Rhodamine Coloring Composition for LCD Heat Resistance
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Solution Overview
Problem
Conventional coloring compositions for color filters, particularly those using rhodamine derivatives, lack sufficient heat resistance, leading to issues like fading and hue changes during the manufacturing process of liquid crystal display elements.
Innovation Solution
A coloring composition comprising a cationic rhodamine derivative with a specific anion and an ethylenically unsaturated bond, or a polymer derived from this compound, which enhances heat resistance and reduces dye elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pigment is used for coloring, then heat resistance and light resistance are improved, but light scattering occurs due to large particle size which decreases contrast
Solution Approach 1:
The pigment particles are micronized to divide them into smaller units, reducing light scattering while maintaining heat resistance. This segmentation allows the particles to be small enough to suppress contrast degradation but still provide the thermal stability of pigments.
Solution Approach 2:
The invention creates a composite system by combining micronized pigment particles with a specific binder resin and solvent. This composite formulation ensures that the micronized pigment maintains dispersion stability while achieving both heat resistance and high contrast.
2Illumination intensity
If a dye is used for coloring, then light scattering is suppressed and contrast is enhanced, but heat resistance deteriorates causing fading and hue change
Solution Approach 1:
The invention changes the chemical parameters of the dye molecule by introducing specific structural modifications - adding an ethylenically unsaturated bond and selecting particular counter anions. These parameter changes enable the dye to withstand high temperatures without fading while maintaining its contrast-enhancing properties.
Solution Approach 2:
The invention uses a specifically selected binder resin as an intermediary between the dye and the substrate. This binder protects the dye molecules from thermal degradation during manufacturing processes while allowing the dye to function effectively in enhancing contrast.
3Illumination intensity
If pigment is micronized to reduce particle size, then light scattering is reduced and contrast is improved, but dispersion stability becomes difficult to secure
Solution Approach 1:
The invention employs a specifically selected binder resin as an intermediary that stabilizes the micronized pigment particles. This binder prevents aggregation and settling of the fine particles, maintaining uniform dispersion throughout the coloring composition while allowing the particles to remain small enough to suppress light scattering.
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 exhibits superior heat resistance, preventing fading even at high temperatures and maintaining color integrity, making it suitable for applications in liquid crystal displays and other optical materials.
Implementation Method 1
a cationic rhodamine derivative having a specific anion, as a counter anion, and an ethylenically unsaturated bond, or a polymer having a monomer unit derived from the compound, as a dye
Data Source
AI summary
A colored resin composition using a conventional rhodamine derivative has not provided heat resistance in a practical range. Therefore, it is an object of the present invention to provide a coloring composition having higher heat resistance as compared with the conventional coloring composition. The present invention relates to a compound represented by the following general formula (1), and a polymer having a monomer unit derived from the compound, and the like. (wherein R1 to R4 each independently represent a hydrogen atom, an alkyl group, and the like; R7 represents a hydrogen atom or a methyl group; R8 and R9 each independently represent a hydrogen atom or an alkyl group; Y represents a nitrogen atom or a group represented by the following formula (1-1): A1 represents an alkylene group which has at least one group selected from -O-, -OCO-, -COO-, -NHCO-, -CONH-, -NHCONH- and an arylene group in the chain, and the like; A2 represents -NH- or -O-; An- represents an anion containing an aryl group having an electron-withdrawing substituent, and the like; n represents an integer of 0 to 3; R8 and R9 may form a cyclic structure of a 5 to 6 membered ring together with -N-(CH2)n-Y bonding thereto.)