suitable light efficiency and relatively high luminance characteristics.