OLED Defect Detection via Transistor Transition Region Operation
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Solution Overview
Problem
Organic light-emitting display devices suffer from dark spot defects due to impurities and outgassing, which degrade over time and are difficult to detect immediately after production.
Innovation Solution
A method and device that operate the driving transistor in a transition region to enhance the visibility of luminance differences, allowing for effective detection of dark spot defects by applying specific voltages and analyzing image data for uniformity and gray deviation indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driving transistor operates in the saturation region (normal mode), then the display device operates stably with normal driving current, but dark spot defects caused by impurities and outgassing cannot be effectively detected
Solution Approach 1:
The patent applies the Dynamics principle by enabling the driving transistor to dynamically switch between saturation region operation (normal mode) and transition region operation (defect determination mode). This dynamic operation mode switching allows the system to maintain stable display performance during normal operation while enabling effective defect detection when needed, resolving the contradiction between operational stability and defect detectability
Solution Approach 2:
The patent applies the Parameter changes principle by changing the operating parameters of the driving transistor, specifically adjusting the potential difference between source and drain to move the transistor from saturation region to transition region operation. This parameter change enhances the sensitivity to luminance differences, making dark spot defects detectable while maintaining the ability to operate stably in normal mode
2Difficulty of detecting and measuring
If the driving transistor operates in the transition region to enhance defect detection, then dark spot defects become visible, but normal display operation is disrupted
Solution Approach 1:
The system dynamically switches between normal mode (saturation region) and defect determination mode (transition region) based on operational requirements. During normal display operation, the transistor operates in saturation region for stability. For defect detection, it temporarily operates in transition region, thus resolving the contradiction between detection capability and normal operation
3Ease of operation
If standard operating voltages are applied, then the display device operates normally, but luminance differences between normal and degraded pixels are not sufficiently highlighted
Solution Approach 1:
The patent applies Parameter changes by modifying the voltage parameters applied to the driving transistor during defect determination mode. By adjusting the potential difference between source and drain to operate in the transition region, the system enhances the luminance difference between normal and degraded pixels, improving measurement precision while maintaining ease of operation through controlled parameter adjustment
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
Enables early detection of dark spot defects by highlighting luminance differences between normal and degraded pixels, ensuring efficient identification and addressing the issue before significant degradation occurs.
Implementation Method 1
an organic light-emitting diode which emits light based on the driving current
Data Source
AI summary
A method of detecting a defect in an organic light-emitting display device includes: preparing an organic light-emitting display device including an organic light-emitting display panel which includes a plurality of pixels, where each of the pixels includes a driving transistor which operates in a saturation region or a transition region based on a potential difference between a source and a drain thereof and outputs a driving current, and an organic light-emitting diode which emits light based on the driving current; providing a plurality of voltages to the organic light-emitting display panel to operate the driving transistor in the transition region, and determining whether the organic light-emitting display device is defective based on an image, which is displayed on the organic light-emitting display panel based on data applied thereto.