Pixel Driving Circuit Storage Capacitor Detection via Light Emission
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Solution Overview
Problem
In OLED display devices, the poor flatness of the active and gate layers in the array substrate can lead to abnormal storage capacitors, making it difficult to detect capacitor breakdown using traditional methods like microscopes, as the film layers limit visibility of capacitor issues.
Innovation Solution
A capacitor detection method that involves sequentially inputting measurement voltages of different values to a pixel driving circuit and detecting the light emitting state of a light emitting device to determine whether the storage capacitor is normal or abnormal, using a circuit comprising a reset sub-circuit, data writing sub-circuit, compensation sub-circuit, and light emitting control sub-circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a microscope is used to detect storage capacitor abnormalities, then visual inspection of capacitor structure is possible, but capacitor breakdown cannot be observed due to film layer limitations
Solution Approach 1:
The patent introduces a light emitting device as an intermediary indicator to indirectly detect capacitor abnormalities. Instead of directly observing the capacitor through the opaque film layers, the system uses the light emitting device's response to voltage changes as a mediator that reveals capacitor status. When measurement voltages are applied, the light emitting device's emission state changes based on whether the capacitor is functioning normally or has broken down, making the invisible capacitor defects visible through optical signals.
2Device complexity
If traditional visual inspection methods are used, then equipment simplicity is maintained, but detection accuracy is insufficient due to inability to observe capacitor breakdown
Solution Approach 1:
The patent replaces the mechanical/optical inspection system (microscope) with an electrical measurement system. Instead of physically examining the capacitor structure through optical means, the system applies electrical measurement voltages and detects the electrical response through the light emitting device. This substitution of electrical measurement for mechanical/optical inspection enables accurate detection of capacitor breakdown while maintaining operational simplicity.
3Measurement precision
If measurement voltages are applied to detect capacitor status, then electrical defect detection is enabled, but additional detection time is required
Solution Approach 1:
The patent employs periodic application of measurement voltages at different levels to efficiently detect capacitor defects. By sequentially applying multiple voltage levels and observing the light emitting device's response at each level, the system can identify capacitor abnormalities through the characteristic changes in emission state. This periodic voltage application allows comprehensive electrical characterization of the capacitor while maintaining a streamlined detection process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for quick detection of electrical defects in storage capacitors by determining the light emitting state under varying measurement voltages, improving the efficiency of capacitor detection without altering the operation timing of the pixel driving circuit.
Implementation Method 1
detecting a light emitting state of a light emitting device in the pixel driving circuit under each measurement voltage
Data Source
AI summary
A set of measurement voltages having different voltage values are subsequently inputted to a measurement voltage input terminal of the pixel driving circuit, a light emitting state of a light emitting device under each measurement voltage is detected, and it is determined whether a storage capacitor in the pixel driving circuit is normal based on the light emitting state of the light emitting device.