Smart Window Optical Laminate With Integrated Polarizer Electrodes

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Solution Overview

Problem

Conventional optical laminates for smart windows face issues such as increased manufacturing complexity and thickness due to the inclusion of separate substrates for conductive layers, leading to potential damage during transport and defects when bonded, and fixed transmittance that can cause glare or visibility issues depending on ambient light conditions.

Innovation Solution

An optical laminate design that forms transparent conductive layers directly on polarizing plates without separate substrates, utilizing a specific elastic modulus range for the polarizing plates to enhance rigidity and prevent damage, with a simplified manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a separate substrate is used to form the conductive layer, then the conductive layer can be properly formed, but the manufacturing process becomes complicated and the thickness increases

Engineering Contradiction:
Improvemanufacturing processVSAvoidthickness of laminate
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent combines the substrate and conductive layer into a single integrated structure. The transparent conductive layer is formed directly on the polarizing plate without requiring a separate substrate, thereby simplifying the manufacturing process and reducing the overall thickness of the optical laminate while maintaining the necessary conductive functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If a separate substrate is used to form the conductive layer, then the conductive layer can be properly formed, but the laminate becomes more prone to damage during transport

Engineering Contradiction:
Improveconductive layer formationVSAvoiddamage resistance during transport
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

By integrating the conductive layer directly onto the polarizing plate substrate, the patent eliminates the interface between separate substrate and conductive layer that would otherwise create weakness points. This unified structure enhances the overall mechanical strength and resistance to damage during transportation and handling.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If a separate substrate is used to form the conductive layer, then the conductive layer can be properly formed, but bonding defects such as lifting and pressing defects may be generated

Engineering Contradiction:
Improveconductive layer formationVSAvoidbonding quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent eliminates the intermediate substrate layer by forming the conductive layer directly on the polarizing plate. This direct integration removes potential bonding interfaces that could generate lifting or pressing defects, thereby improving bonding quality and manufacturing precision.

Inventive Principle:
Principle #5Merging (Combining)

4Object-affected harmful factors

If the transmittance is preset low, then glare is reduced during day, but visibility is poor at night when ambient light is insufficient

Engineering Contradiction:
Improveglare reductionVSAvoidvisibility in low light
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent employs a liquid crystal layer that can dynamically change its optical properties in response to applied voltage. This allows the optical laminate to adjust its light transmittance from a preset low state (reducing glare during daytime) to a higher transmittance state (improving visibility at night), providing adaptive control based on ambient lighting conditions.

Inventive Principle:
Principle #15Dynamics

5Illumination intensity

If the transmittance is preset high, then visibility is good at night, but glare is caused during day when ambient light is sufficient

Engineering Contradiction:
Improvevisibility in low lightVSAvoidglare
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The liquid crystal layer enables dynamic adjustment of light transmittance, allowing the system to switch from a high transmittance state (providing good visibility at night) to a lower transmittance state (reducing glare during daytime), thus adapting to different ambient light conditions as needed.

Inventive Principle:
Principle #15Dynamics

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 achieves reduced thickness, improved handling, and prevents defects during transport and bonding, while allowing adjustable transmittance for enhanced visibility and comfort across varying light conditions.

Implementation Method 1

An optical laminate capable of changing the transmittance of light when a voltage is applied has been developed. The optical laminate is driven to change transmittance by driving liquid crystals in response to application of a voltage.

Methodology Applied
Scientific EffectLiquid crystal effect: Liquid Crystals

Implementation Method 2

a first transparent conductive layer formed on one surface of the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate and opposite to the first transparent conductive layer

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4603903A1Optical laminate, smart window including the same, and automobile or window for building using the same
Publication Date: 2025.08.20 DONGWOO FINE CHEM CO LTD
  • EP4603903A1 patent drawingFigure 1~2c
  • EP4603903A1 patent drawingFigure 2d~2e
  • EP4603903A1 patent drawing

AI summary

Disclosed is an optical laminate including: a first polarizing plate; a first transparent conductive layer formed on one surface of the first polarizing plate; a second polarizing plate opposite to the first polarizing plate; a second transparent conductive layer formed on one surface of the second polarizing plate; and a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer, wherein at least one of the first polarizing plate and the second polarizing plate has an S of 0.5 to 4.0 N·mm as calculated by Equation 1. The optical laminate is free from concerns about damage during transport due to its easy handling, no defects are generated when bonding the optical laminate to a smart window. Also disclosed are a smart window including the optical laminate and an automobile or a window for a building using the same.