Deposition Mask Dummy Pattern Layout for Pixel Accuracy
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Solution Overview
Problem
Wearable devices such as HMDs and AR glasses require high-resolution displays with at least 2000 PPI, but existing deposition methods struggle with pixel position accuracy (PPA) reliability, shadow defects, and accumulation of deposition material on the mask.
Innovation Solution
A deposition mask with a substrate featuring cell patterns and irregular dummy patterns, and deposition equipment incorporating this mask, enhance PPA and reduce shadow defects and material accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition masks with uniform patterns are used, then manufacturing is simple, but pixel position accuracy reliability deteriorates
Solution Approach 1:
The patent applies local quality by creating different dummy pattern configurations in different regions of the mask. The mask includes a first dummy pattern with a first width and a second dummy pattern with a second width greater than the first width, allowing different areas to have optimized characteristics for their specific functions - improving pixel position accuracy while managing overall complexity.
Solution Approach 2:
The patent implements asymmetry by using irregular dummy patterns with varying widths rather than uniform symmetric patterns. The second dummy pattern has a greater width than the first dummy pattern, creating an asymmetric structure that improves deposition control and pixel position accuracy for high-resolution displays.
2Object-affected harmful factors
If conventional masks without irregular dummy patterns are used, then shadow defects are more severe, but the patent introduces irregular dummy patterns to reduce them
Solution Approach 1:
The patent reduces shadow defects by implementing local quality through strategically positioned dummy patterns. The first and second dummy patterns are placed in specific locations with different widths to control deposition material flow locally, preventing shadow defects in critical areas while maintaining overall mask functionality.
3Loss of substance
If conventional masks are used, then deposition material accumulates on the mask, but the patent designs irregular dummy patterns to minimize accumulation
Solution Approach 1:
The patent minimizes deposition material accumulation by using local quality principles in the dummy pattern design. The varying widths of the first and second dummy patterns create different deposition characteristics in different regions, preventing material buildup in areas where it would most affect performance.
Data Source
AI summary
A deposition mask includes a substrate with a cell pattern disposed in each of a plurality of cell openings in the substrate. The cell pattern is formed by an inorganic film and includes a mask membrane pattern with a plurality of openings. A dummy pattern surrounds the mask membrane pattern, and the width of the dummy pattern is irregular. A deposition apparatus includes the deposition mask.