Solar Reflective Coating for VR Headsets
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Solution Overview
Problem
Virtual reality and augmented reality eyewear devices or headsets experience significant unwanted heating due to substantial absorption of the solar spectrum, leading to user discomfort during outdoor use, especially for black-colored devices.
Innovation Solution
A solar reflective coating is applied to the interior or exterior surfaces of these devices, incorporating phosphor microcrystals or other down-conversion/up-conversion materials that absorb visible light and emit non-visible radiation, thereby reducing solar heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a black-colored coating is applied to VR/AR eyewear devices, then the device appears aesthetically pleasing and absorbs visible light, but the device experiences significant unwanted heating due to substantial absorption of the solar spectrum
Solution Approach 1:
The patent changes the optical parameters of the coating by incorporating phosphor materials that convert visible light wavelengths to infrared wavelengths. This parameter change allows the coating to appear black (absorbing visible light) while converting the absorbed energy to infrared radiation that can be thermally managed, thereby reducing unwanted heating in the visible spectrum range.
Solution Approach 2:
The patent uses composite materials consisting of phosphor particles embedded in a matrix material. The phosphor particles (such as Y3Al5O12:Ce, Lu3Al5O12:Ce, or other down-conversion phosphors) are combined with a binder or matrix material to create a coating that simultaneously achieves black appearance and reduced solar heating through wavelength conversion.
2Temperature
If a solar reflective coating is applied to reduce solar heating, then the device temperature decreases, but the coating complexity increases due to incorporation of phosphor microcrystals or down-conversion materials
Solution Approach 1:
The patent merges multiple functions into a single coating layer: the phosphor-containing coating simultaneously provides black coloration, visible light absorption, wavelength conversion to infrared, and solar heat reduction. This consolidation of functions into one integrated coating reduces overall system complexity compared to using multiple separate layers or components.
3Object-affected harmful factors
If phosphor materials are used to convert visible light to infrared radiation, then solar reflectance increases to 85%, but the manufacturing process becomes more complex
Solution Approach 1:
The patent achieves high solar reflectance (up to 85%) by changing the optical parameters of the coating through phosphor incorporation. The phosphor materials convert absorbed visible light to infrared radiation, effectively reflecting solar energy while maintaining a black appearance. This parameter change enables high solar reflectance without requiring complex multilayer structures.
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 solar reflective coating effectively reduces solar heating by converting visible light into infrared radiation, achieving a high solar reflectance of up to 85% and decreasing the absorbed solar heat by approximately 65% compared to a black layer that only absorbs visible radiation.
Implementation Method 1
The solar reflective coating may include an additive such as one or more of a class of photon down-conversion or up-conversion materials or structures, such as phosphor microcrystals dispersed throughout a suitable matrix
Implementation Method 2
The down-conversion or up-conversion materials may be configured to absorb incident light within the visible spectrum and emit visible and/or non-visible light (e.g., UV and/or IR radiation)
Implementation Method 3
A reflective component may include a reflective layer or particles of a reflective medium
Data Source
AI summary
A solar reflective coating includes a reflective layer and a black layer overlying the reflective layer, where the black layer includes active particles dispersed throughout a matrix. Example active particles include phosphor microcrystals adapted to reflect incident non-visible radiation and convert incident visible radiation to non-visible radiation.