Near-Infrared Cutoff Filter Composition for Spectral Stability

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Solution Overview

Problem

Current near infrared cut filters fail to provide effective infrared shielding across a wide wavelength range and are prone to spectral variation, especially in high-temperature and high-humidity environments.

Innovation Solution

A composition comprising two or more near infrared absorbing compounds with absorption maxima between 650 to 1000 nm and solubility of 0.1 mass% or lower in water, where the compounds have a specific absorbance ratio and difference in absorption maxima, is used to create a film with enhanced infrared shielding and moisture resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single near infrared absorbing compound is used in the film, then the manufacturing process is simple, but the infrared shielding coverage is limited and spectral variation occurs

Engineering Contradiction:
Improvecomposition structureVSAvoidinfrared shielding performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the near infrared absorption function into multiple segments by using two or more different near infrared absorbing compounds with different absorption maximum wavelengths. This segmentation allows the film to cover a broader infrared wavelength range and reduces spectral variation while maintaining manageable composition complexity through systematic selection of compounds with specific wavelength differences.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite near infrared absorbing system by combining multiple near infrared absorbing compounds with different spectral characteristics. This composite approach enables the film to achieve comprehensive infrared shielding across a wide wavelength range (650-1000 nm) while the specific selection criteria for compounds control the overall composition structure complexity.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If water-soluble near infrared absorbing compounds are used, then the compounds are easy to process, but the film shows spectral variation in high-temperature and high-humidity environments

Engineering Contradiction:
Improvecompound processingVSAvoidspectral characteristics
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent changes the solubility parameter of the near infrared absorbing compounds by selecting compounds with solubility of 0.1 mass% or lower in water at 23°C. This parameter change maintains ease of processing during film formation while dramatically improving spectral stability in high-temperature and high-humidity environments, as the low solubility prevents compound migration and spectral variation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the absorption maximum difference between compounds is large, then the infrared coverage is wider, but the visible light transmission may be affected

Engineering Contradiction:
Improveinfrared shielding rangeVSAvoidvisible light transmission
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent optimizes the absorption maximum wavelength difference parameter between compounds to fall within 1-150 nm. This parameter optimization ensures wide infrared coverage (650-1000 nm) while controlling the impact on visible light transmission. The specific range allows the compounds to cover infrared wavelengths without creating excessive absorption in the visible range, maintaining good visible light transmission characteristics.

Inventive Principle:
Principle #35Parameter changes

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 provides a film with excellent infrared shielding properties and reduced spectral variation, maintaining performance even in harsh environmental conditions.

Implementation Method 1

two or more near infrared absorbing compounds having an absorption maximum in a wavelength range of 650 to 1000 nm

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP3410162B1Composition, film, near-infrared cutoff filter, laminate, pattern formation method, solid-state image sensor, image display device, infrared sensor and color filter
Publication Date: 2024.08.28 FUJIFILM CORP
  • EP3410162B1 patent drawingFigure 1~4
  • EP3410162B1 patent drawingFigure 5~8
  • EP3410162B1 patent drawing

AI summary

Provided is a composition with which a film having excellent infrared shielding properties and reduced spectral variation can be formed. In addition, provided are a film, a near infrared cut filter, a laminate, a pattern forming method, a solid image pickup element, an image display device, an infrared sensor, and a color filter. The composition includes two or more near infrared absorbing compounds having an absorption maximum in a wavelength range of 650 to 1000 nm and having a solubility of 0.1 mass% or lower in water at 23°C, in which the two or more near infrared absorbing compounds include a first near infrared absorbing compound having an absorption maximum in a wavelength range of 650 to 1000 nm, and a second near infrared absorbing compound having an absorption maximum in a wavelength range of 650 to 1000 nm which is shorter than the absorption maximum of the first near infrared absorbing compound, and a difference between the absorption maximum of the first near infrared absorbing compound and the absorption maximum of the second near infrared absorbing compound is 1 to 150 nm.