Headlamp Light Guide Facets for Cut-Off Line Intensity Control
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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 is designed with facets that deviate from the base surface, allowing controlled redirection of light to reduce intensity at specific points and enhance distribution through total internal reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the lower light deflection surface is designed with facets that deviate from the base surface, then light distribution control is improved and excessive light intensity at defined points is reduced, but device complexity increases
Solution Approach 1:
The lower light deflection surface is segmented into multiple facets (first facet, second facet, third facet) with different orientations. Each facet is responsible for redirecting light to specific regions of the light distribution pattern, enabling precise control of light intensity at defined points while maintaining a manageable structural complexity through modular surface design.
Solution Approach 2:
Different regions of the lower light deflection surface are assigned different local properties through the facet configuration. The first facet redirects light to a first region, the second facet to a second region, and the third facet to a third region. This local differentiation allows optimized light distribution control for each specific area without requiring complex control mechanisms across the entire surface.
2Manufacturing precision
If additional measures such as micro optics are added to control cut-off line sharpness, then light distribution precision is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of adding complex micro-optical elements in the traditional optical path, the invention controls light distribution by modifying the geometry of the lower light deflection surface in a spatial dimension. The facet orientations and angles are carefully designed to redirect light rays to achieve sharp cut-off lines and precise light distribution patterns, replacing complex micro-optics with geometric surface design.
3Illumination intensity
If the facets are designed with specific orientations to redirect light away from defined points, then light intensity control is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention controls light intensity by changing the orientation parameters (angles) of the facets relative to the base surface. The first facet has a first orientation, the second facet has a second orientation, and the third facet has a third orientation. By carefully selecting and optimizing these angular parameters during the design phase, the system achieves precise light intensity control at defined points while establishing clear manufacturing specifications for facet orientations.
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 effectively reduces excessive light intensity at defined points and improves light distribution control, aligning with regulatory luminous intensity limits.
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
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AI summary
A lighting device (1) for vehicles comprises a light source (10), a transparent light guide body (100) with a light coupling area (101) and a projection optics device (200). Light from the light source (10) enters the guide body (100), is totally reflected by the lower light deflection surface (103), exits, and is projected as a light distribution (LV) with a cut-off line. The shape of the lower light deflection surface (103) deviates in a region of deviation (BER) from the shape of a base surface (500'). The region of deviation (BER) is located laterally of a longitudinal center plane (LE) of the lighting device (1), which contains the optical axis (X) of the projection optics device (200). In the region of deviation (BER) the lower light deflection surface (103) deviates from the shape of the base surface (500') the form of a first facet (501), wherein said first facet (501) is a first surface element (501') of the deflection surface (103) which, starting at the edge (105) or in a defined distance from the edge (105), extends counter to the direction of the optical axis (X). The shape of the base surface (500') is such that in the case that the lower light deflection surface would not deviate from the shape of the base surface (500') in form of the first facet (501), the light reflected from the base surface (500') would be projected from the projection optics device (200) into a non-deviation region (NDV) of the light distribution (LV), wherein the non-deviation region (NDV) contains a defined point (50L) of the light distribution (LV).The first surface element (501') is inclined with respect to the base surface (500') in such a way that light totally reflected by the first surface element (501') is imaged in the light distribution (LV) by the projection optics device (200) into a so-called "eraser region" region below the defined point (50L).