Squarylium Dye Optical Filter for Near-Infrared Blocking
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Solution Overview
Problem
Existing optical filters with near-infrared cut-off properties often suffer from low visible light transmittance, particularly in the 430 to 550 nm range, insufficient adhesiveness to substrates, and lack of light resistance, which affects image quality and durability.
Innovation Solution
An optical filter design incorporating a near-infrared absorbing dye with a squarylium skeleton and a urethane group, which enhances adhesiveness to both organic and inorganic materials and improves light resistance, while maintaining high visible light transmittance and near-infrared blocking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a squarylium-based dye with amide group is used to achieve near-infrared cutoff, then near-infrared blocking capability is improved, but visible light transmittance (especially 430-550 nm range) deteriorates
Solution Approach 1:
The patent modifies the chemical structure of the squarylium-based dye by replacing the amide group with a carbonyl group and introducing specific substituents (R1-R6) at different positions. This structural parameter change shifts the absorption spectrum to achieve high near-infrared blocking while improving visible light transmittance, particularly in the 430-550 nm blue region where previous dyes performed poorly.
Solution Approach 2:
The patent uses a composite resin layer containing the modified squarylium-based dye dissolved or dispersed in a transparent resin matrix. This composite structure allows the dye molecules to provide selective wavelength filtering while the resin matrix maintains overall transparency and mechanical properties, achieving both near-infrared blocking and high visible light transmittance.
2Strength
If a resin layer containing dye is stacked on inorganic substrate to increase strength, then mechanical strength is improved, but adhesiveness between layers deteriorates
Solution Approach 1:
The patent introduces specific functional groups (carboxyl, hydroxyl, or amino groups) at localized positions on the squarylium-based dye molecules. These localized functional groups provide specific chemical bonding sites that enhance adhesiveness between the resin layer and inorganic substrate, while the rest of the dye molecule structure maintains its optical filtering properties.
Solution Approach 2:
The modified squarylium-based dye acts as an intermediary substance between the organic resin matrix and the inorganic substrate. The dye molecules contain functional groups that can chemically bond to both the resin and the inorganic substrate surface, creating strong interfacial adhesion and preventing peeling, thus solving the adhesiveness problem between incompatible materials.
3Object-affected harmful factors
If multiple different dyes are used to enhance near-ultraviolet cutoff, then near-ultraviolet blocking capability is improved, but visible light absorption increases
Solution Approach 1:
The patent modifies the squarylium-based dye structure by introducing specific substituents (R1-R6) that extend the absorption cutoff into the near-ultraviolet region while maintaining high visible light transmittance. The careful selection of substituent types and positions allows the single dye molecule to provide both near-ultraviolet and near-infrared blocking without excessive visible light absorption.
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 filter achieves increased visible light transmittance, improved adhesiveness, and enhanced light resistance, leading to better image quality and durability, with specific spectral transmittance characteristics that optimize blue color reproduction and reduce incident angle dependence.
Implementation Method 1
an optical filter using a dye having high absorbency particularly in a near-infrared region and having a high transmitting property in a visible region
Implementation Method 2
adhesiveness between the resin layer and the transparent substrate or between the resin layer and the inorganic multilayer film
Data Source
AI summary
An optical filter includes an absorption layer which increases a visible light transmittance while having a good near-infrared blocking characteristic, and which is excellent in not only adhesiveness with respect to a layer to be abutted, but also light resistance. The optical filter includes: an absorption layer containing a near-infrared absorbing dye containing a squarylium-based dye and a transparent resin; and an inorganic or organic material in contact with the absorption layer. The squarylium-based dye has a squarylium skeleton and condensed ring structures bonded thereto respectively on both sides thereof, the condensed ring structures each including a benzene ring and a nitrogen atom as an annular atom, each benzene ring having an urethane structure in the second position.