Liquid Crystal Display Sub-Electrode Alignment for Gamma Uniformity
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Solution Overview
Problem
Patterned vertically aligned (PVA)-mode liquid crystal displays suffer from lateral gamma curve distortion, resulting in lower visibility and light transmittance compared to twisted nematic (TN)-mode displays, particularly due to electric field distortions and misalignment between electrodes.
Innovation Solution
A liquid crystal display design featuring a first plate with parallel sub-electrodes and a connecting electrode on an insulating substrate, and a second plate with openings corresponding to the pixel area, both covered with alignment films rubbed in specific directions to align liquid crystal molecules horizontally, preventing electric field distortion and enhancing visibility and transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cutouts or protrusions are formed in field-generating electrodes to achieve wide viewing angle in PVA mode, then viewing angle is improved, but lateral gamma curve distortion occurs resulting in reduced visibility and contrast
Solution Approach 1:
The first field-generating electrode is divided into multiple sub-electrodes arranged parallel to each other with predetermined distances, separated by insulating substrates. This segmentation allows independent control of electric field distribution in different regions, enabling uniform lateral gamma curves while maintaining wide viewing angles without requiring cutout patterns.
Solution Approach 2:
Alignment films are introduced as intermediary layers between the field-generating electrodes and liquid crystal molecules. The first alignment film is rubbed in a first direction and the second alignment film is rubbed in a second direction, mediating the orientation of liquid crystal molecules to achieve uniform tilt angles across different viewing angles, thereby resolving the lateral gamma distortion problem.
2Adaptability or versatility
If PVA mode with cutout patterns is used to achieve wide viewing angle, then viewing angle is improved, but light transmittance and visibility are reduced
Solution Approach 1:
By segmenting the electrode into multiple parallel sub-electrodes, the electric field distribution is optimized to maintain high light transmittance while achieving wide viewing angles, eliminating the need for cutout patterns that block light.
Solution Approach 2:
The invention changes the electrode configuration parameter from traditional single electrode with cutouts to multiple parallel sub-electrodes, and adjusts the alignment film rubbing directions to optimize both light transmittance and viewing angle characteristics simultaneously.
3Adaptability or versatility
If traditional PVA electrode patterning is used, then viewing angle is improved, but process complexity and manufacturing steps increase
Solution Approach 1:
The electrode is segmented into parallel sub-electrodes that can be formed using simpler photolithography processes compared to creating cutout patterns, reducing manufacturing complexity while achieving the same wide viewing angle effect.
Solution Approach 2:
The parallel sub-electrode structure serves multiple functions: it creates the necessary fringe fields for wide viewing angles, provides uniform electric field distribution for accurate lateral gamma curves, and simplifies the manufacturing process compared to cutout patterns.
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
The design achieves improved visibility and light transmittance comparable to or exceeding PVA-mode displays, while minimizing electric field distortions and eliminating the need for patterning the common electrode, thus increasing process efficiency and reducing costs.
Implementation Method 1
a first alignment film covering the first field-generating electrode, said first alignment film having been rubbed in a first direction, a second plate having a second field-generating electrode, disposed on an insulating substrate, said second field-generating electrode having a plurality of openings formed parallel to each other in an area corresponding to the pixel area of the first plate, and a second alignment film covering the second field-generating electrode, said second alignment film having been rubbed in a second direction
Implementation Method 2
The liquid crystal display includes two plates having a plurality of electrodes with a liquid crystal layer between them. Voltages applied to the electrodes rearrange the liquid crystal molecules thereby displaying images by varying the amount of transmitted light.
Data Source
AI summary
A liquid crystal display with better visibility and transmittance. The liquid crystal display includes a first plate having a first field-generating electrode, disposed in a pixel area on an insulating substrate, comprising a plurality of sub-electrodes which are separated from each other by a predetermined distance and arranged parallel to each other, and a connecting electrode electrically connecting the sub-electrodes. An alignment film that is rubbed in a first direction covers a first field-generating electrode and an alignment film that is rubbed in a second direction covers a second field-generating electrode to achieve a predetermined orientation of the liquid crystals when no field is applied and more uniform rotation of the liquid crystal molecules when a field is applied.