Curved VA LCD Polymeric Alignment Layers for Voltage Compensation
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Solution Overview
Problem
Liquid crystal displays with misaligned upper and lower panels suffer from transmittance deterioration and loss of common voltage depending on gray levels, affecting display quality, especially in curved configurations.
Innovation Solution
The use of differently charged upper and lower alignment layers, with the first alignment layer having a pre-tilt angle and the second alignment layer being vertically aligned, forming a predetermined DC voltage to compensate for voltage losses and reduce texture generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the upper and lower panels are misaligned to achieve curved display configuration, then the viewer immersion is enhanced, but the transmittance deteriorates and texture is generated
Solution Approach 1:
The patent applies different alignment layers with different properties to different locations (upper and lower panels). Specifically, one alignment layer has a pre-tilt angle while the other has no pre-tilt angle, creating local quality differences that compensate for the misalignment effects in curved displays, thereby maintaining transmittance while achieving the desired curved configuration
Solution Approach 2:
The patent introduces asymmetry by using non-identical alignment layers on the upper and lower panels. The alignment layers have different charges and different pre-tilt angle characteristics, which creates an asymmetric structure that counteracts the symmetric misalignment problem in curved displays, preventing texture generation and transmittance deterioration
2Adaptability or versatility
If misaligned panels are used for curved display, then display immersion is improved, but common voltage is lost depending on gray level
Solution Approach 1:
The patent changes the electrical parameters of the alignment layers by assigning different charges to the upper and lower alignment layers. This parameter change creates a DC voltage that compensates for the common voltage loss occurring in curved displays, thereby maintaining proper voltage levels across different gray levels while preserving the curved configuration
3Reliability
If different alignment layers with different charges are used, then common voltage loss is compensated and transmittance deterioration is reduced, but alignment layer complexity increases
Solution Approach 1:
The patent implements local quality by assigning specific different properties to specific locations - one alignment layer has a pre-tilt angle and the other has no pre-tilt angle. This targeted differentiation achieves the necessary compensation effects without requiring complete redesign of all alignment layers, thus managing complexity while improving reliability
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 approach enhances display quality by reducing transmittance deterioration and compensating for common voltage losses, thereby improving the performance of curved liquid crystal displays.
Implementation Method 1
upper and lower alignment layers with different charges... forming a predetermined DC voltage
Implementation Method 2
liquid crystal molecules may be aligned so that long axes thereof are perpendicular to the upper and lower panels
Implementation Method 3
The electric field may determine the direction of liquid crystal molecules of the liquid crystal layer. The liquid crystal display may display an image by controlling the polarization of incident light.
Data Source
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AI summary
Alignment layers in a curved, vertically-aligned LCD (10) are disclosed for improved display quality. On bending the panels of conventional devices, misalignment between the substrates leads to a liquid crystal "texture" which causes reduced transmittance and poorer display quality. In these devices the common voltage is also reduced according to the Gray level voltage. The upper (21) and lower (11) polymeric alignment layers (on the common and pixel electrodes, respectively) of the disclosed device have different properties: (i.) the lower alignment layer has a non-zero pretilt and a positive charge (resulting from an electron-deficient chemical group); (ii.) the upper alignment layer aligns the liquid crystals either perpendicular or with a non-zero pretilt to the common electrode substrate. It also has a negative charge (resulting from an electron-rich chemical group). The DC voltage due to these charges compensates for the reduction in the common voltage.