Projector Lamp Light Guide Shield Element for Stripe Reduction

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Solution Overview

Problem

The existing lighting units for motor vehicle headlights face challenges in reducing or eliminating vertical and horizontal stripes in the light image due to the inherent wall thickness of partitions between light guides, which affects the precision and quality of light distribution.

Innovation Solution

A screen element with screen openings and partitions is introduced between the light guide unit and the projection lens, where the partitions have a smaller wall thickness than those of the light guide unit, allowing for reduced or eliminated distance between light segments and minimizing stripe formation in the light image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the wall thickness of partitions between light guides is reduced to eliminate stripes in the light image, then the quality of light distribution is improved, but the manufacturing precision and production feasibility deteriorate

Engineering Contradiction:
Improvestripes in light imageVSAvoidpartition wall thickness control
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The invention divides the light guide unit into multiple individual light guides that are separated by partitions. Each light guide is treated as an independent element with its own partition walls, allowing the overall structure to achieve thin effective partition thickness through precise positioning of multiple components rather than relying on a single thick partition wall.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces air gaps or dark spaces between adjacent light guides as intermediary elements. These intermediaries serve as effective partitions that block light leakage and prevent stripe formation without requiring thick solid walls, thus maintaining both optical quality and manufacturing feasibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple light guides are used to create precise light segments, then the control precision of light distribution is improved, but the device complexity increases

Engineering Contradiction:
Improvelight segment definitionVSAvoidnumber of light guides and partitions
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention combines multiple light guides into a single integrated light guide unit with shared partitions and common mounting structures. This merging approach maintains the functional benefits of multiple separated light guides for precise light segment control while reducing overall structural complexity through consolidation of supporting elements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The partitions serving as separators between light guides simultaneously function as mounting surfaces, structural support elements, and light-blocking barriers. This multi-functionality reduces the need for additional separate components, thereby controlling device complexity while achieving precise light segment definition.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Strength

If the light guides are separated by thick partitions to ensure structural integrity, then the strength is improved, but the light image quality deteriorates due to stripe formation

Engineering Contradiction:
Improvestructural integrity of light guide unitVSAvoidstripes in light image
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention applies different wall thicknesses to different regions of the partitions. The partitions have thicker walls at the mounting and support regions to ensure structural integrity, while the regions adjacent to the light decoupling surfaces have reduced thickness to minimize stripe formation. This localized differentiation of quality allows simultaneous achievement of strength and optical quality.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If the wall thickness of partition walls is increased to simplify manufacturing, then the ease of manufacture is improved, but the light image quality worsens due to visible stripes

Engineering Contradiction:
Improvepartition productionVSAvoidlight segment separation
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention addresses the partition thickness problem by transitioning from a single-dimension solution (uniform wall thickness) to a multi-dimensional approach. It combines moderate thickness partitions with precise positioning in the third dimension (depth/distance from light source) and introduces air gaps, thereby achieving effective light segment separation without requiring excessively thin or thick walls, simplifying manufacturing while maintaining precision.

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 configuration significantly reduces or eliminates stripes in the light image, enhancing the sharpness and precision of light segments, and allows for more flexible control of light distribution patterns, such as partial high beam and cornering light functions.

Implementation Method 1

A screen element with screen openings and partitions is introduced between the light guide unit and the projection lens, where the partitions have a smaller wall thickness than those of the light guide unit, allowing for reduced or eliminated distance between light segments and minimizing stripe formation in the light image.

Methodology Applied
Scientific EffectLight redirection and separation: Reflection

Data Source

PatentEP2786064B1Light emitting unit for a projector lamp
Publication Date: 2016.04.20 ZKW GRP GMBH
  • EP2786064B1 patent drawingFigure 1
  • EP2786064B1 patent drawingFigure 2~4
  • EP2786064B1 patent drawingFigure 5~7

AI summary

The invention relates to a light‑emitting unit (1) for a projector lamp, in particular a motor vehicle headlamp, comprising a plurality of light sources (2), a light guidance unit (3) comprising a plurality of light guides (30) and a downstream projection lens (4), wherein each light guide (30) has in each case one light exit surface (30a), and wherein each light source (2) couples light precisely into a light guide (30) assigned thereto, and wherein adjacent light guides (30) are separated from one another by separating walls (31, 32). The invention provides for at least one shield element (5) to be arranged between the light guide unit (3) and the projection lens (4), which shield element (5) has apertures (50) which are separated from one another by aperture separating walls (51, 52), wherein the shield element (5) is arranged in such a way that in each case one aperture (50) is connected upstream of a light exit surface (30a), and wherein the apertures (50) correspond substantially in terms of shape and size to the light exit surfaces (30a) in each case assigned thereto, and wherein, on those surfaces (5a) of the at least one shield element (5) which are remote from the light guide unit (3), at least some of the aperture separating walls (51, 52) have a smaller wall thickness (b) than those separating walls (31, 32) of the light guide unit (3) which are assigned to the respective aperture separating walls (51, 52).