Motor Vehicle Lighting Device Dark Appearance Design

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Solution Overview

Problem

Existing motor vehicle lighting devices with metallic reflective surfaces cause unwanted contrast with dark-colored bodywork in daylight, affecting aesthetic appearance.

Innovation Solution

A lighting device with a dark-toned exterior LED and a translucent screen between the optical reflector and external indicator, which absorbs daylight and homogenizes reflections, maintaining a dark appearance when turned off and reducing visibility of internal components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If metallic reflective surfaces are used in the lighting device, then the light reflection efficiency is improved, but the aesthetic appearance deteriorates due to unwanted contrast with dark-colored vehicle bodywork in daylight

Engineering Contradiction:
Improvelight reflection efficiencyVSAvoidaesthetic appearance
Core Design Contradiction:
Illumination intensityVSShape

Solution Approach 1:

A translucent screen is introduced as an intermediary element between the metallic optical reflector and the external indicator light. This screen diffuses the daylight entering the housing, preventing direct visualization of the metallic reflector while maintaining its light-reflecting function. The screen acts as a mediator that reconciles the conflict between needing high reflectivity and achieving a dark appearance in daylight.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The external indicator light is designed with a dark or black color that absorbs daylight rather than reflecting it. This color choice fundamentally changes the optical interaction from reflection (metallic surfaces) to absorption (dark surfaces), eliminating the unwanted contrast with dark-colored vehicle bodywork while maintaining aesthetic appearance.

Inventive Principle:
Principle #32Color changes

2Shape

If the external indicator light is made dark to match the vehicle body, then the aesthetic appearance is improved, but the visibility of internal components increases in daylight

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidvisibility of internal components
Core Design Contradiction:
ShapeVSDifficulty of detecting and measuring

Solution Approach 1:

The translucent screen serves as a diffusion barrier that obscures the view of internal components (metallic reflector, light source housing) while allowing daylight to pass through and be diffused. This mediator prevents direct line-of-sight to internal components, maintaining the dark appearance without compromising aesthetics.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The translucent screen is positioned specifically between the external indicator light and the optical reflector, creating a localized diffusion zone. This local application of diffusion quality allows the dark exterior to maintain its appearance while preventing the leakage of internal component visibility in specific critical areas.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If the translucent screen is placed close to the external indicator light to improve homogenization, then the light diffusion is improved, but moisture dissipation is reduced

Engineering Contradiction:
Improvehomogeneity of reflected lightVSAvoidmoisture dissipation
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The spacing between the translucent screen and external indicator light is optimized to a specific range (1-10 mm, preferably 2-4 mm). This parameter optimization balances two competing requirements: sufficient distance for moisture dissipation (thermal management) and sufficient proximity for effective light diffusion and homogenization. The specific distance range represents a compromise that satisfies both optical and thermal requirements.

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 effectively minimizes daylight reflection, reducing contrast with the vehicle body and maintaining a uniform, dark appearance in daylight, thus enhancing the aesthetic appeal of dark-colored vehicles.

Implementation Method 1

a translucent screen (26) is interposed between the optical reflector (16) and the external indicator light (18) to homogenize the daylight reflected by the various components inside the optical housing (4)

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

The external indicator light has a dark or black color to darken the interior of the optical housing when the light-emitting device is switched off and exposed to daylight. The outdoor indicator absorbs between 80% and 95% of the intensity of daylight

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP3775677B1Dark appearance light device for a motor vehicle
Publication Date: 2023.09.20 MARELLI AUTOMOTIVE LIGHTING FRANCE
  • EP3775677B1 patent drawingFigure 1~2

AI summary

The invention relates to a dull-looking luminous device (2) for a motor vehicle, comprising an optical housing (4) containing a light source (6A, 6B) and at least one optical reflector (16) arranged in such a way as to direct a light beam emitted by the light source (6A, 6B), through an opening (14) of the optical housing, the opening (14) being closed by an external indicator light (18) in order to protect the light source (6A, 6B) and the optical reflector (16) from bad weather, characterised in that the external indicator light (18) has a dull appearance in the light of day, and in that a translucent screen (26) is inserted between the optical reflector (16) and the external indicator light (18), the translucent screen (26) being at a distance from the external indicator light (18).