Maskless Organic EL Display Structure for High-Resolution Manufacturing
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Solution Overview
Problem
The manufacturing of high-resolution display apparatuses using organic EL devices faces challenges such as deviations in the shape and position of island-shaped light-emitting layers due to inaccuracies in metal masks, leading to reduced yield and increased initial investment for equipment, especially in large-scale production.
Innovation Solution
A display apparatus structure is developed with a first and second light-emitting device, each having a pixel electrode, a light-emitting layer, and a common electrode, where the light-emitting layers cover the side surfaces of the pixel electrodes, and an insulating layer covers the top and side surfaces, allowing for precise alignment and uniform thickness, eliminating the need for metal masks and reducing equipment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vacuum evaporation method using a metal mask is used to form island-shaped light-emitting layers, then the light-emitting layers can be formed with defined shapes and positions, but the manufacturing precision deteriorates due to deviations in mask position, mask-substrate alignment, mask warp, and vapor-scattering-induced expansion
Solution Approach 1:
The patent removes the metal mask from the vacuum evaporation process entirely. Instead of using a mask to define the island shapes, the light-emitting layers are formed by direct deposition onto pixel electrodes that are already positioned on the substrate, eliminating mask-related precision errors
Solution Approach 2:
The pixel electrodes are pre-formed and positioned on the substrate before the light-emitting layers are deposited. This preliminary positioning of the electrodes serves as the reference for subsequent light-emitting layer formation, ensuring accurate placement without requiring a metal mask
2Ease of manufacture
If a vacuum evaporation method using a metal mask is used, then light-emitting layers can be formed, but the outline of the layer blurs during vapor deposition resulting in non-uniform thickness
Solution Approach 1:
The metal mask is completely removed from the process, eliminating the vapor-scattering-induced expansion and outline blurring that occur when vapor deposits around the mask edges. This results in sharp, well-defined light-emitting layer boundaries with uniform thickness
3Ease of manufacture
If metal masks are used for manufacturing, then light-emitting layers can be formed with defined patterns, but the metal mask requires regular cleaning which stops the process and requires multiple equipment lines
Solution Approach 1:
The metal mask is completely eliminated from the manufacturing process. Patterns are defined by the pre-formed pixel electrodes and deposition geometry rather than physical masks, removing the need for mask cleaning and maintenance
Solution Approach 2:
The pixel electrodes serve dual functions: as electrical contacts for the display devices and as pattern definition templates for the light-emitting layer deposition, eliminating the need for separate masking components
4Productivity
If multiple manufacturing equipment lines are prepared to maintain production during mask cleaning, then continuous production is possible, but the initial investment for equipment significantly increases
Solution Approach 1:
The metal mask component is completely removed from the system, eliminating the need for backup equipment lines required for mask maintenance. A single continuous production line can operate without interruption since there are no masks to clean or replace
Solution Approach 2:
The patent replaces expensive, maintenance-intensive metal masks with a simpler, mask-less approach where patterns are defined by the substrate structure itself, reducing equipment complexity and initial investment
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 high-resolution, high-definition display apparatuses with improved aperture ratio and reliability, reducing manufacturing costs and increasing yield by eliminating the need for metal masks and simplifying the manufacturing process.
Implementation Method 1
Light-emitting devices (also referred to as EL devices or EL elements) utilizing electroluminescence (hereinafter referred to as EL)
Data Source
AI summary
A high-resolution or high-definition display apparatus is provided. The display apparatus includes a first light-emitting device, a second light-emitting device, a first insulating layer, and a first layer. The first light-emitting device includes a first pixel electrode, a first light-emitting layer over the first pixel electrode, and a common electrode over the first light-emitting layer; the second light-emitting device includes a second pixel electrode, a second light-emitting layer over the second pixel electrode, and the common electrode over the second light-emitting layer; the first light-emitting layer covers the side surface of the first pixel electrode; the second light-emitting layer covers the side surface of the second pixel electrode; the first layer is positioned over the first light-emitting layer; in a cross-sectional view, one end portion of the first layer is aligned or substantially aligned with an end portion of the first light-emitting layer and the other end portion of the first layer is positioned over the first light-emitting layer; the first insulating layer covers the top surface of the first layer, the side surface of the first light-emitting layer, and the side surface of the second light-emitting layer; and the common electrode is positioned over the first insulating layer.