Vehicle Headlamp Rectangular LED Orientation for Light Distribution

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Solution Overview

Problem

Existing vehicle headlamps using semiconductor light emitting devices face challenges in forming light distribution patterns with high accuracy, leading to irregularities in light intensity and complexity in controlling horizontal and vertical light diffusion.

Innovation Solution

A vehicle headlamp design incorporating a focused-beam lamp unit and a diffused-beam lamp unit, each with a rectangular light emitting surface and a corresponding optical member, where the focused-beam unit forms a vertically narrow pattern and the diffused-beam unit forms a wider pattern, allowing for simplified light distribution control by adjusting the orientation and position of the light source images to minimize intensity irregularities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If both horizontal and vertical light diffusion are controlled by optical members (reflector and projection lens) to form a diffused beam pattern, then the diffused beam pattern can be achieved, but the light distribution control becomes complex

Engineering Contradiction:
Improvediffused beam patternVSAvoidlight distribution control
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The invention divides the light diffusion control into separate horizontal and vertical components. The reflector controls horizontal diffusion while the projection lens controls vertical diffusion, segmenting the complex two-dimensional control into simpler one-dimensional controls that can be independently optimized

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary approach by using the rectangular light emitting surface orientation as a passive geometric element that inherently provides different diffusion characteristics in horizontal and vertical directions, reducing the need for complex active optical control

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If light source images are condensed toward a cutoff line to form a hot zone for focused beam pattern, then the focused beam pattern is achieved, but unnecessary brightness below the hot zone or strong irregularity in light intensity occurs

Engineering Contradiction:
Improvefocused beam patternVSAvoidlight intensity uniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The invention applies local quality by making the light emitting surface rectangular with different side lengths in horizontal and vertical directions, creating locally optimized light distribution characteristics where the longer side provides enhanced diffusion in that direction, thereby controlling the hot zone formation and reducing intensity irregularities

Inventive Principle:
Principle #3Local quality

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 design enables simplified light distribution control and reduces irregularities in light intensity, allowing for a more accurate and efficient formation of low-beam light patterns with improved horizontal and vertical cutoffs.

Implementation Method 1

the semiconductor light emitting devices are light emitting chips, such as light emitting diodes (LEDs)

Methodology Applied
Scientific EffectLight emitting diode (LED): Light Emitting Diode

Implementation Method 2

a first optical member via which light from the first semiconductor light emitting device is projected forward from the focused-beam lamp unit

Methodology Applied
Scientific EffectLight projection through optical member: Lens

Data Source

PatentEP2481974B1Vehicle headlamp
Publication Date: 2019.03.06 KOITO MFG CO LTD
  • EP2481974B1 patent drawingFigure 1
  • EP2481974B1 patent drawingFigure 2
  • EP2481974B1 patent drawingFigure 3

AI summary

A vehicle headlamp (11) has a focused-beam lamp unit (20), and a diffused-beam lamp unit (30). The focused-beam lamp unit has a first semiconductor light emitting device (22) having a first rectangular light emitting surface (22a), and a first optical member (21) that projects light from the first semiconductor light emitting device to form a focused beam pattern. The diffused-beam lamp unit has a second semiconductor light emitting device (32) having a second rectangular light emitting surface (32a), and a second optical member (31) that projects light from the second semiconductor light emitting device to form a diffused beam pattern, the diffused beam pattern being wider than the focused beam pattern in a direction along a vertical line in front a vehicle on which the vehicle headlamp is mounted. The focused-beam lamp unit and the diffused-beam lamp unit are arranged to form a light distribution pattern by combining the focused beam pattern and the diffused beam pattern.