TFT-LCD Array Substrate Common Electrode Testing via Segmented Test Area
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Solution Overview
Problem
Conventional TFT-LCD array substrates lack the ability to individually adjust or test common electrode lines, limiting the flexibility and efficiency of testing processes.
Innovation Solution
Incorporating a test area with a second TFT and specific via holes to allow individual testing of common electrode lines by connecting testing electrodes with the common electrode lines, enabling the application of different test voltages to specific lines while maintaining normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common electrode lines are connected together to provide storage capacitance, then the storage function is improved, but the ability to individually test or adjust each common electrode line is lost
Solution Approach 1:
The patent segments the common electrode line system by introducing separate test area common electrode lines that are electrically isolated from the display area common electrode lines through insulated spacers. This allows individual testing and adjustment of each common electrode line while maintaining the overall storage capacitance function through the display area connections.
Solution Approach 2:
The patent introduces insulated spacers as intermediary elements between the test area common electrode lines and display area common electrode lines. These spacers provide electrical isolation while maintaining physical proximity, enabling independent control and testing of common electrode lines without affecting the storage capacitance function.
2Adaptability or versatility
If a test area is added with separate common electrode lines and second TFTs, then individual testing capability is improved, but the device structure becomes more complex
Solution Approach 1:
The patent merges the test area common electrode lines with the display area common electrode lines in terms of routing and layout, using the same general path but providing electrical isolation through insulated spacers. This reduces structural complexity by avoiding completely separate line layouts while still enabling individual testing capability.
Solution Approach 2:
The common electrode lines serve dual functions: they provide storage capacitance in the display area and enable individual testing in the test area. The insulated spacers allow the same physical line structure to fulfill both purposes simultaneously, reducing the need for entirely separate testing infrastructure.
3Adaptability or versatility
If insulated spacers are introduced to isolate test area common electrode lines, then individual testing is enabled, but the manufacturing process becomes more complex
Solution Approach 1:
The insulated spacers are formed as part of the passivation layer structure during the standard manufacturing process sequence. By integrating the spacer formation into the existing passivation layer deposition and patterning steps, the patent avoids adding separate manufacturing operations, thereby maintaining ease of manufacture while enabling individual testing capability.
Data Source
AI summary
A thin film transistor liquid crystal display (TFT-LCD) array substrate comprises a display area comprising a gate line, a data line and a common electrode line, a pixel electrode and a first thin film transistor (TFT) formed in each sub-pixel area defined by the gate line and data line which are crossed with each other; and a test area located at the peripheral of the display area and comprising a first test one, a second test line, a testing electrode and a second TFT, and the common electrode line extending to the test area from the display area, wherein a part of the second test line constitutes a gate electrode of the second TFT; the source electrode of the second TFT is electrically connected with the first test line; a drain of the second TFT is electrically connected with the common electrode fine; and the common electrode line is connected with the testing electrode.