Flat-Exit Motor Vehicle Light Guide for Color Aberration Control
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Solution Overview
Problem
Existing lighting devices for motor vehicles suffer from optical errors such as color aberrations due to light exiting and re-entering different media, and the demand for flat light exit surfaces contradicts the need for refractive optics to achieve desired light distributions.
Innovation Solution
A lighting device with a light guide body featuring first and second deflection surfaces that form hyperbolic and parabolic curves, respectively, with a shared focal point, allowing internal reflection to create a light-dark boundary without external lenses, thus maintaining a flat exit surface and minimizing optical errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a projection lens is arranged adjacent to the light exit surface to project light distribution, then the light distribution function is improved, but optical errors such as color aberrations occur due to light exiting and re-entering different media
Solution Approach 1:
The patent merges the projection lens function directly into the light guide body by forming a curved light exit surface as an integral part of the light guide structure. This eliminates the air gap between the light guide and projection lens, preventing light from exiting and re-entering different media, thereby eliminating optical errors while maintaining the light distribution function.
2Illumination intensity
If the light exit surface is curved to realize projection lens function, then the light distribution function is improved, but the design flexibility and manufacturing simplicity are reduced
Solution Approach 1:
The curved light exit surface is formed as an integral part of the light guide body through a single molding process. This merging of functions allows the light guide to serve both as a light transmission medium and as a projection optical element, eliminating the need for separate lenses while maintaining design flexibility and manufacturing simplicity.
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 eliminates color aberrations and reduces manufacturing costs by eliminating the need for external lenses, enhancing the efficiency and design flexibility of the lighting system.
Implementation Method 1
a light coupling region which is configured to couple light emitted by the light source into the light guide body
Implementation Method 2
is deflected by the first light deflection surface as a third light beam to the second light deflection surface
Implementation Method 3
is deflected by the second light deflection surface as a fourth light beam to the light exit surface
Implementation Method 4
a transparent light guide body which is configured to image light emitted by the light source as a light distribution
Data Source
Figure 1
Figure 1a
Figure 1b
AI summary
The invention relates to a lighting device (1) for a motor vehicle, wherein the lighting device (1) comprises a light source (10) and a transparent light-guiding body (100) with a light-coupling region (101). The light-guiding body (100) has a first light-deflecting surface (102) on an upper side (1100), a second light-deflecting surface (103) on an underside (1200) and a flat light-exit surface (104), as well as an edge (105) running transversely to the first light propagation direction (Y1). Light from the light source (10) passes the edge (105), is deflected by the first light-deflecting surface (102) to the second light-deflecting surface (103) and from there to the light-exit surface (104). In vertical sections through the light guide body (100), the first light deflection surface (102) forms a first cutting curve (K102), the second light deflection surface (103) forms a second cutting curve (K103).The first intersection curve (K102) is convexly or concavely curved and has the shape of a branch of a hyperbola, with a focal point (F102) of the hyperbola lying outside the light-guiding body (100), in a region of the light-guiding body (100) facing away from the second light-deflecting surface (103). The second intersection curve (K103) is convexly curved and has the shape of a parabola with a focal point (F103), with the focal point (F103) of the parabola coinciding with the focal point (F102) of the first intersection curve (K102) lying outside the light-guiding body (100) in a region of the light-guiding body (100) facing away from the second light-deflecting surface (103).The overall focal point (F200) of the deflection system (200) formed by the first deflection surface (102) and the second deflection surface (103) lies on the edge (105) or in a region of the edge (105), such that the deflection system (200) consisting of the first and second deflection surfaces (101, 102) images the light rays emitted by the light source (10) as a light distribution (LV1 - LV5) with a cut-off line (HDG).