Electrostatic Coating for Curved Substrate Antiglare Film
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Solution Overview
Problem
Existing methods for creating antiglare films on curved substrates for image display devices face challenges such as high costs, prolonged coating times, insufficient homogeneity, and optical unevenness, particularly when dealing with curved surfaces, leading to reduced visibility and color tone inconsistencies.
Innovation Solution
A method involving an electrostatic coating apparatus to apply a composition containing a silica precursor and particles onto a conductive base, ensuring even coverage on both flat and bent portions of the substrate, followed by firing to form a durable and optically even antiglare film with controlled haze and reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-fluid spray nozzle is used to form an antiglare film by spraying, then the antiglare film can be formed on the substrate, but the coating period is prolonged and the cost increases due to the need for a robot to scan with the spray nozzle
Solution Approach 1:
The patent replaces the mechanical spray coating system (two-fluid spray nozzle with robot scanning) with an electrostatic coating system. The electrostatic coating apparatus uses electrostatic attraction to deposit the composition containing silica precursor and particles onto the substrate, eliminating the need for mechanical scanning and significantly reducing the coating period while maintaining film formation quality.
2Ease of manufacture
If a two-fluid spray nozzle is used to form an antiglare film by spraying, then the antiglare film can be formed on the substrate, but the manufacturing cost increases due to the need for a robot to scan with the spray nozzle
Solution Approach 1:
The patent replaces the complex mechanical spray coating system (two-fluid spray nozzle with robot scanning) with a simpler electrostatic coating system. The electrostatic coating apparatus uses electrostatic attraction to deposit the composition, eliminating the need for expensive robotic scanning equipment and significantly reducing manufacturing costs while maintaining film formation capability.
3Ease of operation
If a surfactant is incorporated into the composition in large amounts to render the liquid easy to spread, then the liquid can spread easily on the substrate, but the antiglare film has insufficient optical evenness
Solution Approach 1:
The patent introduces an electrostatic field as an intermediary mechanism to achieve uniform coating. Instead of relying on surfactants to modify liquid surface tension for spreadability, the electrostatic field uniformly attracts and distributes the composition containing silica precursor and particles across the substrate surface, achieving both easy coating and high optical evenness without excessive surfactant addition.
4Shape
If the flat glass plate having an antiglare film formed thereon is shaped to form a bent portion, then a curved substrate can be produced, but the antiglare film structure is damaged due to high temperature exposure during molding
Solution Approach 1:
The patent changes the temporal sequence of operations: the antiglare film is formed on the flat substrate first, then the entire assembly (substrate with film) is heated to form the bent portion. By controlling the heating parameters and using a substrate with appropriate glass transition temperature, the substrate can be bent while the already-formed antiglare film remains intact, avoiding the problem of high-temperature damage to the film structure.
5Object-affected harmful factors
If an antiglare film is formed on a curved substrate, then reflection of external light can be inhibited, but the screen has different color tones depending on portions of the curved substrate when viewed from directly opposite position
Solution Approach 1:
The patent applies local quality control by ensuring uniform distribution of the composition containing silica precursor and particles across different portions of the substrate (flat and bent areas) through electrostatic coating. The electrostatic field adapts to the substrate geometry, delivering consistent film properties locally across the entire surface, which eliminates color tone differences while maintaining reflection inhibition benefits.
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 results in a highly effective, cost-efficient antiglare film with improved in-plane evenness and optical properties, enhancing visibility and maintaining a natural color tone across the substrate, reducing reflections and glare from external light.
Implementation Method 1
a method involving an electrostatic coating apparatus to apply a composition containing a silica precursor and particles onto a conductive base
Implementation Method 2
a composition containing a silica precursor such as a hydrolysis and condensation product of an alkoxysilane
Implementation Method 3
a composition containing a silica precursor such as a hydrolysis and condensation product of an alkoxysilane
Implementation Method 4
an antiglare film having a surface with a rugged structure is disposed on a screen of an image display device to diffusedly reflect external light to thereby blur the reflected image
Data Source
AI summary
A curved substrate with a film includes a substrate having a first main surface, a second main surface and an end surface, and an antiglare film provided on the first main surface. The substrate has a flat portion and a bent portion. A value obtained by dividing a reflected-image diffusibility index value R of the bent portion by the sum of the reflected-image diffusibility index value R of the bent portion and a reflected-image diffusibility index value R of the flat portion is 0.3 or higher and 0.8 or less.