Rotary Reflector Optical Unit for Compact Vehicle Headlamps

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Solution Overview

Problem

Existing optical units for vehicle lamps are wide due to the lateral placement of the light source relative to the rotary reflector, making them unsuitable for vehicle headlamps due to design constraints.

Innovation Solution

The optical unit features a rotary reflector with its axis of rotation intersecting a horizontal plane, positioning the light source below this axis, and includes a projection lens to project light in a way that reduces the unit's length, utilizing multiple light sources and a substrate to minimize components, and incorporating a light-blocking portion to prevent stray light, with the reflector's blades forming a desired light-distribution pattern.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the light source is disposed toward a side of the rotary reflector, then the light can be reflected forward to form a desired light-distribution pattern, but the width of the optical unit becomes large

Engineering Contradiction:
Improvelight-distribution patternVSAvoidwidth of optical unit
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The patent repositions the light source from a lateral arrangement to a lower arrangement relative to the rotary reflector's optical axis. This dimensional change in source placement allows the light to be reflected upward and forward by the rotating reflector surface, achieving the desired light distribution pattern while significantly reducing the width of the optical unit in the lateral direction.

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

2Ease of operation

If the light source is disposed laterally to the rotary reflector, then the light reflection function is achieved, but the length of the optical unit in the front-back direction increases

Engineering Contradiction:
Improvelight reflection functionVSAvoidlength of optical unit
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The patent positions the light source below the optical axis of the rotary reflector rather than laterally. This vertical positioning allows the reflected light to travel upward and forward, achieving effective light reflection while minimizing the front-back length of the optical unit. The projection lens is positioned to receive this reflected light at an optimized distance.

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

3Adaptability or versatility

If multiple light sources are used with separate mounting, then the light distribution patterns can be controlled, but the number of components and manufacturing complexity increase

Engineering Contradiction:
Improvelight-distribution patternsVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent mounts multiple light sources (first and second light sources) on a common substrate. This consolidation reduces the number of separate mounting structures and components required. The substrate serves as a unified platform that holds both light sources in precise positions, simplifying assembly and manufacturing while still enabling independent control of each light source to create different light distribution patterns.

Inventive Principle:
Principle #5Merging (Combining)

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 allows for a compact optical unit design suitable for vehicle headlamps, reducing the front-back length and minimizing manufacturing complexity while preventing glare and forming multiple light-distribution patterns effectively.

Implementation Method 1

a rotary reflector that rotates about an axis of rotation while reflecting light emitted from the light source

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a projection lens that projects the light emitted from the light source and reflected by the rotary reflector

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3633264B1Optical unit
Publication Date: 2023.01.18 KOITO MFG CO LTD
  • EP3633264B1 patent drawingFigure 1
  • EP3633264B1 patent drawingFigure 2
  • EP3633264B1 patent drawingFigure 3~4

AI summary

An optical unit includes a light source 14 and a rotary reflector 16 that rotates about an axis of rotation R while reflecting light emitted from the light source 14. The rotary reflector 16 is disposed such that the axis of rotation R of the rotary reflector intersects a horizontal plane H.