Vehicle Headlamp Reflector Segmentation for Compact ADB
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Solution Overview
Problem
Vehicle headlamps with adaptive driving beam (ADB) function face challenges in reducing size while maintaining even light distribution, as reducing the focal length of the reflector leads to luminance unevenness due to shifting illumination patterns.
Innovation Solution
The vehicle headlamp employs a reflector with multiple reflecting surfaces and light sources arranged in a common configuration, where at least half of the area of one illumination pattern overlaps with the adjacent pattern, and focal lengths are set between 10 mm to 15 mm to minimize luminance unevenness and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the focal length of the reflecting surface is reduced to decrease the upper-lower width of the reflector, then the size of the vehicle headlamp is reduced, but luminance unevenness occurs in the light distribution pattern due to shifting illumination patterns
Solution Approach 1:
The reflector is divided into multiple reflecting surfaces (first reflecting surface, second reflecting surface, third reflecting surface, fourth reflecting surface) arranged in the left-right direction. Each reflecting surface has a different focal length (10-15mm, 15-20mm, 20-25mm, 25-30mm respectively), allowing segmented control of illumination patterns to prevent luminance unevenness while maintaining compact size.
Solution Approach 2:
Different regions of the reflector are assigned different focal lengths based on their specific functions. The first reflecting surface (closest to center) has the shortest focal length (10-15mm) for central illumination, while subsequent surfaces have progressively longer focal lengths to maintain proper illumination pattern positioning and overlap for their respective regions.
2Shape
If the curvature of the reflecting surface is reduced to reduce the upper-lower width of the reflector, then the size of the vehicle headlamp is reduced, but the illumination pattern position shifts causing luminance unevenness
Solution Approach 1:
The reflector is segmented into multiple surfaces with different curvatures and focal lengths. This segmentation allows each surface to be optimized for its specific illumination region, maintaining precise illumination pattern positioning even with reduced overall reflector width.
Solution Approach 2:
The focal length parameter is varied across different reflecting surfaces (10-15mm, 15-20mm, 20-25mm, 25-30mm) to compensate for the reduced curvature. This parameter change ensures that illumination patterns maintain correct positioning and overlap characteristics despite the compact reflector geometry.
3Adaptability or versatility
If multiple light sources are arranged side by side to form individual illumination patterns, then ADB control is achieved, but the headlamp size increases
Solution Approach 1:
Adjacent light sources are combined into common light sources that illuminate the same reflecting surface. This merging reduces the total number of light source-reflector pairs needed, thereby reducing overall headlamp size while maintaining ADB functionality through coordinated control of the common light sources.
Solution Approach 2:
Each light source is designed to serve multiple functions: it contributes to both its own illumination pattern and to the illumination patterns of adjacent light sources through the overlapping design. This multi-functionality allows for more efficient use of light sources, reducing the total number needed for effective ADB control.
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 configuration allows for a reduced vehicle headlamp size with minimized luminance unevenness in the light distribution pattern, enhancing the degree of freedom in light source arrangement and reflector design while maintaining effective ADB functionality.
Implementation Method 1
light emitted from a plurality of light sources under on/off control is reflected by a reflecting surface of a reflector
Data Source
AI summary
A vehicle headlamp includes a reflector having plural reflecting surfaces arranged in a left-right direction, and n light sources which are arranged in the left-right direction and emit light toward any one of the reflecting surfaces. At least two adjacent light sources are provided as a common light source which emits light toward a same reflecting surface. n illumination patterns which illuminate different regions in the left-right direction are formed by light emitted from the n light sources, respectively, and are taken as a first to n-th illumination patterns in this order in the left-right direction. At least half of areas of illumination patterns of an immediately-following number and an immediately-preceding number overlap each other in the left-right direction. Focal lengths of the plural reflecting surfaces are set such that adjacent illumination patterns which do not overlap each other are formed by light emitted from the common light source.