Motor Vehicle Lighting Device Chromatic Defect Reduction
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Solution Overview
Problem
Existing motor vehicle lighting devices suffer from chromatic defects at the cut-off zone of low beams due to differences in optical power between transmitted and reflected light rays, resulting in a red and/or blue tinted border.
Innovation Solution
A lighting device with a first light source centered relative to the optical axis of a projection lens, accompanied by a diaphragm element that optimally shapes the light beam to minimize chromatic defects, using a collimator to collect and redirect light rays and a diaphragm to prevent unwanted light propagation, with optional features including a second light source and a metallized diaphragm surface for precise cut-off profile formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a diaphragm element is used to shape the cut-off zone, then the low beam profile is improved, but chromatic defects appear at the cut-off zone
Solution Approach 1:
A collimator is introduced as an intermediary optical element between the light source and the projection lens. This collimator converts divergent light from the source into parallel beams before they reach the diaphragm, ensuring uniform optical path lengths. The intermediary collimator mediates between the light source and diaphragm system, eliminating the chromatic defects while preserving the cut-off zone shaping capability.
Solution Approach 2:
The invention changes the optical parameters of the system by introducing a collimating stage that transforms the light ray characteristics. By adjusting the collimator's focal length and positioning it appropriately, the system transforms divergent rays into parallel rays, fundamentally changing the optical path parameters to eliminate chromatic aberrations at the cut-off zone.
2Volume of moving object
If the light source is offset from the optical axis, then space for diaphragm element is improved, but optical alignment precision deteriorates
Solution Approach 1:
The optical system is segmented into distinct functional modules: a collimator module with the light source, and a projection module with the lens and diaphragm. This segmentation allows the light source to be positioned at the collimator's focal point (optimized for collimation) while the projection lens and diaphragm maintain their optimal relative alignment. The segmentation resolves the space-alignment contradiction by decoupling the positioning requirements of different components.
Solution Approach 2:
The collimator serves as an intermediary that decouples the light source positioning from the projection lens alignment. The light source is positioned relative to the collimator (at its focal point), and the collimator in turn is positioned relative to the projection lens. This intermediary relationship allows optimal spacing for the diaphragm while maintaining precise optical alignment through the collimator's fixed geometric relationship with both components.
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 reduces chromatic defects at the cut-off zone by ensuring even light distribution and precise shaping of the light beam, enhancing the optical alignment and reducing unwanted light emission.
Implementation Method 1
a first collimator, a projection lens for shaping light rays generated by the first light source
Implementation Method 2
an element fastened to the support and forming a diaphragm for at least some of the light rays emitted by the first light source
Implementation Method 3
The diaphragm element can take the form of an optical element inside which a first portion of the light rays generated by the light source is transmitted and at a surface of which a second portion of the light rays generated by the light source is reflected
Data Source
AI summary
A lighting device for motor vehicles including at least one first light source that is centered on and/or aligned with the optical axis of a projection lens of the lighting device, and a diaphragm element in order to form a cut-off profile in a first light beam shaped by the projection lens. This advantageous configuration enables reduction of chromatic defects linked to interaction between the diaphragm element and light rays generated by the first light source. The lighting device advantageously includes a second light source in order to be able, in collaboration with the first light source, to generate a second light beam. In this case, the diaphragm element is advantageously inclined on the second light source side relative to the optical axis of the projection lens.