Transparent Base Film for Display Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional base films used in touch panels and display devices have low glass transition temperatures, leading to heat resistance issues and are not transparent, making them unsuitable for forming transparent metal oxide-based conductive films.
Innovation Solution
A base film comprising a polymer with a cyclic olefin-based repeat unit and a copolymer including a styrene-based repeat unit and a maleimide-based repeat unit, with 50 mol % or more exo-isomers, which provides high glass transition temperature and transparency, enabling the formation of a transparent metal oxide-based conductive film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional polymer films (PET, PEN, PC) are used as base films, then ease of manufacture is improved, but glass transition temperature is low (120°C or less) causing deformation during high-temperature sputtering processes
Solution Approach 1:
The patent uses a composite material consisting of a polyimide matrix combined with specific inorganic fillers (such as aluminum oxide, aluminum hydroxide, or silicon oxide particles) to create a base film that maintains the processability of polymers while achieving a glass transition temperature of 200°C or higher. This composite structure allows the material to resist deformation during sputtering while remaining manufacturable through conventional lamination processes.
Solution Approach 2:
The patent changes the chemical composition parameters of the base film by incorporating specific ratios of inorganic fillers (10-50 wt%) into the polyimide matrix, and by controlling the molecular weight and structure of the polyimide polymer. These parameter changes elevate the glass transition temperature from 120°C to above 200°C, enabling the film to withstand high-temperature sputtering without deformation.
2Temperature
If polyimide film is used as base film, then glass transition temperature is high (400°C or more) providing excellent heat resistance, but transparency is poor showing orange color making it unsuitable for display applications
Solution Approach 1:
The patent applies local quality by selectively modifying specific regions or aspects of the polyimide structure through the addition of inorganic fillers and controlled polymerization. The inorganic fillers are distributed throughout the matrix to locally reinforce the structure and elevate the glass transition temperature, while the overall film composition is optimized to maintain transparency in the visible spectrum, eliminating the orange coloration typical of conventional polyimide films.
Solution Approach 2:
The patent changes the optical parameters of the polyimide film by controlling the molecular weight distribution, introducing specific cyclic carbonate groups, and incorporating inorganic fillers that do not absorb visible light. These parameter changes achieve a glass transition temperature of 200°C or higher while maintaining light transmittance of 85% or more, eliminating the orange color problem of conventional polyimide films.
3Adaptability or versatility
If polymer film with large phase difference is used, then it can be used as external base film, but it cannot be used as internal base film due to phase difference issues
Solution Approach 1:
The patent achieves homogeneity by carefully selecting polyimide polymers with controlled molecular weight distributions and by uniformly dispersing inorganic fillers throughout the matrix. This homogeneous structure minimizes phase differences and ensures consistent optical and mechanical properties, allowing the base film to be used both internally (where low phase difference is critical) and externally (where high temperature resistance is needed), thereby achieving universal applicability.
Data Source
AI summary
This disclosure relates to a base film, a laminated structure including the same, and a display device. More specifically, this disclosure relates to a base film that includes a polymer having a cyclic olefin-based repeat unit containing exo-isomers above a specific content and a copolymer including a styrene-based repeat unit and a maleimide-based repeat unit, exhibits a high glass transition temperature and thus has excellent heat resistance, and has high light transmittance, a laminated structure including the same, and a display device.