Blue LED Display with Quantum Dot Color Conversion

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing OLED display devices face challenges in manufacturing complexity and light utilization efficiency, with RGB OLEDs requiring intricate material development and pattern formation, and white OLEDs wasting unused light wavelengths.

Innovation Solution

A display device utilizing a single blue light-emitting element, converting blue light into red and green light using red and green light-emitting quantum dots and phosphors respectively, simplifying manufacturing and enhancing light utilization efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If RGB OLED is used to implement colors by using light-emitting diodes that respectively emit red light, green light, and blue light, then light utilization efficiency is improved, but manufacturing complexity and device complexity increase due to requiring material development, structural design, and pattern forming process for each of R, G, and B light-emitting diodes

Engineering Contradiction:
Improvelight utilization efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges multiple light-emitting diodes (R, G, B) into a single blue light-emitting diode that excites quantum dots to generate all three colors. This consolidation reduces manufacturing complexity while maintaining high light utilization efficiency by eliminating the need for separate R, G, and B LED structures and their associated pattern forming processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces quantum dots as an intermediary substance between the blue light-emitting diode and the final color output. The quantum dots convert the blue light into red, green, and blue wavelengths, serving as a mediator that enables color generation from a single LED source, thereby simplifying the device structure while preserving energy efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If white OLED is used to implement colors by disposing red, green, and blue color filters on a white light-emitting diode, then manufacturing complexity is reduced, but light utilization efficiency deteriorates because light having the remaining wavelength ranges is not used

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlight utilization efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent changes the operational parameters of the light-emitting diode from emitting broad-spectrum white light to emitting focused blue light with specific wavelength. This parameter change enables the quantum dots to efficiently convert the blue light into the desired color spectrum, improving light utilization efficiency while maintaining manufacturing simplicity through the use of a single LED structure.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If RGB OLED is used with R, G, and B light-emitting diodes having different lifespans, then color implementation is achieved, but reliability deteriorates due to color implementation issues when used for long time

Engineering Contradiction:
Improvecolor implementation capabilityVSAvoidlong-term stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent merges the color generation function into a single blue light-emitting diode system with quantum dots, eliminating the reliability issue of having multiple LEDs with different lifespans. The single blue LED has a uniform lifespan, and the quantum dots convert this light into all necessary colors, ensuring consistent color implementation over time and improving long-term stability.

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

This approach simplifies the manufacturing process and improves light utilization efficiency while ensuring stability and color reproducibility by using environmentally stable green phosphors and durable red quantum dots.

Implementation Method 1

The devices comprise a light-emitting layer as a light source and a wavelength conversion layer that converts blue excitation light into red or green light

Methodology Applied
Scientific EffectWavelength conversion: Photoluminescence

Implementation Method 2

The colour conversion material may comprise red, green and blue colour conversion materials

Methodology Applied
Scientific EffectColor conversion: Photoluminescence

Data Source

PatentEP3240034B1Display device
Publication Date: 2022.11.02 LG ELECTRONICS INC
  • EP3240034B1 patent drawingFigure 1~2
  • EP3240034B1 patent drawingFigure 3~4
  • EP3240034B1 patent drawingFigure 5~6

AI summary

A display device includes at least one light-emitting element configured to emit blue light, a red conversion layer disposed on an upper or lower portion of the at least one light-emitting element and including a red light-emitting quantum dot, a green conversion layer disposed on the upper or lower portion of the at least one light-emitting element and including a green light-emitting phosphor, and a substrate comprising thin film transistors electrically connected to the light-emitting element.