Liquid Crystal Composition for High Dichroic Ratio Polarizing Films
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Solution Overview
Problem
Current polarizing films with dichroic dyes have a low dichroic ratio and do not effectively absorb light in the desired wavelength range of 350 to 550 nm, limiting their polarizing performance.
Innovation Solution
A composition comprising a specific compound and a polymerizable liquid crystal compound, which forms a polarizing film with a high dichroic ratio by exhibiting a smectic liquid crystal phase and shifting the local maximum absorption wavelength, enhancing polarizing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bisazo type dye having 1,4-naphthyl structure is used as a dichroic dye, then the polarizing film can be formed, but the dichroic ratio is low
Solution Approach 1:
The patent modifies the molecular structure of the dichroic dye by changing the naphthyl group substitution pattern from 1,4- to 2,6-, and adjusts the absorption wavelength range from 390-550 nm to 350-550 nm. This structural parameter change results in a significant improvement of the dichroic ratio from low to 3.0 or more, while maintaining polarizing film formation capability
Solution Approach 2:
The patent creates a composite system by combining the specifically structured dichroic dye (formula 1) with a polymerizable liquid crystal compound. This composite material approach enables the dichroic dye to achieve high orientation within the liquid crystal matrix, resulting in a dichroic ratio of 3.0 or more while maintaining formability
2Reliability
If the absorption wavelength range is extended to 350-550 nm, then the polarizing performance is improved, but the dichroic ratio decreases
Solution Approach 1:
The patent achieves a breakthrough by simultaneously optimizing multiple parameters: the 2,6-naphthyl substitution pattern, the specific azo group positioning, and the absorption wavelength range of 350-550 nm. This multi-parameter optimization resolves the traditional trade-off, achieving both extended absorption range for improved polarizing performance and high dichroic ratio of 3.0 or more
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 composition achieves a high dichroic ratio and extended absorption range, resulting in improved polarizing film performance with a Bragg peak in x-diffraction measurements, suitable for liquid crystal display devices and organic EL display devices.
Implementation Method 1
the polymerizable liquid crystal compound exhibits a smectic liquid crystal phase
Implementation Method 2
a compound represented by formula (1) which has a local maximum absorption in a wavelength range of 390 to 550 nm and has a function as a dichroic dye
Implementation Method 3
a polarizing film containing a dichroic light-absorbing compound (dichroic dye) dispersed in an oriented polymerizable liquid crystal compound
Data Source
AI summary
Provided is a composition that can form a polarizing film with high dichroic ratio, which contains a compound having a function as a dichroic dye and having a local maximum absorption in a wavelength range of 350 to 550 nm. The composition contains a compound represented by the formula (1) and a polymerizable liquid crystal compound:wherein Y represents a group represented by the formula (Y1) or the formula (Y2)