OLED Driving Method for Threshold Voltage Compensation
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Solution Overview
Problem
Organic light emitting displays face challenges in achieving uniform brightness due to variations in threshold voltages of transistors across different pixels, leading to non-uniform image display.
Innovation Solution
The solution involves a driving method where scan signals are applied in alternating sequences between odd-numbered and even-numbered frames, with first and second scan signals being supplied simultaneously and sequentially across scan lines, respectively, to compensate for threshold voltage differences and ensure uniform brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sequential scanning is used, then device complexity is reduced, but brightness uniformity deteriorates due to threshold voltage variations
Solution Approach 1:
The patent applies periodic action by alternating between two different scanning sequences (first scanning sequence and second scanning sequence) in different frames. This periodic alternation compensates for threshold voltage variations across pixels, achieving uniform brightness without requiring complex per-pixel calibration circuits
Solution Approach 2:
The patent implements preliminary action by applying a preliminary scan signal before the main data signal to pre-charge or pre-condition the pixel circuits. This preliminary action equalizes the initial state of pixels before data writing, compensating for threshold voltage differences and ensuring uniform brightness display
2Manufacturing precision
If threshold voltage compensation is implemented, then brightness uniformity is improved, but driving complexity increases
Solution Approach 1:
The patent employs dynamics by making the scanning sequence dynamic and adaptable rather than fixed. The driving method dynamically switches between different scanning sequences based on frame timing, allowing the system to adapt to threshold voltage variations without adding static compensation circuits to each pixel
Solution Approach 2:
The patent applies self-service by using the display panel's own existing structures (scan lines, data lines, pixel circuits) to perform threshold voltage compensation. The compensation is achieved through clever timing and sequencing of existing signals rather than requiring external compensation circuits or additional hardware components
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 method effectively stabilizes the threshold voltage of transistors, allowing for consistent brightness across all pixels, thereby achieving uniform image display.
Implementation Method 1
the organic light emitting display can emit light for itself by electron-hole recombination
Data Source
AI summary
An organic light emitting display and a driving method thereof, in which an image is displayed with uniform brightness. The organic light emitting display includes: a scan driver for supplying a plurality of first scan signals at substantially a same time to a plurality of scan lines in a first period of one frame and for supplying a plurality of second scan signals in sequence to the scan lines in a second period of the one frame; a data driver for supplying a predetermined voltage to a plurality of data lines in the first period and for supplying a plurality of data signals to the data lines in the second period; and a pixel portion comprising a plurality of pixels connected to the scan lines and the data lines, wherein, when the one frame is an odd-numbered frame, the scan driver supplies the second scan signals in a first scanning sequence and wherein, when the one frame is an even-numbered frame, the scan driver supplies the second scan signals in a second scanning sequence differing from the first scanning sequence. With this configuration, a threshold voltage difference between the pixels is stably compensated. Further, in one embodiment, the first scanning sequence is inversely related to the second scanning sequence, so that the emission times of all pixels are equalized on average.