Curved Reflection Layer for Homogeneous Light Distribution

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Solution Overview

Problem

Existing light-guiding devices in rear view systems for motor vehicles suffer from inhomogeneous light distribution, particularly when illuminating larger areas or those farther from the light source, leading to uneven illumination of blind spot assistant displays, which can be misinterpreted by users.

Innovation Solution

A light-guiding device with a reflection layer designed to decrease in distance from the light coupling-in side to the light coupling-out side, allowing for non-linear or curved alignment, ensuring more uniform light distribution across the output surface, utilizing materials like ABS and PMMA, and incorporating optics or recesses for optimal light coupling and reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a light guide device is used to illuminate a large area or area far from the light source, then the illuminated area is expanded, but the light distribution becomes inhomogeneous

Engineering Contradiction:
Improveilluminated areaVSAvoidlight distribution uniformity
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The reflection layer is designed with a curved or non-linear profile where the distance from the reflection layer to the light output side decreases as the distance from the light coupling-in side increases. This curvature compensates for the natural light attenuation over distance, ensuring uniform light distribution across the entire output surface even when illuminating large areas.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

Different regions of the light guide device have different structural characteristics. The reflection layer's distance to the light output side varies locally - being closer to the light source at the coupling-in side and progressively farther away towards the output side. This local variation in structure compensates for the inhomogeneous light propagation, achieving uniform illumination across the entire output area.

Inventive Principle:
Principle #3Local quality

2Reliability

If the line thickness of the pictogram is increased, then the visibility is improved, but the light inhomogeneity becomes more visible and annoying

Engineering Contradiction:
Improvedisplay visibilityVSAvoidlight distribution uniformity
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The curved reflection layer design ensures that even when pictograms with increased line thickness are displayed, the light distribution remains uniform across the entire output surface. This prevents the inhomogeneity that would otherwise become visible and annoying with thicker lines, maintaining both visibility and aesthetic quality.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Illumination intensity

If a reflection layer with non-linear distance profile is used, then light distribution uniformity is improved, but the device complexity increases

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidreflection layer structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflection layer is integrated directly into the light guide device structure, combining the light reflection function with the light guiding function in a single component. This merging approach achieves uniform light distribution without requiring separate complex optical systems, maintaining manufacturing simplicity while improving light distribution uniformity.

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 achieves a significantly more homogeneous light distribution over the illuminated area, enhancing the visibility and reliability of blind spot assistant displays by ensuring consistent illumination, even with limited light sources like LEDs.

Implementation Method 1

the light-guiding device has a light coupling side (4) for coupling light from a light source (18) into the light-guiding device (2), a reflection side (6) with a reflection layer (8) for reflecting the coupled light, and a light coupling-out side (10)

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3392685B1Rear view device for a motor vehicle
Publication Date: 2021.03.03 SMR PATENTS S A R L
  • EP3392685B1 patent drawingFigure 1~3
  • EP3392685B1 patent drawingFigure 4~5
  • EP3392685B1 patent drawingFigure 6~7

AI summary

A light guide device comprising a light input side, a reflection side, a reflective layer, and a light output side, wherein, in plan view, the reflection side is located below the light output side and the reflective layer is located below the reflection side, the light output side is opposite the reflection side and thus also the reflective layer, and the distance between the light output side and the reflection side and thus also the reflective layer decreases with increasing distance from the light input side, wherein a light guide device optimized for a given number of light sources has a reflection side and reflective layer formed with partial funnels of this number, wherein the longitudinal axis of these partial funnels extends along the main direction of the coupled light and the number is 2, 3, 4, 5, 6 or more.