Dye-Based Optical Filter for 900-1000 Nm NIR Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical filters do not effectively transmit near-infrared light with wavelengths longer than 900 nm while blocking other near-infrared light, which is necessary for applications using laser light in the 950 nm range and causing noise, and they do not maintain high transparency for visible light and near-infrared light across various incident angles.
Innovation Solution
An optical filter with a substrate containing a dye having a maximum absorption wavelength of 690 to 900 nm and a dielectric multilayer film, designed to transmit visible light and near-infrared light in the 900 to 1,000 nm range, with specific spectroscopic characteristics ensuring high transparency and near-infrared blocking abilities across different angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing optical filters are used to block near-infrared light, then visible light transmission is maintained, but near-infrared light in the 900 nm or longer wavelength range cannot be transmitted
Solution Approach 1:
The optical filter applies different functional properties to different wavelength ranges: the dye layer provides strong absorption in the 700-900 nm range while being transparent in the 900-1000 nm range, and the dielectric multilayer film provides additional blocking in specific bands while allowing transmission in the 900-1000 nm band. This local differentiation of optical properties resolves the contradiction between blocking harmful near-infrared light and transmitting useful near-infrared light.
Solution Approach 2:
The optical filter combines a resin film containing a specific dye (maximum absorption wavelength 690-900 nm) with a dielectric multilayer film to create a composite structure. The dye absorbs harmful near-infrared light in the 700-900 nm range, while the dielectric multilayer film provides selective reflection and transmission characteristics. This composite approach enables simultaneous achievement of visible light transmission, near-infrared light blocking, and transmission of specific near-infrared wavelengths (900-1000 nm).
2Reliability
If an optical filter transmits visible light and near-infrared light, then image quality is improved, but near-infrared light causing noise is not blocked
Solution Approach 1:
The optical filter segments the near-infrared spectrum into different functional zones: the 700-900 nm range is blocked by the dye absorption, the 900-1000 nm range is transmitted for imaging, and other near-infrared ranges are blocked. This segmentation allows the filter to selectively transmit only the near-infrared wavelengths useful for imaging while blocking those that cause noise, thereby improving both image quality and noise reduction.
Solution Approach 2:
The optical filter uses a dye with a specifically controlled maximum absorption wavelength in the 690-900 nm range, which creates a sharp cutoff characteristic. By precisely controlling this parameter, the filter achieves high transmittance in the visible range and controlled transmission in the near-infrared range, improving image quality while blocking noise-causing wavelengths.
3Object-generated harmful factors
If an optical filter blocks near-infrared light effectively, then noise is reduced, but transparency for visible light and near-infrared light is reduced
Solution Approach 1:
The optical filter extracts and removes only the harmful near-infrared components (700-900 nm and other unwanted ranges) while preserving the useful wavelengths. The dye selectively absorbs the harmful near-infrared light, and the dielectric multilayer film provides additional selective blocking, allowing the filter to reduce noise while maintaining high transparency for visible light and useful near-infrared light (900-1000 nm).
4Illumination intensity
If an optical filter maintains high transmittance at normal incident angles, then visible light transmission is optimized, but transmittance degrades at large incident angles
Solution Approach 1:
The optical filter design accounts for dynamic variations in incident angle by using a dielectric multilayer film with specific optical characteristics that maintain effective near-infrared blocking across a range of angles. The multilayer structure's optical path difference and interference characteristics remain effective even when light enters at large angles, ensuring consistent performance under varying illumination conditions.
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 high transparency for visible and near-infrared light, particularly in the 900 to 1,000 nm range, while effectively blocking near-infrared light in other ranges, maintaining transparency and blocking ability even at large incident angles.
Implementation Method 1
a resin film including a dye (I) having a maximum absorption wavelength in a wavelength of 690 to 900 nm
Implementation Method 2
a dielectric multilayer film laid on or above at least one major surface of the substrate as an outermost layer
Data Source
AI summary
An optical filter including: a substrate; and a dielectric multilayer film laid on or above at least one major surface of the substrate as an outermost layer, in which the substrate includes a resin film including a dye (I) having a maximum absorption wavelength in a wavelength of 690 to 900 nm in dichloromethane, and a resin, the optical filter transmits visible light and light in at least part of a wavelength of 900 to 1,000 nm, and the optical filter satisfies specific spectroscopic characteristics.