Electroluminescent Display Solution Process Mask Elimination
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Solution Overview
Problem
The manufacturing of large-sized and high-definition electroluminescent display devices faces challenges due to the high costs and variations associated with the vacuum thermal evaporation process, particularly the preparation of fine metal masks, which leads to issues like sagging and shadow effects.
Innovation Solution
The electroluminescent display device incorporates a substrate with defined display and non-display areas, featuring sub-pixels arranged in specific configurations, including dummy sub-pixels and partition walls, and utilizes a solution process to form light-emitting layers without a fine metal mask, ensuring uniform thickness and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum thermal evaporation process with fine metal mask is used, then light-emitting layers can be formed with selective deposition, but manufacturing costs increase and manufacturing variations occur including sagging and shadow effects
Solution Approach 1:
The patent removes the fine metal mask from the manufacturing process entirely, extracting the problematic component that causes sagging, shadow effects, and high costs. The light-emitting layers are formed without mask-based selective deposition, eliminating the source of manufacturing variations while maintaining the ability to create precise pixel patterns through alternative methods.
Solution Approach 2:
The patent replaces the expensive, complex fine metal mask with a simpler, more economical approach using solution processing methods. This substitution uses inexpensive materials and processes that can be easily applied and discarded, eliminating the need for costly mask preparation and reducing overall manufacturing costs while maintaining adequate precision for large-sized displays.
2Manufacturing precision
If fine metal mask is prepared for vacuum thermal evaporation, then selective luminescent material deposition is achieved, but manufacturing variations and sagging occur
Solution Approach 1:
The patent replaces the mechanical vacuum thermal evaporation process with a solution processing approach. Instead of using mechanical deposition through vapor phase, the luminescent materials are dissolved in solutions and applied to the substrate, allowing for more uniform distribution and eliminating the sagging and shadow effects associated with mask-based mechanical deposition.
Solution Approach 2:
The patent changes the physical state and application method of the luminescent materials from vapor phase deposition to solution phase application. This parameter change allows for better control of material distribution, improved uniformity, and elimination of the reliability issues associated with mask sagging and shadow effects in vacuum evaporation processes.
3Ease of manufacture
If fine metal mask is used in vacuum thermal evaporation, then light-emitting layers are formed, but shadow effect and manufacturing variations occur
Solution Approach 1:
The patent uses solution processing to create accurate copies or replicas of the desired pixel patterns without requiring physical masks. The luminescent materials in solution are applied in a way that directly forms the required patterns through printing, coating, or other solution-based techniques, eliminating the shadow effects and thickness variations caused by mask interference in vacuum evaporation.
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 large-sized, high-definition electroluminescent display devices with improved uniformity and reduced manufacturing costs by minimizing the deviation in light-emitting layer thickness and preventing the mura effect, thereby enhancing image quality.
Implementation Method 1
an electroluminescent display device including a substrate on which a display area displaying an image and a non-display area disposed adjacent to the display area are defined; first, second and third sub-pixel rows in the display area on the substrate
Data Source
AI summary
An electroluminescent display device includes a substrate on which a display area and a non-display area are defined; first, second and third sub-pixel rows in the display area each including a plurality of sub-pixels arranged along a first direction and disposed along a second direction; a light-emitting diode disposed at each of the plurality of sub-pixels and including a first electrode, a light-emitting layer and a second electrode; a dummy sub-pixel in the non-display area and corresponding to the second sub-pixel row; and a partition wall across the third sub-pixel row along the first direction and disposed on the first electrodes of the third sub-pixel row, wherein a width of the second sub-pixel row along the second direction is larger than a width of the first sub-pixel row and smaller than a width of the third sub-pixel row.