OLED Gate Line Breakpoint Detection via Storage Capacitor Voltage
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Solution Overview
Problem
In OLED display substrates, detecting defects in gate lines, such as breakpoints, is challenging due to voltage drops along the gate lines, which can lead to insufficient gate voltages for pixel circuits, causing display issues like dark sub-pixels.
Innovation Solution
A detection method and device for OLED display substrates that utilize a series of voltage stages to determine if a gate line has a breakpoint by comparing voltages at storage capacitors, with specific voltage levels and thresholds to determine the presence of defects, and a detection device comprising a driving circuit, detection circuit, and determination circuit to implement this method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If driving voltages are applied to both ends of the gate line simultaneously, then the voltage difference along the gate line is reduced, but detecting breakpoint defects becomes difficult due to voltage drops
Solution Approach 1:
The patent applies preliminary action by performing defect detection before the gate line is fully driven. A detection voltage is applied to one end of the gate line before normal operation, allowing the storage capacitor to charge. If a breakpoint exists, the voltage cannot be maintained. This preliminary detection step identifies defects before they affect display performance, resolving the contradiction between maintaining voltage stability and enabling defect detection.
Solution Approach 2:
The storage capacitor serves as an intermediary element in the detection mechanism. It temporarily stores the detection voltage applied to the gate line, allowing the system to measure whether the voltage is maintained. This intermediary component enables defect detection without requiring continuous driving voltages at both ends, thus allowing both voltage stability and defect detection to coexist.
2Length of stationary object
If the gate line is long, then the display device can be larger in size, but voltage drops along the gate line cause insufficient gate voltages for pixel circuits
Solution Approach 1:
The patent applies local quality by making different parts of the pixel circuit perform different functions. The storage capacitor is specifically designed to hold the gate voltage locally at each pixel, compensating for voltage drops along the long gate line. This local voltage storage ensures that each pixel receives sufficient gate voltage regardless of its position on the gate line, enabling large display sizes while maintaining voltage sufficiency.
Solution Approach 2:
The detection mechanism performs preliminary action by checking voltage maintenance capability before full operation. By applying a detection voltage and checking if the storage capacitor maintains it, the system identifies gate lines with breakpoints that would cause voltage insufficiency. This allows selective correction or replacement of problematic gate lines in long gate line configurations.
Data Source
AI summary
Provided are a detection method and a detection device, the detection method includes: in a first writing stage, providing an active voltage to each data line, each power supply terminal, both ends of a first gate line to-be-detected, an absolute value of the active voltage of each data line is smaller than that of the active voltage of the power supply terminal, an absolute value of the active voltage of the first gate line to-be-detected is smaller than that of the active voltage of each data line; in a first detection stage, maintaining the active voltage of the power supply terminal, providing an inactive voltage to the first gate line to-be-detected and providing an active voltage to the data line, detecting voltages at second electrodes of storage capacitors corresponding to the first gate line to-be-detected, determining whether the first gate line to-be-detected has breakpoint according to the detected voltages.