Automotive Light Guide with Segmented Curved Rectilinear Profile
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Solution Overview
Problem
Curved light guides in motor vehicle lighting and signaling devices face challenges in directing light beams towards the interior of the vehicle, leading to heterogeneous or discontinuous light appearances and internal reflection issues.
Innovation Solution
A light guide with an input face, coupler, main reflection face, and output face is designed to transmit light as parallel rays within a 5° angle of the optical axis, improving beam directionality and homogeneity, and reducing internal reflection, with features like convex or concave entrance faces, parabolic sections, and aluminizing surfaces to enhance light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a curved light guide is used, then the light beam can be directed in certain directions, but it becomes difficult to direct the light beam towards the interior of the vehicle
Solution Approach 1:
The light guide is divided into multiple sections with different profiles: a first section with a curved profile for directing light towards the vehicle exterior, and a second section with a rectilinear profile for directing light towards the vehicle interior. This segmentation allows each section to be optimized for its specific directional requirement without compromising the other.
Solution Approach 2:
The invention transitions from a single curved profile to a composite profile that incorporates both curved and rectilinear sections. This dimensional change in the profile geometry enables the light guide to achieve multiple directional objectives that cannot be satisfied by a purely curved design.
2Ease of manufacture
If a rectilinear or curved linear profile light guide is used, then light can be transmitted, but the lit appearance appears heterogeneous or even discontinuous along the profile
Solution Approach 1:
Different sections of the light guide are given different local qualities: the first section has a curved profile optimized for exterior direction, while the second section has a rectilinear profile optimized for interior direction. This local differentiation ensures that each section contributes to homogeneous light appearance in its respective zone, eliminating the heterogeneous effect seen in uniform profiles.
Solution Approach 2:
The invention strategically applies curvature only where needed (first section for exterior direction) while maintaining rectilinearity in sections requiring homogeneous appearance (second section for interior direction). This selective use of curvature resolves the contradiction between manufacturing simplicity and visual homogeneity.
3Ease of operation
If a curved light guide is used, then light can be directed in certain directions, but there may be no beam emerging from the guide in a given direction with total internal reflection occurring
Solution Approach 1:
The light guide is segmented into a curved first section and a rectilinear second section, ensuring that the rectilinear section provides reliable beam emergence towards the vehicle interior without total internal reflection issues that plague purely curved designs.
Solution Approach 2:
The rectilinear second section acts as an intermediary that receives light from the curved first section and reliably transmits it towards the vehicle interior, mediating between the directional requirements of the curved section and the reliability requirements of the output beam.
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 allows for easier beam direction, improved light homogeneity, and reduced internal reflection, resulting in a more uniform and efficient light distribution that complies with regulations and minimizes hot spots.
Implementation Method 1
The entrance face is convex or concave in shape. Thus, the light beam entering the guide is refracted and transmitted to the coupler
Implementation Method 2
the coupler transmits part of this light to the main reflection face which directs it, in the form of a beam with parallel rays, directly or indirectly, towards the exit face
Implementation Method 3
The reflection face comprises, at least over a portion of its length, an aluminizing
Implementation Method 4
The reflection face comprises, at least over a portion of its length, a cross-section with a 'V' profile formed by two surfaces forming an angle between them, for example of 90°. Thus these two surfaces can operate in total internal reflection of the light rays
Data Source
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Figure 3
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AI summary
A light guide for a lighting and/or signaling device of an automobile vehicle comprising an entry face, a coupler, a main reflection face, and an exit face. The light guide is arranged in such a manner that, when a light source is disposed at a predetermined point with respect to the light guide, the entry face transmits the light from the light source to the coupler and the coupler transmits a part of this light to the main reflection face which directs it, in the form of a beam of parallel rays, directly or indirectly, toward the exit face in a direction forming an angle of 5° at the most with respect to the optical axis of the light guide.