Optical Layered Body With Silica Hard Coat for UV-Stable Adhesion
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Solution Overview
Problem
Conventional optical layered bodies used in image display devices suffer from interlayer separation, particularly at the interface between the hard coat layer and anti-reflection layer when exposed to outdoor UV light, and have inadequate anti-blocking properties, especially in vacuum environments.
Innovation Solution
An optical layered body with a hard coat layer containing silica fine particles and a dry film layer, featuring specific surface projections and depressions, along with controlled silica fine particle abundance and distribution, enhances adhesiveness and anti-blocking properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a clear hard coat layer with smooth surface is used to provide glass-like appearance, then anti-reflection function is improved, but anti-blocking properties deteriorate and surface slipperiness decreases
Solution Approach 1:
The invention introduces silica fine particles (0.1-10 μm) into the hard coat layer to create localized surface irregularities. These particles protrude through the clear coat surface, creating micro-scale roughness that provides anti-blocking properties while maintaining the overall glass-like appearance and anti-reflection function of the clear hard coat layer.
2Ease of manufacture
If conventional hard coat layer is used, then manufacturing is simple, but interlayer adhesiveness deteriorates under UV exposure
Solution Approach 1:
The invention creates a composite hard coat layer by combining organic resin components with inorganic silica fine particles. This composite structure improves interlayer adhesiveness under UV exposure because the silica particles provide UV resistance and maintain structural integrity, preventing separation at the interface between the hard coat layer and anti-reflection layer.
3Ease of operation
If silica fine particles are added to hard coat layer, then anti-blocking properties are improved, but manufacturing complexity increases
Solution Approach 1:
The invention specifies precise parameters for the silica fine particles (size: 0.1-10 μm, abundance: 1-50 wt%, protrusion height: 0.1-10 μm) to achieve optimal anti-blocking properties. By controlling these parameters within defined ranges, the invention balances the improvement in anti-blocking performance with manageable manufacturing complexity, allowing standard coating processes to be used with proper material selection.
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 optical layered body exhibits excellent interlayer adhesiveness and anti-blocking properties, even under outdoor conditions and in vacuum environments, preventing separation and ensuring smooth processing.
Implementation Method 1
a hard coat layer containing silica fine particles on at least one surface of the substrate film
Implementation Method 2
excellent interlayer adhesiveness, particularly even in outdoor use
Implementation Method 3
the hard coat layer before the formation of the dry film layer has projections and depressions on the surface on which the dry film layer is to be formed
Implementation Method 4
the silica fine particles are exposed on the dry film layer side surface of the hard coat layer
Data Source
Figure 1(A)~1(B)
Figure 2(A)~2(C)
AI summary
The present invention aims to provide an optical layered body that has excellent interlayer adhesiveness, particularly even in outdoor use, and also has highly excellent anti-blocking properties. The present invention relates to an optical layered body including: a substrate film; a hard coat layer containing silica fine particles on at least one surface of the substrate film; and a dry film layer on a surface of the hard coat layer opposite to the substrate film side surface of the hard coat layer, wherein the silica fine particles are exposed on the dry film layer side surface of the hard coat layer; the dry film layer is directly formed on the surface of the hard coat layer on which the silica fine particles are exposed; the hard coat layer before the formation of the dry film layer has projections and depressions on the surface on which the dry film layer is to be formed; the hard coat layer has an average silica fine particle abundance in ten 0.2 µm × 0.2 µm regions of 30 to 80% and a standard deviation of silica fine particle abundances in the 10 regions of 1 to 7, where the 10 regions are randomly selected from a cross section of the hard coat layer in the thickness direction within the range from the dry film layer side interface to 10% of the thickness in the thickness direction; and the hard coat layer has a silicon atom abundance A of 2 to 10% on the surface opposite to the substrate film side surface as determined by X-ray photoelectron spectroscopy.