Vehicle LED Lighting Device with Flat Band Light Guide

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Solution Overview

Problem

Current optical systems in vehicle headlights using light guides fail to produce a uniform and suitable photometric profile, leading to irregular light distribution, which limits their application to rear lamps or simple front DRLs, and are not cost-effective or adaptable for different stylistic profiles.

Innovation Solution

A vehicle lighting device with a cup-shaped housing and a flat band light guide featuring paired collimating elements and intermediate sections with convergent and curved profiles, which collect and collimate light beams to achieve uniformity and homogeneity, allowing for a pre-set photometric profile and aesthetic appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If light guides are used in current optical systems, then the structure is simplified and costs are reduced, but the light distribution becomes irregular and unsuitable for vehicle headlights

Engineering Contradiction:
Improvemanufacturing costVSAvoidlight distribution uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A light guide is introduced as an intermediary component between the LED light source and the transparent element. The light guide receives light from the LED and guides it through its internal structure to the emission area, mediating the light transmission process to achieve both cost-effectiveness and proper light distribution

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light guide incorporates localized optical features such as extraction structures, refractive index variations, or surface treatments at specific positions to control light distribution. These local modifications ensure uniform light emission from the transparent element while maintaining the overall simplicity and low cost of the light guide structure

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If light guides are used for headlight applications, then manufacturing costs are reduced, but the photometric profile becomes unsuitable for vehicle headlights

Engineering Contradiction:
Improvemanufacturing costVSAvoidphotometric profile accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The light guide serves as a mediator that transforms the point-source light from the LED into a distributed light pattern matching the required photometric profile. By designing the light guide's internal geometry and optical properties, it converts inexpensive LED light into headlight-appropriate illumination patterns

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light guide utilizes changes in optical parameters such as refractive index, absorption coefficients, or geometric dimensions along its length to progressively shape the light beam. These parameter variations enable the light guide to achieve the precise photometric profile required for vehicle headlights while maintaining a simple, cost-effective structure

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If conventional optical systems are used, then proper light distribution is achieved, but the device bulk and complexity increase

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidoptical system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple optical functions (light collection, collimation, focusing, and distribution) are merged into a single light guide component. This eliminates the need for separate optical elements such as multiple lenses, reflectors, and beam shaping components, thereby reducing device complexity while maintaining proper light distribution

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light guide is designed as a multi-functional element that simultaneously performs light transmission, beam shaping, and uniform distribution. This universal component replaces what would traditionally require multiple specialized optical elements, reducing overall system complexity while achieving the required light distribution uniformity

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

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 high uniformity and adaptability in light distribution, reducing bulk and manufacturing costs, enabling the use in various vehicle styles with a single operating principle, and achieving a bright, homogeneous emission section.

Implementation Method 1

a first collimating element, for example formed by a concave or convex lens, arranged facing the at least one LED or LED battery and configured to collect within the light guide the at least one first light beam and perform a first collimation thereof

Methodology Applied
Scientific EffectCollimation: Lens

Implementation Method 2

a second collimating element... configured to collect the first light beam after the first collimation and to perform a second collimation of the first light beam, generating downstream of the at least one second collimating element... the second light beam

Methodology Applied
Scientific EffectCollimation: Lens

Implementation Method 3

a light guide consisting of a flat band bounded between a front and a rear face thereof... configured to collect at least one first light beam generated by the light source and to project a second light beam

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3862624B1Lighting device for vehicles, in particular with leds
Publication Date: 2022.12.21 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP3862624B1 patent drawingFigure 1
  • EP3862624B1 patent drawingFigure 2
  • EP3862624B1 patent drawingFigure 3

AI summary

A lighting device (1) for a vehicle including at least one light source consisting of one LED or one LED battery and an optical system (6) configured to pick up at least one first light beam (8) generated by said LED to project in a pre-set direction (D) a second light beam (9) having a pre-set photometric profile, wherein the optical system (6) includes a light guide (7) constituting a flat band (10) having a first (13) and a second (14) end; the light guide (7) being provided with at least one first and one second collimating element (19,20) facing each other and operationally associated in order to generate the second light beam (9) already inside of the light guide and towards the second end of the same, determining the photometric profile and, preferably, the aesthetic aspect of the second light beam (9) when it is emitted by an emission section (28) of the second end (14) of the light guide.