Multi-Layer Polarization Optical Article Reducing Birefringence

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Solution Overview

Problem

Polarizing optical articles, such as sunglasses and goggles, often suffer from uneven polarization coloring due to orientation birefringence and photoelastic birefringence, which can lead to adverse visual effects and customer dissatisfaction, particularly in injection-molded polycarbonate lenses, while cast-molded lenses are perceived as having better optical properties despite similar birefringence issues.

Innovation Solution

A multi-layered polarization optical article is designed with a linear polarization functional portion, a retardation functional portion, and a back-up resin portion, where the linear polarization and retardation functional portions are arranged to form an angle of 45°±20°, and the back-up resin portion is bonded to the retardation functional side, enhancing the optical properties and reducing visible birefringence effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If injection molding is used to produce back-up resin portion, then productivity is improved, but uneven polarization coloring occurs due to orientation birefringence

Engineering Contradiction:
Improveproduction efficiencyVSAvoiduneven polarization coloring
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

A retardation film is introduced as an intermediary component between the polarizer and the back-up resin portion. This retardation film acts as a mediator that compensates for the orientation birefringence caused by injection molding, thereby reducing uneven polarization coloring while maintaining the high productivity benefits of injection molding

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure consisting of multiple layers: polarizer, retardation film, and back-up resin portion. This composite material approach combines components with different optical properties to counteract the harmful orientation birefringence effects while preserving manufacturing efficiency

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If cast molding is used to produce back-up resin portion, then uneven polarization coloring is reduced, but productivity decreases

Engineering Contradiction:
Improveuneven polarization coloringVSAvoidproduction efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The retardation film serves as an intermediary that allows the use of injection molding (high productivity) while achieving optical quality comparable to cast molding (low productivity). It mediates between the conflicting requirements of manufacturing efficiency and optical performance

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If polarizer is reinforced with back-up resin portion, then strength is improved, but uneven polarization coloring occurs

Engineering Contradiction:
Improvephysical strengthVSAvoiduneven polarization coloring
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The retardation film is positioned as an intermediary layer between the polarizer and the back-up resin portion. It mediates the optical interaction between these components, allowing the back-up resin to provide mechanical strength while the retardation film compensates for the orientation birefringence it introduces

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a multi-layer composite structure where each layer has specific functions: the polarizer provides polarization, the back-up resin provides strength, and the retardation film compensates for optical defects. This composite approach resolves the contradiction between strength enhancement and optical quality

Inventive Principle:
Principle #40Composite 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 solution significantly reduces the visibility of uneven polarization coloring, improving the optical performance and customer perception of polarizing lenses by minimizing birefringence-induced visual defects, thereby enhancing the market competitiveness of injection-molded polycarbonate lenses.

Implementation Method 1

uneven polarization coloring due to orientation birefringence and photoelastic birefringence

Methodology Applied
Scientific EffectBirefringence: Birefringence

Implementation Method 2

a linear polarization functional portion, a retardation functional portion

Methodology Applied
Scientific EffectPolarisation: Polarisation

Data Source

PatentUS9507176B2Polarization optical article in which uneven coloring by polarization color has been improved
Publication Date: 2016.11.29 SWANS

AI summary

An object of the present invention is to improve uneven coloring by polarization color due to birefringence of a polarization optical article.Disclosed is a polarization optical article in which uneven coloring by polarization color has been improved, the polarization optical article being a multi-layered polarization optical article including at least a linear polarization functional portion, a retardation functional portion and a back-up resin portion, characterized in that the linear polarization functional portion, the retardation functional portion and the back-up resin portion are arranged in order from an objective side toward an ocular side. The linear polarization functional portion is, for example, a linear polarizer, the retardation functional portion is, for example, a retardation sheet, and the retardation functional portion has, for example, a retardation of 1,000 nm or more. The back-up resin is a polycarbonate resin, a polyamide resin or the like.