IPS LCD Common Voltage Generation Using Gate Lines
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Solution Overview
Problem
In-plane switching mode LCD devices face issues with low aperture ratio, reduced luminance, and flicker due to coupling between gate and drain electrodes, which deteriorate picture quality.
Innovation Solution
Generating a common voltage based on the difference between n−1th and nth gate voltages and supplying it to common electrodes, while omitting the common voltage circuit and ensuring data and common voltages are charged simultaneously to reduce charge deviation and flicker.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common voltage circuit is used in IPS mode LCD devices, then common voltage can be supplied to common electrodes, but circuit complexity increases and flicker occurs due to coupling between gate and drain electrodes
Solution Approach 1:
The patent extracts and removes the common voltage circuit from the IPS mode LCD device. Instead of using a separate common voltage circuit to supply common voltage to common electrodes, the invention utilizes the gate voltage lines themselves to provide the common voltage, thereby eliminating the need for additional common voltage circuits and reducing overall device complexity while maintaining reliable operation without flicker
Solution Approach 2:
The gate voltage lines are given a dual function: they serve both as switching control lines and as common voltage supply lines. By making the gate voltage lines universal (serving multiple purposes), the patent eliminates the need for separate common voltage circuits, reducing device complexity while ensuring stable voltage supply to prevent flicker
2Reliability
If common voltage circuit is included, then common electrodes can be driven, but aperture ratio decreases due to additional circuit elements
Solution Approach 1:
The gate voltage lines are made multi-functional, serving both as switching control lines and as common voltage supply lines. This universality eliminates the need for separate common voltage circuits and electrodes, thereby increasing the aperture ratio while maintaining reliable common electrode driving capability
Solution Approach 2:
The patent removes the separate common voltage circuit and associated electrodes from the display area. By extracting these unnecessary elements and using the gate voltage lines for dual purposes, the aperture ratio is increased while the common electrode driving function is preserved through the repurposed gate lines
3Device complexity
If data and common voltages are charged at different times, then circuit design is simplified, but charge deviation occurs due to gate line delay and distortion causing flicker
Solution Approach 1:
The patent implements preliminary action by simultaneously charging both data and common voltages before the actual display refresh. By pre-charging both voltages at the same time and using the gate line switching action to apply them together to the liquid crystal, the invention compensates for gate line delays and ensures synchronized voltage application, eliminating flicker while maintaining circuit simplicity
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 aperture ratio, maintains uniform voltage distribution, and reduces flicker, thereby improving picture quality and viewing angle characteristics.
Implementation Method 1
the liquid crystal layer is rearranged by the horizontal electric field between the common electrode and the pixel electrode
Implementation Method 2
LCD devices use the optical anisotropy of liquid crystals to display an image by controlling the transmittance of light
Data Source
AI summary
Disclosed is an IPS mode LCD device, which comprises first and second substrates, N gate lines arranged on the first substrate substantially in parallel, M data lines arranged to cross the gate lines so as to define m×n pixel regions, a plurality of first switching devices formed at each crossing of the gate lines and the data lines, first electrodes electrically connected with the first switching devices, second electrodes generating a horizontal electric field along with the first electrodes in the pixel regions, a common voltage supplier generating a common voltage from an n−1th gate line and an nth gate line and supplying the generated common voltage to the second electrodes, and a liquid crystal layer formed between the first and second substrates.