Asymmetric Optical Element for Uniform Driver Illumination

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Solution Overview

Problem

Current driver observation systems in vehicles face challenges in providing uniform and efficient illumination while being easily and unobtrusively integrated into the vehicle, as existing lighting optics often result in non-uniform illumination and require separate components for installation.

Innovation Solution

A cover plate unit with an integrated optical element, featuring a non-circular cross section and materials that are opaque in the visible range but transparent in the infrared range, allowing for cost-effective and precise production, and enabling efficient infrared illumination with a driver observation system that includes a light source and camera for monitoring driver characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate components are used for lighting optics, then installation flexibility is improved, but device complexity increases and manufacturing cost rises

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidcomponent quantity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the cover plate and optical element into a single integrally formed component. The optical element is formed as an integral part of the cover plate through injection molding or injection-compression molding, eliminating the need for separate assembly of these components while maintaining installation flexibility

Inventive Principle:
Principle #5Merging (Combining)

2Illumination intensity

If conventional lighting optics are used, then basic illumination is achieved, but uniformity of illumination deteriorates

Engineering Contradiction:
Improveillumination uniformityVSAvoidoptical element design complexity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent employs an optical element with an asymmetric exit surface that is free of circular symmetry. The exit surface features varying slopes and angles designed to redirect light rays uniformly across the illumination area. This asymmetric geometry, combined with total internal reflection at the lateral boundary surfaces, achieves uniform illumination without requiring complex additional optical components

Inventive Principle:
Principle #4Asymmetry

3Illumination intensity

If visible transparent materials are used, then aesthetic appearance is improved, but infrared illumination capability deteriorates

Engineering Contradiction:
Improveinfrared transmissionVSAvoidmaterial selection flexibility
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent specifies that the optical element be made from a material that is opaque in the visible spectrum and transparent in the infrared spectrum. This parameter change in material optical properties enables the cover plate to block visible light (providing aesthetic appearance and hiding internal components) while allowing infrared light to pass through for driver illumination and camera operation

Inventive Principle:
Principle #35Parameter changes

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 provides uniform illumination with elongated illumination areas, enhancing driver monitoring capabilities while being easily integrated into vehicle cockpits, reducing component complexity and production costs.

Implementation Method 1

There are various types of illumination optics that utilize the total internal reflection of light to enable the uniform radiation of approximately point-like light with, for example, a hemispherical radiation pattern in a preferred direction

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a light beam coming from an optically denser medium impinges on the interface with an optically thinner medium. Due to optical principles, it is refracted at an angle of refraction that is greater than the angle of incidence

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3948391B1Optical element and cover pane with an optical element
Publication Date: 2025.01.01 ROBERT BOSCH GMBH
  • EP3948391B1 patent drawingFigure 1~2
  • EP3948391B1 patent drawingFigure 3a
  • EP3948391B1 patent drawingFigure 3b

AI summary

The invention relates to an optical element (1) for illuminating a defined area, the optical element (1) being formed such that a part of the light beams irradiated by the at least one light source (10) into the optical element is reflected in the optical element by total reflection on an interface (2) and then exits the optical element in a preferred direction in an exit plane (4), the cross-section (22, 24, 26) of the optical element in the exit plane (4) having two or less axes of symmetry.