Transflective LCD Panel Slit Electrodes and Pretilt Alignment
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Solution Overview
Problem
Transflective-type LCD devices face challenges in optical structure and manufacturing, including phase delay differences between transmissive and reflective areas, leading to low transmissivity and increased manufacturing costs, as well as issues with viewing angle and power consumption.
Innovation Solution
The use of an LCD panel design with slit electrodes on both reflective and transparent electrodes, along with reactive mesogenic monomers to form hardened layers with specific pretilt angles, aligns liquid crystals for improved transmissivity and reflectivity, and a method of manufacturing that involves applying different voltages to control these alignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a transflective-type LCD is designed with different cell gaps for transmissive and reflective areas, then phase delay differences are corrected, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies local quality by creating different pretilt angles in different regions of the liquid crystal layer. Specifically, the liquid crystal molecules are oriented with a first pretilt angle in the reflective area and a second pretilt angle (different from the first) in the transmissive area. This regional differentiation allows each area to have optimized optical characteristics without requiring different cell gaps, thereby correcting phase delay issues while maintaining uniform device structure.
2Manufacturing precision
If TN mode with different cell gaps is used to correct phase delay, then optical performance improves, but viewing angle becomes narrow
Solution Approach 1:
The patent employs parameter changes by controlling the pretilt angles of liquid crystal molecules rather than changing cell gap dimensions. By setting specific pretilt angle values (first pretilt angle for reflective area, second pretilt angle for transmissive area), the patent optimizes both phase delay correction and viewing angle characteristics. This parameter-based approach allows simultaneous achievement of optical performance and wide viewing angle without the limitations of TN mode with different cell gaps.
3Productivity
If vertical alignment mode is used to improve transmissivity, then light efficiency increases, but V-T and V-R curve characteristics become difficult to match
Solution Approach 1:
The patent applies local quality by implementing region-specific pretilt angle control. In the reflective area, liquid crystal molecules are oriented with a first pretilt angle optimized for reflectivity characteristics, while in the transmissive area, a second pretilt angle is used to optimize transmissivity. This localized optimization allows both V-T and V-R curve characteristics to be independently tuned and matched, achieving high light efficiency while maintaining precise curve characteristic control.
4Manufacturing precision
If independent TFTs are used in reflective and transmissive areas to adjust curves, then performance optimization is achieved, but aperture ratio decreases and manufacturing cost increases
Solution Approach 1:
The patent employs universality by using a single common electrode that serves both reflective and transmissive areas, eliminating the need for independent TFTs in each region. The liquid crystal orientation control is achieved through the combined effect of the common electrode and region-specific alignment layers with different pretilt angles. This multi-functional approach allows curve characteristic control without adding extra active components, thereby maintaining high aperture ratio and reducing manufacturing complexity.
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 design enhances light efficiency, achieves high transmissivity and reflectivity, and widens the viewing angle while matching transmittance and reflectance curves, reducing manufacturing costs and improving overall display performance.
Implementation Method 1
a liquid crystal layer interposed between the array substrate and the opposite substrate
Implementation Method 2
reactive mesogenic monomers to form hardened layers with specific pretilt angles
Data Source
AI summary
A liquid crystal display panel includes; an array substrate including a pixel electrode disposed in a pixel area, the pixel electrode including a reflective electrode disposed in a reflective area of the pixel area and a transparent electrode disposed in a transmissive area of the pixel area, at least one of the reflective electrode and the transparent electrode including a plurality of first slit electrodes, an opposite substrate including a first common electrode disposed in alignment with the reflective area, the first common electrode including a plurality of second slit electrodes each having a width wider than that of an individual first slit electrode of the plurality of first slit electrodes, and a liquid crystal layer interposed between the array substrate and the opposite substrate.