Organic EL Panel Mask Alignment and Blue Pixel Life Extension
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Solution Overview
Problem
The manufacturing of organic EL panels faces challenges in achieving high-precision image quality and longevity due to the difficulty in forming evaporation masks with microscopic patterns, which results in low yield ratios, decreased evaporation efficiency, and misalignment issues, particularly affecting blue pixels with shorter life cycles.
Innovation Solution
A method involving the use of masks with larger opening portions to allow incoming particles to form layers efficiently, allowing for partial overlap of electrodes to adjust chromaticity and correct misalignment, and forming conductive body layers to enhance the structure, while also optimizing the dimensions and shapes of light-emitting parts to extend the life cycle of blue pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an evaporation mask with a microscopic pattern is used to form high-precision RGB pixels, then image quality precision is improved, but the yield ratio decreases and manufacturing complexity increases
Solution Approach 1:
The patent segments the mask formation process into multiple steps: first forming a coarse mask pattern, then using it as a substrate for subsequent precise layer formation. This divides the difficult single-step microscopic mask fabrication into manageable stages, improving yield while maintaining precision.
Solution Approach 2:
The patent performs preliminary action by first forming the coarse mask pattern and electrode structures before adding the precise organic EL layers. This preliminary framework serves as a robust base that tolerates manufacturing variations, allowing subsequent precise layers to be formed with higher yield.
2Productivity
If the thickness of the evaporation mask is decreased to utilize particles incoming from the inclination direction, then evaporation efficiency is improved, but the strength of the evaporation mask decreases
Solution Approach 1:
The patent applies local quality by creating regions of different mask thicknesses: thicker regions provide structural strength and support, while thinner regions allow efficient particle passage. This spatial variation in thickness optimizes both strength and evaporation efficiency locally.
Solution Approach 2:
The patent uses composite mask structures combining materials with different properties - some providing mechanical strength, others optimized for particle transmission. This composite approach allows the mask to simultaneously achieve high strength and high evaporation efficiency.
3Illumination intensity
If blue pixels are driven with higher current to increase brightness, then brightness is improved, but the life cycle of blue pixels is shortened
Solution Approach 1:
The patent applies local quality by giving blue pixels different structural characteristics than red and green pixels. Specifically, blue pixels have optimized electrode areas and organic layer configurations that reduce current density, allowing higher overall brightness while extending life cycle through localized structural optimization.
Solution Approach 2:
The patent changes key parameters for blue pixels compared to other colors: adjusting electrode area, organic layer thickness, and material composition. These parameter modifications optimize the brightness-to-life-cycle ratio specifically for blue pixels, which have inherently shorter lifetimes.
4Manufacturing precision
If adjustment precision of the evaporation mask is increased to reduce misalignment, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements beforehand cushioning by designing the mask and substrate with built-in alignment tolerance features. The coarse mask pattern and electrode structures are designed to accommodate certain misalignments, cushioning against the effects of positioning errors and reducing the need for ultra-precise adjustment mechanisms.
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 enables the production of organic EL panels with improved precision, increased efficiency, and extended life cycles by allowing for easier alignment and correction of misalignment, and reducing the cost of mask production through the use of fewer mask types and less frequent cleaning.
Implementation Method 1
technology in which a same shape as an opening portion of an evaporation mask is transferred using an evaporation mask to the substrate by using a vapor deposition method
Implementation Method 2
since organic EL elements that configure the organic EL panels are elements that directly emit light
Data Source
AI summary
There is provided a method of manufacturing an organic EL panel by using a mask that includes a blocking portion blocking incoming particles and a plurality of opening portions through which the incoming particles can pass. The method includes forming a first light emitting part corresponding to a first color on a substrate by using a first mask, forming a first electrode that is overlapped with the first light emitting part by using the first mask, forming a second light emitting part corresponding to a second color on the substrate next to the first light emitting part so as to cover at least a part of the first electrode by using a second mask, forming a third light emitting part corresponding to a third color on the substrate in a position for facing the second light emitting part with the first electrode interposed therebetween in the plan view so as to cover at least a part of the first electrode or the second light emitting part, by using a third mask, forming a second electrode in an area corresponding to the second light emitting part and the third light emitting part by using a fourth mask, and removing a material that is deposited on the first electrode and the second electrode by using the first electrode and the second electrode as a mask.