Mask Inspection Grayscale Analysis for OLED Defect Detection
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Solution Overview
Problem
Current mask inspection methods fail to effectively detect defects in masks used for organic light emitting diode (OLED) display manufacturing, particularly in the bending of sticks that can cover openings, leading to increased defect rates during the deposition process.
Innovation Solution
A mask inspection apparatus and method that uses a camera and light source to photograph and analyze the grayscale of openings in the mask, comparing it to a reference grayscale to determine if the sticks are bent and overlapping the openings, thereby identifying defective masks before the deposition process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mask inspection methods are used, then the inspection process is simple, but the defect detection capability is insufficient, especially for bent sticks covering openings
Solution Approach 1:
The patent introduces a third dimension (Z-axis) by placing a light source beneath the mask and capturing images from above. This dimensional approach allows light to pass through openings and reflect off bent sticks, making defects visible through grayscale variations that cannot be detected by conventional single-plane inspection methods.
Solution Approach 2:
The patent uses light as an intermediary substance to detect defects. By irradiating light through the mask openings and capturing the reflected light patterns, the system converts physical defects (bent sticks) into detectable optical signals (grayscale variations) without requiring direct contact or complex mechanical scanning.
2Measurement precision
If grayscale comparison method is used to detect bent sticks, then defect detection accuracy improves, but inspection time increases
Solution Approach 1:
The patent focuses inspection efforts on specific high-risk areas by defining edge inspection areas adjacent to mask edges where bent sticks are most likely to occur. By concentrating analysis on these critical zones rather than uniformly inspecting the entire mask surface, the system achieves high detection accuracy while minimizing inspection time.
Solution Approach 2:
The patent applies different inspection criteria to different regions of the mask. Edge areas are subjected to grayscale comparison analysis for bent stick detection, while other areas may use different or simplified inspection methods. This localized approach optimizes the balance between detection accuracy and inspection efficiency.
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 reduces the defect rate in the deposition process by accurately identifying bent sticks and their impact on mask openings, ensuring higher quality OLED display manufacturing.
Implementation Method 1
irradiating light to the cell mask from under the cell mask
Implementation Method 2
a camera photographing a cell mask through which a plurality of openings is formed to obtain an image
Data Source
AI summary
A mask inspection method includes photographing a cell mask through which openings is formed to obtain an image, setting an area of the image adjacent to an edge of the cell mask as an inspection area, comparing a grayscale of the openings in the inspection area with a reference grayscale, and checking a defect of the cell mask according to a result of the comparing of the grayscale of the openings.