Wavelength-Selective Absorbing Layer Stack for Low Color Travel
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Solution Overview
Problem
Conventional decorative pigments using quarter wave stacks or Fabry-Perot structures face issues with poor hiding and high color travel, and the use of metal layers increases manufacturing costs and corrosion risks.
Innovation Solution
A stack of layers comprising high and low refractive index layers, with at least one layer incorporating a wavelength selective absorbing material, such as metal sulfides or metal oxides, to absorb light selectively without using thin metal layers, ensuring opacity and controlled reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional quarter wave stack designs use transparent materials, then color travel is low, but hiding and flop are poor
Solution Approach 1:
The patent applies local quality by incorporating wavelength selective absorbing material specifically in certain layers of the stack (either high or low refractive index layers) rather than uniformly across all layers. This localized application of absorption properties enables good hiding and flop while maintaining low color travel in the transparent regions, resolving the contradiction between transparency and opacity requirements.
2Reliability
If thin layers of metal are used in Fabry-Perot structures, then decorative effect is achieved, but manufacturing cost increases and corrosion risk increases
Solution Approach 1:
The patent extracts the metal layer from the decorative pigment structure and replaces it entirely with a stack of non-metallic layers comprising high and low refractive index materials with wavelength selective absorbing material. This extraction eliminates the need for vacuum deposition techniques and removes corrosion risks while maintaining the decorative effect through optical interference in the layered structure.
Solution Approach 2:
The patent replaces expensive metal layers requiring vacuum deposition with cheaper non-metallic materials that can be deposited using conventional techniques. The layered structure achieves comparable or superior decorative effects without the high manufacturing costs and corrosion issues associated with metal thin films.
3Reliability
If thin layers of metal are used in Fabry-Perot structures, then decorative effect is achieved, but manufacturing time increases
Solution Approach 1:
The patent removes the metal layer requirement from the decorative structure, eliminating the need for time-consuming vacuum deposition processes. The non-metallic layered stack can be manufactured using faster, conventional coating techniques, significantly reducing manufacturing time while preserving the decorative effect through optical interference.
4Reliability
If wavelength selective absorbing material is added to achieve opacity, then hiding improves, but device complexity increases
Solution Approach 1:
The patent merges the function of opacity (hiding) with the existing layered structure by incorporating wavelength selective absorbing material directly into the high or low refractive index layers. This integration achieves good hiding and flop properties without requiring additional separate layers or complex structures, as the absorbing material works in conjunction with the refractive index differences already present in the stack.
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 achieves good hiding, high flop, and low color travel while eliminating the need for vacuum deposition, reducing manufacturing costs and corrosion risks.
Implementation Method 1
at least one layer of the stack includes a wavelength selective absorbing material; and wherein the stack of layers has a transparent region with an edge at a wavelength in which light is absorbed by the wavelength selective absorbing material
Implementation Method 2
A quarter wave stack is a well-known optical design that is highly reflective within a range of the spectrum... The reflectivity in this region can even exceed the reflectivity afforded by metals
Implementation Method 3
a reflection band with an edge at a wavelength in which light is reflected
Data Source
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AI summary
An article including a stack of layers including a high refractive index layer and a low refractive index layer; wherein at least one layer of the stack includes a wavelength selective absorbing material; and wherein the stack of layers has a transparent region with an edge at a wavelength in which light is absorbed by the wavelength selective absorbing material, and a reflection band with an edge at a wavelength in which light is reflected is disclosed. Compositions and optical devices including the article are also disclosed. Additionally, there is disclosed a method of making the article, the composition, and the optical device.