Vehicle Lighting Device Using Coherent Light for Sharp Illumination

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Solution Overview

Problem

Existing vehicle interior illumination devices suffer from chromatic aberrations and inability to produce sharp images, particularly in compact forms like those found in motor vehicles.

Innovation Solution

A compact illumination device using a coherent light source, such as a laser diode or optical fiber, coupled with a transparent body featuring an incident surface with variable refractive index and arithmetic roughness, which splits and directs coherent light to eliminate chromatic aberrations and enhance image sharpness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a transparent body with variable refractive index is used to illuminate the headliner, then the illumination coverage is improved, but chromatic aberrations occur and image sharpness deteriorates

Engineering Contradiction:
Improveillumination coverageVSAvoidimage sharpness
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent changes the wavelength parameter of the light source to coherent light (laser) with a single wavelength, which eliminates chromatic aberration caused by variable refractive index in the transparent body. This allows the transparent body to expand illumination coverage while maintaining image sharpness, as coherent light does not suffer from wavelength-dependent refraction variations.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the total size of the illumination device is reduced for compact vehicle installation, then the device becomes more compact, but image sharpness deteriorates

Engineering Contradiction:
Improvedevice sizeVSAvoidimage sharpness
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

By using coherent light with a single wavelength, the patent eliminates chromatic aberration that would otherwise worsen with reduced device size. The coherent light source maintains image sharpness even in compact configurations because it does not exhibit wavelength-dependent refraction variations that plague conventional broadband light sources in small-scale optical systems.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a coherent light source is used to eliminate chromatic aberrations, then image sharpness is improved, but the device complexity increases

Engineering Contradiction:
Improveimage sharpnessVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a transparent body as an intermediary element that works synergistically with the coherent light source. This transparent body with variable refractive index serves as a compact beam-shaping element that expands illumination coverage without requiring complex optical assemblies, thereby managing device complexity while maintaining image quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If multiple light sources with different wavelengths are used to provide color variation, then adaptability is improved, but chromatic aberrations worsen

Engineering Contradiction:
Improvecolor variation capabilityVSAvoidchromatic aberration
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the color variation function into multiple coherent light sources, each emitting at a specific single wavelength. This segmentation approach allows independent control of each wavelength channel, enabling color variation and pattern differentiation without the chromatic aberration problems that would arise from using a single broadband source or conventional multi-wavelength sources.

Inventive Principle:
Principle #1Segmentation

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 enables sharp, aberration-free patterned illumination in vehicle interiors, improving image quality and flexibility through the use of coherent light sources and strategically designed transparent bodies.

Implementation Method 1

at least one light source arranged to emit light... said at least one light source is a coherent light source. The device uses a coherent light source, which means that the emitted light has a single wavelength.

Methodology Applied
Scientific EffectCoherent light emission: Laser

Implementation Method 2

at least one transparent body arranged to refract the light emitted by the light source

Methodology Applied
Scientific EffectLight refraction: Refraction

Implementation Method 3

said at least one incident surface is at least partially grained and/or at least partially has an arithmetic roughness of at least 0.2 micrometers. This implementation allows the beam of coherent light to be diffused in multiple directions

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP3186108B1Vehicle comprising a lighting device
Publication Date: 2021.09.29 PSA AUTOMOBILES SA
  • EP3186108B1 patent drawingFigure 1a~3

AI summary

The invention relates to a lighting device of a portion of a passenger compartment of a car such as a roof trim, comprising: at least one light source (20) arranged so as to emit light; and at least one transparent body (10) arranged so as to refract the light emitted by the light source (20). The light source (20) is a coherent light source.