Black Resin Composition for NIR Transmission and Visible Light Blocking
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Solution Overview
Problem
Existing technologies fail to achieve both high visible-light-blocking ability and near-infrared penetrability while maintaining image resolution and design aesthetics, particularly in decorative films for near-infrared sensors or cameras, due to light scattering and insufficient light resistance of conventional dyes and pigments.
Innovation Solution
A black resin composition containing a specific ratio of red and blue pigments with controlled crystalline size, ranging from 5 to 25 nm, is used to create a pseudo-black color that enhances visible-light-blocking and near-infrared penetrability, reducing scattered light and providing an achromatic reflected color tone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dyes are used as colorants, then near-infrared transmittance is achieved, but light resistance is insufficient and optical properties are degraded over time
Solution Approach 1:
The patent changes the fundamental parameter of the colorant from organic dye to inorganic pigment, specifically using a combination of red and blue pigments with controlled particle sizes (5-25 nm). This parameter change provides excellent light resistance while maintaining near-infrared transmittance, resolving the contradiction between achieving infrared penetration and maintaining long-term optical stability.
Solution Approach 2:
The patent employs a composite colorant system combining red pigment and blue pigment in specific proportions (red pigment 30-80 wt%, blue pigment 20-70 wt%). This composite approach creates a pseudo-black color that blocks visible light while transmitting near-infrared rays, and the combination of different pigments enhances overall light resistance compared to single dyes.
2Reliability
If metal fine particles or semimetal fine particles are used to transmit infrared rays and hide visible light, then near-infrared penetration is achieved, but light scattering decreases image resolution
Solution Approach 1:
The patent precisely controls the particle size parameter of the pigments to be 5-25 nm, which is smaller than the wavelength of near-infrared light. This parameter control reduces light scattering effects that would otherwise degrade image resolution, while still maintaining effective near-infrared transmittance. The small particle size allows infrared rays to pass through with minimal scattering.
Solution Approach 2:
The patent applies different pigment types with specific properties to different functional requirements: red and blue pigments are selected and sized to create selective optical properties where visible light is blocked through absorption while near-infrared transmission is maintained through minimal scattering, achieving localized optimization of both image quality and infrared penetration.
3Shape
If a filter or coating material is used to hide the near-infrared sensor, then design aesthetics are improved, but visible-light transmittance decreases
Solution Approach 1:
The patent utilizes the color absorption properties of red and blue pigments to create a pseudo-black appearance that blocks visible light effectively. The specific combination and ratio of red and blue pigments are optimized to achieve a neutral black color that provides excellent aesthetic appearance while maintaining the desired visible-light blocking performance for sensor concealment.
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 composition achieves excellent light resistance, high visible-light-blocking ability, and near-infrared penetrability, resulting in clear near-infrared camera images and a jet-black design with reduced scattered light.
Implementation Method 1
a black resin composition containing a specific ratio of red and blue pigments with controlled crystalline size, ranging from 5 to 25 nm, is used to create a pseudo-black color that enhances visible-light-blocking and near-infrared penetrability
Implementation Method 2
light scattering due to the particles significantly decreases the image resolution of a near-infrared camera
Data Source
AI summary
A black resin composition is provided that presents an achromatic reflected color tone, has a high visible-light-blocking ability and a high near-infrared penetrability, and exhibits a smaller amount of transmitted scattered light, where the black resin composition includes (A) a resin, (B) a colorant, and (C) an organic solvent, wherein the black composition includes a red pigment and a blue pigment as (B) the colorant, wherein amount of the red pigment is 20 to 80 wt % with respect to the total amount of (B) the colorant, and wherein crystalline size of the red pigment in a colored film composed of a cured product of the black resin composition is 5 nm or more and 25 nm or less, as calculated from a half bandwidth determined from a main peak of an X-ray diffraction spectrum obtained using CuKα rays as an X-ray source.