OLED Data Driver Feedback Loop for Brightness Stability
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Solution Overview
Problem
Organic light emitting diode (OLED) displays face issues with brightness reduction due to increased threshold voltage caused by deterioration or high temperature, which affects the driving voltage and overall performance.
Innovation Solution
The OLED display device incorporates a feedback mechanism with a data driver that compensates for the driving voltage of each pixel using feedback voltages, adjusting the data voltage levels through a differential amplification process to maintain optimal brightness, employing a combination of PMOS and NMOS transistors for switching and amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OLED displays operate under high temperature or prolonged use conditions, then the threshold voltage increases due to deterioration, but the brightness reduces and performance degrades
Solution Approach 1:
The patent implements a feedback mechanism where the driving voltage of each pixel is fed back to the data driver through feedback lines. The data driver receives this feedback voltage and uses it to adjust subsequent data voltages, creating a closed-loop control system that automatically compensates for threshold voltage shifts caused by deterioration or high temperature, thereby maintaining stable brightness and performance
Solution Approach 2:
The patent dynamically adjusts the data voltage parameter based on feedback voltages. By changing the voltage level parameter in response to detected threshold voltage shifts, the system compensates for performance degradation and maintains consistent display quality under varying operating conditions
2Illumination intensity
If the threshold voltage increases due to deterioration, then the driving voltage requirement changes, but the data driver cannot maintain optimal brightness without compensation
Solution Approach 1:
The data driver incorporates a feedback mechanism that receives the actual driving voltage from each pixel through feedback lines. This feedback voltage information is used to dynamically adjust subsequent data voltages, enabling the driver to adapt to threshold voltage changes and maintain optimal brightness without manual intervention
Solution Approach 2:
The patent transforms the static data driving system into a dynamic one by implementing real-time voltage adjustment. The data driver continuously adapts its output voltage based on feedback information, making the system flexible and responsive to changing pixel characteristics over time
Data Source
AI summary
An organic light emitting diode display device and a driving method are provided. The organic light emitting diode display device comprises a data driver that generates a plurality of reference data voltages that have a level proportional to a gray scale level of a digital data supplied from the timing controller. The data driver supplies the data voltages to the plurality of data lines and compensates for the data voltages in accordance with a magnitude of the feedback voltages from the plurality of pixels fed back through the plurality of feedback lines under control of the timing controller.