Dichroic Azo Compound for Polarizing Films
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Solution Overview
Problem
Current polarizing films lack a dichroic pigment with a maximum absorption wavelength in the range of 350 nm to 510 nm and high dichroic ratio, which is essential for optimal performance in various display devices.
Innovation Solution
A novel compound represented by Formula (1) is developed, which includes specific alkyl, alkoxy, acyl, and azo groups, and is used in conjunction with a polymerizable liquid crystal compound to create a polarizing film with a maximum absorption wavelength in the desired range, enhancing the dichroic ratio and light resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a bisazo pigment with a 1,4-naphthyl structure is used as a dichroic pigment, then the maximum absorption wavelength can be in the range of 350 nm to 550 nm, but the dichroic ratio becomes low
Solution Approach 1:
The patent changes the molecular structure parameters of the dichroic pigment by replacing the conventional 1,4-naphthyl structure with a 1,2,4-triazole ring structure and introducing specific substituent groups (R1-R5) with defined characteristics. This structural parameter change shifts the maximum absorption wavelength to 350-510 nm while simultaneously improving the dichroic ratio to 2.0 or higher, resolving the contradiction between absorption wavelength range and dichroic ratio
Solution Approach 2:
The patent creates a composite dichroic pigment molecule by combining a 1,2,4-triazole core structure with specific substituent groups including alkyl, alkoxy, acyl, and amino groups. This composite molecular structure achieves both the desired absorption wavelength range (350-510 nm) and high dichroic ratio (≥2.0) that cannot be achieved with conventional single-structure pigments
2Reliability
If a dichroic pigment with maximum absorption wavelength of 518 nm or higher is used, then the dichroic ratio can be high, but the maximum absorption wavelength is outside the desired range of 350 nm to 510 nm
Solution Approach 1:
The patent precisely controls the molecular structure parameters of the dichroic pigment, specifically the triazole ring structure with defined substituent groups R1-R5, to achieve a maximum absorption wavelength of 350-510 nm. This parameter optimization maintains the high dichroic ratio (≥2.0) while shifting the absorption peak to the desired wavelength range, unlike conventional pigments that absorb at 518 nm or higher
3Ease of manufacture
If conventional dichroic pigments are used in polarizing films, then the film can be manufactured, but the light resistance and overall performance are insufficient
Solution Approach 1:
The patent employs a composite dichroic pigment structure with a 1,2,4-triazole core and specifically designed substituent groups (R1-R5) that provide both high light resistance and desired optical properties. This composite molecular structure maintains ease of manufacture through conventional coating and drying processes while dramatically improving light resistance and dichroic performance compared to conventional pigments
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 novel compound allows for the production of polarizing films with high dichroic ratios and improved light resistance, achieving superior polarizability and performance in display devices.
Implementation Method 1
a compound serving as a dichroic pigment... which absorbs dichroic light... having a maximum absorption wavelength in a range of 350 nm to 510 nm
Data Source
AI summary
A compound serving as a dichroic pigment which has a maximum absorption wavelength in a range of 350 nm to 510 nm is represented by the following Formula (1):In Formula (1), R1 represents a hydrogen atom or a C1-C20 alkyl group; R2 through R4 are substituents which are not hydrogen atoms and each independently represent a C1-C4 alkyl group; m, p, and q are each independently an integer of 0 to 2; and R5 is (i) a C1-C10 alkyl group in which a hydrogen atom is substituted by at least one hydroxy group or (ii) a C1-C10 alkyl group which has carbon atoms and in which at least one —O— is inserted between the carbon atoms.