Alignment Mark Layout for Stable Substrate Edge Detection

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Solution Overview

Problem

Existing methods for detecting the edge of a substrate using alignment marks are inaccurate due to variations in mark positions and are influenced by luminance changes and image blurs, leading to unstable and time-consuming detection.

Innovation Solution

A substrate with alignment marks whose cutting lines coincide with the substrate's cutting lines, combined with an edge detection device that includes a mounting stand, image-taking portion, memory unit, and control unit, allowing precise edge detection by comparing images in the X, Y, and Z directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If alignment marks are used for edge detection, then edge position can be detected, but detection accuracy deteriorates due to partition tolerance variations in singulated substrates

Engineering Contradiction:

Improveedge detection accuracyVSAvoiddetection stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The alignment mark is segmented into multiple marks arranged in a specific pattern. By detecting multiple segmented marks and calculating their average position, the detection system compensates for partition tolerance variations in singulated substrates, thereby maintaining both accuracy and reliability in edge detection

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The alignment mark pattern is pre-designed with specific geometric relationships and positioning before substrate singulation. This preliminary configuration allows the detection system to accurately determine edge positions even when substrates are later separated with tolerance variations

Inventive Principle:

Principle #10Preliminary action

2Productivity

If threshold-based edge detection is used, then detection speed can be improved, but detection accuracy deteriorates due to luminance variations and image blur

Engineering Contradiction:

Improvedetection speedVSAvoidedge detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The alignment mark is pre-configured with specific geometric patterns and luminance characteristics that are optimized for correlation-based detection. This preliminary design enables the system to perform accurate edge detection through template matching without being affected by luminance variations or image blur, while maintaining fast processing speeds

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detection system uses correlation processing to compare the captured alignment mark image with a pre-stored reference pattern. This copying and comparison method allows for rapid and accurate edge detection that is insensitive to luminance variations and image quality fluctuations

Inventive Principle:

Principle #26Copying

Data Source

PatentUS20250357360A1Substrate including alignment mark and edge detection device for substrate including alignment mark

Publication Date: 2025.11.20 SHARP DISPLAY TECHNOLOGY CORP

AI summary

An active matrix substrate that is a substrate including an alignment mark includes an active matrix substrate and an alignment mark provided on part of a first surface that is a surface on one side of the active matrix substrate, and each of the active matrix substrate and the alignment mark has a cutting line, and the cutting line of the alignment mark coincides with the cutting line of the active matrix substrate in a plan view.