LCD Vertical Alignment Without Rubbing Layer
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Solution Overview
Problem
Liquid crystal display (LCD) devices face issues with smudges and alignment defects due to the thickness distribution and material properties of the alignment layer, which affect the reliability and processability of the liquid crystal molecules.
Innovation Solution
An LCD device design that aligns liquid crystal molecules without using an alignment layer, utilizing first and second pixel electrodes with alternately arranged branch electrodes and applying different voltages to them to generate an electric field for vertical alignment, thereby preventing smudges and alignment defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an alignment layer is used to control liquid crystal molecule orientation, then liquid crystal molecules can be pretilted and aligned, but smudges are formed due to thickness distribution and material properties of the alignment layer
Solution Approach 1:
The patent removes the alignment layer from the LCD structure entirely. Instead of using an alignment layer to control liquid crystal molecule orientation, the invention uses electrode structures (first and second pixel electrodes with branch electrodes) to generate electric fields that directly align the liquid crystal molecules. This extraction of the alignment layer eliminates the source of smudges and thickness distribution problems while maintaining the necessary alignment function through electrical means.
Solution Approach 2:
The patent replaces the mechanical/chemical alignment layer system with an electrical field-based alignment system. The alignment function previously performed by the physical alignment layer is substituted by electric fields generated between the first and second pixel electrodes, which control liquid crystal molecule orientation through electrostatic forces rather than physical contact or chemical interaction.
2Manufacturing precision
If an alignment layer is used to align liquid crystal molecules, then pretilt angle control is achieved, but reliability and processability of the material are compromised
Solution Approach 1:
The patent replaces the material-based alignment layer with an electrical field-based system. The branch electrodes of the first and second pixel electrodes generate controlled electric fields that determine liquid crystal molecule pretilt angles and orientation, eliminating dependence on alignment layer material properties and their associated reliability and processability issues.
Solution Approach 2:
The patent changes the method of controlling liquid crystal alignment from material-based parameters (alignment layer thickness, material composition, rubbing direction) to electrical parameters (voltage applied to branch electrodes, electric field strength and direction). This parameter transformation allows precise control of pretilt angles through electrical means without the constraints of material science limitations.
3Manufacturing precision
If an alignment layer is used for liquid crystal alignment, then orientation control is achieved, but afterimages are generated due to alignment layer material
Solution Approach 1:
The patent removes the alignment layer that causes afterimages. By eliminating the alignment layer material from the system, the source of afterimage generation is removed. The orientation control function is maintained through the electrical field generated by the first and second pixel electrodes with their branch electrode structures, which can dynamically control liquid crystal orientation without the residual effects associated with alignment layer materials.
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 solution effectively aligns liquid crystal molecules vertically without an alignment layer, preventing smudges and defects, and allows for reliable operation by controlling the electric field between the pixel electrodes, ensuring proper light polarization and image display.
Implementation Method 1
an electric field is generated between the first and second pixel electrodes in a way such that the liquid crystal molecules are aligned in a vertical direction
Implementation Method 2
the liquid crystal molecules are aligned vertically with respect to the first display panel in a black state
Implementation Method 3
two different voltages having different levels from each other are applied to the first branch electrodes and the second branch electrodes, respectively, in the black state
Implementation Method 4
the liquid crystal molecules are aligned vertically with respect to the first display panel in a black state
Data Source
AI summary
A liquid crystal display (“LCD”) device includes: a first display panel including a first substrate, a first pixel electrode disposed on the first substrate, and a second pixel electrode disposed on the first substrate and insulated from the first pixel electrode; a second display panel including a second substrate opposite to the first substrate, and a common electrode disposed on the second substrate; and a liquid crystal layer disposed between the first and second display panels and including a plurality of liquid crystal molecules. In a black state, no voltage is applied to the common electrode and an electric field is generated between the first and second pixel electrodes in a way such that the liquid crystal molecules are aligned in a vertical direction with respect to the first substrate.