Organic Light-Emitting Display Common Layer Uniformity
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Solution Overview
Problem
Organic light-emitting display apparatuses face challenges with white angular dependency (WAD) due to varying thickness of common layers across subpixel areas, leading to color shift when viewed from different angles.
Innovation Solution
A method of manufacturing organic light-emitting display apparatuses involving a substrate with multiple subpixel areas, where a first common layer and a second common layer are formed using specific mask processes to ensure uniform thickness across subpixel areas within a pixel, reducing the need for large and complex patterning masks and aligning them precisely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask processes are used to form common layers on pixel areas, then the common layers can be formed on the substrate, but the thickness of common layers varies across subpixel areas leading to white angular dependency
Solution Approach 1:
The substrate is divided into pixel areas and connection areas, and the mask process is segmented into multiple steps (first mask process for initial formation, second mask process for thickness uniformity). This segmentation allows precise control of common layer thickness in different regions, solving the WAD problem while managing process complexity through systematic division of the manufacturing steps.
Solution Approach 2:
The first common layer is formed in advance on pixel areas before forming the emission layer, and its thickness is pre-controlled through the two-stage mask process. This preliminary action ensures that the common layer serves as a uniform base for subsequent layers, preventing thickness variations that would cause white angular dependency.
2Ease of manufacture
If the first common layer is formed on all pixel areas using a single mask process, then the process is simpler, but the mask becomes large and complex making alignment difficult
Solution Approach 1:
The mask process is divided into a first mask process and a second mask process. The first mask forms the common layer on pixel areas, while the second mask refines the thickness uniformity. This segmentation creates smaller, more manageable masks that are easier to align precisely, solving both the simplicity and precision requirements.
Solution Approach 2:
The first mask process forms the common layer on pixel areas, and the second mask process applies additional material only where needed to achieve uniform thickness. This partial action approach uses multiple smaller masks rather than one large mask, improving alignment precision while maintaining manufacturing feasibility.
3Productivity
If common layers are formed without precise thickness control, then the manufacturing process is faster, but white angular dependency occurs due to thickness variations
Solution Approach 1:
The first common layer is formed in advance with controlled thickness through the two-stage mask process before subsequent layers are deposited. This preliminary thickness control prevents the need for rework or adjustment later, maintaining manufacturing speed while ensuring uniform thickness to eliminate white angular dependency.
Solution Approach 2:
The patent replaces mechanical thickness control methods with a chemically precise mask-based deposition process. The two-stage mask process provides accurate thickness control through controlled material deposition, achieving both speed and precision by using chemical vapor deposition or similar processes that offer better control than mechanical methods.
Data Source
AI summary
Provided is a method of manufacturing an organic light-emitting display apparatus which may reduce white angular dependency (WAD). The method includes forming a common layer on each of subpixel areas at the same time without discretion within one pixel area, the common layer not being formed on connection areas between pixel areas.