Far Infrared Filter Composition Using Metal Particles
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Solution Overview
Problem
Existing near infrared ray cut filters are ineffective in selectively transmitting light with wavelengths greater than 1 μm, limiting their application in sensing applications that require longer wavelength infrared rays.
Innovation Solution
A composition comprising metal particles and a resin, with specific absorbance ratios and band gaps, is used to create a formed body that selectively transmits light in the 1 to 14 μm wavelength range, enabling the manufacture of far infrared ray transmitting filters, solid-state imaging elements, and infrared sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a near infrared ray cut filter is used to shield light in the wavelength range of 800 to 1300 nm, then the transmittance in this range is reduced to 60% or less, but the filter has high transmitting performance for light having a wavelength greater than 1 μm, making it ineffective for sensing applications using longer wavelength infrared rays
Solution Approach 1:
The patent changes the optical parameters of the filter by incorporating metal particles with specific absorbance characteristics. The metal particles are selected to have a minimum absorbance value Amin in the 800-1300 nm range and a maximum absorbance value Bmax in the 3-14 μm range, with Amin/Bmax ≥ 3. This parameter change enables the filter to selectively transmit longer wavelength infrared rays (1-14 μm) while maintaining shielding performance in the near-infrared range, thus expanding the application range to sensing applications.
Solution Approach 2:
The patent uses a composite structure consisting of metal particles dispersed in a resin matrix. The metal particles provide selective absorbance properties for different wavelength ranges, while the resin provides structural support and optical transparency. This composite material approach enables the filter to achieve both near-infrared shielding and far-infrared transmission, resolving the contradiction between selective transmission performance and application versatility.
2Manufacturing precision
If a filter is designed to shield near infrared rays (800-1300 nm), then the transmittance in this range is reduced, but the filter cannot effectively transmit or shield light in the longer wavelength range (1-14 μm) required for sensing applications
Solution Approach 1:
The patent achieves precise wavelength selectivity while expanding wavelength range coverage by carefully selecting metal particles with specific absorbance parameters. The key parameter is the ratio Amin/Bmax ≥ 3, where Amin is the minimum absorbance in the 800-1300 nm range and Bmax is the maximum absorbance in the 3-14 μm range. This parameter control enables the filter to maintain high wavelength selectivity for near-infrared shielding while simultaneously achieving effective transmission or shielding in the 1-14 μm range, thus expanding adaptability without sacrificing manufacturing precision.
3Ease of manufacture
If existing near infrared ray cut filter materials are used, then the filter structure is simple and easy to manufacture, but the filter cannot achieve selective transmission of light in the 1 to 14 μm wavelength range required for sensing applications
Solution Approach 1:
The patent maintains manufacturing simplicity by using a composite material system where metal particles are dispersed in a resin matrix. This structure can be manufactured using conventional coating and curing processes. The metal particles provide the necessary infrared transmission performance for the 1-14 μm range, while the resin provides structural integrity and optical properties. This composite approach achieves both ease of manufacture and reliable infrared transmission performance, resolving the contradiction between manufacturing simplicity and functional reliability.
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 allows for the production of filters and sensors that effectively transmit specific wavelength ranges, enhancing signal-to-noise difference and sensitivity in infrared applications, while being cost-effective and easily manufacturable through coating processes.
Implementation Method 1
the composition in a wavelength range of 1 to 14 μm has a wavelength band A having a wavelength band width of 1 μm or more, and a wavelength band B having a lower absorbance than the wavelength band A
Data Source
AI summary
A composition includes a metal particle and a resin and has a wavelength band A having a wavelength band width of 1 μm or more in a wavelength range of 1 to 14 μm and a wavelength band B having a lower absorbance than the wavelength band A and having a wavelength band width of 1 μm or more, and a ratio Amin/Bmax between a minimum value Amin of an absorbance of the wavelength band A and a maximum value Bmax of an absorbance of the wavelength band B is 3 or more.