Auxiliary Capacitance Line Structure for IPS Display Transmissivity
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Solution Overview
Problem
Conventional liquid crystal display devices face challenges in achieving high transmissivity and maintaining display quality due to electric field leaks and cross-talk phenomena, particularly in the IPS mode, which affect the aperture ratio and viewing angle.
Innovation Solution
The design incorporates an auxiliary capacitance line that branches along the source line, allowing for a smaller width of the trunk portion of the auxiliary capacitance line, which in turn enables a larger main pixel electrode length and improved alignment uniformity, while also using shield layers to control electric field leaks and cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the auxiliary capacitance line is designed with a conventional structure, then the manufacturing process is simpler, but the main pixel electrode length is reduced and alignment uniformity deteriorates
Solution Approach 1:
The auxiliary capacitance line is divided into a trunk portion and multiple branch portions. The trunk portion has a smaller width and extends in the first direction, while branch portions extend in the second direction to contact the drain line at multiple positions. This segmentation allows the main pixel electrode to have a larger length in the second direction with improved alignment uniformity, while the capacitance function is distributed through multiple contact points.
2Reliability
If shield layers are added to control electric field leaks and cross-talk, then display quality is improved, but device complexity increases
Solution Approach 1:
Shield layers are introduced as intermediary structures between functional elements to control electric field distribution. These shield layers act as mediators that redirect or contain electric fields, preventing leaks and cross-talk between adjacent pixels or conductors, thereby improving display quality and reducing visual artifacts.
3Illumination intensity
If the main pixel electrode length is increased to improve transmissivity, then aperture ratio is improved, but alignment uniformity becomes difficult to maintain
Solution Approach 1:
The auxiliary capacitance line structure is optimized locally to support the larger main pixel electrode. The branch portions are positioned at specific locations along the drain line to provide distributed capacitance support, while the trunk portion with smaller width maintains compact layout. This local optimization allows the main pixel electrode to achieve larger length and improved transmissivity while maintaining alignment uniformity through the distributed capacitance structure.
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 enhances transmissivity by 1.07 times compared to conventional designs, maintains high display quality, and supports various pixel pitches without requiring microscopic processing, thus addressing issues of electric field leaks and cross-talk.
Implementation Method 1
Liquid crystal molecules are switched by the lateral electric field substantially in parallel with the principal surface of the array substrate
Implementation Method 2
a liquid crystal layer held between the array substrate and the counter substrate and containing liquid crystal molecules
Data Source
AI summary
An array substrate includes a gate line extending in a first direction, a source line extending in a second direction orthogonally crossing the first direction and an auxiliary capacitance line having a trunk portion extending in the first direction so as to cross the source line and a branch portion branched from the trunk portion and extending along the source line. A switching element includes a drain line arranged under the auxiliary capacitance line so as to face the trunk portion and the branch portion thereof. A pixel electrode includes a main pixel electrode extending substantially in parallel to the source line and a contact portion electrically connected with the drain line. A counter substrate includes a couple of main common electrodes extending substantially in parallel to the main pixel electrode on the both sides sandwiching the main pixel electrode.