Sealant Elastic Modulus for Narrow Frame Adhesion
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Solution Overview
Problem
The challenge in liquid crystal display devices is to develop a sealant with sufficient adhesion strength, especially when the area of the sealant is reduced, and it needs to adhere to both organic and inorganic materials while maintaining the display quality and preventing misalignment and image lag.
Innovation Solution
A sealant comprising an epoxy resin without an acrylate skeleton and a resin with an acrylate skeleton, with a storage elastic modulus between 1.0×10^7 Pa and 1.5×10^9 Pa, is used, which is photocuring-thermosetting and contacts the alignment films and inorganic material layers, ensuring strong adhesion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the sealant area is reduced to achieve a narrower frame structure, then the device size is reduced, but the adhesion strength of the sealant deteriorates
Solution Approach 1:
The patent changes the physical and chemical parameters of the sealant by specifying a storage elastic modulus range (1.0×10^7 to 1.5×10^9 Pa) and using specific resin compositions (epoxy resin without acrylate skeleton combined with acrylate skeleton resin). This allows the sealant to maintain sufficient adhesion strength even when the sealant area is reduced, resolving the contradiction between narrower frame structure and adequate adhesion strength.
Solution Approach 2:
The patent employs a composite resin composition combining epoxy resin without an acrylate skeleton and resin with an acrylate skeleton. This composite material approach enables the sealant to achieve both the required adhesion strength to organic films and the appropriate elastic modulus, allowing reduced sealant area while maintaining bonding performance.
2Length of stationary object
If the sealant area is reduced to achieve a narrower frame structure, then the device size is reduced, but the reliability of the display device deteriorates
Solution Approach 1:
By precisely controlling the storage elastic modulus within the range of 1.0×10^7 to 1.5×10^9 Pa and selecting specific resin compositions, the patent ensures that the reduced sealant area still provides sufficient adhesion to both organic alignment films and inorganic material layers, thereby maintaining display reliability despite the narrower frame structure.
Solution Approach 2:
The patent applies different resin components strategically: epoxy resin without acrylate skeleton provides strong adhesion to inorganic materials, while acrylate skeleton resin ensures adequate bonding to organic alignment films. This localized material optimization ensures reliable performance in the reduced sealant area.
3Strength
If a sealant with high adhesion strength is used to adhere to organic films, then the adhesion strength is improved, but the risk of image lag increases
Solution Approach 1:
The patent specifies a controlled storage elastic modulus range (1.0×10^7 to 1.5×10^9 Pa) that balances adhesion strength and flexibility. This parameter control allows the sealant to adhere strongly to organic alignment films while maintaining sufficient elasticity to prevent image lag, resolving the contradiction between adhesion strength and image quality.
Solution Approach 2:
The patent controls the glass transition temperature (Tg) of the sealant to be 30°C or higher, which ensures the sealant maintains appropriate rigidity at operating temperatures. This prevents excessive deformation that could cause image lag while still providing sufficient adhesion strength to organic films.
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 solution provides improved adhesion between the substrates and alignment films, enhances display reliability, prevents misalignment, and reduces the risk of image lag, while maintaining the display quality even with a narrower frame structure.
Implementation Method 1
a sealant which adheres the first substrate and the second substrate
Implementation Method 2
a first alignment film which is formed on the first substrate, and aligns the liquid crystal molecules; wherein the first alignment film is an optical alignment film
Implementation Method 3
a storage elastic modulus of the sealant is greater than or equal to 1.0×10^7 Pa and less than or equal to 1.5×10^9 Pa
Data Source
AI summary
According to one embodiment, a liquid crystal display device includes a first substrate, a second substrate, a liquid crystal layer, a first alignment film, and a sealant, wherein the first alignment film is an optical alignment film, the sealant includes an epoxy resin not having an acrylate skeleton and a resin having an acrylate skeleton, a storage elastic modulus of the sealant is greater than or equal to 1.0×107 Pa and less than or equal to 1.5×109 Pa, and at least a part of the sealant is in contact with the first alignment film.