Variable Light Transmission Panels with Reflective Coating for Uniform Appearance
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Solution Overview
Problem
Variable light transmission panels (VLTPs) with electrochromic technology change their optical state in response to electrical stimuli, causing a noticeable 'checkerboard effect' when viewed from outside, as different optical states result in varying appearances, which is undesirable for building aesthetics and uniformity.
Innovation Solution
The use of a configuration with two transmissive substrates, a coating stack including a transparent conductor and an electrochromic layer, and an electrolyte layer, optimized to achieve a color difference of greater than 40 in transmitted color while maintaining a reflection color difference of less than 6, ensuring a uniform appearance from the outside, even when in different optical states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrochromic variable light transmission panels are used to change optical state for energy efficiency and privacy, then light transmission control is improved, but external appearance uniformity deteriorates due to checkerboard effect
Solution Approach 1:
The patent applies color changing principles by introducing a reflective coating on the external surface of the VLTP that maintains a consistent reflected color appearance across different optical states. The coating is designed to reflect ambient light in a way that masks the underlying color changes of the electrochromic layer, ensuring that windows appear uniform from the outside while still providing variable light transmission control from the inside.
Solution Approach 2:
The reflective coating serves multiple functions simultaneously: it maintains external appearance uniformity by masking color changes, provides glare reduction, and enhances energy efficiency by reflecting solar radiation. This multi-functional approach allows the VLTP to achieve both aesthetic consistency and performance benefits without requiring separate systems for each function.
2Ease of operation
If VLTP optical state changes are made noticeable for internal light control, then light transmission functionality is improved, but external visual distinction increases which is undesirable for building aesthetics
Solution Approach 1:
The patent utilizes controlled color changes in the reflective coating that compensate for the color changes in the electrochromic layer. When the electrochromic layer changes color to control internal light transmission, the reflective coating simultaneously adjusts its reflected color to maintain visual consistency from the external viewpoint, effectively canceling out the visual distinction while preserving full light transmission functionality.
Solution Approach 2:
The reflective coating acts as an intermediary layer between the electrochromic variable light transmission panel and the external environment. It mediates the visual appearance by reflecting light in a controlled manner that masks the underlying optical state changes, allowing the VLTP to function fully while presenting a uniform appearance to external observers.
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
This configuration ensures that the external appearance of buildings with VLTPs remains largely unchanged during the day, allowing for uniform design and reduced visual distinction between windows with and without VLTP elements, while still providing desired light transmission changes internally.
Implementation Method 1
electrochromic (EC) technology... upon application of an electric voltage change their optical state, i.e., color, opacity, and/or transparency (light transmission or reflection)
Implementation Method 2
coating stack comprising of at least two layers, followed by a coating of a transparent conductor
Data Source
AI summary
This disclosure includes variable light transmission panels (VLTPs), which can be incorporated into buildings. Disclosed windows provide uniform appearance from outside during the day when a number of such windows are incorporated in a building regardless of their state of light transmission. These disclosures may also be used to make windows which tint to different transmitted colors but during the day still appear to be uniform from outside.