Organic EL Display Continuous Emission Layer Patterning
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Solution Overview
Problem
The challenge in manufacturing high-resolution organic electroluminescent (EL) displays is the difficulty in forming patterned emitting layers without using fine metal masks, which are prone to inaccuracies and deformation, especially for larger displays, leading to color mixture issues and reduced yield.
Innovation Solution
The solution involves forming continuous emitting layers over an insulating substrate with an array of electrodes, where specific regions of the emitting layers are irradiated with light to alter their properties, eliminating the need for fine metal masks and enabling the creation of multi-color images without positional inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fine metal masks are used in vacuum evaporation to form patterned emitting layers, then pattern definition can be achieved, but manufacturing precision deteriorates due to mask expansion and deformation from radiant heat
Solution Approach 1:
The patent extracts the pattern formation step from the vacuum evaporation process by using photomasks separately for organic material deposition, eliminating the fine metal mask from the evaporation chamber and thus removing the source of heat-induced deformation
Solution Approach 2:
The patent introduces photomasks as an intermediary tool for pattern formation during organic material deposition, replacing the direct fine metal mask approach and enabling precise patterning without heat-induced mask deformation
2Manufacturing precision
If fine metal masks are used for high-resolution pattern formation, then pixel size can be reduced, but color mixture occurs due to position accuracy limitations
Solution Approach 1:
The patent replaces the mechanical fine metal mask system with a photomask-based optical system for pattern formation, achieving superior position accuracy and preventing color mixture in small pixel displays
3Area of stationary object
If large fine metal masks are used for oversized displays, then coverage area increases, but manufacturing difficulty increases due to mask deformation
Solution Approach 1:
The patent removes the fine metal mask from the manufacturing process entirely, replacing it with photomasks that can be used for large-area displays without suffering from heat-induced deformation and manufacturing difficulties
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 method allows for high-quality, high-yield production of organic EL displays with precise color emission, even at small pixel sizes, by using photomasks and rough metal masks to form continuous emitting layers, thereby overcoming the limitations of fine metal masks.
Implementation Method 1
irradiating a region of the first emitting layer that faces a part of the electrodes with a first light without irradiating a region of the first emitting layer that faces another part of the electrodes with the first light so as to transform the first luminescent organic material in the region of the first emitting layer irradiated with the first light into a material different from the first luminescent organic material
Data Source
AI summary
An organic EL display includes an array of electrodes including first and second electrodes, a counter electrode, and an organic layer including a first emitting layer interposed between the array of electrodes and the counter electrode and a second emitting layer interposed between the first emitting layer and the counter electrode. Each of the first and second emitting layers is a continuous layer extending over a display region. Portions of a laminate including the array of electrodes, the organic layer and the counter electrode that correspond to the first and second electrodes form first and second organic EL elements different in luminous colors from each other.