Liquid Crystal Display Driving Method Reducing Leakage Current
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Solution Overview
Problem
Conventional liquid crystal displays require a large number of data driving units as the pixel array scale increases, leading to high manufacturing costs and potential image quality issues due to leakage currents in thin-film transistors, which affect the uniformity of pixel voltages and luminance.
Innovation Solution
A liquid crystal display system where a single data driving unit sequentially drives pixels of the same color, using a scan driving circuit and switches to reduce the number of data driving units required, while adjusting switch controlling signals to minimize leakage current differences between thin-film transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of data driving units is increased to match the number of column pixels in large-scale liquid crystal displays, then the image quality and coverage are improved, but the manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent segments the pixel array by color (red, green, blue pixels) and assigns each color group to a separate data driving unit. This allows one data driving unit to drive multiple pixels of the same color through time-sequential operation, reducing the total number of data driving units from N (number of column pixels) to 3 (number of color types), thereby resolving the contradiction between display area and device complexity
Solution Approach 2:
The patent employs periodic scanning signals to sequentially activate different color pixel groups (red, green, blue) in time-sequential order. Each data driving unit periodically drives its assigned color group during different time slots within a frame period, enabling one data driving unit to serve multiple pixels through time-multiplexed operation, thus reducing the number of required data driving units while maintaining full display coverage
2Ease of manufacture
If thin-film transistors are used in pixel circuits, then the manufacturing process is simplified, but leakage currents occur causing non-uniform pixel voltages and degraded image quality
Solution Approach 1:
The patent ensures continuous voltage maintenance in pixel circuits by optimizing the timing of scanning signals and data signals. The data signal is held in the data line until the scanning signal activates the pixel switch, ensuring continuous voltage supply to compensate for leakage currents in thin-film transistors, thereby maintaining pixel voltage uniformity while using easily manufacturable TFT technology
Solution Approach 2:
The patent applies preliminary action by pre-charging data lines and maintaining data signals ready before pixel switching occurs. The data driving unit outputs signals in advance, and the scanning signal is timed to activate pixel switches when the data signal is already prepared and held in the data line, ensuring uniform voltage distribution across pixels before leakage occurs, thus improving manufacturing precision without complicating the manufacturing process
Data Source
AI summary
A liquid crystal display and its driving method are disclosed. Among the pixels driven by the same data driving unit, firstly the pixels of same color are sequentially driven, and then the pixels of other colors are sequentially driven, so that the pixels have almost the same leakage current.