Vehicle Lighting Device with Longitudinal Steps for Stray Light Control
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Solution Overview
Problem
Conventional vehicle lighting devices using semiconductor-type light sources face challenges in achieving ideal light distribution patterns due to vertical and lateral stray light, which can compromise traffic safety, especially in passing scenarios.
Innovation Solution
The vehicle lighting device employs longitudinally divided parabolic reflecting surfaces with longitudinal steps to redirect reflected light laterally, preventing vertical stray light and optimizing light distribution patterns by controlling the reflection of light from multiple surfaces to concentrate and diffuse light effectively on the road surface, while also utilizing a shade to cut off and control light for passing scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If horizontal steps are formed among parabolic reflecting surfaces divided laterally, then light can be reflected in the longitudinal direction, but vertical stray light is generated
Solution Approach 1:
The parabolic reflecting surfaces are divided into multiple segments in the longitudinal direction, with each segment having a different longitudinal position. This segmentation allows light to be reflected in the longitudinal direction while preventing vertical stray light by ensuring that reflected light does not reach the opposite lane side.
Solution Approach 2:
The invention transitions from lateral division to longitudinal division of the parabolic reflecting surfaces. By forming longitudinal steps instead of horizontal steps, the light reflection direction is changed from longitudinal to lateral, effectively preventing vertical stray light while maintaining proper light distribution.
2Illumination intensity
If multiple lamp units are used to achieve ideal light distribution patterns, then light distribution can be optimized, but device complexity increases
Solution Approach 1:
A single lamp unit is designed to perform multiple functions by incorporating longitudinally divided parabolic reflecting surfaces with different reflection characteristics. This allows one lamp unit to generate multiple light distribution patterns (including cutoff line patterns and main light distribution patterns) that would otherwise require multiple separate lamp units.
Solution Approach 2:
The invention combines multiple light distribution functions into a single lamp unit by integrating longitudinally divided reflecting surfaces with different optical characteristics. This merging of functions reduces the total number of lamp units needed while achieving ideal light distribution patterns.
3Illumination intensity
If light is reflected in the vertical direction at the steps, then light distribution is achieved, but stray light in the opposite lane direction is generated
Solution Approach 1:
The invention changes the division direction from lateral to longitudinal, which changes the light reflection direction from longitudinal to lateral. This dimensional change ensures that reflected light is directed away from the opposite lane side, preventing stray light generation while maintaining effective light distribution.
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 enables the achievement of ideal light distribution patterns by one lamp unit, effectively reducing stray light and enhancing traffic safety, particularly for passing and overhead sign illumination, while efficiently utilizing the light source and reducing manufacturing complexity.
Implementation Method 1
Part of light radiated from the semiconductor-type light source is then reflected by the first reflecting surface. Part of the reflected light is reflected by the third reflecting surface
Implementation Method 2
if the reflected light from the first reflecting surface is incident to the longitudinal steps, the incident light is reflected in the lateral direction, i.e., in the transverse direction at the steps
Implementation Method 3
A vehicle lighting device of this type is conventionally disclosed in Japanese Laid-open Patent Application No. 2008-41557... employing a semiconductor-type light source as a light source
Data Source
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AI summary
A lighting device of the present invention includes: a first reflecting surface (11) which is an elliptical reflecting surface; a semiconductor-type light source (3) which is disposed at a first focal point (F11) of the first reflecting surface (11); and parabolic reflecting surfaces (12, 13, 14) for controlling reflected light (L2) from the first reflecting surface (11) and reflecting the controlled reflected light on a road surface, as predetermined light distribution patterns (LP, SP, WP). The parabolic reflecting surfaces (12, 13, 14) are a plurality of reflecting surfaces which are longitudinally divided into three sections. As a result, longitudinal steps (24) are formed among the three parabolic reflecting surfaces (12, 13, 14) that are longitudinally divided. Thus, if the reflected light (L2) from the first reflecting surface (11) is incident to the longitudinal steps (24), the incident light is reflected in the lateral direction, i.e., in the transverse direction at the steps (24). In this manner, vertical stray light can be prevented.