In-Plane Switching LCD Driving Method for Power Reduction
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Solution Overview
Problem
Liquid crystal display (LCD) devices, particularly those using the twisted nematic (TN) mode, suffer from narrow viewing angles and high power consumption due to the wide swing width of the data voltage relative to the constant common voltage, leading to increased power consumption and potential display quality issues.
Innovation Solution
The implementation of an in-plane switching (IPS) mode LCD device with a driving method that involves alternating polarity inversion of common voltages across neighboring row lines, synchronized with gate and data voltage supply, reduces power consumption and improves display quality by minimizing capacitive coupling and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant common voltage is supplied to all pixels, then the circuit design is simplified, but the data voltage swing width increases leading to high power consumption
Solution Approach 1:
The patent divides the common voltage supply into multiple independent common lines (CL1, CL2, CL3, etc.), each serving specific row lines. This segmentation allows different common voltage levels to be applied to different regions, enabling reduced data voltage swing width for pixels connected to the same common line while maintaining simplified circuit design within each segment.
Solution Approach 2:
The patent applies different common voltage characteristics to different local regions of the display panel. Specifically, pixels connected to the same common line receive the same common voltage, creating local uniformity that reduces the swing width of data voltage locally, thereby reducing power consumption while maintaining overall system functionality.
2Ease of manufacture
If the common voltage is supplied to all pixels uniformly, then manufacturing is simplified, but display quality deteriorates due to flicker and crosstalk
Solution Approach 1:
The patent segments the common voltage supply system into multiple common lines, each responsible for specific row lines. This segmentation reduces capacitive coupling between adjacent pixels by isolating their common voltage references, thereby minimizing flicker and crosstalk while maintaining manufacturing simplicity through modular implementation.
Solution Approach 2:
The patent inverts the traditional approach by making the common voltage line-specific rather than panel-wide. Instead of one common voltage for all pixels, each common line has its own voltage reference, which inverts the problem-solving approach to eliminate capacitive coupling effects that cause display quality issues.
3Use of energy by moving object
If multiple common lines with different voltages are used, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The patent implements local quality by assigning specific common voltages to specific common lines based on their connected row lines. Each common line is configured with a voltage optimized for its local pixel group, reducing power consumption locally while the overall device complexity remains manageable through systematic patterning.
Solution Approach 2:
The patent employs periodic action through alternating polarity inversion for adjacent common lines. Common lines connected to alternating row lines have inverted voltage polarities, creating a periodic pattern that reduces power consumption while maintaining symmetry and simplifying the control logic for managing multiple common lines.
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 reduces power consumption and enhances display quality by reducing the swing width of the data voltage and preventing flicker and crosstalk, while maintaining uniform brightness across the panel.
Implementation Method 1
a voltage applied between the electrodes induces an electric field across the liquid crystal material
Implementation Method 2
Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field
Implementation Method 3
thereby changing the light transmissivity of the LCD device
Implementation Method 4
When the gate voltage is supplied, the switching transistor T of the pixel P connected to the corresponding gate line GL1, GL2 or GL3 is turned on and a data voltage is supplied to the pixel P
Implementation Method 5
The liquid crystal capacitor Clc includes a pixel electrode, a common electrode, and a liquid crystal layer between the pixel and common electrodes
Data Source
AI summary
A liquid crystal display device includes a plurality of pixels at intersections of a plurality of row lines and a plurality of column lines, wherein each pixel includes a switching transistor, and pixel and common electrodes that induce an in-plane electric field; a plurality of gate lines each connected to the pixels on each row line; a plurality of data lines each connected to the pixels on each column line; and a plurality of common lines each connected to the common electrodes of the pixels alternately located on neighboring two row lines per one column line.