OLED Display Panel Defect Detection via Transistor Electrical Signal Analysis
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Solution Overview
Problem
Display panels with organic light-emitting diodes (OLEDs) face issues with brightness uniformity due to varying threshold voltages and mobility of driving transistors, leading to display defects like spots, which require efficient detection methods to identify defective pixel units quickly.
Innovation Solution
A detection method and device that monitor the electrical signal at the first electrode of each pixel unit's driving transistor when the panel reaches target brightness, calculating differences from standard values to determine defective units and their defect types, using a combination of calculators, comparators, and image processing to identify and count defective pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual image analysis is used to detect defective pixel units, then detection accuracy can be maintained, but detection efficiency and production yield deteriorate due to time-consuming processes
Solution Approach 1:
The patent replaces manual image analysis (mechanical/human operation) with an automated detection system that measures electrical signals at the first electrode of driving transistors. This substitution of mechanical inspection with electrical measurement dramatically improves detection efficiency while maintaining accuracy, directly resolving the contradiction between productivity and device complexity.
2Measurement precision
If electrical signal detection is implemented for each pixel unit, then detection accuracy improves, but device complexity increases due to additional detectors and circuitry
Solution Approach 1:
The patent integrates the detection function into the existing pixel circuit structure by utilizing the first electrode of the driving transistor as the measurement point. This multi-functional approach allows the same circuit elements to serve both their original driving function and the new detection function, thereby improving measurement precision without significantly increasing device complexity.
3Stability of the object's composition
If threshold voltage variations are not compensated, then device simplicity is maintained, but brightness uniformity deteriorates leading to display defects
Solution Approach 1:
The patent implements threshold voltage compensation by detecting and recording the threshold voltage of each driving transistor before the display panel is put into service. This preliminary measurement and compensation action ensures brightness uniformity across all pixel units, preventing display defects like spots. The compensation data is stored and used to adjust driving signals, maintaining stability without requiring complex real-time adjustment mechanisms during manufacturing.
Data Source
AI summary
A detection method and a detection device of a display pane are provided. The detection method includes: detecting an actual value of an electric signal at a first electrode of a driving transistor in each of pixel units when the display panel reaches target brightness, the electric signal including a current signal and/or a voltage signal; and determining according to the actual value of the electrical signal corresponding to each of the pixel units, whether each of the pixel units is defective. The present disclosure may help an operator determine if each of the pixel units is defective quickly.