Vehicle Ambient Lighting Light Guide Segmentation

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Solution Overview

Problem

The existing ambient lighting systems in motor vehicles face issues with light flux loss and space constraints, leading to uneven lighting and 'hot spots' due to the arrangement of a single light source at one end of the light guide, which affects the aesthetic appeal and perceived quality.

Innovation Solution

An ambient lighting system with a main light guide and two light guide segments forming an open circular loop, where light sources are placed at the ends of the segments to ensure total reflection and distribution of light along the guide, and a masking wall is used to prevent light leaks and 'hot spots' by being integrated into the trim element with a diffusing screen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single light source is placed at one end of the light guide, then the device complexity is reduced, but the illumination intensity becomes uneven with significant loss of luminous flux along the guide

Engineering Contradiction:
Improvelight source arrangementVSAvoidluminous flux distribution
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The light guide is divided into multiple segments with light sources placed at strategic positions along the guide rather than at a single end. This segmentation allows light to be introduced at multiple points, ensuring more uniform illumination distribution along the entire length of the light guide while reducing the total luminous flux loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a one-dimensional light propagation approach (single end source) to a multi-dimensional approach by placing light sources at multiple positions along the light guide's length. This spatial redistribution of light sources in the longitudinal dimension achieves more uniform illumination without increasing overall system complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If the light guide is made longer to cover more trim area, then the area of stationary object is increased, but the loss of luminous flux increases significantly

Engineering Contradiction:
Improvetrim coverage areaVSAvoidluminous flux loss
Core Design Contradiction:
Area of stationary objectVSLoss of energy

Solution Approach 1:

The extended light guide is divided into multiple segments with intermediate light sources placed at strategic positions. This allows the light to be replenished along the guide's length, maintaining high illumination intensity even over extended trim areas while reducing the cumulative luminous flux loss that would occur with a single end source.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By placing light sources at multiple positions along the light guide, the invention ensures continuous light injection throughout the guide's length. This continuous useful action maintains high illumination levels across the entire extended area, preventing the progressive dimming that occurs with single-end illumination over long distances.

Inventive Principle:
Principle #20Continuity of useful action

3Illumination intensity

If light guide segments are connected to form a closed loop, then the aesthetics and homogeneity of lighting is improved, but light leaks and hot spots occur at the connection zones

Engineering Contradiction:
Improvelighting homogeneityVSAvoidlight leaks and hot spots
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The harmful light leaks and hot spots generated at the connection zones are extracted and contained using light-absorbing materials. The black paint or light-absorbing coating is applied specifically at the connection zones to absorb stray light and prevent it from creating visible defects, while the rest of the light guide maintains its reflective properties for efficient light propagation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies different surface properties to different zones of the light guide. The connection zones are treated with light-absorbing materials to prevent light leaks, while the main body of the light guide maintains highly reflective internal surfaces for efficient light propagation. This local differentiation of surface quality eliminates harmful effects at specific locations without compromising overall system performance.

Inventive Principle:
Principle #3Local quality

4Volume of stationary object

If the light guide is positioned closer to the trim surface to reduce bulk, then the volume of moving object is reduced, but light leaks from the connection zones become more visible

Engineering Contradiction:
Improvelight guide assembly bulkVSAvoidvisible light leaks
Core Design Contradiction:
Volume of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The light leaks that would become visible with compact positioning are extracted and neutralized by applying light-absorbing materials at the connection zones. This allows the light guide to be positioned closer to the trim surface, reducing overall bulk, while the absorbed light prevents visible leakage defects from occurring.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

By applying light-absorbing treatments specifically at the connection zones, the invention enables compact positioning of the light guide without compromising appearance. The local modification of surface properties at critical locations allows the system to achieve space efficiency while eliminating the visibility of light leaks that would otherwise be exacerbated by close positioning.

Inventive Principle:
Principle #3Local quality

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 arrangement provides uniform lighting over the entire length of the main guide without 'hot spots', enhancing the aesthetic appeal and perceived quality while minimizing space usage.

Implementation Method 1

Two light sources 6 and 7 (LEDs) are placed, respectively, opposite the two free ends of each branch 3 and 4, in a direction perpendicular to the entrance surface of the two branches 3 and 4 for totally reflective guidance of the light generated by the two light sources 6 and 7 inside the branches 3 and 4

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a screen diffusing the light from the main light guide outwards from the trim element

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3401164B1Vehicle interior trim element comprìsing an arrangement of an ambient lighting system
Publication Date: 2020.03.11 PSA AUTOMOBILES SA
  • EP3401164B1 patent drawingFigure 1~2
  • EP3401164B1 patent drawingFigure 3~5

AI summary

Interior trim element (9) of a motor vehicle (V) comprising an arrangement of an ambient lighting system (1), wherein a main light guide (2) of the lighting system (1), of elongated shape, is disposed between the first and second parts (11 and 12) of the trim element (9), wherein a screen (16) diffusing the light from the main light guide (2) outwards from the trim element, of elongated shape, comprising a projecting portion (15) extending parallel to the main guide (2), is disposed on the main light guide (2), and wherein a mask (13) is attached to the lighting system (1) and the screen (16), between the first and second parts (11 and 12) of the trim element (9), leaving the projecting portion (15) of the screen (16) visible between the mask (13) and one of the two parts of the element. filling (11 or 12),and wherein a light-opaque occulting means (17) is locally provided on or in the screen (16) to occult light leaks generated by the main light guide (2) without occulting the light diffused by the protruding part (15) of the screen (16), and wherein the lighting system (1) comprises first and second light guide segments defining respectively first and second light entry branches (3, 4) joining each other in the same connection zone (ZR) on the face of the main guide (2), oriented towards the inside of the trim; the occulting means (17) being located opposite the front face of the main guide (2), oriented towards the outside of the trim, in the connection zone (ZR).