IPS LCD Electrode Symmetry for Afterimage Reduction
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Solution Overview
Problem
In IPS mode liquid crystal display devices, the asymmetrical structure of pixel and common comb electrodes leads to asymmetrical light emission between frames, causing signal asymmetry and deteriorated afterimages due to uneven electric fields and DC offset during flicker adjustment.
Innovation Solution
The solution involves structuring the pixel comb electrodes and common comb electrodes to be symmetrical, with at least one pixel comb electrode having a larger width equal to the common shield electrode, and ensuring the number and width of electrodes are balanced to reduce electric field concentration and achieve symmetrical light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel comb electrodes and common comb electrodes are structured asymmetically in conventional IPS mode, then the electrode area ratio is optimized for display region coverage, but asymmetrical light emission between frames occurs causing deteriorated afterimages
Solution Approach 1:
The patent applies asymmetry principle by intentionally designing one pixel comb electrode with a larger width than the common comb electrodes, creating a symmetrical structure between the larger pixel electrode and the two common electrodes. This structural symmetry balances the electric field distribution and achieves symmetrical light emission between frames, resolving the afterimage problem caused by conventional asymmetrical electrode structures
2Area of stationary object
If common shield electrodes completely cover image signal wiring lines in wiring line width direction, then openings can be expanded to the vicinity of image signal wiring lines, but asymmetrical electric fields are generated between pixel and common electrodes
Solution Approach 1:
The patent applies local quality principle by making the width of one pixel comb electrode locally larger to match the width of the common shield electrode, while keeping other pixel comb electrodes with standard width. This localized structural adjustment creates symmetrical electric field distribution in the critical region without compromising the overall opening ratio achieved by the complete shielding structure
3Area of stationary object
If the number of pixel comb electrodes is greater than common comb electrodes by one, then complete coverage of image signal wiring lines is achieved, but asymmetrical light emission occurs between positive and negative frames
Solution Approach 1:
The patent applies asymmetry principle by intentionally designing one pixel comb electrode with a larger width than the common comb electrodes, creating a symmetrical structure between the larger pixel electrode and the two common electrodes. This structural symmetry balances the electric field distribution and achieves symmetrical light emission between frames, resolving the afterimage problem caused by conventional asymmetrical electrode structures
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 structural symmetry results in symmetrical light emission between frames, reducing signal asymmetry and improving afterimages by maintaining equivalent luminance and minimizing DC offset during flicker adjustment.
Implementation Method 1
a display is produced by rotating a molecular axis of the liquid crystal layer in a plane parallel to the first substrate by an electric field that is applied between the pixel comb electrode and the common comb electrode
Data Source
AI summary
Provided is a lateral-electric-field mode active matrix liquid crystal display device in which an afterimage can be improved. The width of one pixel comb electrode 109B of a plurality of pixel comb electrodes 109 is larger than each of the widths of the other pixel comb electrodes 109 and common comb electrodes 110 and is equivalent to the width of a common shield electrode 110B that covers an image signal wiring line 104 via a second insulating film. A display region is divided into two subregions by the wide pixel comb electrode 109B. In each subregion, the number of pixel comb electrodes 109 is equal to that of common comb electrodes 110. In addition, the width of the common shield electrode 110B is equivalent to that of the wide pixel comb electrode 109B, and the concentration of an electric field in the vicinity of each pixel comb electrode is reduced. Since structural symmetry is achieved, an electric potential distribution becomes symmetrical, and the asymmetry of the manners of emitting light between frames is reduced. As a result, the DC offset component of an image signal after flicker adjustment is reduced to improve an afterimage.