Mask Position Inspection Patterns for OLED Pixel Alignment
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Solution Overview
Problem
Existing thin film deposition methods for organic light-emitting display devices face challenges in accurately positioning masks to form precise pixel patterns, leading to potential misalignment and reduced display quality.
Innovation Solution
A method and mask design that includes shifting and aligning masks with determined pitches to form thin film layers of different colors, incorporating inspection patterns to measure and correct mask position accuracy, ensuring precise pixel positioning and overlapping conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If masks are used to form thin film pixel patterns through vapor deposition, then thin film patterns can be formed on substrates, but mask position accuracy is difficult to control leading to misalignment
Solution Approach 1:
The patent applies preliminary action by forming inspection patterns (such as reference marks or alignment features) together with the pixel patterns on the substrate before the actual mask deposition process. These pre-formed inspection patterns serve as reference points that enable subsequent measurement and correction of mask positioning accuracy, allowing the system to detect and compensate for positioning errors that would otherwise go unnoticed until after deposition.
Solution Approach 2:
The patent implements feedback by using the formed inspection patterns to measure actual mask positions and comparing them against intended positions. This measurement information feeds back into the deposition process, enabling real-time or iterative adjustment of mask positioning to achieve the required pixel pattern alignment accuracy, thereby closing the control loop for position precision.
2Adaptability or versatility
If masks are shifted and aligned to form multiple color thin film layers, then pixel patterns of different colors can be formed, but misalignment errors accumulate reducing display quality
Solution Approach 1:
The patent applies preliminary action by pre-forming inspection patterns that span across multiple color deposition regions on the substrate. These inspection patterns are created before sequential mask shifts and depositions, serving as permanent reference markers that enable consistent position measurement and alignment correction across all color layers, preventing error accumulation during multi-color pattern formation.
Solution Approach 2:
The patent implements feedback by continuously measuring mask positions relative to the pre-formed inspection patterns during each color deposition step. This feedback mechanism allows the system to detect and correct alignment deviations after each mask shift, ensuring that multi-color pixel patterns maintain precise registration and preventing cumulative misalignment errors that would degrade display quality.
3Measurement precision
If inspection patterns are incorporated into the mask design, then mask position accuracy can be measured and corrected, but mask complexity increases
Solution Approach 1:
The patent applies segmentation by separating the mask structure into functional regions: pixel pattern formation areas and inspection pattern areas. The inspection patterns are positioned in dedicated regions that do not interfere with the primary pixel deposition function. This spatial segmentation allows the mask to perform both deposition and self-measurement functions without compromising pixel pattern quality or requiring complex integrated structures.
Solution Approach 2:
The patent uses inspection patterns as intermediary elements that mediate between the mask positioning system and the measurement system. These intermediary patterns serve as reference markers that translate physical mask positions into measurable quantities without requiring direct measurement of the mask itself, thereby simplifying the overall measurement and control architecture while maintaining high positioning accuracy.
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
This approach enhances the accuracy of thin film deposition, reduces misalignment errors, and improves the quality of organic light-emitting display devices by allowing for precise measurement and correction of mask positions during the deposition process.
Implementation Method 1
Vapor deposition typically involves generating vapor from a deposition source and allowing the vapor to adhere to a substrate surface
Data Source
AI summary
A method for pixel patterning and pixel position inspection of an organic light-emitting display device includes: forming, on a substrate using a first mask, a thin film layer of a first color corresponding to a first pixel pattern and a first pixel positioning pattern for inspecting a position of a first pixel; shifting, by a determined pitch, the first mask from a position associated with forming the thin film layer of the first color; aligning the shifted first mask with respect to the substrate; and forming, on the substrate using the shifted first mask, a thin film layer of a second color corresponding to the first pixel pattern and another first pixel positioning pattern for inspecting a position of a second pixel.