Multi-color dielectric coating for wireless charging transparency
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Solution Overview
Problem
There is a need for optical coatings on mobile device casings that provide an opaque appearance while maintaining transparency to electromagnetic radiation, as metallic coatings interfere with wireless transmission and reception and prevent wireless charging.
Innovation Solution
A multi-color dielectric coating is applied using interleaved layers of high and low refractive index materials, with selective etching to create reflections at different wavelengths, allowing the coating to appear as different colors without interfering with electromagnetic radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metallic coating is applied to provide opaque appearance, then the opaque appearance is achieved, but wireless transmission and reception are interfered with and wireless charging is prevented
Solution Approach 1:
The patent introduces dielectric coating as an intermediary material between the glass substrate and the external environment. This dielectric layer acts as a mediator that provides the required optical properties (opacity at visible wavelengths) while being transparent to electromagnetic radiation, thus enabling wireless communication and charging functions to pass through without interference.
Solution Approach 2:
The patent replaces the metallic coating system with a dielectric coating system. Instead of using metal layers that inherently block electromagnetic waves, the invention uses dielectric materials with specific refractive indices and thicknesses to achieve the desired optical effects through constructive and destructive interference, thereby substituting a mechanical/optical solution with an electromagnetic-wave-compatible solution.
2Reliability
If dielectric coating is applied to maintain transparency to electromagnetic radiation, then wireless functionality is enabled, but the opaque appearance is not achieved
Solution Approach 1:
The patent applies different optical properties to different regions of the dielectric coating. By varying the thickness of the dielectric layers at different locations, the coating can provide opaque appearance in certain areas (where destructive interference occurs for visible light) while maintaining transparency to electromagnetic radiation throughout. This local variation in layer thickness enables simultaneous achievement of both requirements.
Solution Approach 2:
The patent utilizes optical interference effects to create color changes in the dielectric coating. By carefully controlling the thickness of dielectric layers, the coating can reflect specific wavelengths of visible light (creating opaque, colored appearances) while allowing electromagnetic radiation to pass through. The multi-layer structure creates constructive and destructive interference patterns that produce desired colors and opacity levels.
3Adaptability or versatility
If multiple interleaved dielectric layers are applied to create multi-color reflection, then customizable color designs are achieved, but the manufacturing complexity increases
Solution Approach 1:
The patent divides the dielectric coating into multiple discrete interleaved layers, each with specific refractive indices and thicknesses. This segmentation allows independent control of optical properties for each layer, enabling customization of color and optical characteristics. The segmented structure facilitates modular manufacturing where each layer can be deposited with precise control, and the cumulative effect creates the desired multi-color appearance.
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 provides an attractive, opaque appearance for mobile device casings while ensuring transparency to electromagnetic radiation, enabling wireless charging and transmission, and allowing for customizable color designs without degrading wireless functionality.
Implementation Method 1
The reflections from the low-index layers have exactly half a wavelength in path length difference, but there is a 180-degree difference in phase shift at a low-to-high index boundary, compared to a high-to-low index boundary, which means that these reflections are also in phase.
Implementation Method 2
The coating is generated by applying multiple interleaved layers of high and low refractive index dielectric materials. The reflections from the low-index layers have exactly half a wavelength in path length difference
Implementation Method 3
Etching of selected layers at selected locations changes the color appearance of the etched locations, thus generating a coating having multiple colors
Data Source
AI summary
A multi-color dielectric coating is formed using interleaved layers of dielectric material, having alternating refractive index, to create reflections at selected wavelengths, thus appearing as different colors. Etching of selected layers at selected locations changes the color appearance of the etched locations, thus generating a coating having multiple colors. The thicknesses of the layers are chosen such that the path-length differences for reflections from different high-index layers are integer multiples of the wavelength for which the coating is designed.