Variable-Transmittance Optical Laminate With Matched Spacer Modulus
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Solution Overview
Problem
Conventional variable transmittance optical stacks suffer from defects such as cracks and reduced durability due to the correlation between the hardness of the stack and spacer, leading to inconsistent light transmission and potential glare or visibility issues.
Innovation Solution
A variable transmittance optical stack with a spacer having a compressive modulus ratio of 0.75 to 1.55 relative to the stack and a content of 0.5 to 3.0% by weight, ensuring smooth light transmission and preventing cracks by optimizing the compressive modulus ratio and spacer content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the transmittance of the external light-blocking coating is preset low, then glare to the driver is reduced during the day, but visibility of the surroundings deteriorates at night
Solution Approach 1:
The patent applies a variable transmittance optical stack that dynamically changes its light transmittance based on ambient light conditions. The optical stack transitions between different transmittance states (high and low) depending on whether it is day or night, allowing the window to adapt to changing environmental conditions rather than being fixed at one transmittance level.
Solution Approach 2:
The patent changes the transmittance parameter of the optical stack based on external light conditions. By controlling the transmittance parameter to be high during nighttime and low during daytime, the system optimizes both visibility and glare reduction for different operating conditions.
2Illumination intensity
If the transmittance of the external light-blocking coating is preset high, then visibility of the surroundings is improved during the day, but glare to the driver occurs
Solution Approach 1:
The variable transmittance optical stack dynamically adjusts its transmittance property based on ambient light conditions. During daytime when ambient light is sufficient, the optical stack transitions to a low transmittance state to prevent glare while maintaining adequate visibility.
Solution Approach 2:
The transmittance parameter of the optical stack is changed according to external light conditions. The system sets the transmittance to low during daytime to reduce glare and to high during nighttime to improve visibility, optimizing performance for each condition.
3Ease of manufacture
If the compressive modulus of the spacer is not matched with the stack, then manufacturing is simplified, but cracks occur and durability deteriorates
Solution Approach 1:
The patent specifies a particular compressive modulus range for the spacer (2.0 to 5.0 GPa) to match the compressive modulus of the stack. This parameter matching prevents cracks from occurring at the interface between the spacer and stack, thereby improving durability while maintaining manufacturing feasibility.
Solution Approach 2:
The patent uses a spacer made of a material with specific mechanical properties (compressive modulus of 2.0 to 5.0 GPa) that is matched to the stack material. This composite structure with matched mechanical properties prevents crack propagation and improves overall device reliability.
4Ease of manufacture
If the spacer content in the dispersion liquid crystal is not optimized, then manufacturing is easier, but the liquid crystal gap becomes unstable and defects occur
Solution Approach 1:
The patent optimizes the spacer content in the dispersion liquid crystal to a specific range (0.01 to 5.0 wt%). This optimized concentration ensures that the spacer particles are sufficiently distributed to maintain a stable and uniform liquid crystal gap, preventing defects while remaining compatible with standard manufacturing processes.
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 provides an optical stack with enhanced durability and reduced defect occurrence, ensuring consistent light transmission and improved reliability by stabilizing the liquid crystal gap.
Implementation Method 1
The variable transmittance optical stack is driven by changing the transmittance by driving liquid crystal according to voltage application
Data Source
AI summary
The present invention relates to a transmittance-variable optical laminate and a manufacture method therefor, and a smart window comprising same, the laminate including: a first laminate in which a first polarization plate, a first transparent conductive layer, and a first alignment film are sequentially laminated; a second laminate in which a second polarization plate, a second transparent conductive layer, and a second alignment are sequentially laminated; and a dispersion liquid crystal disposed between the first laminate and the second laminate, wherein the dispersion liquid crystal includes a spacer, a compressive modulus of the spacer to a compressive modulus of one of the first laminate and the second laminate is 0.75 to 1.55, and the spacer is included in an amount of 0.5 to 3.0% by weight based on the total weight of the dispersion liquid crystal.