Optical Laminate Void Structure for Protected Convex Functional Layers

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Solution Overview

Problem

Protecting the convex surface of an optical functional layer with a pressure-sensitive adhesive can lead to a decrease or loss of its functional properties.

Innovation Solution

A laminate is created with an optical functional layer having protrusions and a low-refractive index layer with voids formed between them, where the low-refractive index layer has a refractive index of 1.30 or less, and is directly in contact with the optical functional layer, ensuring protection while maintaining its functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a pressure-sensitive adhesive is applied to protect the convex surface of the optical functional layer, then the surface is protected, but the function of the optical functional layer decreases or is lost

Engineering Contradiction:
Improveprotection of optical functional layerVSAvoidfunctionality of optical functional layer
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The protective structure is segmented into multiple functional layers: a low-refractive index layer with voids that protects the convex surface while maintaining optical functionality, and a pressure-sensitive adhesive layer applied separately. This segmentation allows the optical functional layer to be protected without the adhesive directly contacting the convex surface, thus preserving its light-changing function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The low-refractive index layer with voids acts as an intermediary between the optical functional layer and the pressure-sensitive adhesive layer. This intermediary structure provides mechanical protection to the convex surface while the voids prevent direct adhesion to the optical layer, maintaining its optical functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the convex surface is protected with a pressure-sensitive adhesive layer, then mechanical strength is improved, but transparency and optical function are compromised

Engineering Contradiction:
Improvemechanical strengthVSAvoidtransparency and optical function
Core Design Contradiction:
StrengthVSIllumination intensity

Solution Approach 1:

The low-refractive index layer is designed with a porous structure containing voids. This porous structure provides mechanical strength and protection to the convex surface while the voids maintain transparency and optical functionality by allowing light to pass through without significant refraction or absorption that would compromise the optical layer's function.

Inventive Principle:
Principle #31Porous materials

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 laminate effectively protects the optical functional layer's convex surface while preserving its functionality, enhancing mechanical strength and transparency.

Implementation Method 1

a low-refractive index layer having a refractive index of 1.30 or less... the laminate has voids formed between the optical functional layer and the low-refractive index layer

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4692865A1Laminate and method for manufacturing laminate
Publication Date: 2026.02.11 NITTO DENKO CORP
  • EP4692865A1 patent drawingFigure 1
  • EP4692865A1 patent drawingFigure 2
  • EP4692865A1 patent drawing

AI summary

To achieve both the protection of an optical functional layer having a convex surface and the suppression of a decrease in function of the optical functional layer, provided is a laminate including: an optical functional layer including a first main surface and a second main surface facing each other, the first main surface having protrusions formed thereon; and a low-refractive index layer formed on the first main surface side of the optical functional layer, the low-refractive index layer having a refractive index of 1.30 or less, wherein the laminate has voids formed between the optical functional layer and the low-refractive index layer.