Alternating Electrode Layout for FFS LCD Brightness Uniformity
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Solution Overview
Problem
Conventional liquid crystal display devices face issues with uneven brightness due to signal distortion when combining line inversion drive and common electrode AC drive, and struggle to reduce drive voltage and simplify the peripheral circuit structure, especially when trying to implement dot inversion drive with common electrode AC drive.
Innovation Solution
The layout of pixels is optimized by alternating the vertical position of pixel electrodes relative to common electrodes row by row or column by column, allowing for either frame inversion drive or common electrode AC drive to perform line or dot inversion drive, respectively, without the need for additional circuit complexity or increased power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If line inversion drive and common electrode AC drive are combined, then power consumption is reduced, but brightness unevenness due to signal distortion occurs
Solution Approach 1:
The pixel electrodes are segmented into two types (first pixel electrodes and second pixel electrodes) with different vertical positions relative to the common electrode. This segmentation allows different rows of pixels to use different drive methods (line inversion or dot inversion), thereby reducing brightness unevenness while maintaining low power consumption through common electrode AC drive.
Solution Approach 2:
Different regions (rows) of the display are assigned different drive characteristics. Odd rows use one inversion method while even rows use another, allowing each region to be optimized for its specific requirements and reducing overall brightness unevenness.
2Manufacturing precision
If dot inversion drive with common electrode AC drive is implemented, then brightness uniformity is improved, but peripheral circuit structure becomes more complex
Solution Approach 1:
The display is divided into two types of pixels (first pixels and second pixels) with different electrode configurations. This segmentation enables dot inversion drive to be achieved through structural design rather than complex circuit control, simplifying the peripheral circuit while maintaining brightness uniformity.
3Ease of manufacture
If traditional pixel layout is used, then manufacturing is simpler, but signal distortion and brightness unevenness occur
Solution Approach 1:
The pixel electrodes are positioned asymmetrically relative to the common electrode in alternating rows. First pixel electrodes are positioned at one vertical level while second pixel electrodes are positioned at a different vertical level, creating an asymmetric layout that reduces signal distortion and brightness unevenness.
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 signal distortion-related brightness unevenness, simplifies the peripheral circuit, and decreases power consumption by alternating the electric potential between pixel and common electrodes, improving display quality and reducing the complexity of the drive circuits.
Implementation Method 1
an alignment direction of liquid crystal molecules is controlled by a lateral electric field generated between a pixel electrode and a common electrode
Implementation Method 2
a method to realize a light switching function by rotating the liquid crystal molecules in a plane parallel to the substrate with the lateral electric field
Data Source
AI summary
In a liquid crystal display device according to a FFS method, a line inversion drive with suppressed crosstalk due to a signal distortion is made available. Pixels A are disposed in sequence in a left to right direction in a first row, while pixels B are disposed in sequence in the left to right direction in a second row that is below the first row. In the pixel A, a pixel electrode is formed of the first layer transparent electrode and connected with a thin film transistor through a contact hole. In the pixel B, a common electrode is formed of the first layer transparent electrode and connected with a common electric potential line through a contact hole. Also in the pixel A, a common electrode having a plurality of slits is formed of the second layer transparent electrode and connected with the common electric potential line through a contact hole. In the pixel B, a pixel electrode having a plurality of slits is formed of the second layer transparent electrode and connected with a thin film transistor through a contact hole.