Optical Filter Laminate Composition for Heat-Stable NIR Spectra

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Solution Overview

Problem

Existing laminates with near infrared light absorbing layers and color filter layers experience variations in spectral characteristics when heated, particularly when an oxygen barrier film is added, leading to reduced heat resistance and stability.

Innovation Solution

Incorporating a compound with an acid group, such as a sulfo, phosphate, or carboxyl group, bonded to the colorant skeleton in the near infrared light absorbing layer or color filter layer, with a content of 0.1 to 99.9 mass % to maintain spectral stability and heat resistance, even when an oxygen barrier film is applied.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a color filter layer is laminated on a near infrared light absorbing layer, then the optical filter can perform both color filtering and near infrared absorption functions, but the spectral characteristics of the near infrared light absorbing layer vary when heated

Engineering Contradiction:

Improvefunctional integrationVSAvoidspectral characteristic stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the near infrared absorbing colorant by introducing acid groups (carboxyl, sulfo, or phosphate groups) at specific ratios (0.1-99.9 mass%). This compositional modification enhances the colorant's heat resistance and prevents spectral characteristic variations during heating, while maintaining the laminated structure's dual functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite near infrared absorbing colorant system by combining colorant molecules with specific acid group-containing compounds. This composite approach results in a material that exhibits both the desired optical filtering properties and improved thermal stability, resolving the contradiction between functional integration and reliability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the content of acid group-containing colorant compound is increased, then the heat resistance and spectral stability are improved, but the manufacturing cost and complexity increase

Engineering Contradiction:

Improveheat resistanceVSAvoidmanufacturing simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent establishes an optimal parameter range (0.1-99.9 mass% of acid group-containing colorant compound) that balances performance and manufacturability. Within this range, even low concentrations (0.1-10 mass%) are sufficient to achieve the desired heat resistance and spectral stability, avoiding the need for complex manufacturing processes while ensuring reliable performance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12078828B2Laminate, optical filter, solid image pickup element, image display device, infrared sensor, and kit

Publication Date: 2024.09.03 FUJIFILM CORP

AI summary

A laminate includes: a near infrared light absorbing layer that includes a near infrared absorbing colorant; and a color filter layer that is arranged adjacent to the near infrared light absorbing layer in a thickness direction and includes a chromatic colorant, in which in at least one of the near infrared light absorbing layer or the color filter layer, a content of a compound in which an acid group selected from a sulfo group, a phosphate group, or a carboxyl group is bonded to a colorant skeleton is 0.1 to 99.9 mass % with respect to a total mass of compounds having a colorant skeleton.