Lighting Device with Local Photon Supply and Light Guide

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Solution Overview

Problem

Current lighting devices with light-emitting diodes and light guides used in vehicles require either diverse LEDs or electronic intensity control circuits to achieve increasing light intensity, leading to complexity, increased size and cost, weight, power consumption, and potential failures.

Innovation Solution

A lighting device design where photons from a local supply zone on the entry face are distributed to create a decreasing light intensity on the output face without using different LEDs or electronic control circuits, utilizing identical LEDs and a light guide made of polycarbonate or PMMA, with angular sectors and facets to manage photon distribution and homogenization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If diverse light-emitting diodes with different intensities are used to achieve increasing light intensity, then the light intensity distribution is improved, but the device complexity and inventory management become worse

Engineering Contradiction:
Improvelight intensity distributionVSAvoiddevice complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a light guide with spatially varying properties - the absorption coefficient varies along the length of the light guide, and selective extraction zones are created at different positions. This allows identical LEDs to produce different effective intensities at different output zones without requiring diverse LED components, thus resolving the contradiction between light intensity distribution and device complexity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the light guide itself rather than changing the LED parameters. By varying the absorption coefficient, extraction efficiency, or geometric parameters along the light guide length, the system achieves different light intensities at different zones using identical LEDs, thereby improving illumination distribution while maintaining simple inventory management

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If electronic intensity control circuits are used to supply variable light intensities, then the light intensity distribution is improved, but the size and costs increase

Engineering Contradiction:
Improvelight intensity distributionVSAvoidsize and costs
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent replaces electronic control circuits with an optical-passive solution. Instead of using active electronic components to control LED intensity, the system uses passive optical elements within the light guide (such as absorption layers, extraction structures, or geometric configurations) to achieve the desired light intensity distribution, thereby eliminating the need for complex electronic control hardware and reducing size and cost

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

3Quantity of substance

If a large number of light-emitting diodes are used to uniformly supply the entire input face, then the photon supply is improved, but the weight, size, and power consumption increase

Engineering Contradiction:
Improvephoton supplyVSAvoidweight
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

The patent segments the light guide into distinct functional zones - a localized input zone where photons are introduced and multiple extraction zones along the length where light is delivered. This segmentation allows efficient photon utilization through the light guide's internal physics, reducing the need for numerous LEDs while maintaining adequate photon supply across the output face, thereby reducing weight

Inventive Principle:
Principle #1Segmentation

4Quantity of substance

If a large number of light-emitting diodes are used to uniformly supply the entire input face, then the photon supply is improved, but the power consumption increases

Engineering Contradiction:
Improvephoton supplyVSAvoidpower consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent creates continuous light extraction along the length of the light guide through strategically positioned extraction zones rather than requiring discrete LED sources at multiple locations. This continuous action approach allows photons to be efficiently distributed along the entire output face using fewer LEDs, reducing the total power consumption while maintaining adequate photon supply

Inventive Principle:
Principle #20Continuity of useful action

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

This design significantly reduces the number of LEDs needed, minimizes weight, size, and power consumption, while avoiding the complexity and cost of diverse LEDs and electronic controls, achieving a 'comet' or 'shooting star' effect with a decreasing light intensity along the output face.

Implementation Method 1

a light guide of flat type and comprising a guide part placed between input and output faces

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

light-emitting diodes generating photons

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

Data Source

PatentEP3351991B1Lighting device with local photon supply area and photon distribution
Publication Date: 2022.08.24 PSA AUTOMOBILES SA
  • EP3351991B1 patent drawingFigure 1~2

AI summary

A lighting device (ED) comprises light-emitting diodes (D1-D4) and a flat light guide (LG) with a guiding portion (PG) positioned between entrance (FE) and exit (FS) faces. The entrance face (FE) supplies photons to the guiding portion (PG), and the exit face (FS) emits guided photons to the outside. The light-emitting diodes (D1-D4) are all placed opposite input zones (ZE1-ZE4), defined in a supply zone (ZA) of the input face (FE) located opposite a first output zone (ZS1) of the output face (FS), and arranged to distribute the received photons into predefined angular sectors (SA1-SA4) in order to induce on a second output zone (ZS2) of the output face (FS), located next to the first output zone (ZS1), a decreasing light intensity from the first output zone (ZS1).