LCD Substrate Dummy Patterns for Orientation Film Uniformity
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Solution Overview
Problem
In liquid crystal display (LCD) devices, the non-uniform thickness of orientation films during the printing process leads to a 'mount' effect, causing deterioration in the subsequent rubbing step and resulting in an enlarged bezel region due to zigzag lines at the starting and ending portions of the orientation film.
Innovation Solution
The introduction of dummy patterns in the non-display areas of the substrates, with varying lengths and patterns, helps to adjust the thickness and distribution of the orientation film, preventing the 'mount' effect and ensuring a uniform film thickness, thereby reducing the bezel region and improving the display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the orientation film is printed without dummy patterns, then the manufacturing process is simple, but the orientation film thickness becomes non-uniform with mount effects at starting and ending portions
Solution Approach 1:
Dummy patterns are formed in the non-display area before printing the orientation film. These dummy patterns serve as preliminary structures that guide the orientation film deposition process, ensuring uniform thickness by preventing mount effects at the starting and ending portions of the printing process.
Solution Approach 2:
The dummy patterns act as intermediary structures between the substrate and the orientation film. They provide a controlled surface that mediates the orientation film deposition, ensuring uniform thickness distribution and preventing direct contact issues at the printing boundaries.
2Area of stationary object
If the orientation film is printed without dummy patterns, then the device structure is compact, but zigzag lines appear at the starting and ending portions enlarging the bezel region
Solution Approach 1:
Dummy patterns are formed in advance in the non-display area to define the printing boundaries. This preliminary action ensures that the orientation film is deposited uniformly without creating zigzag lines at the starting and ending portions, thereby preventing bezel region enlargement.
Solution Approach 2:
The dummy patterns are specifically placed in the non-display area with different lengths and patterns to address the local quality issues at the starting and ending portions of the orientation film printing process.
Data Source
AI summary
A substrate for a liquid crystal display device includes: a substrate including a display region displaying an image and a non-display region surrounding the display region; a dummy pattern in the non-display area over the substrate, the dummy pattern having a length that corresponds to a side of the display area; and an orientation film on the dummy pattern, the orientation film covering the non-display area and the whole display area.