Active Matrix Substrate Inspection Layout for Signal Line Reliability
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Solution Overview
Problem
High-resolution and narrow picture-frame liquid crystal panels for smartphones and tablets face issues with disconnection, leakage current, and luminance unevenness during inspection due to the formation of numerous signal lines on the active matrix substrate without specialized devices.
Innovation Solution
The active matrix substrate is designed with lead-out lines connected to data lines and signal lines, where the signal lines are divided on either side of a control line, and switching elements control the conduction state between lead-out and signal lines, allowing for a wider layout without thinning the wiring width or reducing the pitch, thus minimizing disconnection and leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lot of signal lines for inspection are formed on the active matrix substrate without any special device, then the inspection of the liquid crystal panel can be conducted, but a disconnection or a leakage current occurs easily and a luminance unevenness occurs in the screen for inspection
Solution Approach 1:
The signal lines are divided into first signal lines arranged on one side of the control line and second signal lines arranged on the other side. This segmentation allows adjacent lead-out lines to be connected to different signal lines via switching elements, increasing spacing between connected lines and reducing the risk of disconnection and leakage current while maintaining inspection capability
Solution Approach 2:
Switching elements are introduced to dynamically control the conduction state between lead-out lines and signal lines based on inspection requirements. This dynamic control allows the system to maintain reliable connections only when needed while reducing the risk of permanent disconnection or leakage current in the wiring structure
2Quantity of substance
If the wiring width is thinned or the pitch is reduced to accommodate more signal lines, then the number of signal lines can be increased, but the disconnection and leakage current occur more easily
Solution Approach 1:
The signal lines are arranged in two different spatial arrangements (first signal lines on one side of the control line, second signal lines on the other side), effectively utilizing the two-dimensional layout space. This dimensional arrangement allows more signal lines to be accommodated without reducing individual line width or pitch, thereby maintaining wiring reliability while increasing the number of signal lines
Data Source
AI summary
Inside of a region for inspection set outside a display region of an active matrix substrate, lead-out lines (27a to 27f) connected to data lines pass through in a column direction, and a control line for inspection (31) and six signal lines for inspection (32a to 32f) extend in a row direction. TFTs for inspection (51a to 51f) control a conduction state between the lead-out line and the corresponding signal line for inspection in accordance with a signal on the control line for inspection. Inside the region for inspection, three of the six signal lines for inspection are arranged on one side of the control line for inspection, and the remaining three are arranged on other side of the control line for inspection. One of the two adjacent lead-out lines is connected to one of the former signal lines for inspection via the TFT for inspection (51a, 51c, 51e), and the other is connected to one of the latter signal lines for inspection via the TFT for inspection (51b, 51d, 51f). This suppresses a disconnection, a leakage current, and a luminance unevenness of a screen for inspection.