Single-Layer Quantum Dot Light-Emitting Device for Multi-Color Emission
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Solution Overview
Problem
Existing organic electro-luminescence (EL) elements require multiple patterning steps to achieve light emission in multiple colors, increasing production costs and complexity.
Innovation Solution
A light-emitting device with a single light-emitting layer containing quantum dots emitting different colors, where the power supply unit controls the frequency and voltage of a drive signal to achieve blue, green, and red light emission, reducing the need for multiple patterning steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If three sub light-emitting layers are stacked to emit blue, green, and red light, then multi-color emission is achieved, but the number of patterning steps increases and production cost rises
Solution Approach 1:
The patent combines multiple light-emitting materials (first light-emitting material emitting blue light, second light-emitting material emitting green light, and third light-emitting material emitting red light) into a single light-emitting layer. This merging approach eliminates the need for stacking multiple separate light-emitting layers, thereby reducing the number of patterning steps while maintaining multi-color emission capability.
Solution Approach 2:
The single light-emitting layer is designed to perform multiple functions by incorporating different light-emitting materials that can emit blue, green, and red light simultaneously or selectively. This universal design allows the same layer structure to achieve multi-color emission without requiring separate dedicated layers for each color.
2Adaptability or versatility
If multiple sub light-emitting layers are stacked for different colors, then color gamut coverage is improved, but manufacturing precision requirements increase
Solution Approach 1:
By merging multiple light-emitting materials into a single light-emitting layer, the patent eliminates the need for precise alignment between multiple stacked layers. The single-layer structure with multiple materials inherently avoids alignment issues while maintaining the ability to cover a wide color gamut through selective emission from different materials.
3Device complexity
If a single light-emitting layer with multiple materials is used, then the number of patterning steps is reduced, but controlling emission color becomes more difficult
Solution Approach 1:
The patent employs time-division multiplexing with periodic drive signals of different frequencies to control which light-emitting material emits light at any given time. The first, second, and third light-emitting materials are excited at different periodic intervals, allowing sequential emission of blue, green, and red light from the same layer, thereby achieving color control without additional patterning steps.
Solution Approach 2:
The emission color is dynamically controlled by adjusting the frequency and timing of drive signals applied to the single light-emitting layer. By dynamically switching which light-emitting material is excited at any moment, the system can control the emitted color while maintaining a simple single-layer structure.
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 allows for efficient emission of multiple colors with fewer patterning steps, reducing production costs and improving chromatic purity, while covering a wide color gamut such as BT2020.
Implementation Method 1
a light-emitting layer provided between the anode and the cathode, and containing a first light-emitting material emitting a first-color light and a second light-emitting material emitting a second-color light greater in peak wavelength than the first-color light, at least one of the first light-emitting material or the second light-emitting material being quantum dots
Data Source
AI summary
A light-emitting device includes: an anode; a cathode; a light-emitting layer provided between the anode and the cathode, and containing a first light-emitting material emitting a first-color light and a second light-emitting material emitting a second-color light greater in peak wavelength than the first-color light, at least one of the first light-emitting material or the second light-emitting material being quantum dots; and a power supply unit controlling a frequency of a voltage to be applied between the anode and the cathode, in accordance with the first-color light and the second-color light.