Liquid Crystal Display Polymer Pre-Tilt Angle Fixing
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Solution Overview
Problem
Vertical alignment mode liquid crystal displays (LCDs) with cutouts in field-generating electrodes suffer from large response times and instantaneous afterimages due to random motion of liquid crystal molecules far from cutouts, leading to irregular domains and reduced viewing angles.
Innovation Solution
A liquid crystal display panel with homeotropic alignment layers and a polymer that fixes the pre-tilt angle of liquid crystal molecules, formed by polymerizing specific monomers, is used to improve response time and reduce afterimages. The polymer is applied close to the alignment layers and can be present in micro slits or partitions, adjusting the tilt directions of liquid crystal molecules across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cutouts are made in field-generating electrodes to achieve wide viewing angle, then reference viewing angle is improved, but response time deteriorates due to random motion of liquid crystal molecules far from cutouts
Solution Approach 1:
The patent introduces a polymer layer with specific local properties (pre-tilt angle fixing capability) at strategic positions within the liquid crystal layer. This polymer layer provides different functional characteristics to different regions: near cutouts it stabilizes the fringe field alignment, while far from cutouts it prevents random motion through its pre-tilt angle fixing property, thus resolving the contradiction between wide viewing angle and fast response time
Solution Approach 2:
The patent creates a composite structure by combining the liquid crystal material with a polymer component that has specific pre-tilt angle fixing properties. This composite system allows the liquid crystal molecules to benefit from both the fringe field alignment near cutouts (for wide viewing angle) and the stabilizing effect of the polymer (for fast response time), effectively resolving the technical contradiction
2Adaptability or versatility
If cutouts are made in field-generating electrodes to distribute tilt directions, then reference viewing angle is improved, but instantaneous afterimage is generated due to irregular domains
Solution Approach 1:
The polymer layer is strategically positioned and configured to provide local quality enhancement: it fixes pre-tilt angles in regions far from cutouts where random motion occurs, while allowing fringe field dominance near cutouts for tilt direction distribution. This localized functional differentiation resolves the contradiction between wide viewing angle and afterimage elimination
Solution Approach 2:
The patent uses the polymer layer to create a consistent pre-tilt angle pattern across different regions of the liquid crystal layer, effectively copying the desired alignment state from regions near cutouts to regions far from cutouts. This ensures uniform domain structure and eliminates irregular domains that cause afterimages, while maintaining the tilt direction distribution needed for wide viewing angle
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 significantly reduces the random motion of liquid crystal molecules, enhancing response time and preventing irregular arrangements, thereby improving the contrast ratio and widening the viewing angle of the LCD.
Implementation Method 1
a polymer fixing a pre-tilt angle of liquid crystal molecules of the liquid crystal materials. Herein, the polymer is formed by polymerizing at least one selected from monomers
Implementation Method 2
a homeotropic alignment layer formed on the first field generating electrode and the second field-generating electrode
Implementation Method 3
the LC molecules disposed close to the cutouts may be readily aligned by the fringe field with a perpendicular direction to the fringe field
Data Source
AI summary
A liquid crystal display panel includes: a first substrate and a second substrate facing each other, a first field-generating electrode and a second field-generating electrode formed on at least one of the first substrate and the second substrates, a homeotropic alignment layer formed on the first field-generating electrode and the second field-generating electrode and a liquid crystal material formed between the first substrate and the second substrate. The liquid crystal display panel further includes a polymer fixing a pre-tilt angle of liquid crystal molecules of the liquid crystal material, wherein the polymer is formed by polymerizing at least one selected from monomers represented by Chemical Formulas (I), (II), (III), and (IV).wherein, each of R1 and R2 includes at least one of acrylate, a vinyl group, and an epoxy group, n is 0 to 2, each of X1 to X4 is hydrogen or fluorine, Y is at least one selected from —CH2—, —O—, —CO—, —C(CF3)2—, and a single bond.