Light-blocking coat for optical devices using composite dye and microparticles

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Solution Overview

Problem

Existing light-blocking materials for optical devices face challenges in maintaining sufficient light-blocking properties while achieving low gloss, especially when forming extremely thin light-blocking coats, which can lead to defects like 'ghosts' and reduced product performance.

Innovation Solution

A method involving a coating liquid with a binder resin, black microparticles, and a dye is used to form a light-blocking coat, where the dye, in addition to black microparticles, ensures both low gloss and adequate light-blocking properties even at thin film thicknesses, with the coating liquid also including a solvent and optionally a matting agent to enhance delustering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the light-blocking coat is formed to be thinner, then the light-blocking property is improved, but the delustering property declines

Engineering Contradiction:
Improvelight-blocking coat thicknessVSAvoiddelustering property
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent combines black microparticles with a specific dye (having a maximum absorption wavelength of 780 nm or more) to create a composite coating system. This composite approach allows the thin light-blocking coat to maintain both sufficient light-blocking property and delustering property, resolving the contradiction between thinness and functional performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges for the dye (maximum absorption wavelength of 780 nm or more) and controls the blending ratios of components in the coating liquid. By optimizing these parameters, the coating achieves low gloss (specular gloss ≤ 10%) while maintaining adequate light-blocking property even at reduced thickness, thus resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If the amount of black microparticles is increased to improve light-blocking property, then the light-blocking property is improved, but the delustering property declines due to reduced surface unevenness

Engineering Contradiction:
Improveamount of black microparticlesVSAvoiddelustering property
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent creates a composite system where black microparticles work synergistically with a specific dye. The dye compensates for the reduced surface unevenness caused by high black microparticle content, maintaining delustering property while enabling sufficient light-blocking property even with optimized (not excessive) microparticle amounts.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent utilizes the optical absorption properties of a specific dye (with maximum absorption wavelength of 780 nm or more) to enhance light-blocking capability. This color-based approach allows achieving adequate light-blocking property without relying solely on increased black microparticle content, thereby preserving surface delustering properties.

Inventive Principle:
Principle #32Color 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 effectively maintains necessary light-blocking properties and achieves low gloss, preventing defects like 'ghosts' and ensuring high delustering effects, even when the light-blocking coat is extremely thin, thereby enhancing the performance of optical devices.

Implementation Method 1

applying the coating liquid to a substrate and drying to form a light-blocking coat

Methodology Applied
Scientific EffectDeposition: Deposition (physical)

Implementation Method 2

applying the coating liquid to a substrate and drying to form a light-blocking coat

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10634825B2Light-blocking material for optical devices, and production method therefor
Publication Date: 2020.04.28 KIMOTO CO LTD

AI summary

Provided is a method for producing a light-blocking material for optical devices which is provided with a light-blocking coat achieving low gloss while maintaining the necessary physical properties of a light-blocking coat, i.e. a light-blocking property, even when the light-blocking coat is formed extremely thinly. In the method for producing the light-blocking material for optical devices which is provided with the light-blocking coat, a coating liquid including at least a binder resin, black microparticles, and a dye is prepared. A dye including a metal such as chrome oxide, iron oxide, or cobalt oxide is preferably used as the dye. The coating liquid is subsequently applied to a base material, and dried to form the light-blocking coat.