Motor Vehicle Light Guide Coupling via Prism Air Gap
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Solution Overview
Problem
The existing light guide arrangements for motor vehicle lighting devices, which use separate light guides for central coupling, suffer from inefficiencies and an inhomogeneous appearance due to imperfections at the connection points, leading to uncontrolled light exit and an unattractive visual effect.
Innovation Solution
The implementation of a light guide arrangement where the light exit surface of one light guide has a prism structure complementary to the light output surface of another, with decoupling elements and an air gap to prevent imperfections, allowing efficient light coupling and a homogeneous appearance by ensuring light enters and exits the first light guide unimpeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate light guides are used for central coupling, then light can be efficiently coupled into the first light guide via the second light guide, but connection points between light guides create imperfections causing uncontrolled light exit and inhomogeneous appearance
Solution Approach 1:
The patent introduces an intermediary optical element (transparent body with prism structures) between the first and second light guides. This intermediary component mediates the light coupling process, allowing efficient light transfer while preventing direct contact between light guides that would create visible connection imperfections. The prism structures in this intermediary element control light propagation and exit, ensuring homogeneous appearance.
Solution Approach 2:
The patent extracts the connection point between light guides from the visible optical path. By removing the direct interface between light guides and replacing it with a transparent body containing prism structures, the connection imperfections are taken out of the light transmission path, preventing them from causing uncontrolled light exit and visual inhomogeneity.
2Ease of manufacture
If light guides are connected directly at connection points, then assembly is simplified, but light exits in an uncontrolled manner at connection points creating dark areas and unattractive appearance
Solution Approach 1:
The transparent body with prism structures serves as an intermediary component that replaces direct light guide connection. This intermediary element provides controlled light exit through its prism structures while maintaining assembly simplicity, as it can be integrated into the existing light guide arrangement without complex modifications.
Solution Approach 2:
The patent applies local quality by introducing prism structures at specific locations within the transparent body. These localized prism structures control light exit at the connection region while leaving other regions of the light guides unaffected, thus preventing uncontrolled light exit at connection points without compromising the overall simplicity of the assembly.
3Manufacturing precision
If prism structures are added to light guide surfaces, then light coupling efficiency and appearance homogeneity are improved, but device complexity increases
Solution Approach 1:
The patent merges the prism structures with the transparent body in a single integrated component. Rather than adding separate prism elements to existing light guides, the prism structures are combined with the transparent intermediary body, reducing the number of discrete components and simplifying the overall device structure while maintaining appearance homogeneity.
Solution Approach 2:
The transparent body with prism structures serves multiple functions simultaneously: it acts as an intermediary optical element for light coupling, provides controlled light exit through prism structures, and ensures homogeneous appearance. This multi-functionality reduces the need for additional components, thereby limiting the increase in device complexity.
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 solution enhances the efficiency and appearance of the light guide arrangement by preventing imperfections and ensuring a uniform light distribution, maintaining brightness and color consistency, and allowing for various lighting functions to be implemented with different colored light sources.
Implementation Method 1
The light guides are transparent bodies made of glass or plastic in which the bundling of the light is then caused by refraction when entering the body and/or exiting the body
Implementation Method 2
The light guides are transparent bodies made of glass or plastic in which the bundling of the light is then caused by refraction when entering the body and/or exiting the body and/or by total reflection at the outer boundary surfaces of the body takes place
Data Source
Figure 1
Figure 2
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AI summary
The invention relates to a lighting device (1) for a motor vehicle, comprising: - a first light guide (12) for propagating light by means of total internal reflection, wherein light propagated in the light guide (12) strikes a light-emitting surface (18) of the light guide (12) and is at least partially reflected in the direction of an opposite light-exiting surface (20) and exits the light guide (12), and - at least one second light guide (24) for propagating light by means of total internal reflection, wherein light from the second light guide (24) is coupled into the first light guide (12) via a central coupling point. The light exiting the second light guide (24) via a light-exiting surface (30) enters the first light guide (12) via the light-emitting surface (18). An air gap (32) is formed between the light output surface (18) of the first light guide (12) and the light exit surface (30) of the second light guide (24).