Infrared Cut Filter Composition With Low Angle Dependency

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Solution Overview

Problem

Dielectric multi-layer films used for infrared light shielding in solid image pickup elements have poor productivity and incidence angle dependency, requiring a large number of manufacturing steps and varying optical characteristics based on incidence angle.

Innovation Solution

An infrared absorbing composition comprising at least one polymethine colorant with an absorption maximum at 650 nm or longer, specifically squarylium colorants, and a fluorine surfactant with 3 to 40 mass% fluorine content, is used to form an infrared cut filter, improving incidence angle dependency and reducing manufacturing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dielectric multi-layer film is used for infrared light shielding, then infrared absorption is achieved, but the number of manufacturing steps increases and productivity decreases

Engineering Contradiction:

Improveinfrared absorptionVSAvoidproductivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the material parameter from inorganic dielectric materials to organic polymethine colorants, enabling infrared absorption through molecular absorption characteristics rather than physical layering. This single-layer organic film approach maintains infrared blocking performance while dramatically reducing manufacturing complexity and steps

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining polymethine colorants with specific polymers and fluorine-containing compounds. This composite approach achieves both the desired infrared absorption properties and improved film formation characteristics in a single layer, eliminating the need for multiple dielectric layers

Inventive Principle:

Principle #40Composite materials

2Reliability

If a dielectric multi-layer film is used for infrared light shielding, then infrared absorption is achieved, but incidence angle dependency worsens

Engineering Contradiction:

Improveinfrared absorptionVSAvoidincidence angle dependency

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent fundamentally changes the infrared absorption mechanism from physical interference in multi-layer dielectric structures to molecular electronic transitions in polymethine colorants. This parameter change makes the absorption property intrinsic to the material rather than dependent on layer structure, thereby eliminating incidence angle dependency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/optical interference system of multi-layer dielectric films with a chemical/electronic absorption system based on polymethine colorant molecules. This substitution transitions from structure-dependent optical properties to material-intrinsic absorption characteristics, resolving the incidence angle dependency issue

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a dielectric multi-layer film is used for infrared light shielding, then infrared absorption is achieved, but manufacturing complexity increases

Engineering Contradiction:

Improveinfrared absorptionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential infrared absorption function from the complex multi-layer dielectric structure and concentrates it into a single organic film layer containing polymethine colorants. This extraction eliminates unnecessary intermediate layers and simplifies the overall filter structure while maintaining the core infrared blocking capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges multiple functions (infrared absorption, film formation, adhesion) into a single integrated organic film system. By combining polymethine colorants with polymer matrices and fluorine-containing compounds, the invention achieves multiple performance requirements simultaneously in one layer rather than requiring separate functional layers

Inventive Principle:

Principle #5Merging (Combining)

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 enables the production of infrared cut filters with enhanced incidence angle dependency and reduced manufacturing complexity, maintaining excellent infrared absorption capacity while improving optical characteristics across various incidence angles.

Implementation Method 1

at least one infrared absorber having an absorption maximum at a wavelength of 650 nm or longer which is selected from polymethine colorants

Methodology Applied

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

Implementation Method 2

a fluorine surfactant with 3 to 40 mass% fluorine content

Methodology Applied

Scientific EffectSurface tension modification: Surfactant

Data Source

PatentEP3299422B1Infrared absorbing composition, infrared cut filter, lamination, pattern forming method, and solid-state image capturing element

Publication Date: 2023.11.29 FUJIFILM CORP

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AI summary

Provided are an infrared absorbing composition which is used for forming an infrared cut filter in a solid image pickup element having the infrared cut filter, a pattern forming method using the infrared absorbing composition, an infrared cut filter which is formed by curing the infrared absorbing composition, and a laminate and an solid image pickup element including the infrared cut filter. The infrared absorbing composition includes at least one infrared absorber having an absorption maximum at a wavelength of 650 nm or longer which is selected from polymethine colorants.