Rotating Reflector Optical Unit for LED Color Mixing

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Solution Overview

Problem

Existing automotive lamps using LEDs and phosphors suffer from reduced light efficiency and uneven color or brightness due to light absorption by phosphors, and combining multiple LEDs with different colors can result in inconsistent light distribution.

Innovation Solution

An optical unit featuring a rotating reflector with fan-shaped blades that superimpose light from multiple LEDs of different colors to create a desired light distribution pattern, allowing for efficient light use and adjustable color through current adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If white light is achieved by combining an LED and a phosphor, then white light can be produced, but the efficiency in using the light emitted by the LED is decreased due to light absorption by the phosphor

Engineering Contradiction:
Improvelight efficiencyVSAvoidlight absorption loss
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention extracts and removes the phosphor component from the light generation system. Instead of using phosphor to convert LED light to white light, the patent uses multiple LEDs of different colors (blue, green, red) to directly generate white light, thereby eliminating the light absorption loss caused by phosphor and improving overall light efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a composite approach by combining multiple LED types with different emission colors (blue LED, green LED, red LED) to create white light. This composite light source approach replaces the single LED plus phosphor system, achieving white light with higher efficiency by avoiding phosphor absorption losses

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If white light is achieved with a lot of LEDs having different light colors, then white light can be produced, but the color or brightness is likely to be uneven within an irradiation range

Engineering Contradiction:
Improvewhite light outputVSAvoidcolor uniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The invention segments the white light generation into three distinct color components (blue, green, red) from separate LED sources. By controlling each color component independently and combining them through optical elements, the system achieves uniform white light distribution across the irradiation range, avoiding the color unevenness that would result from using many different colored LEDs

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple LEDs with different colors are combined, then white light can be achieved, but the color or brightness is likely to be uneven within an irradiation range

Engineering Contradiction:
Improvecolor adjustment capabilityVSAvoidlight distribution uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention introduces dynamic control of the multiple LED sources, allowing independent adjustment of each LED's emission intensity. This dynamic control capability enables the system to adaptively balance the color and brightness output, achieving uniform white light while maintaining the versatility to adjust color temperature and brightness levels as needed

Inventive Principle:
Principle #15Dynamics

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 optical unit achieves a desired light distribution pattern with improved efficiency and uniformity, enhancing luminance and color consistency across the irradiation range.

Implementation Method 1

a rotating reflector configured to be rotated in one direction around a rotational shaft, while reflecting the light having a first color and the light having a second color, which have been emitted from the light source

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2700869B1Optical unit
Publication Date: 2020.02.12 KOITO MFG CO LTD
  • EP2700869B1 patent drawingFigure 1
  • EP2700869B1 patent drawingFigure 2~3
  • EP2700869B1 patent drawingFigure 4(a)~4(j)

AI summary

An optical unit 180 includes: a light source 172 having both a first light emitting element for emitting light having a first color and a second light emitting element for emitting light having a second color that is different from the first color; and a rotating reflector 26 configured to be rotated in one direction around a rotational shaft, while reflecting the light having the first color and the light having the second color, which have been emitted from the light source. In the rotating reflector 26, a reflecting surface is provided such that a predetermined light distribution pattern is formed with the light having the first color and the light having the second color, which have been reflected by the rotation of the rotating reflector, being superimposed one on another.