Light Guide With Deflection Surfaces For Parallel Homogeneous Emission
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Solution Overview
Problem
Existing light guides for motor vehicle lighting devices fail to achieve parallel and homogeneous light emission, as radially directed light is not effectively reflected onto the strip-shaped light exit surface, leading to non-uniform illumination and increased divergence.
Innovation Solution
The light guide employs a two-stage parallelization process, where the first parallelization occurs in the coupling optics, and the second in the light guide itself, using a parabolic reflector and a roof-edge reflector to deflect light by at least the critical angle's product, ensuring all light is directed onto further deflection surfaces without shadowing losses, resulting in a strong reduction in divergence and achieving a homogeneous, parallel luminous flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single reflector is used to parallelize light in one plane, then light propagation in that plane is parallelized, but light propagation in the perpendicular plane remains divergent and cannot be parallelized
Solution Approach 1:
The light guide is divided into multiple sections, each containing a reflector oriented at different angles. The first reflector parallelizes light in the first plane, while the second reflector (oriented at a non-parallel angle) parallelizes light in the second plane. This segmentation allows independent control of light propagation in perpendicular planes, resolving the contradiction between achieving parallelization in both planes and maintaining simple device structure.
2Illumination intensity
If the reflector is positioned to parallelize light in one plane, then that plane achieves parallel propagation, but the perpendicular plane experiences shadowing losses and cannot be parallelized
Solution Approach 1:
The reflectors are oriented at asymmetric angles relative to each other, with the second reflector specifically positioned at a non-parallel angle to the first. This asymmetric arrangement creates complementary reflection paths that cover different angular ranges, allowing both reflectors to contribute effectively without overlapping shadow regions, thus eliminating shadowing losses while achieving parallelization in both planes.
Solution Approach 2:
The solution transitions from single-plane parallelization to two-plane parallelization by introducing a second reflector oriented in a different angular dimension. The second reflector is specifically angled to address the perpendicular plane that the first reflector cannot control, effectively adding another dimensional aspect to light control and eliminating the shadowing problem that limited single-reflector designs.
3Shape
If a plate-shaped light guide with a strip-shaped light exit surface is used, then the light exit surface can be positioned in a narrow side, but light radiated radially into the half-space does not hit the reflector and cannot be parallelized
Solution Approach 1:
The light guide system uses multiple reflectors with different orientations to dynamically adapt to radially divergent light from the strip-shaped exit surface. As light rays travel in different directions from the strip surface, the first and second reflectors (oriented at different angles) selectively capture and parallelize rays from different angular ranges, ensuring that all radially emitted light is eventually parallelized rather than lost.
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 reduces light divergence and achieves a high degree of parallelism and homogeneity in light emission, enabling efficient distribution of light into rule-compliant patterns, even if complete parallel alignment is not achieved, thereby enhancing the design of light guides for motor vehicle lighting.
Implementation Method 1
coupling optics that are set up to diverge onto it to couple incident light into the interior of the light guide
Implementation Method 2
The deflection of this light by an angle that is at least as large as the product of the value of the critical angle of total reflection and the factor 2 allows all the light incident on the first deflection surface to be deflected onto the other deflection surfaces without shadowing losses
Data Source
Figure 1~2
Figure 3
Figure 4a~5
AI summary
The light guide (10) has a coupling optic (24) that is adapted to the light (12) in such a way that it has a small divergence in planes than in other planes, where a deflection surface (36) is located between the coupling optics and a light exit surface (18). The light deflects to the deflection incident by an angle. Another deflection surface (38) is illuminated with light outgoing from the former deflection surface, where the light incident from latter deflection surface forth in a common preferential direction is addressed for former deflection surface. An independent claim is included for a motor vehicle lighting device.