Display Substrate Alignment Key for COA LCD Manufacturing
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Solution Overview
Problem
In the manufacturing process of color filter on array (COA) type liquid crystal display (LCD) devices, the recognition rate of the key pattern by the exposure apparatus is reduced due to the low reflection ratio of the light-blocking layer, which hinders accurate alignment during the formation of the light-blocking pattern.
Innovation Solution
A display substrate with a signal line, thin-film transistor (TFT), key pattern, and light-blocking pattern is designed, where an alignment key is formed on the light-blocking pattern to enhance recognition. The alignment key can be either a reflective metal part or a groove within the light-blocking pattern, allowing the exposure apparatus to accurately detect the key pattern position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light-blocking layer is formed to cover the key pattern, then light-blocking performance is improved, but the recognition rate of the key pattern by the exposure apparatus is reduced
Solution Approach 1:
The patent divides the key pattern into two functional parts: the original key pattern on the substrate and a separate alignment key formed on the light-blocking layer. This segmentation allows the light-blocking layer to fulfill its light-blocking function while the alignment key provides a separate recognition target for the exposure apparatus, resolving the contradiction between light-blocking performance and pattern recognition capability
Solution Approach 2:
The alignment key acts as an intermediary element between the light-blocking layer and the exposure apparatus. It is formed on the light-blocking layer using a reflective material that serves as a mediator to enable optical detection by the exposure apparatus without compromising the light-blocking function of the underlying layer
2Object-affected harmful factors
If the light-blocking layer has low reflection ratio, then light-blocking effectiveness is improved, but the exposure apparatus cannot accurately detect the key pattern position
Solution Approach 1:
The patent applies local quality by creating a specific region (alignment key) on the light-blocking layer with different optical properties (high reflectivity) compared to the rest of the light-blocking layer. This localized change in quality allows the exposure apparatus to detect the alignment key position accurately while the rest of the light-blocking layer maintains its light-blocking effectiveness
Solution Approach 2:
The patent utilizes optical property changes by forming the alignment key with a reflective material that has different light interaction characteristics compared to the light-blocking layer. This creates a detectable optical contrast that enables the exposure apparatus to identify the alignment key position without affecting the overall light-blocking performance
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 enhanced recognition rate of the key pattern improves the accuracy of the light-blocking pattern formation, ensuring precise alignment and enhancing the overall manufacturing efficiency of the display substrate.
Implementation Method 1
The alignment metal part may have reflective properties, e.g., may be configured to reflect light
Data Source
AI summary
A display substrate includes a signal line, a thin-film transistor (“TFT”), a key pattern, a light-blocking pattern, a color filter, a pixel electrode and an alignment key. The signal line and the key pattern are formed on a substrate. The TFT is electrically connected to the signal line. The light-blocking pattern is formed on the substrate and covers the signal line, the TFT and the key pattern. The color filter is formed in a unit pixel area of the substrate. The pixel electrode is formed on the color filter and is electrically connected to the TFT. The alignment key is formed on the light-blocking pattern, and a position of the alignment key on the substrate corresponds to a position of the key pattern on the substrate.