Polarizing Plate Structure to Eliminate Smart Window Surface Spots
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Solution Overview
Problem
Conventional smart windows with liquid crystal layers suffer from visible spots due to level differences between the liquid crystal layer and sealant, and are prone to deformation from moisture and heat, affecting visibility and durability.
Innovation Solution
A polarizing plate with protective films of 100 μm to 300 μm thickness and in-plane retardation less than 4,000 nm, directly forming conductive layers on the polarizing plates without substrates, and including retardation matching and hard coating layers to prevent level differences and enhance moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealant is applied to the outer peripheral surface of the liquid crystal layer, then the liquid crystal layer is prevented from detaching, but a level difference is generated on the outer surface causing surface waviness and bubbles
Solution Approach 1:
A buffer layer is introduced as an intermediary between the liquid crystal layer and the sealant. This buffer layer has a thickness greater than the sealant height, allowing the sealant to attach to the liquid crystal layer while the buffer layer absorbs the level difference, preventing surface waviness and bubbles on the outer surface.
Solution Approach 2:
The solution moves from a two-dimensional surface problem to a three-dimensional structural solution by adding a buffer layer with specific thickness in the vertical dimension. The buffer layer's thickness is designed to be greater than the sealant height, creating a stepped structure that resolves the surface flatness issue while maintaining attachment reliability.
2Object-affected harmful factors
If a protective film with high moisture permeability is applied to the smart window, then protection is provided, but bubbles enter the liquid crystal layer when exposed to high-temperature and high-humidity environments
Solution Approach 1:
The buffer layer acts as a barrier creating a protected environment around the liquid crystal layer. By selecting buffer layer materials with appropriate moisture permeability characteristics and designing the layer structure, the liquid crystal layer is shielded from moisture and heat penetration, preventing bubble formation in high-temperature and high-humidity conditions.
3Duration of action of stationary object
If the protective film thickness is increased to prevent deformation, then durability is improved, but the overall thickness and complexity of the optical laminate increases
Solution Approach 1:
The buffer layer is designed as a thin film structure with optimized thickness that provides sufficient mechanical support and environmental protection without excessive bulk. The film is engineered to have appropriate flexibility and strength characteristics, maintaining durability while minimizing added thickness and structural complexity.
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
Prevents visible spots and deformation, ensuring excellent visibility and durability by minimizing level differences and improving moisture and heat resistance, with enhanced conductive layer integration for faster switching and reduced thickness.
Implementation Method 1
a protective film formed on one surface of the polarizer... prevents defects from occurring due to the level difference between a liquid crystal layer and a sealant
Implementation Method 2
the protective film has an in-plane retardation of less than 4,000 nm for light having a wavelength of 550 nm
Implementation Method 3
enhanced conductive layer integration for faster switching and reduced thickness... hard coating layers to prevent level differences and enhance moisture resistance
Implementation Method 4
The optical laminate is driven to change transmittance by driving liquid crystals in response to application of a voltage. The optical laminate achieves a desired transmittance by including a liquid crystal layer whose phase changes in response to the application of an electric field
Implementation Method 5
in order to prevent the liquid crystal layer from detaching, a sealant is applied to the outer peripheral surface of the liquid crystal layer
Data Source
AI summary
The present disclosure provides a polarizing plate for an optical laminate, including a polarizer and a protective film formed on one surface of the polarizer, wherein the protective film has a thickness of 100 μm to 300 μm. Also provided is an optical laminate including the polarizing plate. Accordingly, the present disclosure relates to a smart window in which defects due to the level difference between a liquid crystal layer and a sealant are prevented and which has excellent visibility, and an automobile or a window for a building using the same.