Vehicle Lighting Device With Segmented Waveguide Input
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Solution Overview
Problem
Existing vehicle lighting devices with flat optical waveguides suffer from non-homogeneous illumination and reduced photometric efficiency due to total reflection of light at opposing flat sides, leading to brightness differences and light loss.
Innovation Solution
A light input surface with a central and outer input section, where the central section directs a first sub-light bundle to a central region of the light output surface and the outer section directs a second sub-light bundle to an adjacent outer region, minimizing total reflections and enhancing light guidance for homogenous illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar light input surface is used, then the device structure is simple, but non-homogeneous illumination occurs at the light output surface
Solution Approach 1:
The light input surface is divided into multiple zones (central zone and outer zones) with different optical functions. The central zone has a first curvature radius while the outer zones have a second curvature radius, allowing different light bundles to be directed to different regions of the output surface, achieving homogeneous illumination across the entire output surface.
Solution Approach 2:
Different regions of the light input surface are assigned different optical properties (different curvature radii). The central region focuses light to the central output area while outer regions direct light to peripheral output areas, creating locally optimized light distribution that results in global illumination homogeneity.
2Illumination intensity
If spherical reflective light input surfaces are used, then illumination homogeneity is improved, but photometric efficiency is compromised due to light diffusion
Solution Approach 1:
The curvature radius parameter is varied across different zones of the light input surface. By precisely controlling the curvature radius values (first curvature radius for central zone, second curvature radius for outer zones) and their transition, the patent achieves both homogeneous illumination and high photometric efficiency, avoiding the light diffusion problems of spherical surfaces.
Solution Approach 2:
The patent employs curved surfaces with specifically controlled curvature radii instead of flat or purely spherical surfaces. The gradual transition between different curvature radii zones creates optimized light paths that maintain directionality while achieving uniform distribution, preventing light diffusion losses.
3Device complexity
If light enters undirected via a planar light input surface, then device complexity is reduced, but brightness differences occur at the light output surface
Solution Approach 1:
The light input surface is segmented into functional zones with different curvatures. This segmentation provides directed light guidance without requiring complex external optical components, achieving brightness uniformity through the inherent geometry of the input surface itself.
Solution Approach 2:
The curved light input surface acts as an intermediary element that transforms undirected light from the source into controlled light bundles. The specific curvature geometry mediates between the simple light source and the required uniform output, providing directionality without adding mechanical complexity.
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 achieves high photometric efficiency and homogenous illumination along the light output surface by controlling light distribution and reducing diffusion losses, ensuring consistent brightness across the output surface.
Implementation Method 1
an optical waveguide (1) having opposing flat sides (4), which are designed for total reflection of light entering the waveguide
Data Source
AI summary
The present invention relates to a lighting device for vehicles. The lighting device has a flat optical waveguide containing two opposing flat sides, a light input surface for the entry of light, and a light output surface for emitting the entering light at a light output side of the flat waveguide. The light input surface has a central input section disposed in the main beam direction in front of the light source, and an outer input section adjacent thereto. The central input section and the outer input section are shaped such that a first sub-light bundle of the light striking the central input section strikes a central region of a sub-surface of the light output surface disposed in the main beam direction in front of the light input surface after being reflected at the flat sides. A second sub-light bundle of the light source, striking the outer input section, strikes an outer region of the same sub-surface, adjacent to the central region.