Electrochromic Optical Coating for Angle-Dependent Color Control
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Solution Overview
Problem
Existing electrochromic devices exhibit color in reflection due to the interface between the electrochromic device and the substrate, which varies with the reflection angle and is affected by nonuniformities in layer thickness, requiring complex layer arrangements for control.
Innovation Solution
An optical system with a coating on the substrate surface that controls reflection color by modifying the electrochromic device's color, ensuring the final color is closer to a reference color and reducing angle-dependent variations, without needing additional layers or complex manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a reflection-modifying layer is interposed between the PVB and the counter-substrate to control reflection color, then the color in reflection can be modified, but the device complexity increases due to complex lamination arrangement
Solution Approach 1:
The invention extracts the color control function from the internal structure of the electrochromic device and relocates it to an external coating on the substrate. This separates the color modification function from the electrochromic switching mechanism, eliminating the need for complex internal layer arrangements while maintaining color control capability.
Solution Approach 2:
The invention moves the color control from the lateral dimension (internal layer arrangement within the electrochromic stack) to the surface dimension (coating on the substrate). This dimensional shift simplifies the overall device structure by placing the color-modifying function on the outer surface rather than requiring complex internal layering.
2Ease of manufacture
If the electrochromic device interface with the substrate is used for color control, then the color can be modified, but the color varies with reflection angle
Solution Approach 1:
The invention applies a coating with specific optical properties to the substrate surface, creating a localized color control mechanism that is independent of the reflection angle. The coating's optical characteristics are engineered to provide consistent color appearance across different viewing angles, unlike interface-based solutions where color varies with angle.
3Productivity
If standard electrochromic device layers are used, then the device can be manufactured, but small nonuniformities in layer thickness lead to large nonuniformities in reflected color
Solution Approach 1:
The invention applies a preliminary color-control coating on the substrate before final assembly. This coating pre-establishes the optical characteristics and compensates for potential nonuniformities in subsequent electrochromic layers, ensuring color uniformity in the final product without requiring extremely precise manufacturing tolerances.
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 system allows simple, effective, and reliable control of reflection color, minimizing angle-dependent variations and nonuniformities, while maintaining a desired color range and reducing the need for complex layer arrangements.
Implementation Method 1
The color is mainly due to the reflection of incident light from the interface between the electrochromic device and an adjacent layer
Implementation Method 2
Electrochromic devices have certain characteristics that may be modified, under the effect of a suitable supply of electrical power, between a clear state and a tinted state, these characteristics most particularly being transmittance, absorbance and/or reflectance
Data Source
AI summary
An optical system includes an optical assembly including a substrate having two opposite main faces and an electrochemical functional device with electrically controllable optical and/or energetic properties formed on a main face, this optical assembly having an initial color state with an initial color value in reflection at a first reflection angle, a coating for controlling color in reflection formed on the other main face and forming an external face of the system, the optical system having a final color state with a final color value in reflection at this first angle, this final color state being closer than the initial color state to a reference color state having a reference color value at the first angle, this corresponding to a variation in color distance between the initial and reference values, and between the final color and the reference values smaller than 0 at the first angle.