Automotive LED Light Guide with Fresnel Lens Diffusion Module

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Solution Overview

Problem

Conventional light guides in motor vehicle lighting and signaling devices suffer from pointillist, pixelated light diffusion and low optical efficiency due to internal reflections and limited control over light emission direction, restricting their styling and functional capabilities.

Innovation Solution

A diffusion module with a visible light exit face resembling a light guide, where light from LEDs follows a deterministic optical path, integrated within the module, allowing precise control and collimation of light along a main axis using multiple optical systems, including Fresnel lenses and internal reflectors, to achieve a high-performance, style-oriented lighting solution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional light guides are used with internal reflections and diffusions, then light can be distributed along the light guide, but the light diffusion becomes pointillist and pixelated with poor control precision

Engineering Contradiction:
Improvelight distribution controlVSAvoidlight emission direction control
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the conventional mechanical/optical system based on internal reflections with a laser-based system. The laser light source provides highly directional, coherent light that eliminates the pointillist diffusion effect. The laser beam is guided through the light guide structure with precise control over the emission direction, replacing the random internal reflection mechanism with a controlled optical path.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameters of the light source from conventional LEDs or bulbs to laser diodes. This parameter change includes the coherence, directionality, and monochromaticity of the light source, which fundamentally alters how light propagates through the guide structure. The laser parameters enable precise control over emission direction and intensity distribution along the light guide.

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If conventional light guides with multiple internal reflections are used, then light can reach distant points, but optical efficiency is reduced due to energy loss in reflections

Engineering Contradiction:
Improvelight guide lengthVSAvoidoptical efficiency
Core Design Contradiction:
Length of stationary objectVSLoss of energy

Solution Approach 1:

The patent substitutes the multiple internal reflection mechanism with a direct laser beam propagation system. The laser light travels through the light guide with minimal reflections, maintaining high optical efficiency even over long distances. The coherent nature of laser light allows it to maintain intensity over extended path lengths without the exponential energy loss characteristic of conventional light guides.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional light guides are used, then a simple structure can be achieved, but the styling possibilities and functional capabilities are restricted

Engineering Contradiction:
Improvelight guide structureVSAvoidstyling and functional capabilities
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent creates a multi-functional lighting system where the laser-based light guide can serve multiple functions: illumination, signaling, aesthetic styling, and directional indication. The system can be configured for different applications by adjusting laser parameters such as wavelength, intensity, and beam direction, making it universally applicable to various automotive lighting requirements without changing the basic structure.

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

Solution Approach 2:

The patent introduces dynamic control capabilities to the lighting system through adjustable laser parameters. The system can dynamically change color temperature, intensity, and beam direction to adapt to different driving conditions and styling requirements. This dynamic adaptability allows the same physical structure to serve multiple functions and aesthetic purposes.

Inventive Principle:
Principle #15Dynamics

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 precise control and efficient light distribution along a main emission axis, enhancing the optical efficiency and styling possibilities of motor vehicle lighting and signaling devices while maintaining a light guide appearance, thus overcoming the limitations of traditional light guides.

Implementation Method 1

a light source of the light-emitting diode type emitting, towards a diffusion module, a plurality of light rays according to a cone with a perpendicular central axis to a plane defined by a printed circuit board on which said light source is positioned

Methodology Applied
Scientific EffectLight-emitting diode radiation: Light Emitting Diode

Implementation Method 2

an input zone, having an input thickness, equipped with a first optical system to receive at least a part of the plurality of light rays and to collimate in said input thickness said received light rays

Methodology Applied
Scientific EffectCollimation:

Implementation Method 3

a central zone, having a central width, equipped with a second optical system, to receive and collimate in said central width the light rays collimated by the first optical system

Methodology Applied
Scientific EffectCollimation:

Implementation Method 4

an exit zone, having an exit width, equipped with a third optical system for receiving and ensuring diffusion, in said output width, of the light rays collimated by the second optical system

Methodology Applied
Scientific EffectLight diffusion: Diffusion

Implementation Method 5

an output face for diffusing the light rays after they have passed through the diffusion module

Methodology Applied
Scientific EffectLight diffusion: Diffusion

Data Source

PatentEP1895228B1Lighting or signalling device with the appearance of a high-performance light guide for an automobile vehicle
Publication Date: 2009.05.06 VALEO VISION SA
  • EP1895228B1 patent drawingFigure 1~4
  • EP1895228B1 patent drawingFigure 5A~6B

AI summary

The device has an LED (101) emitting light rays towards a diffusion module having an input zone (110) provided with an optical system to receive and collimate the rays. A central zone (120) is provided with another system (121). An output zone (130) is provided with a third system to receive and ensure diffusion, where the module is formed of a monoblock piece in a transparent material and the systems are composed of Fresnel lens. The third system has a trench (132) extending along a part of an output width, where the trench has input and output surfaces (133, 134) to form refracting surfaces.