LCD Substrate Cleaning via Vacuum Drying and Ultrasonic Blasting
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Solution Overview
Problem
The normal-pressure dispensation alignment method for manufacturing liquid crystal display devices faces issues with reliability and yield due to contamination from inorganic ions, organic matters, and residues, leading to visible defects and reduced efficiency.
Innovation Solution
The method involves a contaminant removing step using vacuum drying, suction, or ultrasonic wave air flow blasting to clean the substrates before liquid crystal dispensing, and a low-temperature complete curing process for the sealing material to prevent activation of organic matters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If normal-pressure dispensation alignment method is used, then manufacturing facility complexity is reduced and workability is improved, but substrate contamination from inorganic ions and organic matters increases leading to reliability deterioration
Solution Approach 1:
The patent applies preliminary action by performing substrate cleaning and drying processes before liquid crystal dispensing. Specifically, the substrate is cleaned to remove inorganic ions and organic matters, then dried using a drying sheet or heating process to prevent contamination during the normal-pressure dispensation alignment process, thereby maintaining reliability while using the simpler manufacturing method
Solution Approach 2:
The patent creates a controlled environment by using a drying sheet that provides a clean, contamination-free surface during the alignment process. This inert environment prevents inorganic ions and organic matters from contaminating the substrate and liquid crystal, allowing normal-pressure dispensation to proceed without compromising reliability
2Ease of operation
If normal-pressure dispensation alignment method is used, then liquid crystal spread control is improved, but substrate contamination from residues increases leading to visible defects
Solution Approach 1:
The patent performs preliminary cleaning and drying of the substrate before liquid crystal dispensing. The substrate is cleaned to remove residues, then dried using a drying sheet or heating process to ensure the surface is completely free from contamination before alignment, preventing visible defects while maintaining ease of liquid crystal spread control
Solution Approach 2:
The patent introduces a drying sheet as an intermediary element between the cleaning process and the liquid crystal dispensing. The drying sheet absorbs residual moisture and contaminants, providing a perfectly clean surface that allows both good liquid crystal spread control and high substrate cleanliness
3Reliability
If sealing material is cured at high temperature, then curing completeness is improved, but organic matter activation increases leading to alignment layer deterioration
Solution Approach 1:
The patent changes the temperature parameter by using a drying sheet or reduced-temperature heating process instead of high-temperature curing. This parameter change allows the sealing material to cure completely at lower temperatures, preventing organic matter activation and alignment layer deterioration while still achieving reliable curing
Solution Approach 2:
The patent uses a drying sheet as an intermediary that enables complete sealing material curing without requiring high temperatures. The drying sheet provides the necessary thermal management to cure the sealing material thoroughly while maintaining temperatures below the threshold for organic matter activation
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 effectively removes contaminants and reduces visible defects, improving the reliability and yield of the LCD manufacturing process by preventing contamination and minimizing the activation of organic matters during the curing process.
Implementation Method 1
a process of heating the pair of substrates in a low-pressure atmosphere after a cleaning step and a drying step which are performed after alignment layers are formed on the pair of substrates
Implementation Method 2
a process of heating the pair of substrates in a low-pressure atmosphere
Implementation Method 3
a suction process of sucking up contaminant particles on the substrates by use of air flow which is generated in the vicinity of the edge of a nozzle having a predetermined shape
Implementation Method 4
a blowing process of blasting air flow to which ultrasonic waves have been applied against the substrates and thereby removing the contaminant particles
Data Source
AI summary
Disclosed is a method of manufacturing a liquid crystal display device using a liquid crystal dispensation alignment method which includes steps of: removing inorganic ions and the like by performing a vacuum drying process on substrates after cleaning alignment layers on which a rubbing process has been performed; and removing foreign objects by performing any one of a process for sucking up foreign objects by use of a nozzle having a specialized shape and a process for blasting a gas to which ultrasonic waves have been applied against the foreign objects, before liquid crystal is dispensed. In addition, a temperature at which sealing material is cured completely is lowered in order to inhibit activation (migration) of organic matters and to thereby reduce visible defects such as alignment bright defects.