Squarylium Dye Optical Filter for Near-Infrared Blocking
Find Innovative SolutionsGenerate Solutions
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 excellent near-infrared light blocking properties, which affects color reproducibility, especially for blue-colored images.
Innovation Solution
An optical filter design incorporating a near-infrared absorbing dye with specific absorption characteristics, including a maximum absorption wavelength between 670 to 730 nm, a high absorption coefficient ratio between 430 to 550 nm and 670 to 730 nm wavelengths, and a steep spectral transmittance curve change, ensuring high transmittance in the visible region while effectively blocking near-infrared light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a squarylium-based dye is used to achieve high near-infrared cutoff property, then the cutoff property is excellent, but the visible light transmittance particularly in the 430 to 550 nm range is insufficient
Solution Approach 1:
The patent modifies the molecular structure parameters of the squarylium-based dye by introducing specific substituents (electron-withdrawing groups at positions 2 and 6, and electron-donating groups at positions 1 and 4) to change the absorption characteristics. This structural parameter change shifts the absorption maximum to 670-730 nm and increases the absorption coefficient ratio, thereby improving visible light transmittance while maintaining near-infrared cutoff property
Solution Approach 2:
The patent creates a composite dye structure by combining squarylium core with specific substituent groups having different electronic properties. The composite molecular structure integrates both the near-infrared absorption capability of the squarylium core and the visible light transmission enhancement provided by the carefully selected substituent groups
2Reliability
If multiple different dyes are used in combination to improve visible light transmittance, then color reproducibility may improve, but visible light absorption increases collaterally, reducing overall transmittance
Solution Approach 1:
Instead of combining multiple different dyes, the patent extracts and optimizes the light absorption properties within a single squarylium-based dye molecule. By carefully selecting and positioning specific substituent groups, the invention achieves both good color reproducibility and high visible light transmittance without the collateral absorption increase that would result from using multiple dye components
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, enhancing color reproducibility and maintaining excellent near-infrared blocking capabilities, thereby improving image quality.
Implementation Method 1
an absorption layer containing a near-infrared absorbing dye with an absorption characteristic measured by dissolved in dichloromethane
Data Source
AI summary
An optical filter includes an absorption layer containing a near-infrared absorbing dye with an absorption characteristic in dichloromethane satisfying (i-1) to (i-3). (i-1) In an absorption spectrum of a wavelength of 400 to 800 nm, there is a maximum absorption wavelength λmax in 670 to 730 nm. (i-2) Between a maximum absorption coefficient εA of light with a wavelength of 430 to 550 nm and a maximum absorption coefficient εB of light with a wavelength of 670 to 730 nm, the following relational expression: εB/εA≥65 is established. (i-3) In a spectral transmittance curve, the difference between a wavelength λ80 with which the transmittance becomes 80% on a shorter wavelength side than the maximum absorption wavelength with the transmittance at the maximum absorption wavelength λmax set to 10% and the maximum absorption wavelength λmax is 65 nm or less.