Organic Light Emitting Display Device With Sensing Transistor Defect Detection
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Solution Overview
Problem
Conventional organic light emitting display devices face challenges in detecting and addressing growing defects, such as shorts between electrodes, which can lead to errors during image display and external compensation, due to their fragile structure and inability to detect small substances or gradually developing defects during manufacturing.
Innovation Solution
The implementation of a driving method that includes a sensing transistor to detect shorts between electrodes by using a sensing signal, allowing for the initialization, programming, charging, and sensing of voltages in a sensing line to identify and compensate for defects, thereby improving defect detection and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional manufacturing process is used, then production efficiency is maintained, but growing defects cannot be detected leading to display errors
Solution Approach 1:
The patent divides the pixel circuit into multiple functional components including a sensing transistor separate from the driving transistor. This segmentation allows the sensing transistor to specifically detect growing defects between electrodes without interfering with the normal driving function, thereby improving defect detection capability while maintaining manageable circuit complexity through modular design
Solution Approach 2:
The patent introduces a sensing transistor as an intermediary element between the driving transistor and the external circuit. This sensing transistor acts as a mediator that detects voltage changes caused by growing defects (such as shorts between electrodes) without disrupting the normal operation of the driving transistor, enabling reliable defect detection while preserving the simplicity of the overall circuit structure
2Measurement precision
If the sensing transistor is added to detect shorts, then defect detection precision is improved, but the circuit complexity increases
Solution Approach 1:
The sensing transistor is designed to serve multiple functions: it detects growing defects between electrodes, provides voltage sensing capability, and integrates with the existing pixel circuit structure. By making the sensing transistor multi-functional, the patent achieves high short detection precision without requiring additional separate components, thereby limiting the increase in circuit complexity
Solution Approach 2:
The patent merges the sensing function with the existing pixel circuit by integrating the sensing transistor into the pixel structure. The sensing transistor shares the pixel area and circuit nodes with other components, combining defect detection functionality with the display circuit rather than adding completely separate detection hardware, thus improving measurement precision while controlling device complexity
3Reliability
If growing defects are not detected, then device simplicity is maintained, but display quality deteriorates due to errors
Solution Approach 1:
The patent implements preliminary defect detection by incorporating the sensing transistor that can detect growing defects during the manufacturing process before the display device is fully assembled and shipped. This preliminary detection action allows defects to be identified early, preventing display quality deterioration, while the sensing transistor integrates seamlessly with existing manufacturing processes
Solution Approach 2:
The sensing transistor provides feedback information about the electrical state of the pixel circuit, including presence of growing defects such as shorts between electrodes. This feedback mechanism enables real-time monitoring of pixel health during manufacturing and operation, improving display quality through early defect detection without significantly complicating the manufacturing process
Data Source
AI summary
An organic light emitting display device includes a display panel, a data driver, and a scan driver. The display panel includes sub-pixels. The data driver supplies a data signal to the sub-pixels. The scan driver supplies a scan signal for controlling a switching transistor of each sub-pixel, and a sensing signal for controlling a sensing transistor of each sub-pixel. The sensing transistor has a turn-on time for detecting whether a short has occurred between at least two electrodes of a switching transistor in response to a sensing signal.