Near-Infrared-Absorbing Dye for High Visible Transmittance
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Solution Overview
Problem
Current optical filters used in imaging devices face challenges in achieving high visible light transmittance, particularly in the 430 to 550 nm wavelength range, while maintaining effective near-infrared light blocking properties, which affects color reproducibility, especially for blue colors.
Innovation Solution
A near-infrared-absorbing dye with specific absorption characteristics, such as those represented by Formulas (AI) and (AII), is used in an optical filter, which includes an absorption layer containing the dye and a resin, to enhance visible light transmittance and near-infrared blocking capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional squarylium-based dyes are used to achieve high near-infrared blocking, then the cutoff property of near-infrared light is excellent, but the transmittance of light with wavelength of 430 to 550 nm is insufficient
Solution Approach 1:
The patent modifies the molecular structure parameters of squarylium-based dyes by introducing specific substituents (Formula (AI) and (AII)) to change the absorption spectrum characteristics, achieving high absorption in near-infrared region while maintaining high transmittance in the 430-550 nm visible region
Solution Approach 2:
The patent uses composite dye structures combining squarylium core with specific heterocyclic rings and substituent groups to achieve multi-functional properties: strong near-infrared absorption and high visible light transmittance simultaneously
2Illumination intensity
If multiple different dyes are used in combination to attempt to increase visible light transmittance, then various wavelengths can be covered, but visible light absorption increases collaterally resulting in failed attempt to obtain high visible light transmittance
Solution Approach 1:
The patent extracts and eliminates the problematic characteristic of collateral visible light absorption that occurs with multi-dye combinations, by using a single optimized squarylium-based dye structure that selectively absorbs only in the near-infrared region
Solution Approach 2:
The patent introduces a specifically designed squarylium-based dye as an intermediary substance that mediates between near-infrared blocking and visible light transmission, achieving both functions without the need for multiple dye combinations
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 solution achieves high transmittance in the visible region, particularly in the 430 to 550 nm range, while maintaining excellent near-infrared blocking properties, thereby improving color reproducibility and visibility in imaging devices.
Implementation Method 1
an absorption characteristic measured by dissolving the dye in dichloromethane satisfies the following requirements (i-1) to (i-3)
Data Source
AI summary
Provided is a near-infrared-absorbing dye increasing a visible light transmittance and having a near-infrared blocking characteristic. The near-infrared-absorbing dye has an absorption characteristic measured by dissolving the dye in dichloromethane satisfying the following requirements. ⋅In an absorption spectrum at a wavelength of 400 to 800 nm, there is a maximum absorption wavelength λmax in a wavelength region of 670 nm or more. ⋅The following relational expression is established between a maximum absorption constant εA with respect to light with a wavelength of 430 to 550 nm and a maximum absorption constant εB with respect to light with a wavelength of 670 nm or more, where εB/εA≥65. ⋅In a spectral transmittance curve, an average transmittance of light with a wavelength of 430 to 460 nm is 94.0% or more when a transmittance at the maximum absorption wavelength λmax is set to 1%.