Electrochromic Privacy Window with Scattering Layer
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Solution Overview
Problem
Conventional electrochromic (EC) windows are inadequate for privacy applications due to their inability to achieve a sufficiently dark state, limiting their use in environments requiring privacy.
Innovation Solution
An electrochromic privacy window comprising an EC pane unit with a bright and dark state, combined with a privacy device that attenuates visible radiation, utilizing switchable mirror devices, polymer-dispersed liquid crystal devices, or tunable liquid crystal filters to achieve high haze and low transmittance levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional EC devices are used, then energy efficiency is improved, but privacy capability deteriorates due to insufficient dark state
Solution Approach 1:
The patent combines an electrochromic (EC) device with a privacy device in a single window assembly. The EC device provides energy efficiency through dynamic transmittance control, while the privacy device (comprising scattering particles or structures) provides privacy through light scattering. Both devices are integrated into the same window unit, allowing them to work together to simultaneously achieve energy efficiency and privacy protection.
Solution Approach 2:
The privacy device incorporates scattering particles (such as titanium dioxide, zinc oxide, or silica particles) within a matrix material to create a composite structure that scatters visible light. This composite material approach allows the window to maintain the EC device's energy-saving properties while adding privacy functionality through the light-scattering composite layer.
2Ease of manufacture
If static window coatings are used, then manufacturing cost is reduced, but adaptability to varying climates deteriorates
Solution Approach 1:
The patent employs dynamic electrochromic devices that can change their optical properties in response to electrical signals, allowing the window to adapt to varying climate conditions. The EC device can switch between different transmittance states based on external factors such as solar intensity, temperature, and user preferences, providing dynamic adaptability that static coatings cannot achieve.
Solution Approach 2:
The electrochromic device changes its optical parameters (transmittance, reflectance) in response to applied voltage, enabling the window to adapt to different climate conditions. By controlling the voltage applied to the EC device, the window can optimize its performance for various climates - allowing more light and heat in cold climates and blocking them in hot climates.
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 enables EC windows to achieve a transmitted haze of over 80% and visible transmittance of 0.1% or less in privacy states, effectively addressing the limitations of conventional EC windows for privacy applications.
Implementation Method 1
an EC device having a bright state and a dark state
Implementation Method 2
a privacy device facing the EC pane unit and having a bright state and a privacy state configured to attenuate visible radiation transmitted through the window
Data Source
AI summary
An electrochromic (EC) privacy window includes an EC pane unit including a first EC device having a bright state and a dark state, and a privacy device facing the EC pane unit and having a bright state and a privacy state configured to attenuate visible radiation transmitted through the window. In some embodiments, when the privacy device is in the privacy state, the window has transmitted haze of greater that 80%. In other embodiments, when the privacy device is in the privacy state and the first EC device is in the dark state, the window has a visible transmittance of about 0.1% or less.