Variable-Transmittance Window Film with Complementary Color Control
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Solution Overview
Problem
Existing variable-transmittance window technologies, such as those using suspended particle devices (SPDs), are limited by their prominent blue color in the absence of an electric field, restricting their application.
Innovation Solution
A window film configuration comprising a suspended particle layer and a polymer dispersed liquid crystal layer, where the polymer dispersed liquid crystal layer includes a dye with a second color complementary to the first color of the suspended particle layer, allowing for control of the film's transparency and color through electric field applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a suspended particle device (SPD) is used for variable-transmittance control, then large area and continuous transmission control are achieved, but the film exhibits a prominent blue color in the absence of an electric field
Solution Approach 1:
The patent combines SPD particles with liquid crystal molecules in a single composite layer. The SPD particles provide variable-transmittance control through electric field application, while the liquid crystal molecules compensate for the blue color tint by providing optical anisotropy that adjusts the polarization state of transmitted light, thereby resolving the color distortion issue while maintaining the transmittance control capability
Solution Approach 2:
The patent introduces different functional components (SPD particles and liquid crystal molecules) at different locations within the same layer to address different problems: SPD particles are distributed throughout for transmittance control, while liquid crystal molecules are positioned to specifically address the color distortion issue by modifying the optical path of transmitted light
2Device complexity
If a single-layer SPD structure is used, then the device complexity is low, but the film can only operate in two states (transparent and blue-tinted opaque)
Solution Approach 1:
By creating a composite layer containing both SPD particles and liquid crystal molecules, the patent achieves multi-color operation capability without adding multiple separate layers. The interaction between SPD particles and liquid crystal molecules enables the film to display different colors (blue, orange, green, red) depending on the applied voltage, thereby increasing operational versatility while maintaining relatively simple structure
Solution Approach 2:
The composite layer performs multiple functions simultaneously: it provides variable-transmittance control through SPD particles, color compensation through liquid crystal molecules, and enables multi-color display capability. This multi-functionality is achieved within a single integrated layer rather than requiring separate layers for each function
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
Enables the window film to operate in four different color states: transparent, opaque or translucent in the first color, opaque or translucent in the second color, and opaque or translucent in black, addressing the color limitation of existing SPD technologies.
Implementation Method 1
A suspended particle layer may be positioned between the first substrate and the third film, and a polymer dispersed liquid crystal layer may be positioned between the second substrate and the third film
Implementation Method 2
a polymer dispersed liquid crystal layer may be positioned between the second substrate and the third film
Data Source
AI summary
Provided is a variable-transmittance window film capable of being operated in four different colors, and the window film of the present invention includes a first film, a second film spaced apart from the first film, a third film interposed between the first film and the second film, a suspended particle layer between the first film and the third film, and a polymer dispersed liquid crystal layer between the second film and the third film, wherein the polymer dispersed liquid crystal layer includes a dye having a second color complementary to a first color of the suspended particle layer.