Liquid Crystal Cell Adhesive Layer for Stable Gap Under Autoclave
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Solution Overview
Problem
Existing methods for maintaining cell gap and adhesion between substrates in liquid crystal cells face challenges, particularly during high-temperature and high-pressure processes, leading to pressing black spots and adhesive contamination.
Innovation Solution
An optical device with specific properties, including a pressure-sensitive adhesive layer on the upper substrate and spacers on the lower substrate, utilizing materials with controlled storage elastic modulus and tangent delta values to maintain cell gap and adhesion, preventing pressing black spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a pressure-sensitive adhesive layer is used to maintain cell gap and provide adhesion between substrates, then adhesion force and cell gap maintenance are improved, but pressing black spots occur during high-temperature and high-pressure autoclave processes
Solution Approach 1:
The patent applies parameter changes by precisely controlling the storage elastic modulus (10^4 to 10^6 Pa) and tangent delta value (0.05 to 0.5) of the pressure-sensitive adhesive layer at elevated temperatures (80-120°C). These parameter specifications ensure the adhesive maintains optimal balance between elasticity and viscosity during autoclave processing, preventing pressing black spots while securing sufficient adhesion force and cell gap maintenance.
2Strength
If adhesive is applied on column surface or wall surface to fix substrates, then adhesion between substrates is improved, but adhesive control becomes difficult and contamination risk increases
Solution Approach 1:
The patent extracts the adhesive application from problematic column or wall surfaces and relocates it to a flat substrate surface. By forming the pressure-sensitive adhesive layer directly on the substrate before liquid crystal filling, the invention eliminates the need for complex micro-stamping processes, enables precise control of adhesive thickness and area, and prevents contamination of alignment films and liquid crystal.
Solution Approach 2:
The patent applies preliminary action by pre-forming the pressure-sensitive adhesive layer on the substrate before assembling the liquid crystal cell. This advance preparation ensures the adhesive is already in optimal position and condition, facilitating precise control during subsequent assembly steps and preventing contamination issues that would arise from later adhesive application.
3Reliability
If liquid crystal cell is subjected to high-temperature and high-pressure autoclave process for bonding, then adhesion between substrates is improved, but pressing black spots are expressed
Solution Approach 1:
The patent resolves this contradiction by specifying optimal ranges for storage elastic modulus (10^4 to 10^6 Pa) and tangent delta (0.05 to 0.5) of the pressure-sensitive adhesive layer at autoclave temperatures (80-120°C). These parameter changes ensure the adhesive maintains appropriate mechanical properties during high-temperature and high-pressure bonding, achieving reliable adhesion while preventing pressing black spots.
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 maintains cell gap and adhesion between substrates, ensuring stability and preventing defects even after high-temperature and high-pressure processes.
Implementation Method 1
the pressure-sensitive adhesive layer (10c) has a storage elastic modulus of 18,000 Pa or more at a temperature of 110°C and a frequency of 1 rad/sec, and a tangent delta value of 0.32 or less at a temperature of 110°C and a frequency of 1 rad/sec
Data Source
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AI summary
The present application relates to an optical device. The optical device of the present application can properly maintain a cell gap of a liquid crystal cell, have excellent adhesion between an upper substrate and a lower substrate, and can prevent pressing black spots after a high-temperature and high-pressure autoclave process.