Coloring Composition for Infrared Sensors with Visible Light Noise Reduction

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Solution Overview

Problem

Existing films used in optical sensors for infrared light with wavelengths of 900 nm or longer suffer from noise generated by visible light, which is not effectively mitigated by current technologies.

Innovation Solution

A coloring composition incorporating a light-shielding material that absorbs visible light and an infrared absorber, allowing for the transmission of infrared light while minimizing noise from visible light, is developed. This composition includes a pigment or dye with specific spectral characteristics and particle size distribution, along with an infrared absorber like pyrrolopyrrole, cyanine, or phthalocyanine compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing films are used to transmit infrared light, then infrared light transmission is achieved, but visible light noise is not effectively blocked

Engineering Contradiction:

Improveinfrared light transmissionVSAvoidvisible light noise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite material consisting of carbon black particles dispersed in a transparent resin matrix. This composite structure combines the infrared absorption properties of carbon black with the optical transparency of the resin, achieving both infrared light transmission and visible light noise reduction simultaneously

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the particle size distribution of carbon black particles, specifying that particles with a diameter of 0.5 μm or less account for 80% or more of the total particle number. This parameter control ensures effective visible light absorption while maintaining infrared transmission capabilities

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If carbon black is used to block visible light, then visible light noise is reduced, but infrared light transmission may be affected

Engineering Contradiction:

Improvevisible light noiseVSAvoidinfrared light transmission

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent precisely controls the particle size parameter of carbon black, specifying that particles with a diameter of 0.5 μm or less account for 80% or more of the total particle number. This parameter optimization allows the material to absorb visible light effectively while maintaining infrared transmission

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates local quality differences in the material by dispersing carbon black particles of specific size ranges within the transparent resin. The particle size distribution is optimized locally to achieve different optical properties for different wavelength ranges, allowing visible light blocking while maintaining infrared transmission

Inventive Principle:

Principle #3Local quality

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 formation of films that transmit infrared light with reduced noise from visible light, enhancing the performance of optical sensors by effectively shielding visible light and absorbing infrared light within the desired wavelength range.

Implementation Method 1

a coloring composition including a coloring material that shields light in the visible range and an infrared absorber

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

an infrared absorber like pyrrolopyrrole, cyanine, or phthalocyanine compounds

Methodology Applied

Scientific EffectInfrared absorption: Absorption (EM radiation)

Data Source

PatentEP3299423B1Coloring composition, film, color filter, method for forming pattern, method for producing color filter, solid-state imaging device, and infrared sensor

Publication Date: 2021.10.27 FUJIFILM CORP

Figure 1~2

AI summary

Provided is a coloring composition with which a film capable of allowing transmission of infrared light in a state where noise generated from visible light is small can be formed. In addition, also provided are a film, a color filter, a pattern forming method, a method for manufacturing a color filter, a solid image pickup element, and an infrared sensor in which the coloring composition is used. The coloring composition includes a coloring material that shields light in a visible range; and an infrared absorber. It is preferable that the coloring material that shields light in the visible range includes two or more chromatic colorants and that a combination of the two or more chromatic colorants forms black. Alternatively, it is preferable that the coloring material that shields light in the visible range includes an organic black colorant. It is preferable that the organic black colorant is at least one selected from the group consisting of a perylene compound and a bisbenzofuranone compound.