Radar-Compatible Plastic Part with Absorption Pigments
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Solution Overview
Problem
Conventional metallic paints used in vehicle construction for radar devices reflect, attenuate, or absorb radar waves, reducing the functionality of radar systems, and existing solutions fail to achieve both radar compatibility and a visually metallic appearance without metal-effect pigments.
Innovation Solution
A multilayered coating on plastic parts using flake-form effect pigments with absorbent properties, specifically silver-grey absorption pigments like iron oxide or mixed oxides, to achieve high hiding power, lightness flop, and radar wave transparency, mimicking a metallic finish without metal pigments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If metallic paints containing aluminium-based metal-effect pigments are used for radar device cover parts, then the visual appearance and hiding power are improved, but the radar wave transmission is impaired due to reflection and attenuation
Solution Approach 1:
The patent creates a visual copy of metallic paint effects using non-metallic means. Instead of using actual metal pigments, it employs flake-form effect pigments (such as mica, glass, or plastic flakes) coated with transparent or translucent layers that replicate the optical properties of metallic paints - including light reflection, scattering, and the characteristic metallic sheen - without the harmful radar-wave-interfering properties of real metals
Solution Approach 2:
The patent changes the fundamental material parameter from metallic to non-metallic while maintaining the desired optical appearance. By using flake-form effect pigments with specific surface treatments and coating combinations, the system achieves metallic-like visual properties through controlled light interaction parameters (reflection angles, scattering patterns, surface sheen) rather than through metallic composition
2Reliability
If vapour-deposited metal layers are used to achieve radar wave transparency, then the radar functionality is preserved, but the visual appearance differs from conventional silver-coloured metallic paints
Solution Approach 1:
The patent employs composite material structures combining multiple layers with different functions: flake-form effect pigments provide the metallic visual appearance through light scattering and reflection, while transparent or translucent coating layers (such as clear coats, primer layers, or top coats) allow radar waves to pass through with minimal attenuation. This composite approach integrates the visual and radar-performance requirements into a single multi-layer system
3Reliability
If interference pigments comprising titanium dioxide-coated mica are used, then radar wave transparency is achieved, but the hiding power and metallic lightness flop are insufficient
Solution Approach 1:
The patent segments the coating system into distinct functional layers: a base layer containing flake-form effect pigments that provide the metallic appearance and light scattering properties, and subsequent transparent or translucent coating layers that enhance radar wave transmission. This segmentation allows each layer to be optimized for its specific function - appearance versus radar compatibility - while working together as an integrated system
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 coating provides a visually appealing silver-metallic appearance with high hiding power and radar wave transparency, ensuring radar device functionality is not impaired, while avoiding the use of metal pigments.
Implementation Method 1
a colouring coating that is free from metal-effect pigments and comprises flake-form effect pigments having absorbent properties
Implementation Method 2
achieving the strong lightness flop that is usual in the case of metallic paints containing metal pigments
Implementation Method 3
the usual metallic paints, which contain aluminium-based metal-effect pigments, can reflect, attenuate or absorb the radar waves
Data Source
AI summary
A radar-compatible plastic part that has a surface provided with a colouring coating that is free from metal-effect pigments; a process for the production of a radar-compatible plastic part of this type; and the use thereof in vehicle construction. The radar-compatible, coated plastic part is suitable for use for cover parts of radar devices, omits conventional metal-effect pigments in its colouring coating, and has a silver-coloured metallic appearance, high hiding power, and a strong lightness flop, and at the same time, a good radar wave transparency.