Optical Stack Housing for Metallic Look and RF/IR Transmission
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Solution Overview
Problem
Electronic device housings often lack the ability to provide a metallic appearance while maintaining transmissivity to radio waves and infrared wavelengths, which is essential for functions like 5G communication and infrared sensing.
Innovation Solution
The use of an optical film bonded to a rigid optically transparent substrate, which includes a multilayer structure of alternating polymeric layers, providing high reflectance in the visible range, high transmittance in the near-infrared range, and a sharp band edge, along with a skin layer to achieve a metallic appearance and transparency to radio frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a metallic coating is applied to the housing to achieve a metallic appearance, then the aesthetic appearance is improved, but the transmittance of radio waves and infrared wavelengths deteriorates
Solution Approach 1:
The patent applies a multilayer composite structure consisting of alternating high-refractive-index and low-refractive-index polymer layers. This composite material design enables the housing to simultaneously achieve metallic appearance through visible light reflection and maintain transmittance for radio waves and infrared wavelengths by optimizing the layer thicknesses and refractive index contrasts at different wavelength ranges.
Solution Approach 2:
The patent utilizes controlled variations in layer thickness parameters and refractive index parameters across different wavelength ranges. By adjusting these parameters, the optical film achieves high reflectance in the visible range (400-700 nm) for metallic appearance while maintaining high transmittance in the infrared range (700 nm - 1 mm) and radio frequency range for communication functionality.
2Shape
If the housing material is made opaque to achieve a metallic appearance, then the aesthetic quality is improved, but the functionality for 5G communication and infrared sensing deteriorates
Solution Approach 1:
The patent implements local quality by creating different optical properties at different wavelength ranges within the same housing structure. The multilayer optical film provides high reflectance (metallic appearance) for visible wavelengths while maintaining high transmittance for infrared and radio frequency wavelengths, enabling both aesthetic and functional requirements to be met simultaneously in different spectral regions.
3Reliability
If a multilayer optical film is applied to achieve selective reflectance and transmittance, then the optical performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent achieves complex optical performance through controlled parameter variations in a systematic multilayer structure. By optimizing the thickness and refractive index parameters of alternating layers, the housing achieves high reflectance in visible range and high transmittance in infrared and radio frequency ranges. The systematic approach to parameter optimization balances manufacturing feasibility with desired optical performance.
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 enables electronic device housings to maintain a metallic appearance while being substantially transmissive to radio waves and infrared wavelengths, supporting functions such as 5G communication and infrared sensing.
Implementation Method 1
The optical film has a high reflectance (e.g., greater than about 90%) in a visible wavelength range... A multilayer structure of alternating polymeric layers
Implementation Method 2
high transmittance (e.g., greater than about 80%) in a near infrared wavelength range... an average optical transmittance of the optical film is greater than about 80% in the second wavelength range
Implementation Method 3
for at least one frequency in a range of about 0.1 GHz to about 90 GHz... the optical film transmits at least about 95% of the incident radiation... a dielectric loss tangent of the optical film is less than about 0.02
Data Source
AI summary
A housing for an electronic device includes an optical film having an optical transmittance for substantially normally incident light having a band edge separating first and second wavelength ranges, where the first wavelength range extends from about 400 nm to about 700 nm and the second wavelength range is at least about 100 nm wide and disposed between about 800 nm and about 1100 nm. For substantially normally incident light, an average optical reflectance of the optical film is greater than about 90% in the first wavelength range, and an average optical transmittance of the optical film is greater than about 80% in the second wavelength range. For at least one frequency in a range of about 0.1 GHz to about 90 GHz and for substantially normally incident radiation, the optical film transmits at least about 95% of the incident radiation. An optical stack can include the optical film.