Blue Light Efficiency in Electroluminescence Displays
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Solution Overview
Problem
The efficiency of blue light emitting layers in electroluminescence display apparatus is lower compared to red and green light emitting layers, leading to reduced brightness and luminous efficiency.
Innovation Solution
Incorporating a fourth light emitting layer that emits blue light, formed through a deposition process, overlapping with the existing red and green light emitting layers and banks, to enhance the blue light emission efficiency, while preventing damage to the existing layers by using a solvent-resistant process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blue light emitting layer is formed through a solution process, then the manufacturing process is simple, but the luminous efficiency is low
Solution Approach 1:
The patent combines organic light emitting materials with inorganic metal complexes (iridium, platinum, osmium) to create a composite light emitting layer. This composite structure leverages the high luminous efficiency of inorganic materials while maintaining the solution processability of organic materials, thereby resolving the contradiction between manufacturing simplicity and luminous efficiency.
Solution Approach 2:
The patent modifies the chemical composition parameters of the light emitting layer by introducing specific inorganic metal complexes with unique photophysical properties. These parameter changes in material composition directly improve luminous efficiency while the materials remain compatible with solution processing methods.
2Loss of energy
If a fourth light emitting layer is added to improve blue light emission, then luminous efficiency improves, but device complexity increases
Solution Approach 1:
The patent merges the function of the fourth light emitting layer with the existing light emitting layers by using a common solution process and compatible materials. The fourth layer is integrated into the existing device architecture without requiring separate processing equipment or complex additional structures, thus improving luminous efficiency while minimizing increases in device complexity.
3Loss of energy
If a deposition process is used for the fourth light emitting layer, then luminous efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The patent uses a solvent-resistant underlayer as an intermediary between the existing light emitting layers and the fourth light emitting layer deposited by deposition process. This intermediary layer protects the underlying organic layers from solvent damage during and after the deposition process, enabling the use of deposition methods for improved luminous efficiency while maintaining ease of manufacture through a protective interface.
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
Improves the luminous efficiency of blue light emission by forming the fourth light emitting layer through a deposition process, preventing damage to the existing layers and ensuring uniform light emission profiles across the display.
Implementation Method 1
an electroluminescence display apparatus which may be manufactured through a solution process
Implementation Method 2
a fourth light emitting layer provided on the first light emitting layer, the second light emitting layer, the third light emitting layer, and the bank
Data Source
AI summary
An electroluminescence display includes a substrate, a bank defining a first light emitting area, a second light emitting area, and a third light emitting area on the substrate, a first light emitting layer provided in the first light emitting area, a second light emitting layer provided in the second light emitting area, a third light emitting layer provided in the third light emitting area, and a fourth light emitting layer provided on the first light emitting layer, the second light emitting layer, the third light emitting layer, and the bank, wherein the fourth light emitting layer emits light having the same color light of the third light emitting layer. If red light is emitted from the first light emitting layer, green light is emitted from the second light emitting layer, and blue light is emitted from the third light emitting layer and the fourth light emitting layer, the luminous efficiency of blue light can be improved.