LED Headlight Module Decoupling Surface for Cut-Off Line Elimination
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Solution Overview
Problem
Existing headlight modules with LEDs for low and high beams exhibit a visible cut-off line in the distant field during high beam operation, which is undesirable.
Innovation Solution
An optical element with a decoupling surface featuring surface structuring, such as roughness, is used to scatter the high beam light into the low beam range, eliminating the visible cut-off line by blending the intensity transition, while maintaining the bezel edge effect for the low beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single optical element with a sharp bezel edge is used to create the low beam cut-off line, then the low beam function achieves precise light distribution, but a visible cut-off line appears in the high beam distant field which is undesirable
Solution Approach 1:
The optical element features a decoupling surface with surface structuring (roughness) localized in a specific area. This surface structuring selectively scatters high beam light in the distant field region while preserving the sharp bezel edge geometry for low beam light distribution. The local modification of surface quality resolves the contradiction by applying different optical properties to different functional zones of the same component.
Solution Approach 2:
The patent changes the surface parameter (roughness) of the decoupling surface to control light scattering. By introducing controlled surface irregularities with specific roughness parameters, the high beam light is scattered to eliminate visible cut-off lines in the distant field, while the overall geometric parameters of the optical element remain unchanged to maintain low beam precision.
2Illumination intensity
If the decoupling surface has high scattering properties to eliminate cut-off lines, then high beam uniformity improves, but the low beam bezel edge definition may be compromised
Solution Approach 1:
The surface structuring is applied locally to specific areas of the decoupling surface rather than uniformly across the entire optical element. This localized scattering approach affects only the high beam light paths in the distant field while leaving the bezel edge regions with smooth surfaces to maintain their sharp geometric definition for low beam applications.
Solution Approach 2:
The optical element's surface is segmented into different functional zones: areas with surface structuring for high beam scattering and areas with smooth surfaces for low beam bezel edge definition. This segmentation allows independent optimization of scattering properties for high beam uniformity while preserving geometric precision for low beam cut-off line sharpness.
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 eliminates the visible cut-off line during high beam operation without compromising the low beam's bezel edge depiction, ensuring a seamless light transition and reducing edge sharpness to prevent glare for oncoming traffic.
Implementation Method 1
the optical element features a decoupling surface that at least partially includes a surface structure with a composition such that, in the area of the surface structure, light is emitted that can be decoupled from the optical element
Data Source
AI summary
A headlight module with a minimum of one LED for generating a low beam and with a minimum of one LED for generating a high beam. An optical element is provided into which light from the minimum of one LED for generating the high beam can be emitted. The optical element is arranged as a cover for a portion of the light that can be generated by the LED for generating a low beam. The optical element features a decoupling surface that at least partially includes a surface structure with a composition such that, in the area of the surface structure, light is emitted that can be decoupled from the optical element.