OLED Evaporation Mask Sheet Rib Shielding Design
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Solution Overview
Problem
In the manufacturing of OLED display devices, existing mask technologies face challenges with accuracy and special-shaped shielding, leading to evaporation defects due to mask warping and gaps between the mask and the substrate, which result in shadow regions and defects during the evaporation process.
Innovation Solution
A mask sheet with intersecting first and second ribs forming opening regions, including a third rib with sub-ribs and a spacer to shield overlapping exposure regions, and a magnetic plate to attract the mask sheet and mask for precise alignment, reducing warping and gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a mask sheet is stretched under external force to reduce sagging, then the mask sheet's flatness is improved, but the mask sheet may warp during evaporation due to stress concentration, leading to gaps between the mask and substrate
Solution Approach 1:
The mask sheet is divided into multiple regions by introducing first ribs and second ribs that extend in different directions. These ribs segment the mask sheet into multiple smaller areas, preventing stress concentration and warping during the evaporation process. The segmentation allows the mask sheet to maintain flatness without requiring excessive stretching.
Solution Approach 2:
Different regions of the mask sheet are designed with different rib structures to address local requirements. For example, the third rib with sub-ribs and spacers is specifically designed for the boundary region between first and second exposure regions, while other regions have standard rib patterns. This local differentiation optimizes both flatness and warping resistance where needed.
2Manufacturing precision
If the mask sheet is stretched tightly to eliminate gaps, then contact with substrate is improved, but evaporation defects occur due to mask warping and stress concentration
Solution Approach 1:
The mask sheet is segmented into multiple regions by first ribs and second ribs, creating a grid-like structure that prevents stress concentration during stretching. This segmentation allows the mask to be stretched tightly for good substrate contact without causing warping-induced evaporation defects.
Solution Approach 2:
The rib structures are pre-formed on the mask sheet before the evaporation process. These ribs preliminarily establish the stress distribution pattern that will prevent warping during subsequent stretching and evaporation operations, eliminating the need for excessive stretching that would cause defects.
3Device complexity
If a single exposure region is used for evaporation, then the process is simplified, but special-shaped display patterns and narrow borders cannot be achieved
Solution Approach 1:
The mask sheet is divided into multiple exposure regions (first exposure region, second exposure region, etc.) separated by ribs. This segmentation allows different areas to be evaporated separately, enabling the formation of special-shaped display patterns and narrow borders that cannot be achieved with a single exposure region.
Solution Approach 2:
Different exposure regions on the mask sheet are designed with different patterns and characteristics to meet specific display requirements. For example, some regions are optimized for narrow borders while others are optimized for special shapes, allowing the same mask sheet to handle diverse display patterns through localized design.
4Ease of manufacture
If the third rib has the same width as other ribs, then manufacturing is simplified, but overlapping exposure regions cannot be properly shielded
Solution Approach 1:
The third rib, located at the boundary between first and second exposure regions, is designed with a greater width than standard ribs. This local differentiation ensures proper shielding of overlapping exposure regions during evaporation, preventing material deposition in areas that should remain protected.
Solution Approach 2:
Instead of making all ribs the same width for simplicity, the invention inverts the approach by making the third rib wider than other ribs. This inverted design prioritizes shielding accuracy for overlapping regions over manufacturing uniformity, ensuring that critical boundary regions are properly protected during evaporation.
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 solution effectively reduces evaporation defects by ensuring precise alignment and contact between the mask and substrate, improving the accuracy of film pattern formation and reducing shadow regions.
Implementation Method 1
a magnetic plate to attract the mask sheet and mask for precise alignment
Data Source
AI summary
A mask sheet for evaporation on a substrate is provided, and the mask sheet includes: a plurality of first ribs extending in a first direction; and a plurality of second ribs extending in a second direction intersecting the first direction, the mask sheet includes a first region for an evaporation of a first exposure region of the substrate and a second region for an evaporation of a second exposure region of the substrate, a third rib is provided at a boundary of the first region and the second region so as to shield an overlapping exposure region between the first exposure region and the second exposure region, the third rib includes a first sub-rib, a second sub-rib, and a spacer for separating the first sub-rib and the second sub-rib, and the third rib has a width greater than that of the first rib.