Dot Inversion LCD Driving Reduces Power Consumption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
LCD devices driven by vertical electric fields suffer from asymmetric light transmittance and viewing angle limitations, leading to image inversion and narrowed viewing angles, which are addressed by the in-plane switching (IPS) method but still face issues with power consumption and picture quality due to the need for high voltage differences between pixel and common electrodes.
Innovation Solution
The implementation of a dot inversion method in LCD devices, where the common voltage is swung in different directions at adjacent pixels and image data has a polarity different from the common voltage, increasing the voltage difference between pixel and common electrodes, thereby reducing power consumption and preventing picture quality deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a vertical electric field is used to drive the liquid crystal, then the light transmittance is symmetrically distributed in right and left directions, but the viewing angle is narrowed due to asymmetric distribution in up and down directions causing image inversion
Solution Approach 1:
The patent applies in-plane switching (IPS) method which inverts the driving mechanism from vertical electric field to horizontal electric field. This inversion of the electric field direction enables symmetrical light transmittance distribution in both right-left and up-down directions, thereby expanding the viewing angle while maintaining image quality without inversion artifacts
2Adaptability or versatility
If the in-plane switching (IPS) method is used to expand viewing angle, then the viewing angle characteristics are enhanced, but the power consumption increases due to the need for high voltage difference between pixel and common electrodes
Solution Approach 1:
The patent applies dot inversion method which dynamically changes the polarity of the common voltage applied to adjacent pixels. By alternating the common voltage polarity between adjacent pixels, the voltage difference across the liquid crystal layer is optimized, enabling effective liquid crystal switching at lower absolute voltage levels while maintaining the benefits of IPS method for wide viewing angle
Solution Approach 2:
The dot inversion method implements periodic polarity reversal of the common voltage at adjacent pixels. This periodic action creates alternating positive and negative voltage regions, which reduces the required voltage magnitude for liquid crystal switching while maintaining effective control over the liquid crystal orientation, thereby reducing power consumption
3Reliability
If high voltage difference is applied between pixel and common electrodes to maintain picture quality, then the liquid crystal switching is effective, but power consumption increases
Solution Approach 1:
The patent employs dot inversion method that changes the polarity parameter of the common voltage applied to adjacent pixels. This parameter change enables the system to achieve effective liquid crystal switching with reduced voltage magnitude by utilizing the alternating polarity to enhance the effective voltage difference across the liquid crystal layer without requiring high absolute voltage levels
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 enhances the voltage difference between pixel and common electrodes, reducing power consumption while preventing horizontal cross-talk and maintaining picture quality, even when using lower voltages, thus improving the overall performance of LCD devices.
Implementation Method 1
LCD devices use the optical anisotropy of liquid crystals to display an image by controlling the transmittance of light supplied from a light source. The transmittance of the light is controlled by applying an electric field to liquid crystals contained between a thin film transistor array substrate and a color filter substrate, thereby rearranging the liquid crystals.
Implementation Method 2
The transmittance of the light is controlled by applying an electric field to liquid crystals contained between a thin film transistor array substrate and a color filter substrate, thereby rearranging the liquid crystals.
Implementation Method 3
An in-plane switching (IPS) method for driving the liquid crystal using a horizontal electric field has been proposed. The voltage difference generates a horizontal electric field thereby re-arranging the liquid crystal inside the pixel P1. The arrangement of the liquid crystal changes according to the size of the electric field thereby varying the transmittance of the light supplied from a lamp.
Data Source
AI summary
A liquid crystal display (LCD) device capable of reducing the driving power and preventing cross talk is provided. The LCD device comprises: a plurality of data lines arranged on a substrate in a vertical direction for transmitting image data; a plurality of gate lines arranged on the substrate in a horizontal direction for transmitting a scan signal; a plurality of pixels formed at each intersection between the gate lines and the data lines and arranged on the substrate in a matrix formation; a first electrode and a second electrode respectively provided at each pixel for forming a horizontal electric field; and a plurality of first common voltage lines and second common voltage lines alternately arranged on the substrate in a horizontal direction, wherein the second electrodes provided at each pixel of a line unit are alternately connected to the first common voltage line and the second common voltage line.