Alignment Film Material for PDLC Display Transmittance
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Solution Overview
Problem
Existing display devices using polymer dispersed liquid crystal (PDLC) technology face challenges in achieving high transparency and uniform display due to light absorption by alignment films, leading to decreased luminance and color shifts as distance from the light source increases.
Innovation Solution
A method of manufacturing a display device involves applying an alignment film material with a specific composition of photolytic and non-photolytic components to substrates, where the photolytic component contains a polyamic acid ester with structural units that absorb less light, and the non-photolytic component has a higher content, reducing light absorption and allowing for thinner alignment films, thereby enhancing transmittance and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional alignment films are used in PDLC display devices, then the alignment function is achieved, but light absorption increases causing decreased luminance and color shifts
Solution Approach 1:
The patent changes the chemical composition parameters of the alignment film material by incorporating specific photolytic components (compounds with cinnamyl, coumarin, or oxa-coumarin structures) that have lower light absorption coefficients in the visible range. This parameter change allows the alignment film to maintain its alignment function while reducing light absorption, thereby improving luminance and reducing color shifts.
Solution Approach 2:
The patent uses composite alignment film materials consisting of multiple components including photolytic components, non-photolytic components, and solvents in specific ratios. This composite structure combines the alignment properties of photolytic materials with the optical transparency benefits of carefully selected non-photolytic components, achieving both alignment function and reduced light absorption.
2Reliability
If thicker alignment films are used to ensure sufficient alignment, then alignment reliability improves, but light absorption increases causing non-uniform display
Solution Approach 1:
The patent changes the optical parameters of the alignment film material by selecting compounds with inherently lower light absorption coefficients. This allows the use of thinner film layers (reducing total light absorption path length) while maintaining sufficient alignment reliability through optimized molecular structures and compositions that provide effective alignment at reduced thicknesses.
Solution Approach 2:
The patent optimizes the local composition and thickness of the alignment film to achieve uniform optical properties across the entire display area. By controlling the spatial distribution of photolytic and non-photolytic components and adjusting film thickness locally, the patent ensures consistent alignment performance and uniform light transmission across the display surface.
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 results in improved luminance and reduced color shift across the display, maintaining high transparency and uniformity by minimizing light absorption and allowing for thinner alignment films, which are sufficient for PDLC display devices.
Implementation Method 1
applying ultraviolet light or visible light to the alignment film material to decompose the photolytic component, thus forming a first alignment film on the first substrate and a second alignment film on the second substrate
Implementation Method 2
applying ultraviolet light to the liquid crystal material to polymerize the polymerizable monomer in the liquid crystal material to form a polymer containing a polymer chain
Data Source
AI summary
According to one embodiment, a method of manufacturing a display device comprises applying an alignment film material containing a photolytic component and a non-photolytic component to a surface of a first substrate and a surface of a second substrate, forming a first alignment film on the first substrate and a second alignment film on the second substrate, introducing a liquid crystal material containing liquid crystal molecules and a polymerizable monomer between the first alignment film and the second alignment film, and applying ultraviolet light to the liquid crystal material to polymerize the polymerizable monomer in the liquid crystal material to form a polymer dispersed liquid crystal layer.