Quantum Dot Color Conversion Layer for Display Devices

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Solution Overview

Problem

Current display devices face challenges in achieving improved display quality and reliability, particularly in the light functional layers of electronic devices such as liquid crystal display devices and organic electroluminescent display devices, where quantum dots are used to enhance display quality but require optimization for better performance.

Innovation Solution

A display device incorporating a light-emitting element with a color conversion layer containing a first quantum dot with an absorption peak in the UV-vis spectrum and a second quantum dot without this peak, along with specific core and shell compositions, ligands, and weight ratios, to optimize light emission and absorption characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If quantum dots are used to enhance display quality, then color conversion performance is improved, but reabsorption occurs reducing external quantum efficiency

Engineering Contradiction:

Improvedisplay qualityVSAvoidexternal quantum efficiency

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The quantum dot layer is segmented into two distinct types: first quantum dots with a specific absorption peak in the green region (500-560 nm) and second quantum dots without this absorption peak. This segmentation allows the first quantum dots to perform color conversion while the second quantum dots emit light without reabsorption, thereby resolving the contradiction between color conversion performance and external quantum efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the absorption spectrum parameters by selecting quantum dots with specific properties. The first quantum dots are chosen to have an absorption peak in the green region to match the emission spectrum of green light-emitting diodes, while the second quantum dots are selected to lack this absorption peak, preventing reabsorption losses and improving external quantum efficiency.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If quantum dots are used for color conversion, then color accuracy is improved, but light absorption efficiency decreases due to reabsorption

Engineering Contradiction:

Improvecolor accuracyVSAvoidlight absorption efficiency

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The quantum dot composition is segmented into two functional groups: first quantum dots that provide color conversion with accurate green emission, and second quantum dots that emit light without reabsorption. This segmentation ensures that color accuracy is maintained through the first quantum dots while light absorption efficiency is improved by the second quantum dots that do not cause reabsorption losses.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention optimizes light absorption efficiency by changing the spectral parameters of the quantum dots. The first quantum dots are selected with absorption peaks matching the green LED emission spectrum for accurate color conversion, while the second quantum dots are selected without this absorption peak to minimize reabsorption and maximize light transmission efficiency.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If a single type of quantum dot is used, then manufacturing is simplified, but display quality and reliability are insufficient

Engineering Contradiction:

Improvequantum dot fabricationVSAvoiddisplay quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

While maintaining a relatively simple manufacturing process, the invention segments the quantum dot layer into two types that can be applied using existing quantum dot deposition techniques. The first and second quantum dots are mixed or layered in specific configurations, allowing standard manufacturing equipment to be used while achieving superior display quality and reliability through the complementary properties of the two quantum dot types.

Inventive Principle:

Principle #1Segmentation

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 proposed solution enhances display quality by optimizing the light emission spectrum and absorption efficiency, leading to improved color conversion and reduced reabsorption, thereby increasing the external quantum efficiency and light absorption rate.

Implementation Method 1

a first quantum dot that exhibits a first absorption peak in a UV-vis absorption spectrum

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a color conversion layer on the light-emitting element and including a first quantum dot that exhibits a first absorption peak in a UV-vis absorption spectrum

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS20250107385A1Display device and electronic device including the same

Publication Date: 2025.03.27 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a light emitting element on a substrate and that generates light of a preset color and a color conversion layer on the light emitting element and including a first quantum dot that exhibits a first absorption peak in a UV-vis absorption spectrum and a second quantum dot that is different from the first quantum dot and does not exhibit a first absorption peak in a UV-vis absorption spectrum.