LCD Driving Method Stabilizes Kickback Voltage to Reduce Flicker
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Solution Overview
Problem
LCDs suffer from flicker and image sticking due to variations in kickback voltage caused by differences in grayscale and polarity, which degrade display quality.
Innovation Solution
The implementation of a driving method that applies alternating positive and negative polarity data voltages to pixels, with corresponding adjustments in gate on voltages, and a higher refreshment rate, to minimize the kickback voltage difference and reduce flicker and image sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If data voltage is applied by frame with opposite polarity to reduce kickback voltage variation, then flicker and image sticking are reduced, but device complexity increases due to additional voltage generating units and control mechanisms
Solution Approach 1:
The gate on voltage is segmented into multiple levels (first level and second level) depending on the polarity of the data voltage. When positive polarity data voltage is applied, a first level gate on voltage is used; when negative polarity data voltage is applied, a second level gate on voltage is used. This segmentation allows kickback voltage variation to be compensated by selecting appropriate voltage levels, thereby reducing flicker and image sticking without requiring complex real-time adjustment mechanisms.
Solution Approach 2:
The gate driving unit is designed to preliminarily determine and apply the appropriate gate on voltage level based on the polarity of the incoming data voltage before the actual pixel driving occurs. The voltage generating unit prepares both first level and second level gate on voltages in advance, and the gate driving unit selects the appropriate level based on data voltage polarity detection, enabling proactive compensation of kickback voltage variation rather than reactive correction.
2Object-affected harmful factors
If higher refreshment rate is applied to reduce flicker, then display quality improves, but power consumption increases
Solution Approach 1:
The invention changes the parameter of gate on voltage level based on data voltage polarity. By having two distinct gate on voltage levels (first level for positive polarity, second level for negative polarity), the system compensates for kickback voltage variation caused by different grayscale values and polarities. This parameter change approach allows effective flicker reduction through proper voltage selection rather than relying solely on increasing refreshment rate, thereby avoiding excessive power consumption.
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 approach effectively reduces flicker and image sticking by stabilizing the kickback voltage, enhancing display quality and reducing residual DC voltage effects.
Implementation Method 1
The transmittance of light through the liquid crystal panel depends on the alignment of the liquid crystal
Implementation Method 2
The alignment of the liquid crystal varies in accordance with an electric field formed between a pixel voltage Vp across the pixel and a common voltage Vcom formed in a common electrode of the color filter substrate
Data Source
AI summary
A liquid crystal display (LCD) and a driving method thereof are provided. The LCD comprises a liquid crystal panel having a gate line, a data line, and a pixel defined by the intersection of the gate line and the data line; a grayscale voltage generating unit for generating a grayscale voltage; a driving voltage generating unit for generating a gate off voltage, a positive polarity gate on voltage, and a negative polarity gate on voltage, wherein the negative polarity gate on voltage is lower than the positive polarity gate on voltage; a gate driving unit for supplying the gate line with at least one of the positive polarity gate on voltage and the negative polarity gate on voltage; a data driving unit for supplying the pixel with a data voltage, wherein the data driving unit is supplied with the grayscale voltage from the grayscale voltage generating unit; and a signal control unit for controlling the data driving unit so that a positive polarity data voltage and a negative polarity data voltage are alternately applied to the pixel, and for controlling the gate driving unit so that the positive polarity gate on voltage is applied to the pixel supplied with the positive polarity data voltage and the negative polarity gate on voltage is applied to the pixel supplied with the negative polarity data voltage. Accordingly, the degree of flicker and image sticking is reduced.