Polarizer-Alignment Dual Function Film for LCD
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Solution Overview
Problem
Conventional polarizers and alignment films for liquid crystal displays have poor resistance to environmental factors like moisture and heat, require complex fabrication processes, and induce dust and static charge, making them inconvenient and inefficient.
Innovation Solution
A polarizer-alignment dual function film with an optically anisotropic material layer comprising liquid crystals and optically dichroic materials, integrated with a substrate using a mold to form strips for both polarization and alignment functions, simplifying the manufacturing process and eliminating the need for separate polarizers and alignment films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional polarizer and alignment film are used separately, then both polarization and alignment functions are achieved, but the device complexity and number of fabrication processes increase
Solution Approach 1:
The patent combines the polarizer and alignment film into a single integrated film structure. The optically anisotropic material layer contains both the polarization function (through dichroic dyes or iodine) and the alignment function (through polyimide or polyamic acid), eliminating the need for separate films and reducing fabrication complexity
Solution Approach 2:
The single film performs multiple functions simultaneously: it provides polarization through optically anisotropic materials and provides liquid crystal alignment through polyimide/polyamic acid components. This multi-functional design replaces what previously required separate specialized films
2Reliability
If conventional rubbing process is used for alignment, then liquid crystal molecules are aligned, but dust and static charge are induced
Solution Approach 1:
The patent replaces the mechanical rubbing process with a photoalignment method using UV irradiation. The photopolymerization of polyamic acid creates the alignment structure through light-induced chemical reactions rather than mechanical contact, eliminating dust generation and static charge accumulation
3Ease of manufacture
If polyamic acid is used for alignment film, then alignment function is provided, but it decomposes at high temperature during storage
Solution Approach 1:
The patent utilizes the phase transition from polyamic acid to polyimide through thermal imidization. The film is initially formed as polyamic acid which can be coated from solution, then undergoes controlled thermal treatment to convert to the more thermally stable polyimide form, combining the advantages of both materials
Solution Approach 2:
The patent performs preliminary coating of the alignment layer as polyamic acid from solution, which is easier to process, then applies a controlled thermal treatment to convert it to polyimide before final device assembly. This preliminary action allows easy coating while subsequent treatment provides thermal stability
4Stability of the object's composition
If polyimide is used for alignment film, then thermal stability is improved, but it is hard to dissolve and coat on substrate
Solution Approach 1:
The patent inverts the conventional approach by first coating the film as polyamic acid (which is soluble and easy to process) and then converting it to polyimide through thermal treatment. This reverses the traditional sequence of making polyimide first and then attempting to process it, solving the solubility problem
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 dual function film enhances the contrast ratio and view angle of liquid crystal displays, reduces thickness, and eliminates issues like dust and static charge, while providing a single-layered solution for both polarization and alignment, improving the overall display performance.
Implementation Method 1
the optically anisotropic components therein such as crystals containing iodine are arranged in order, thus the light into the polarizer with a specific electric field direction is absorbed to generate a polarized light
Implementation Method 2
an optically dichroic material
Implementation Method 3
A pair of alignment films 105 and 106 is disposed between the upper and lower substrates sandwiching a liquid crystal layer 110, such that the liquid crystal molecules therein are arranged in order
Data Source
AI summary
A polarizer-alignment dual function film. The film comprising an optically anisotropic material layer having a plurality of strips integrally formed thereon. The strips provide an alignment function for aligning the liquid crystal molecules while the optically anisotropic material provides a polarization function such that the two functions can be integrated into a single-layered film.