Projection Lens Surface Deformation for Vehicle Headlight Light Distribution

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Solution Overview

Problem

Existing projection lenses for motor vehicle headlights cannot generate light source images of different sizes, limiting their ability to achieve optimal light distribution with a sharp light-dark boundary and adequate illumination of both front and side areas.

Innovation Solution

A method to calculate the surfaces of projection lenses, allowing for the generation of light source images of varying sizes by deforming the lens surfaces to position their highest points at or near the light-dark boundary, enabling precise control over light distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional projection lens is used, then the light distribution can be projected onto the roadway, but light source images of different sizes cannot be generated, limiting the ability to illuminate different areas effectively

Engineering Contradiction:
Improveability to generate light source images of different sizesVSAvoidlens surface design complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by deforming specific regions of the projection lens surface to create different imaging characteristics in different areas. The lens surface is divided into zones that produce small light source images for the light-dark boundary and large light source images for front and side illumination, allowing each region to serve its specific function optimally

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters of the lens surface through controlled deformation. By modifying the surface curvature and shape in specific regions, the lens can generate light source images of varying sizes from a single optical element, enabling versatile light distribution patterns

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If small light source images are used to achieve the light-dark boundary, then the range of light distribution is maximized, but the illumination of front and side areas is insufficient

Engineering Contradiction:
Improveillumination of front and side areasVSAvoidrange of light distribution
Core Design Contradiction:
Illumination intensityVSLength of moving object

Solution Approach 1:

The patent segments the light distribution function by using different sized light source images for different spatial regions. Small light source images are positioned at the light-dark boundary to define the range, while large light source images are directed to front and side areas to provide supplementary illumination, achieving both goals simultaneously

Inventive Principle:
Principle #1Segmentation

3Illumination intensity

If large light source images are used to illuminate front and side areas, then the illumination intensity is improved, but the light-dark boundary becomes less sharp and the range is reduced

Engineering Contradiction:
Improveillumination of front and side areasVSAvoidsharpness of light-dark boundary
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent resolves the contradiction by adding spatial dimensionality to the light distribution strategy. Instead of using a single light source image size, the system creates multiple light source images of different sizes at different positions, with large images for front/side illumination and small images for the light-dark boundary, achieving both illumination intensity and boundary sharpness

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 approach allows for the creation of projection lenses that produce small light source images for sharp boundaries and large images for front and side illumination, enhancing the range and gradient of the light distribution while meeting regulatory requirements.

Implementation Method 1

The projection lens is designed to project at least part of the light emitted by a light source of the light module onto a roadway in front of the motor vehicle equipped with the headlight in order to generate a dimmed light distribution

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

deforming a first surface of the lens with the aim of generating light source images of different sizes in the light distribution

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2837962B1Method for calculating the surfaces of optical lenses and projection lens calculated according to the method for a light module of a motor vehicle headlight
Publication Date: 2019.12.11 MARELLI GERMANY GMBH
  • EP2837962B1 patent drawingFigure 1~2
  • EP2837962B1 patent drawingFigure 3
  • EP2837962B1 patent drawingFigure 4

AI summary

The invention relates to a method for calculating the surfaces (12, 13) of optical lenses (10) and a projection lens (10) with surfaces (12, 13) calculated according to this method.The procedure comprises: a) specifying a desired light distribution, b) deforming a first surface (13) to generate light source images (30) of different sizes, c) deforming a second surface (12) to shift all light source images (30) so that their highest point lies on a light-dark boundary of the resulting light distribution, d) determining the quality of the resulting light distribution by comparison with the specified light distribution, e) if the quality is above a predefinable limit, saving the calculated surfaces (12, 13) and ending the procedure, f) otherwise, re-deforming the first surface (13), g) re-deforming the second surface (12), h) repeating steps f) and g) until the quality of the resulting light distribution is above the limit, and i) saving the calculated surfaces (12, 13) and ending the procedure.