OLED Burn-In Compensation via Parasitic Capacitor Sensing
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Solution Overview
Problem
Organic light emitting diodes (OLEDs) in flat panel displays experience luminous efficiency degradation over time, leading to burn-in issues due to differences in luminance and color, requiring accurate measurement of energy compensation to maintain display quality.
Innovation Solution
A device and method utilizing a sensing line with a parasitic capacitor to measure the charged voltage, allowing for energy compensation by charging the capacitor and sensing the voltage, which reduces the number of scan lines needed and enables measurement using an external current source, simplifying the configuration and improving pixel luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate scan lines are used for sensing and driving OLEDs, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines the sensing line and driving line into a single integrated scan line structure. The sensing line includes a parasitic capacitor that is charged through the OLED during the driving phase, allowing energy measurement to be performed using the same physical infrastructure as the driving operation, thereby eliminating the need for completely separate scan lines while maintaining measurement capability
Solution Approach 2:
The scan line is designed to serve multiple functions: it acts as both the driving line that supplies current to the OLED and the sensing line that measures the energy consumed by the OLED. The parasitic capacitor on the sensing line is utilized as a measurement element that accumulates charge during the driving cycle, enabling dual functionality from a single line structure
2Device complexity
If parasitic capacitor of sensing line is used for measurement, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The parasitic capacitor inherent in the sensing line is utilized as the measurement element without requiring additional external capacitors or measurement devices. The sensing line's own parasitic properties are harnessed to perform the energy measurement function, eliminating the need for separate measurement components and simplifying the overall device structure
Solution Approach 2:
The measurement system uses the charged voltage of the parasitic capacitor as feedback information about the OLED's energy consumption. By measuring the voltage across the parasitic capacitor after the driving cycle, the system obtains precise measurement data about the energy consumed by the OLED, compensating for any limitations of using the parasitic capacitor
3Illumination intensity
If OLED is kept on during measurement, then pixel luminance is maintained, but measurement accuracy deteriorates due to active light emission
Solution Approach 1:
The measurement is performed periodically during the driving cycle by utilizing the charge accumulated in the parasitic capacitor during the OLED's active emission period. The system measures the voltage across the capacitor after the driving pulse, capturing energy consumption data during the luminance emission phase without requiring the OLED to remain continuously on, thus maintaining pixel luminance while achieving accurate measurement
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 approach allows for effective energy compensation and reduced scan line configuration, enhancing pixel luminance and enabling fast sensing regardless of panel load, while measuring deviations in capacitances and current sources, thus addressing burn-in issues efficiently.
Implementation Method 1
a sensing line formed with a parasitic capacitor; a current source configured to provide current to the sensing line; and a sensing circuit configured to sense a charged voltage of the parasitic capacitor
Data Source
AI summary
Disclosed are a device and method for measuring an organic light emitting diode, which measures an amount of energy for compensating for a burn-in of an organic light emitting diode, by sensing a charged voltage of a sensing line connected to the organic light emitting diode. The device for measuring an organic light emitting diode includes an external current source, and is configured to measure an amount of energy for compensating for a burn-in, by sensing a charged voltage of a parasitic capacitor of a sensing line.