Motor Vehicle Lighting Device with Dual Reflector Light Guide
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Solution Overview
Problem
Existing motor vehicle lighting devices suffer from light losses due to undesirable internal reflections and non-parallel light distribution, particularly in the 180° angular range where the second reflector fails to parallelize light, leading to inefficient light distribution and reduced photometric performance.
Innovation Solution
The design includes a second reflector that reverses the direction of deflected light, ensuring it passes at a distance from the first reflector, with a recess depth between 40% and 60% of the distance between the reflector sides, and a rotationally symmetrical configuration to maximize useful light contribution to the desired light distribution, using a polycarbonate light guide for improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the second reflector is designed to parallelize light in a 180° angular range, then light distribution homogeneity is improved, but light losses occur in the remaining 180° range due to internal total reflections and non-contributory refractions
Solution Approach 1:
The reflector system is segmented into a first reflector for initial light deflection and a second reflector for parallelization in a 180° angular range. This segmentation allows different zones of the reflector system to handle different angular ranges optimally, with the first reflector managing the remaining 180° range through additional reflection surfaces that redirect light toward the light exit surface.
Solution Approach 2:
The patent introduces a third dimensional aspect by creating a complex three-dimensional reflector geometry that goes beyond simple two-dimensional parallelization. The first reflector adds radial reflection surfaces that deflect light in multiple directions, transforming the light path from a planar to a spatial configuration, thereby utilizing the full three-dimensional space within the lighting device to redirect light effectively.
2Ease of manufacture
If the first reflector is rotationally symmetrical, then manufacturing is simplified, but light path blocking occurs when additional optical elements are added
Solution Approach 1:
While the first reflector maintains rotational symmetry for ease of manufacture, the patent introduces asymmetric elements in the form of additional reflection surfaces and light-deflecting structures that break the symmetry to create optimized light paths. This selective asymmetry allows complex light path management while preserving manufacturing simplicity for the primary reflector components.
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 configuration significantly increases the proportion of coupled-in light that contributes to the desired light distribution, enhancing the efficiency and homogeneity of the lighting device by minimizing light losses and ensuring effective light utilization across the light exit surface.
Implementation Method 1
A first reflector (24) has a multiplicity of first reflection surfaces (32), which direct incident light from the light source (28) onto second reflection surfaces (34)
Implementation Method 2
This part is desirably parallelized by the parabolic second reflector (26)
Implementation Method 3
A plate-shaped light guide (10) is known from US 2006/0274621 A1, which couples in light from a light source via a broad side and out via a narrow side
Implementation Method 4
light losses occur there due to undesirable internal total reflections or due to refractions in directions that do not contribute to the desired light distribution
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A motor vehicle lighting device (18) is presented, comprising a light guide (10) having a first side (12), a second side (14) opposite the first side, a first reflector (24) and a second reflector (26), wherein the first reflector is a recess in the first side (12) extending to a certain depth into the light guide, with a light source (28) arranged such that its light illuminates the first reflector (24) and light reflected from it is directed radially onto the second reflector (26), the latter being arranged to deflect this light twice.The second reflector (26) is designed to reverse the direction of the incident light during deflection, the deflection being such that the further path of the deflected light between the first reflector (24) and the second side (14) passes the first reflector (24) at a distance from the first side (12) that corresponds at least to the determined depth of the first reflector.