Near-Infrared Absorbing Dye Filter for Visible Light Transmission
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Solution Overview
Problem
Current near-infrared cut filters fail to achieve both high visible light transmission and effective blocking of long-wavelength near-infrared light, compromising color reproducibility in imaging devices.
Innovation Solution
A near-infrared absorbing dye with a specific molecular structure, including a squarylium skeleton and thiophene groups, is used in an optical filter to enhance near-infrared blocking properties while maintaining high visible light transmission, specifically designed for imaging devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional near-infrared absorbents are used to block long-wavelength near-infrared light, then near-infrared blocking property is improved, but visible light transmission is reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the maximum absorption wavelength (λmax) of the squarylium dye to be within 800-1000 nm, and by controlling the full width at half maximum (FWHM) to be 50-150 nm. These parameter optimizations enable the dye to selectively absorb long-wavelength near-infrared light while transmitting visible light, resolving the contradiction between NIR blocking and visible light transmission
Solution Approach 2:
The patent uses composite materials by combining squarylium dye with specific resins to form an absorption layer. The composite structure allows the dye molecules to be dispersed in the resin matrix, creating a material that simultaneously achieves high NIR absorption and maintains visible light transmission properties of both components
2Object-affected harmful factors
If the absorption layer thickness is increased to improve near-infrared blocking, then blocking property is improved, but visible light transmission is reduced
Solution Approach 1:
The patent optimizes the thickness parameter of the absorption layer to be within 1-10 μm. This parameter control, combined with the optimized dye concentration (0.1-10 wt%), achieves the right balance where the layer is thick enough to block NIR light effectively but thin enough to allow visible light transmission, preventing the trade-off between blocking performance and light transmission
3Object-affected harmful factors
If conventional dyes with broad absorption are used, then near-infrared blocking is improved, but color reproducibility is worsened
Solution Approach 1:
The patent applies local quality by designing the dye's absorption spectrum to have high absorption specifically in the long-wavelength NIR region (800-1000 nm) while maintaining low absorption in the visible region. The localized absorption peak with controlled FWHM of 50-150 nm ensures that only the harmful long-wavelength NIR light is blocked, preserving color information in the visible spectrum for accurate color reproduction
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 optical filter using this dye achieves excellent near-infrared blocking, particularly for long-wavelength near-infrared light, and ensures high visible light transmission, thereby improving color reproducibility in imaging devices.
Implementation Method 1
a near-infrared absorbing dye including a compound represented by formula (A)... an optical filter including an absorption layer containing the near-infrared absorbing dye... transmits light in the visible wavelength range and blocks light in the near-infrared wavelength range
Implementation Method 2
an optical filter that transmits light in the visible region... and blocks light in the near-infrared region
Data Source
AI summary
A near-infrared absorbing dye includes a compound represented by formula (A). Each of R11 to R14 is independently a hydrogen atom, a halogen atom, a hydroxyl group, or an alkyl, aryl or alaryl group. Each of pairs R11 and R12, R12 and R13, and R13 and R14 may combine with one another to form a monocyclic ring or a polycyclic ring in which from 2 to 4 rings are fused. Each of R15 and R16 is independently an alkyl or alaryl group. R15 and R16 may combine with one another to form a cyclohetero ring having from 5 to 10 members together with the nitrogen atom.