Vehicle Light Guide Facets for Sharp Headlamp Cut-Off
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Solution Overview
Problem
Existing lighting devices for vehicle headlamps struggle to control the sharpness of the cut-off line in the light distribution, leading to excessive light intensity in certain regions, necessitating additional measures like micro optics.
Innovation Solution
The lower light deflection surface in the lighting device is shaped with facets that deviate from a base surface, allowing controlled redirection of light to reduce intensity at defined points and enhance distribution in other regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional light guide body with a base surface is used, then the light distribution is simple to manufacture, but the sharpness of the cut-off line cannot be controlled and excessive light intensity occurs in certain regions
Solution Approach 1:
The lower light deflection surface is segmented into multiple facets (first facet, second facet, third facet) with different orientations. Each facet redirects light to specific regions of the light distribution pattern, enabling precise control over light intensity in different areas while maintaining a manufacturable polyhedral structure.
Solution Approach 2:
Different regions of the lower light deflection surface are given different local properties through the facet configuration. The first facet redirects light to reduce intensity at defined points, the second facet directs light to specific regions, and the third facet handles remaining light distribution, allowing localized control of light intensity without complicating the entire structure.
2Manufacturing precision
If additional measures like micro optics are added to control light distribution, then the sharpness of the cut-off line is improved, but the device complexity increases
Solution Approach 1:
The light distribution control function is merged into the light guide body itself through the faceted lower light deflection surface. This integrates the secondary optics function directly into the primary optics structure, eliminating the need for separate micro optics components while achieving the desired sharp cut-off line and controlled light intensity distribution.
Solution Approach 2:
The light guide body is designed to perform multiple functions: guiding light from the light source, redistributing light through total internal reflection at the faceted surfaces, and controlling the final light distribution pattern. This multi-functionality replaces the need for additional dedicated optical 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 design effectively reduces excessive light intensity at specific points while improving light distribution, adhering to regulatory luminous intensity limits and enhancing control over the light pattern.
Implementation Method 1
at least part of the light propagating in the light guide body is totally reflected at the lower light deflection surface before it emerges from the light guide body through the light exit surface
Data Source
AI summary
A lighting device for vehicles including a light source, a transparent light guide body with a light coupling area and a projection optics device. The shape of the lower light deflection surface deviates from the shape of a base surface. The shape of the base surface is such that if the lower light deflection surface would not deviate from the shape of the base surface in form of the first facet, the light reflected from the base surface would be projected from the projection optics device into a non-deviation region of the light distribution, wherein the non-deviation region contains a defined point of the light distribution. The first surface element is inclined with respect to the base surface such that light totally reflected by the first surface element is imaged in the light distribution by the projection optics device into an “eraser region” region below the defined point.