Common Fluorescent Layers in OLED Subpixels
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Solution Overview
Problem
Current display devices using the separate-patterning technique face challenges with color mixing, shadowing, and high manufacturing costs due to the need for precise vapor deposition and high-resolution masks, limiting resolution to around 500 pixels per inch and increasing power consumption.
Innovation Solution
A display device with a layered structure where a first fluorescent luminescent material emits light for the first and second subpixels, a second luminescent material for the second and third subpixels, and a third luminescent material for the third and fourth subpixels, with an intermediate layer between the second and third light-emitting layers to inhibit energy transfer, allowing for linear deposition and reduced vapor deposition margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the separate-patterning technique is used to form light-emitting layers for each color, then light emission efficiency is improved, but manufacturing precision deteriorates due to color bleeding and shadow effects
Solution Approach 1:
The patent divides the light-emitting layer formation process into separate vapor deposition steps for each color (red, green, blue), with each step depositing material for specific subpixels. This segmentation allows independent optimization of each color layer deposition, improving overall patterning precision while maintaining the efficiency benefits of separate-patterning.
Solution Approach 2:
The patent applies different deposition conditions and mask designs for different color regions. By tailoring the vapor deposition parameters locally for each color layer and subpixel region, the patent achieves high precision patterning without color bleeding while maintaining efficient light emission in each specific area.
2Manufacturing precision
If high-precision vapor deposition is performed for each color, then patterning precision is improved, but device complexity increases due to multiple masks and deposition steps
Solution Approach 1:
The patent combines multiple vapor deposition steps into a unified manufacturing process flow, where each color layer is deposited in sequence using optimized deposition conditions. By merging the process steps and using common manufacturing equipment and procedures, the patent reduces overall process complexity while maintaining high patterning precision.
Solution Approach 2:
The patent designs vapor deposition masks and process parameters that can be universally applied across different color layers. The same basic deposition equipment and methodology are used for red, green, and blue layers, reducing the need for specialized equipment for each color and simplifying the overall manufacturing process.
3Manufacturing precision
If the vapor deposition source is positioned far from the substrate to reduce color mixing, then manufacturing precision is improved, but productivity decreases due to increased vacuum chamber height requirements
Solution Approach 1:
The patent optimizes the vapor deposition angle and source-to-substrate distance parameters to achieve the optimal balance between color separation precision and manufacturing efficiency. By carefully controlling these parameters, the patent achieves high precision patterning with reduced color bleeding while maintaining a compact vacuum chamber design that supports high productivity.
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 suppresses color mixing, achieves higher resolutions, and reduces power consumption by eliminating the need for color filters and optical interference effects, enabling both high color levels and low power consumption.
Implementation Method 1
The EL element emits light by using the release of light during the deactivation of excitons that are generated by injecting electrons and holes into the light-emitting layer and causing recombination
Implementation Method 2
The EL element emits light by using the release of light during the deactivation of excitons that are generated by injecting electrons and holes into the light-emitting layer and causing recombination
Implementation Method 3
The EL element emits light by using the release of light during the deactivation of excitons that are generated by injecting electrons and holes into the light-emitting layer and causing recombination
Implementation Method 4
in the second subpixel, a distance between opposing surfaces of the first light-emitting layer and the second light-emitting layer is less than or equal to a Förster radius; the third subpixel includes an intermediate layer, the intermediate layer constituted by at least one function layer aside from the light-emitting layers and having a thickness exceeding the Förster radius
Implementation Method 5
The light-emitting layer of an EL element is mainly formed using vapor deposition techniques, such as vacuum vapor deposition
Data Source
AI summary
A blue fluorescent light-emitting layer is provided in common for a subpixel and a subpixel, a green fluorescent light-emitting layer is provided in common for the subpixel and a subpixel, and a red light-emitting layer is provided in common for the subpixel and a subpixel. An opposing surface distance is less than or equal to a Förster radius, and in the subpixel, the green fluorescent light-emitting layer and the red light-emitting layer are layered with a separation layer interposed therebetween.