Smart Window Optical Laminate Without Substrates or Spacers
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Solution Overview
Problem
Conventional transmittance variable optical laminates face issues such as increased manufacturing complexity and cost, thickness, retardation, and damage due to the inclusion of separate substrates and spacers, which affect surface hardness, antifouling properties, and uniformity of light transmission.
Innovation Solution
A transmittance variable optical laminate is designed without a separate substrate for the conductive layer, incorporating a pressure-sensitive adhesive layer with high elastic modulus and a liquid crystal layer with a polymer network for uniform alignment, ensuring excellent surface hardness, antifouling properties, and reduced thickness, while maintaining a uniform cell gap without spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a separate substrate is included to form the conductive layer, then the conductive layer can be formed, but the manufacturing process becomes complicated, the manufacturing cost increases, and the thickness of the laminate increases
Solution Approach 1:
The patent merges the substrate and conductive layer into a single integrated structure. The conductive layer is formed directly on the outer surface of the polarizing plate, eliminating the need for a separate substrate. This integration simplifies the manufacturing process and reduces the overall number of components while maintaining the necessary electrical conductivity function.
2Length of moving object
If a separate substrate is included to form the conductive layer, then the conductive layer can be formed, but the thickness of the laminate increases
Solution Approach 1:
The substrate and conductive layer are combined into one component, with the conductive layer formed directly on the polarizing plate surface. This eliminates the additional thickness contributed by a separate substrate while preserving the conductive layer's essential function for liquid crystal driving.
3Length of moving object
If the optical laminate has a smaller thickness, then the thickness is reduced, but the optical laminate is damaged or surface-scratched when applied
Solution Approach 1:
The patent employs a composite structure where a polarizing plate with high surface hardness (H or higher) serves as both the substrate and protective surface. This inherently durable material forms the outer surface of the laminate, providing scratch resistance and surface protection without requiring additional protective layers, thus maintaining thin overall dimensions.
4Manufacturing precision
If a column spacer is included within the liquid crystal layer, then the cell gap can be maintained, but the manufacturing process becomes more complicated and the transmittance changes as the alignment film is damaged
Solution Approach 1:
The patent removes the column spacer component entirely from the liquid crystal layer. Instead, the cell gap is maintained through the inherent structural design and material properties of the laminate, eliminating the need for additional spacer elements and their associated manufacturing complexities while preserving alignment film integrity.
5Manufacturing precision
If a ball spacer is used to maintain the cell gap, then the cell gap can be maintained, but it is impossible to maintain a uniform cell gap and a short circuit occurs
Solution Approach 1:
The ball spacer is completely removed from the structure. The uniform cell gap is achieved through the precise structural design of the laminate itself, eliminating the risk of short circuits associated with ball spacers while maintaining the necessary optical performance.
6Reliability
If the laminate includes a separate substrate, then the conductive layer can be formed, but the surface hardness and antifouling properties are compromised
Solution Approach 1:
The substrate and surface protection functions are merged into the polarizing plate itself, which possesses high surface hardness (H or higher). This integrated structure provides both structural support and surface durability, eliminating the need for separate substrate layers that would compromise surface properties.
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 prevents scratching and damage, maintains uniform light transmission, and reduces thickness, enhancing flexibility and adhesion, thus improving manufacturing efficiency and reducing costs.
Implementation Method 1
The transmittance variable optical laminate is driven to change transmittance by driving liquid crystals in response to application of a voltage
Implementation Method 2
a pressure sensitive adhesive layer having excellent elastic modulus, may have excellent flexural resistance, may be prevented from being damaged, and is attachable to and detachable from an adherend
Data Source
Figure 1~2c
Figure 2d~2f
AI summary
Disclosed is a transmittance variable optical laminate including: a first polarizing plate; a surface treatment layer formed on one surface of the first polarizing plate; a first transparent conductive layer formed on the other 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; a liquid crystal layer provided between the first transparent conductive layer and the second transparent conductive layer; and a pressure sensitive adhesive layer provided on one surface of the second polarizing plate, wherein the thickness of the first polarizing plate is equal to or greater than the thickness of the second polarizing plate, and the optical laminate has a surface hardness of H or higher. Also disclosed are a smart window comprising the laminate, and an automobile or a window for a building using the same.