Mask Plate Corner Compensation for OLED Evaporation Uniformity
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Solution Overview
Problem
The existing mask plates used in thin film evaporation for organic light-emitting display devices suffer from rounded corners due to isotropic wet etching, resulting in insufficient margins at corners, leading to darker corner pixels and non-uniform display quality.
Innovation Solution
A method and mask plate design that includes a first opening portion with linear edges intersecting at a vertex and a second opening portion protruding outward to compensate for the corner, used in conjunction with photolithography and wet etching to create a substrate pattern that increases the corner margin for uniform evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching is used to form the mask plate opening, then the manufacturing process is simple and cost-effective, but the corner regions become rounded and insufficient margin is formed
Solution Approach 1:
The patent applies preliminary action by pre-forming a protruding structure at the corner region of the mask plate opening before the etching process. This protruding structure serves as a compensation feature that anticipates the rounding effect of isotropic wet etching, ensuring that after etching, sufficient margin remains at the corner to maintain proper evaporation coverage and display quality.
2Productivity
If the mask plate corner margin is insufficient due to rounded corners, then the evaporation process is simplified, but darker pixel phenomenon occurs and display uniformity deteriorates
Solution Approach 1:
The patent applies local quality by introducing a protruding structure specifically at the corner region of the mask plate opening, while the rest of the opening maintains its standard shape. This localized modification ensures that the corner margin is sufficiently large to prevent darker pixel formation, while the overall manufacturing process remains efficient and cost-effective.
3Manufacturing precision
If a protruding structure is added to compensate for corner rounding, then corner margin is improved and display uniformity is enhanced, but the mask plate structure becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the mask plate opening into distinct regions: a main opening area and a separate protruding corner compensation structure. This segmentation allows the corner region to be independently optimized for margin compensation while the main opening maintains its simple geometry for efficient manufacturing, thus balancing precision and complexity.
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
The design enhances the corner margin, ensuring uniform evaporation and improved display quality by maintaining sufficient thickness of the function layer across the display area, reducing the darker pixel phenomenon and enhancing overall luminescence.
Implementation Method 1
The etching method comprises exposure by using a photolithography mask plate
Implementation Method 2
The etching method is wet etching
Implementation Method 3
The vapor evaporation method has the advantages of simple operation, easy control of film thickness
Data Source
AI summary
A mask plate, a method for manufacturing a mask plate, and a method for manufacturing an organic light-emitting device are disclosed. The mask plate includes a substrate and a first opening portion and a second opening portion formed on the substrate. The first opening portion includes a first edge and a second edge, an extending line of the first edge and an extending line of the second edge intersect at a first vertex to form a first corner, the second opening portion is at the first corner and protrudes outward, and an edge of the second opening portion intersects with the first edge and the second edge. The first opening portion and the second opening portion are used for evaporation on a display area of an organic light-emitting device, and the second opening portion is used to compensate for a corner of the display area during evaporation.