Tilted Light Guide Plate for Headlamp Luminance Homogeneity
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Solution Overview
Problem
Motor vehicle headlights with projection light modules for high and low beams exhibit inhomogeneous luminance and color differences when switching between low and high beam modes, leading to an uneven appearance.
Innovation Solution
The implementation of a tilted light guide plate in the projection light modules, combined with additional light sources and colored LEDs, ensures uniform illumination and adjustable light color, achieving a consistent appearance between high and low beam modes by directing additional light transversely through the light guide plate and using colored LEDs for customizable illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If additional light sources and reflectors are used to illuminate the projection lens, then the luminance homogeneity of the projection lens is improved, but the light color uniformity between high beam and low beam deteriorates
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the additional light source and the projection lens. The light guide plate receives light from the additional light source and distributes it uniformly across the projection lens entrance surface, achieving homogeneous illumination without disrupting the matrix light path. This mediator enables independent control of lens illumination color and intensity.
Solution Approach 2:
The illumination system is segmented into separate functional components: the matrix light path for high beam generation and the additional light path through the light guide plate for lens illumination. This segmentation allows independent optimization of each path, enabling uniform lens illumination without affecting the matrix light color coordinates.
2Area of stationary object
If metallized reflectors are used to direct additional light to the projection lens, then the illumination coverage is improved, but the light color consistency deteriorates
Solution Approach 1:
The light guide plate serves as an intermediary that replaces the need for complex metallized reflector arrangements. It uniformly distributes light from a single additional light source across the entire projection lens entrance surface, achieving full coverage without the color inconsistencies introduced by tilted reflector surfaces.
3Adaptability or versatility
If the additional light path uses a different optical system from the low beam module, then the high beam matrix function is achieved, but the light color matching between high and low beam deteriorates
Solution Approach 1:
The light guide plate acts as a universal intermediary that decouples the additional light path from the specific optical system details. It receives light from the additional light source and delivers uniform illumination to the projection lens regardless of the upstream optical configuration, enabling color matching between high and low beam modes while maintaining matrix function capability.
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 enhances the homogeneity of the projection lens illumination, allowing for a uniform and adjustable light color, eliminating the inhomogeneous appearance and enabling customizable lighting effects such as colored welcome lights.
Implementation Method 1
a first light guide plate (28) having a first light entry surface (32), which can be illuminated with additional light (34) from a first additional light source (26) through the first light guide plate (28)
Implementation Method 2
The light guide plate is arranged in a tilted position in which the first part (42) of the first light guide plate (28) is located further away from the first projection lens (24) along the first optical axis (30) than the second part (44) of the first light guide plate (28)
Implementation Method 3
The implementation of a tilted light guide plate in the projection light modules, combined with additional light sources and colored LEDs, ensures uniform illumination and adjustable light color
Data Source
Figure 1
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AI summary
A vehicle headlight with a first projection light module is presented, comprising a first projection lens, a first auxiliary light source, and a first light guide plate. The light guide plate is arranged in a tilted position, such that the first part of the first light guide plate is located further away from the first projection lens along the first optical axis than the second part of the light guide plate. Configurations with partially colored light guide plates and white-emitting auxiliary light sources, as well as configurations with colorless light guide plates and colored auxiliary light sources, and with colorless light guide plates and white-emitting auxiliary light sources, are described.