Gate Driver Segmentation for Faster OLED Pixel Sensing
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Solution Overview
Problem
In OLED display devices, differences in electrical characteristics between pixels due to process deviations and device characteristics lead to degradation of image quality and reduced lifetime, and existing sensing methods are hindered by increased sensing time and inaccuracy due to resistance and capacitive load (RC) in the sensing path.
Innovation Solution
A gate driver design incorporating cascade-connected signal transmission units with specific transistors (A, B, and C transistors) to reduce capacitive load and improve sensing accuracy, including a display device with n th< and (n+1) th< signal transmission units and pixel line sets for external compensation during sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If many pixels are electrically connected to a sensing path for sensing electrical characteristics, then sensing coverage is improved, but sensing time increases and sensing accuracy deteriorates due to RC load
Solution Approach 1:
The gate driver is divided into multiple signal transmission units (first, second, and subsequent units) that operate in a cascaded manner. Each unit handles a portion of the pixel lines, allowing parallel sensing operations across different segments of the display panel. This segmentation enables simultaneous sensing of multiple pixel groups without increasing the RC load on a single sensing path, thus maintaining sensing accuracy while reducing total sensing time.
2Adaptability or versatility
If process deviation and device characteristic differences exist between pixels, then manufacturing flexibility is improved, but electrical characteristic uniformity deteriorates leading to image quality degradation
Solution Approach 1:
The patent implements a sensing mechanism that measures the electrical characteristics (such as threshold voltage) of driving transistors in each pixel. The sensed data is fed back to calculate compensation values that adjust the driving signals for each pixel individually. This feedback loop compensates for process deviations and device characteristic differences, ensuring uniform electrical performance across all pixels despite manufacturing variations, thereby preventing image quality degradation.
Data Source
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AI summary
The present specification discloses a gate driver including first and second pull-up transistors, first and second pull-down transistors, a first output terminal configured to output a carry signal, an Ath transistor disposed between the first and second pull-up transistors and configured to electrically separate a Q node in response to a control signal, a Bth transistor disposed between the Ath and second pull-up transistors and configured to supply a low potential voltage to the second pull-up transistor in response to a control bar signal, and a Cth transistor connected to the second output terminal to supply the low potential voltage in response to the control bar signal. According to the present specification, by reducing a capacitive load compared to the related art at the same time upon sensing for electrical characteristic compensation of a pixel circuit, it is possible to quickly charge a capacitance and enable accurate sensing.