Gradient-Index Radar Lens for Compact Vehicle Sensor Integration

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Solution Overview

Problem

Existing vehicle radar systems face issues with bulky, heavy, and expensive curved lenses that absorb radar waves, leading to reduced detection range and false object detection due to internal reflections.

Innovation Solution

A vehicle assembly featuring a flat, graded-index lens composed of a sublayer and a pattern layer with sub-wavelength motifs, designed to adjust the radar sensor's field of view and minimize internal reflections by optimizing the refractive index and thickness to achieve destructive interference of reflected waves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a radar sensor is integrated into a vehicle body component, then the number of separate components is reduced and installation space is saved, but the manufacturing precision and positioning accuracy of the radar sensor deteriorate

Engineering Contradiction:
Improveinstallation spaceVSAvoidpositioning accuracy of radar sensor
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The vehicle assembly is divided into functionally independent modules: the radar sensor remains a separate, removable component that can be precisely manufactured and calibrated independently, then mounted onto the vehicle body component (such as a headlight assembly). This segmentation allows the radar sensor to be produced with high precision in a controlled environment while still achieving compact integration in the final assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A gradient-index lens is introduced as an intermediary optical element between the radar sensor and the surrounding medium. This lens serves multiple functions: it focuses and directs the radar waves with high precision, compensates for positioning tolerances, and enables accurate beam formation. The gradient-index lens acts as a mediator that decouples the positioning requirements of the radar sensor from the final beam accuracy requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the radar sensor is fixed directly in the vehicle body component, then the device complexity is reduced, but the adaptability for different vehicle models and configurations is limited

Engineering Contradiction:
Improvenumber of componentsVSAvoidadaptability to different vehicle models
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The radar sensor is designed with a removable and replaceable mounting mechanism that allows it to be dynamically adapted to different vehicle models and configurations. Rather than being permanently fixed, the radar sensor can be easily removed, repositioned, or replaced depending on the specific vehicle requirements, enabling the same radar sensor design to serve multiple vehicle platforms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The radar sensor assembly is designed with universal mounting features and standardized interfaces that enable it to be installed on various vehicle body components across different vehicle models. The gradient-index lens and housing are designed to accommodate different mounting positions and orientations, making the radar sensor a universal component that can adapt to diverse vehicle configurations without requiring model-specific customizations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Device complexity

If conventional lenses are used in the radar sensor, then the device complexity is low, but the beam formation quality and detection precision are insufficient

Engineering Contradiction:
Improvelens structureVSAvoiddetection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs a gradient-index lens where the refractive index varies continuously through the lens material according to a specific gradient profile. This parameter change in the refractive index allows for precise control of radar wave propagation paths, enabling superior beam formation and focusing compared to conventional homogeneous lenses. The gradient-index profile is optimized to achieve desired beam patterns while maintaining a relatively simple single-piece lens structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The gradient-index lens is constructed using composite material structures or material compositions that achieve the desired refractive index gradient. This may involve using multiple materials with different refractive indices arranged in layers or gradients, or using specially formulated composite materials that provide the required optical properties. The composite structure enables precise beam control without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #40Composite 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 reduces the overall size and cost of the vehicle assembly, maintains radar detection range, and enhances the signal-to-noise ratio by eliminating first-order reflections, thus improving detection accuracy.

Implementation Method 1

the radar sensor (1) comprises a gradient-index lens (3)

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4363882B1Vehicle assembly comprising a radar sensor and a gradient-index lens
Publication Date: 2026.04.29 VALEO VISION SA
  • EP4363882B1 patent drawingFigure 1
  • EP4363882B1 patent drawingFigure 2~3
  • EP4363882B1 patent drawingFigure 4

AI summary

The invention relates to a vehicle assembly (1) for a vehicle (2), said vehicle assembly (1) comprising: - a radar sensor (10) having a field of vision (FOV) and configured to transmit radar waves (R1) over a range (∆1) of wavelengths (λ) in the field of vision (FOV), and - a lens (11) arranged opposite the radar sensor (10), - characterised in that the lens (11) is a gradient-index lens and comprises a sublayer (12) and a layer (13) of patterns (130) forming a subwavelength-structured dielectric element with a repetition period of the patterns (130) that is less than quarter of a wavelength (λ) of the range (∆1), and characterised in that the layer (13) of patterns (130) has a local refractive index (n1) which is calculated as a function of a local density (τr) of the patterns (130) in the layer (13).