OLED Pixel Compensation for Luminance Consistency
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Solution Overview
Problem
Organic light emitting devices face issues with blurring due to discrete frame-based display methods, leading to power consumption increases and luminance deviations between pixels, as they struggle to maintain consistent luminance and accurately depict motion.
Innovation Solution
A display device and driving method that measure the threshold voltage and mobility of the driving transistor, and the degradation of the organic light emitting element, using this data to adjust the input data voltage and apply it to the pixels, thereby ensuring constant luminance and improved display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If impulse drive method is used to reduce display time, then blurring is reduced, but luminance decreases and power consumption increases
Solution Approach 1:
The patent implements a feedback mechanism by measuring the threshold voltage of the driving transistor and using this measurement to compensate and adjust the data voltage. The data driver measures the threshold voltage through the pixel circuit and feeds back this information to adjust subsequent data voltages, creating a closed-loop system that adapts to transistor characteristic variations without requiring increased power consumption
Solution Approach 2:
The patent changes the parameter being controlled from display time duration to threshold voltage compensation. Instead of adjusting the display time or luminance parameters, the system measures and compensates for the threshold voltage parameter of the driving transistor, which fundamentally addresses the root cause of luminance deviation without affecting power consumption
2Object-affected harmful factors
If impulse drive method is used to reduce display time, then blurring is reduced, but luminance decreases
Solution Approach 1:
The data driver measures the threshold voltage of the driving transistor and feeds back this information to compensate and adjust the data voltage applied to the pixel. This feedback mechanism ensures that each pixel receives the appropriate compensated voltage to achieve the desired luminance level
Solution Approach 2:
The patent performs preliminary measurement of the threshold voltage before applying the data voltage for display. By measuring the threshold voltage in advance and using this information to pre-compensate the data voltage, the system ensures correct luminance output from the beginning without requiring subsequent adjustments
3Manufacturing precision
If threshold voltage compensation is implemented, then luminance consistency is improved, but device complexity increases
Solution Approach 1:
The patent makes the data driver perform multiple functions: it not only applies data voltage to the pixels for display but also measures the threshold voltage of the driving transistors and compensates for variations. This multi-functionality eliminates the need for separate measurement and compensation circuits, reducing overall device complexity
Solution Approach 2:
The patent merges the threshold voltage measurement function and the data voltage application function into a single integrated process within the data driver. By combining these functions and using the same data driver circuitry for both measurement and display operations, the system reduces complexity compared to having separate independent circuits
Data Source
AI summary
The present invention relates to a structure and a method of a pixel and a data driver to measure degradation of an organic light emitting element, and a threshold voltage and mobility of a driving transistor in an organic light emitting device such that degradation of the organic light emitting element and the threshold voltage and mobility of the driving transistor are measured in a turn-on interval of the display device and a data voltage applied to the pixel is amended, and thereby images of improved and uniform quality may be displayed.