White Polyester Film Void Nucleation for Reflectivity

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Solution Overview

Problem

Existing reflective films for liquid crystal displays, particularly in slimmed and downsized devices like mobile phones and televisions, face challenges in achieving high reflectivity and light concealing properties while maintaining film-forming stability without increasing thickness.

Innovation Solution

A white film configuration incorporating a polyester resin, an incompatible thermoplastic resin, and inorganic particles, specifically titanium oxide, with a void nucleating agent, where the thermoplastic resin forms domains and includes inorganic particles, enhancing reflectivity and light concealing properties without thickness increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the number of interfaces is increased to increase reflectivity, then reflectivity is improved, but film-forming property is deteriorated

Engineering Contradiction:
ImprovereflectivityVSAvoidfilm-forming property
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the physical-chemical parameters of the system by introducing a thermoplastic resin that is incompatible with the polyester resin. This incompatibility parameter causes phase separation and automatic void formation during film formation, achieving high reflectivity without manually increasing interface number through complex multi-layer structures that would harm film-forming properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes porous material principles by forming voids within the film structure through incompatible resin phase separation. These voids create numerous light scattering interfaces that enhance reflectivity while the voids are naturally formed during the film formation process, maintaining good film-forming properties without requiring complex multi-layer constructions.

Inventive Principle:
Principle #31Porous materials

2Illumination intensity

If the thickness of the reflective film is increased to improve reflectivity and light concealing property, then reflectivity is improved, but it becomes difficult to reduce film thickness for slimmed devices

Engineering Contradiction:
ImprovereflectivityVSAvoidfilm thickness
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent employs porous material principles by incorporating voids within the film structure. These voids create multiple light scattering interfaces that significantly enhance reflectivity and light concealing properties. Consequently, high optical performance can be achieved with a reduced film thickness, enabling slimmed display devices without compromising reflectivity.

Inventive Principle:
Principle #31Porous materials

3Object-affected harmful factors

If the number of interfaces is increased to improve light concealing property, then light concealing property is improved, but film-forming property is deteriorated

Engineering Contradiction:
Improvelight concealing propertyVSAvoidfilm-forming property
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent modifies the system parameters by incorporating a thermoplastic resin incompatible with the polyester resin. This parameter change induces phase separation and automatic void formation during film formation, creating numerous light scattering interfaces that improve light concealing property while maintaining good film-forming stability through the natural phase separation process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies porous material principles by forming voids within the film structure through incompatible resin phase separation. These voids provide multiple light scattering interfaces that enhance light concealing property. The voids are naturally formed during film formation, improving light concealing without requiring complex multi-layer structures that would deteriorate film-forming properties.

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 film achieves high reflectance and light concealing properties with good film-forming stability, even at a thin thickness, by optimizing the configuration of voids and inorganic particles, thereby meeting the demands of modern display technologies.

Implementation Method 1

a configuration is widely employed in which reflection of light due to a difference in refractive index at the interface between the fine bubbles included in the film and the matrix resin is utilized

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

formation of a void in which an inorganic particle having a relatively small particle size functions as a nucleus has been studied

Methodology Applied
Scientific EffectNucleation: Nucleation

Implementation Method 3

a thermoplastic resin (B) incompatible with the polyester resin (A), and an inorganic particle (C), the thermoplastic resin (B) forming a domain in the layer

Methodology Applied
Scientific EffectPhase separation:

Data Source

PatentUS11541647B2White polyester film
Publication Date: 2023.01.03 TORAY INDUSTRIES INC

AI summary

A white polyester film is described that includes at least a layer including, as a main component, a polyester resin (A), a thermoplastic resin (B) incompatible with the polyester resin (A), and an inorganic particle (C), where the white polyester film achieves high reflectance and a concealing property without increasing the thickness of the reflective film, the layer including voids in which the thermoplastic resin (B) functions as nuclei, wherein in a vertical section of the white film, NB2/NB1×100 (%) is 15% or more, wherein NB1 represents the number of the nuclei of the thermoplastic resin (B), and NB2 represents the number of the sections of the thermoplastic resin (B), the sections including the inorganic particle (C) inside.