TFT Module Current Sensing for Wire Breakage Detection
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Solution Overview
Problem
The manufacturing process of TFT modules often results in defects such as wire breakage and short circuits, which are difficult to detect, especially in large display devices and scanned antennas, where visual inspection is challenging due to non-transparent electrodes and complex layouts.
Innovation Solution
Incorporating current sensing circuits and feedback lines in the TFT module, connected to both gate and source bus lines, allows for the detection of wire breakage and short circuits by sensing electric currents, enabling easy identification and repair of defects without visual inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection is used to detect defects in TFT modules, then defect detection is possible for small devices, but defect detection becomes difficult for large display devices and scanned antennas due to non-transparent electrodes and complex layouts
Solution Approach 1:
The patent replaces visual inspection (mechanical/optical system) with electrical measurement using current sensing circuits. By monitoring current flow through feedback lines connected to bus lines, the system detects wire breakage and short circuits electrically rather than visually, solving the problem of detecting defects in large devices with non-transparent electrodes
Solution Approach 2:
The patent introduces feedback lines as intermediary elements that connect current sensing circuits to bus lines. These feedback lines serve as mediators that carry current information from the bus lines to the sensing circuits, enabling indirect detection of defects without requiring direct visual access to the electrodes
2Reliability
If current sensing circuits and feedback lines are added to detect wire breakage and short circuits, then defect detection capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the defect detection function into separate current sensing circuits that are distributed around the peripheral portion of the TFT module. Each sensing circuit monitors specific bus lines independently, allowing modular addition of detection capabilities without overwhelming complexity in the central pixel regions
Solution Approach 2:
The patent moves the current sensing circuits from the pixel regions to the peripheral portion of the TFT module, utilizing the spatial dimension around the pixel array. This placement strategy adds detection functionality without interfering with the pixel structure and minimizes impact on device complexity
3Reliability
If inspection is performed on all bus lines, then comprehensive defect detection is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent implements partial inspection by placing current sensing circuits only in the peripheral portion of the TFT module rather than distributing them throughout the entire device. This approach detects defects in the bus lines that pass through the peripheral region, providing sufficient reliability while maintaining manufacturing efficiency
Data Source
AI summary
A TFT module includes TFTs; gate bus lines; a plurality of source bus lines; unit electrodes connected with the source bus lines via the TFTs; a gate driver configured to supply a scan signal from a first end of the gate bus lines and a source driver configured to supply a data signal from a first end of the source bus lines, the gate driver and the source driver being provided in a second region lying around a first region in which the unit electrodes are provided; current sensing circuits provided in the second region; and feedback lines. Each of the feedback lines is connected with a corresponding current sensing circuit and with a second end of a corresponding source bus line or gate bus line, the second end being opposite to the first end.