Metal Mask Aperture Structure to Reduce OLED Shadow Effect
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The traditional metal masks used in the evaporation process for OLED panel manufacturing suffer from a 'shadow effect' due to lateral erosion during manufacturing, leading to uneven or mixed color deposition on the substrate, resulting in poor evaporation quality.
Innovation Solution
A metal mask design with specific dimensions and features, including a first and second opening, through holes forming an evaporation hole, and an annular protrusion, optimized to minimize the shadow effect by controlling the horizontal and vertical distances and angles, ensuring precise particle deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a traditional mask is manufactured using double-sided etching, then the manufacturing process is simple, but lateral erosion causes breaches on the periphery leading to severe shadow effect
Solution Approach 1:
The mask structure is segmented into multiple components: a substrate layer, a first protective layer, a second protective layer, and an evaporation hole layer. The etching process is divided into multiple steps with different protective layers exposed at different stages, allowing precise control of each opening's position and size while maintaining manufacturing feasibility
Solution Approach 2:
Protective layers are applied in advance to specific regions before etching begins. The first protective layer is applied to areas that should remain intact during first etching, and the second protective layer is applied to areas that should remain intact during second etching. This preliminary protection prevents lateral erosion breaches and ensures precise opening formation
2Productivity
If the mask opening is designed to be large, then evaporation efficiency is improved, but the shadow effect becomes more severe causing color unevenness
Solution Approach 1:
Different regions of the mask are given different properties through selective protective layer application. The protective layers ensure that only specific local areas are etched to form openings, while other areas remain intact. This allows optimization of opening size for evaporation efficiency while preventing lateral erosion that would cause shadow effect and color unevenness
Solution Approach 2:
The invention changes the etching parameters by performing multiple etching steps with different protective layer configurations. This allows precise control of opening dimensions, position, and shape, achieving both adequate evaporation efficiency and minimal shadow effect by optimizing the balance between opening size and lateral erosion control
Data Source
AI summary
A metal mask has a first surface, a second surface opposite to the first surface, first and second openings provided on the first and second surfaces respectively, and first and second through holes communicating with the first and second openings respectively. The juncture of the first and second through holes further has an annular protrusion. The mask satisfies the in equations:1μm2<12×W×H<15μm2 and 30°<θ<65°,wherein W is the horizontal distance between an edge of the first opening and an imaginary connecting line passing through an edge of the second opening and an end edge of the annular protrusion, H is the vertical distance between the end edge of the annular protrusion and the first surface, and θ is the included angle between the imaginary connecting line and an imaginary extending plane of the first surface. The metal mask is effective in reducing shadow effect, thereby improving evaporation quality.