Active Matrix Substrate Contact Hole Design for LCD Display
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Solution Overview
Problem
Existing active matrix substrates for liquid crystal display devices with touch detection functionality suffer from display irregularities due to raised contact lines on the surface, which disrupt the uniform formation of alignment films and lead to image display issues.
Innovation Solution
The active matrix substrate design includes a counter electrode control line positioned in a lower layer relative to the organic insulating film, ensuring that the surface is flat and allowing for uniform alignment film formation, with the counter electrode control line connected to the counter electrode through a contact hole that passes through the flattening film, preventing raised areas and potential display irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact lines are provided on the outermost surface of the active matrix substrate, then the common electrodes can be connected with conductive lines for touch detection, but raised areas are formed on the surface causing non-uniform alignment film formation and display irregularities
Solution Approach 1:
The contact line is moved from the surface dimension to the cross-sectional dimension by passing through the flattening film. The control line extends from the outer surface through the flattening film to reach the counter electrode, utilizing the vertical dimension (depth) rather than remaining on the surface plane. This dimensional transition eliminates surface raised areas while maintaining electrical connectivity for touch detection.
2Ease of manufacture
If contact lines are provided on the outermost surface of the active matrix substrate, then electrical connectivity is achieved, but the surface becomes uneven leading to display irregularities
Solution Approach 1:
The electrical connection path is transitioned from a surface-level configuration to a cross-sectional configuration. The control line passes through the flattening film vertically, utilizing the depth dimension to connect the outer surface to the counter electrode. This eliminates surface irregularities that would compromise display quality while preserving electrical connectivity functionality.
3Manufacturing precision
If the counter electrode control line is positioned in a lower layer relative to the organic insulating film, then raised areas are prevented and uniform alignment film formation is enabled, but the connection structure becomes more complex
Solution Approach 1:
The control line structure is merged with the existing multilayer insulating film structure. The control line is integrated into the cross-section of the flattening film, combining the electrical connection function with the insulating film layers. This unified structure achieves surface flatness while the added complexity is confined to the internal cross-sectional arrangement rather than requiring separate surface-level components.
Data Source
AI summary
An active matrix substrate 10 includes: switching elements 120 that are connected with gate lines and data lines provided on a substrate; pixel electrodes 130 that are connected with the switching elements 120; counter electrodes 140 that overlap with the pixel electrodes 130 when viewed in a plan view; a flattening film 154; and lines 142. The flattening film 154 covers the switching elements 120, and first contact holes CH1 that pass through the flattening film 154 are formed at positions that overlap with the lines 142 when viewed in a plan view. The pixel electrodes 130 and the counter electrodes 140 are arranged so that each of the same partially covers the flattening film 154. The line 142 and the counter electrode 140 are connected with each other in the first contact hole CH1.