Liquid Crystal Display Device With Segmented Common Electrodes
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Solution Overview
Problem
In active-matrix liquid crystal display devices using a lateral electric field, existing techniques face challenges in efficiently controlling liquid crystal molecule alignment with oblique electric fields, particularly in achieving high transmissivity and display quality due to limitations in pixel electrode and common electrode designs.
Innovation Solution
The design incorporates a second common electrode with segments formed in an island shape around the pixel electrode, including second main and sub-common electrodes with intermittent positions, and a lattice-shaped third common electrode on the counter-substrate, allowing for an oblique electric field that enhances liquid crystal alignment and display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cross-shaped pixel electrode or I-shaped pixel electrode is combined with a common electrode disposed above source lines to produce an oblique electric field, then liquid crystal molecule alignment is improved, but device complexity increases due to multiple electrode structures
Solution Approach 1:
The common electrode is divided into multiple segments (first common electrode, second common electrode, third common electrode) with different functions and positions. The second common electrode is segmented into island-shaped regions around the pixel electrode. This segmentation allows each electrode to contribute specifically to generating the oblique electric field components needed for precise liquid crystal alignment, resolving the contradiction by making the complex structure functional rather than arbitrary.
Solution Approach 2:
The patent introduces electrodes in multiple spatial dimensions and orientations. The pixel electrode has main and sub-electrodes extending in different directions, while common electrodes are positioned at different heights and orientations. This multi-dimensional electrode arrangement creates oblique electric field components that effectively control liquid crystal molecules, transforming a two-dimensional planar structure into a three-dimensional electrode system.
2Reliability
If multiple common electrodes with different configurations are used to enhance display quality, then transmissivity and alignment stability improve, but the number of components and manufacturing steps increase
Solution Approach 1:
Multiple common electrodes serve universal functions of establishing reference potentials and generating electric field components, while each has specialized roles. The first common electrode provides a baseline potential, the second common electrode with island regions creates localized field control around the pixel, and the third common electrode on the counter-substrate completes the field configuration. This multi-functionality approach allows a single electrode system to achieve both alignment stability and transmissivity enhancement without requiring entirely separate structures for each function.
3Reliability
If the second common electrode has intermittence at positions adjacent to pixel electrodes, then electrical short-circuits are prevented, but the continuity of the common electrode structure is reduced
Solution Approach 1:
The second common electrode exhibits local quality variations through its island-shaped segmentation. At positions adjacent to pixel electrodes, the electrode is interrupted (intermittent) to prevent electrical short-circuits between the common electrode and pixel electrode. In other regions, the electrode maintains continuity to provide stable potential reference. This local differentiation of electrode continuity resolves the contradiction by applying discontinuity only where electrically necessary while preserving continuity where functionally beneficial.
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 configuration improves transmissivity and display quality by stabilizing liquid crystal molecule alignment, increasing the display area, and preventing electrical short-circuits, while maintaining initial alignment states at equipotential surfaces, thus enhancing brightness and preventing color mixture.
Implementation Method 1
the alignment of liquid crystal molecules is controlled by a lateral electric field which is substantially parallel to the main surface of the array substrate
Implementation Method 2
a technique of controlling the alignment of liquid crystal molecules by producing an oblique electric field between a pixel electrode formed on the array substrate and a counter-electrode formed on the counter-substrate
Data Source
AI summary
A liquid crystal display device includes a gate line, a source line, a first common electrode opposed to the gate line and the source line, an interlayer insulating film covering the first common electrode, a pixel electrode including a main pixel electrode and a sub-pixel electrode, the pixel electrode formed on the interlayer insulating film, a second common electrode formed on the interlayer insulating film. The second common electrode includes a second main common electrode which has intermittence at a position adjacent to the sub-pixel electrode, and a second sub-common electrode which has intermittence at a position adjacent to the main pixel electrode.