Asymmetrical V-Shape Pattern for Liquid Crystal Alignment
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Solution Overview
Problem
Existing methods for forming patterns on liquid crystal orientation films for zenithal bi-stable liquid crystal panels face challenges in achieving large-area uniformity and asymmetry, leading to difficulties in minimizing unnecessary power consumption.
Innovation Solution
A method involving the manufacture of a silicon substrate with an asymmetrical V-shaped pattern, followed by deposition of a silicon-based compound, imprint lithography to form a guide pattern, dry etching to transfer the pattern, wet etching to form an asymmetrical pattern, and finally transferring this pattern onto a glass substrate using a dielectric intermediary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If dry etching by reactive ion etching (RIE) is performed with the specimen in an inclined form to form asymmetrical patterns, then asymmetrical pattern formation is achieved, but the chamber size needs to be very large and ion beam position varies making large-area uniform pattern formation difficult
Solution Approach 1:
The patent applies asymmetry by forming patterns with different etching depths on the front and rear surfaces of the substrate. The front surface has patterns etched to a first depth while the rear surface has patterns etched to a second depth greater than the first depth, creating an asymmetrical structure that enables zenithal bi-stable liquid crystal display without requiring inclined specimen positioning in large chambers
Solution Approach 2:
The patent transitions from two-dimensional surface patterning to three-dimensional depth-based patterning by etching patterns to different depths on opposite surfaces of the substrate. This dimensional approach allows asymmetrical pattern formation using standard horizontal chamber equipment, eliminating the need for inclined specimen positioning and large chamber sizes
2Reliability
If a pattern is formed on the liquid crystal orientation film to enable zenithal bi-stable state, then liquid crystal direction is maintained at zero-potential, but the process complexity increases due to multiple etching and deposition steps
Solution Approach 1:
The patent segments the pattern formation process into distinct front surface and rear surface etching operations, each performed on opposite sides of the substrate. This segmentation allows for independent control of pattern depth on each surface, simplifying the overall process by avoiding complex inclined positioning while achieving the required asymmetry for zenithal bi-stable operation
Solution Approach 2:
The patent performs preliminary pattern formation on both surfaces before final assembly, using standard horizontal etching processes. By pre-forming the asymmetrical patterns on separate surfaces and then assembling the substrate, the method avoids complex in-situ inclined etching while ensuring the liquid crystal orientation film receives the correct asymmetrical pattern for direction maintenance
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 method enables the uniform formation of asymmetrical patterns on liquid crystal orientation films, effectively maintaining liquid crystal direction at zero-potential after voltage application, thereby minimizing unnecessary power consumption.
Implementation Method 1
depositing a silicon-based compound on the silicon substrate
Implementation Method 2
transferring a pattern from the formed guide pattern onto the silicon-based compound layer by dry etching
Implementation Method 3
forming the pattern in an asymmetrical form on the silicon substrate by wet etching
Implementation Method 4
hydrophobically treating a pattern surface of the silicon substrate
Implementation Method 5
transferring the pattern in an asymmetrical form onto a glass substrate by disposing the surface-treated silicon substrate to face the glass substrate
Data Source
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Figure 5(A)~6
AI summary
Disclosed are a method for forming a pattern for liquid crystal orientation of a zenithal bi-stable liquid crystal panel, which can prevent or minimize unnecessary power consumption because a liquid crystal direction is maintained even at a zero-potential after application of voltage by forming an asymmetrical pattern on a liquid crystal orientation film of a zenithal bi-stable liquid crystal panel, a liquid crystal orientation substrate including the pattern formed thereby, and a mask substrate used for forming the pattern. The method for forming a pattern for liquid crystal orientation of a zenithal bi-stable liquid crystal panel, includes: (a) depositing a silicon-based compound on a silicon substrate, (b) forming a guide pattern on an upper portion of the deposited silicon-based compound layer by using an imprint lithography, (c) discontinuously exposing the silicon substrate by transferring a pattern from the formed guide pattern onto the silicon-based compound layer by dry etching, (d) forming a pattern in an asymmetrical form on the silicon substrate by wet etching, (e) removing a remaining silicon-based compound layer, and then hydrophobically treating a pattern surface of the silicon substrate; and (f) transferring a pattern in an asymmetrical form onto a glass substrate by allowing the surface-treated silicon substrate to face the glass substrate, and supplying a dielectric therebetween.