Lighting Device With Microstructured Light Guide

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Solution Overview

Problem

Current light devices for motor vehicles, which mix light beams from different sources, are often fragile, bulky, and produce inhomogeneous beams, making them unsuitable for use as warning lights, and polychromatic options are expensive and limited in power choice.

Innovation Solution

A light device featuring at least two light sources of different colors combined using a light guide with pointed-shaped microstructures on its input face, which disperses light rays to produce a homogeneous mixture, minimizing reflections and optimizing the distribution of light, and optionally incorporating a multi-chip LED for reduced size and white light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If semi-reflecting blades are used to mix light beams from different sources, then light mixing is achieved, but the device becomes fragile and bulky

Engineering Contradiction:
Improvelight mixing capabilityVSAvoiddevice fragility
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces the mechanical semi-reflecting blade system with an optical solution using a light guide with microstructures on its input face. The microstructures refract and reflect light internally to achieve beam mixing without moving mechanical parts, thereby eliminating fragility associated with mechanical components while maintaining the light mixing function.

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

Solution Approach 2:

The light guide acts as an intermediary element between the light sources and the output. It receives light from multiple sources, processes it through internal refraction and reflection at the microstructured input face, and delivers a mixed beam, thereby achieving the mixing function without direct interaction between light sources.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If semi-reflecting blades are used to mix light beams, then light mixing is achieved, but the device becomes bulky

Engineering Contradiction:
Improvelight mixing capabilityVSAvoiddevice size
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

The mechanical blade assembly is replaced by a compact light guide with microstructures. This optical solution achieves the same light mixing function in a much smaller volume, as the microstructures are formed directly on the light guide surface rather than requiring separate mechanical components.

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

3Ease of operation

If conventional light mixing devices are used, then light beams are mixed, but the resulting beam is inhomogeneous

Engineering Contradiction:
Improvelight mixing functionVSAvoidbeam homogeneity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The light guide features localized microstructures at specific regions of its input face. These microstructures create localized refraction and reflection effects that distribute light from different sources more uniformly across the output face, thereby improving beam homogeneity through spatially varying optical properties.

Inventive Principle:
Principle #3Local quality

4Adaptability or versatility

If polychromatic light-emitting diodes are used, then color variety is available, but they are expensive and offer limited power choices

Engineering Contradiction:
Improvecolor varietyVSAvoidcost and power availability
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple monochromatic light-emitting diodes (each emitting a single color) with a light guide system. By merging the output of several inexpensive monochromatic LEDs and mixing their beams through the light guide, the system achieves color variety comparable to polychromatic LEDs but at lower cost with broader power availability options.

Inventive Principle:
Principle #5Merging (Combining)

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 a compact, durable, and homogeneous light mixture suitable for motor vehicle warning lights, allowing for customizable color shades and efficient light distribution, such as achieving white light from red, green, and blue sources.

Implementation Method 1

The pointed-shaped microstructures make it possible to disperse the incident light rays in different directions so as to produce a relatively homogeneous mixture of the rays originating from the two light sources

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

a light guide comprising an input face and an output face and configured to transmit the light rays coming from the at least two light sources from its input face to its output

Methodology Applied
Scientific EffectLight transmission: Optical Fibre

Implementation Method 3

In addition, the pointed shapes make it possible to minimize the number of light rays reflected at the entry surface

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3191878B1Lighting device
Publication Date: 2018.12.26 VALEO SYST THERMIQUES SAS
  • EP3191878B1 patent drawingFigure 1
  • EP3191878B1 patent drawingFigure 2
  • EP3191878B1 patent drawingFigure 3~4

AI summary

The invention relates to a lighting device (1) comprising: at least two different-coloured light sources (3a, 3b); and a light guide (5) having an input face (5a) and an output face (5b) and configured to transmit the light rays (7) from the at least two light sources (3a, 3b) from the input face (5a) towards the output face (5b). According to the invention, the at least two light sources (3a, 3b) are disposed beside one another and the light guide (5) includes a plurality of pointed microstructures (9) distributed over the input face (5a) thereof.