Liquid Crystal Display Voltage Control for Color Shift Reduction
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Solution Overview
Problem
Current liquid crystal display devices, particularly those using the VA scheme with multi-domain vertical alignment or multi-pixel drive, face challenges in achieving a wide viewing angle with minimal color shift at low gray-scale levels, leading to issues like image sticking and flicker, especially in high transmittance conditions.
Innovation Solution
A liquid crystal display device that applies different voltages in subframe periods based on the original gradation number, using a threshold value to determine the application of first, second, and third voltages across various pixels to improve color shift and luminance consistency, especially at oblique viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If time division drive is conducted in intermediate gray-scale region with high application voltage, then white floating is reduced, but image sticking occurs
Solution Approach 1:
The patent changes the voltage application parameters based on gray-scale regions. For low gray-scale regions, it applies different voltages in different subframe periods instead of using high application voltage time division drive, thereby avoiding image sticking while maintaining display uniformity through parameter optimization.
Solution Approach 2:
The patent applies different voltage strategies to different gray-scale regions. Low gray-scale regions use a specialized two-subframe voltage application method, while other regions use conventional time division drive, thereby locally optimizing performance to avoid image sticking in sensitive low gray-scale areas.
2Illumination intensity
If time division drive is performed at high transmittance gray-scale number, then display brightness is improved, but flicker or color breakup occurs
Solution Approach 1:
The patent optimizes voltage application parameters by dividing gray-scale regions and applying appropriate voltage patterns. This reduces excessive voltage switching at high transmittance levels, thereby maintaining display brightness while minimizing flicker and color breakup through parameter optimization.
3Adaptability or versatility
If MPD driving is performed in 4D-VA scheme, then viewing angle is improved, but chromaticity shift in oblique viewing angle at low gray-scale display remains large
Solution Approach 1:
The patent applies a specialized voltage application method specifically to low gray-scale regions in 4D-VA displays. By using different voltage patterns for low gray-scales while maintaining MPD driving for other regions, it locally optimizes chromaticity performance in oblique viewing angles at low gray-scale levels while preserving wide viewing angle characteristics.
Solution Approach 2:
The patent changes voltage application parameters for low gray-scale regions in 4D-VA displays, using a two-subframe method that reduces chromaticity shift. This parameter optimization maintains the multi-domain vertical alignment benefits for wide viewing angle while correcting the chromaticity issue at low gray-scales.
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
The solution effectively reduces color shift and minimizes image sticking and flicker, enhancing the display's ability to maintain clarity and brightness across a wide viewing angle, particularly in low gray-scale regions.
Implementation Method 1
a liquid crystal layer which exhibits vertical alignment
Implementation Method 2
control unit that controls a voltage which is supplied to the liquid crystal display unit
Data Source
AI summary
A liquid crystal display device of one aspect of the present invention includes a liquid crystal display unit that includes a liquid crystal layer which exhibits vertical alignment and plural picture elements, and a control unit that controls a voltage which is supplied to the liquid crystal display unit. The control unit performs display by sequentially applying a first voltage that corresponds to a larger gradation number than an original gradation number and a second voltage that corresponds to zero gradation respectively in plural subframe periods that result from division of one frame period of an image signal in a case where the original gradation number of the input image signal is a low gradation number that is less than a prescribed threshold value, performs display by applying the second voltage in the one frame period in a case where the original gradation number is the zero gradation, and performs display by applying a third voltage that corresponds to the original gradation number in the one frame period in a case where the original gradation number is a high gradation number that is equivalent to or more than the threshold value.