Display Device Pixel Gate Control for Afterimage Reduction
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Solution Overview
Problem
Display devices face challenges in reducing or preventing afterimages due to the inability to effectively control the emission and reset of pixels, leading to motion blur and image retention issues.
Innovation Solution
The display device incorporates a configuration with multiple gate lines and a gate driver that supplies distinct gate signals to control the operation of transistors and capacitors within each pixel, allowing for concurrent and sequential signal supply to manage pixel emission and reset, including a third gate signal for non-emission or low gray scale operation, thereby reducing afterimages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pixel control is used, then device complexity is reduced, but afterimage and motion blur occur due to inability to effectively control pixel emission and reset
Solution Approach 1:
The gate control is segmented into three separate gate lines (first gate line for emission control, second gate line for reset control, third gate line for non-emission control) instead of using a single gate line. This segmentation allows independent control of pixel emission, reset, and non-emission states, effectively preventing afterimages while maintaining manageable device complexity through modular control architecture.
Solution Approach 2:
The pixel control system is made dynamic by enabling sequential switching between different gate signals on the three gate lines during different time periods within a frame. The pixels can be dynamically controlled to emit light during the emission period, reset during the reset period, and maintain non-emission state during the non-emission period, allowing adaptive response to prevent afterimages.
2Reliability
If multiple gate lines and signals are used to control pixel emission and reset, then afterimage reduction is achieved, but power consumption increases due to distributed load and instantaneous current
Solution Approach 1:
The gate signals are applied periodically in distinct time periods: emission period (first gate signal), reset period (second gate signal), and non-emission period (third gate signal). This periodic action allows the pixels to be driven only when necessary for image display, reset when needed to prevent afterimages, and kept in low-power non-emission state otherwise, thereby improving image quality while managing power consumption through time-multiplexed control.
3Manufacturing precision
If concurrent gate signal supply is used, then pixel control precision is improved, but manufacturing complexity increases
Solution Approach 1:
The gate driver functionality is segmented into separate control circuits for each of the three gate lines, with each circuit responsible for generating and supplying its specific gate signal during appropriate time periods. This segmentation achieves precise control of pixel states while simplifying manufacturing by assigning dedicated control functions to separate circuits rather than requiring a single complex integrated driver.
Data Source
AI summary
A display device includes pixels, and first, second, and third gate lines and data lines connected to the pixels. At least one of the pixels includes a light emitting element, a first transistor connected between a first power source and the light emitting element for driving the light emitting element according to a voltage of a first node, a second transistor connected between the first node and a corresponding data line, and driven according to a voltage of a corresponding first gate line, a capacitor connected between the first node and a second node between the first transistor and the light emitting element, a third transistor between the second node and an initialization power line, and driven according to a voltage of a corresponding second gate line, and a fourth transistor connected between the first and second nodes, and driven according to a voltage of a corresponding third gate line.