Radar-Transparent Light Guide Layout for Automotive Lamp Units
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Solution Overview
Problem
The placement of a light guide member in front of a millimeter wave radar causes electromagnetic wave attenuation and reflection due to differences in permittivity and dielectric loss tangent, leading to reduced detection performance and radar function deterioration.
Innovation Solution
A lamp device is designed with a light emitting unit that includes light guide members made of transparent resin, positioned to minimize radar wave attenuation and reflection, and incorporates an electromagnetic wave absorber to suppress thermal noise, maintaining radar function integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a light guide member is placed in front of a millimeter wave radar to improve appearance and hide the radar, then the aesthetic appearance is improved, but electromagnetic wave attenuation and reflection occur due to permittivity differences, deteriorating radar detection performance
Solution Approach 1:
The patent applies parameter changes by carefully selecting and controlling the thickness of the light guide member to be an integer multiple of half the radar wavelength, and by adjusting the relative permittivity of the light guide material. These parameter optimizations minimize electromagnetic wave reflection and attenuation while maintaining the light guide's aesthetic function, thus resolving the contradiction between appearance improvement and radar performance.
2Use of energy by moving object
If a light guide member with larger thickness is used to improve light transmission, then light transmission efficiency is improved, but electromagnetic wave attenuation increases due to greater dielectric loss
Solution Approach 1:
The patent resolves this contradiction by optimizing the thickness parameter of the light guide member to satisfy the half-wavelength condition for radar waves while simultaneously ensuring adequate light transmission. By precisely controlling this geometric parameter and the material's electromagnetic properties, the design achieves both efficient light transmission and minimal radar wave attenuation.
3Ease of manufacture
If a light guide member made of transparent resin is used to simplify manufacturing, then manufacturing complexity is reduced, but thermal noise is generated that interferes with radar reception
Solution Approach 1:
The patent introduces a heat dissipation structure as an intermediary element between the light guide member and the radar receiver. This mediator conducts away the thermal noise generated by the transparent resin light guide, preventing it from interfering with radar reception while maintaining the manufacturing simplicity of using resin materials.
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 effectively suppresses radar wave attenuation and reflection, maintains radar function, and ensures accurate detection by minimizing thermal noise interference.
Implementation Method 1
a light guide member that transmits millimeter waves is provided between a front cover and the millimeter wave radar
Implementation Method 2
The placement of a light guide member in front of a millimeter wave radar causes electromagnetic wave attenuation and reflection due to differences in permittivity and dielectric loss tangent
Implementation Method 3
The placement of a light guide member in front of a millimeter wave radar causes electromagnetic wave attenuation and reflection due to differences in permittivity and dielectric loss tangent
Implementation Method 4
incorporates an electromagnetic wave absorber to suppress thermal noise, maintaining radar function integrity
Data Source
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Figure 3A~4
Figure 5~7A
AI summary
Provided is a lamp device which can suppress the attenuation and reflection of a radar wave attributable to a light guide body, does not change an electromagnetic wave radiation pattern, and does not impair a radar function. The lamp device includes: a light guide body that covers at least a part of an electromagnetic wave radiation surface of a radar device; and a light source that supplies light to the light guide body, wherein, when the thickness of the light guide body is denoted by TG, and the wavelength of a radiated electromagnetic wave from the radar device in the light guide body is denoted by λd, TG is set such that TG < λd / 2 is satisfied when the reflection loss of the light guide body with respect to the radiated electromagnetic wave is below a transmission loss, and a reflection loss is -10 dB or less when the reflection loss is equal to or more than a transmission loss.