Hybrid Reflector System for LED Lighting

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Solution Overview

Problem

Conventional reflector systems for solid state light sources, such as LEDs, face challenges in achieving uniform color mixing across various viewing angles and optical efficiency, often resulting in poor color uniformity and increased optical loss due to the need for multiple reflective bounces.

Innovation Solution

A hybrid reflector system comprising a bowl-shaped outer reflector and an intermediate reflector, which allows some light to pass uncontrolled while redirecting light at higher angles to achieve a tighter beam, minimizing optical loss and improving color uniformity by working in concert to shape the light into a desired beam with a combination of LEDs of different colors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple reflective bounces are used to improve color mixing, then color uniformity is improved, but optical loss increases

Engineering Contradiction:
Improvecolor uniformityVSAvoidoptical loss
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent applies partial action by allowing some light to pass through the device without undergoing multiple reflective bounces. The housing includes transparent or translucent portions that permit direct light transmission, while only a portion of the light interacts with the reflective surfaces. This selective application of reflection achieves adequate color mixing for the portion that does bounce while maintaining overall optical efficiency by not forcing all light through multiple lossy reflections.

Inventive Principle:
Principle #16Partial or excessive action

2Manufacturing precision

If intermediate diffusion mechanisms are used to mix colors, then color uniformity is improved, but optical efficiency decreases

Engineering Contradiction:
Improvecolor uniformityVSAvoidoptical efficiency
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent segments the light management functions by separating the housing into distinct functional portions: transparent/translucent portions for direct light transmission, reflective portions for color mixing, and openings for light emission. This segmentation allows different portions of light to take different paths - some light passes directly through with minimal loss while other light undergoes reflection for color mixing, thereby maintaining overall optical efficiency while achieving color uniformity.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If all emitted light is controlled through multiple reflections, then beam control is improved, but optical loss increases

Engineering Contradiction:
Improvebeam controlVSAvoidoptical loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies local quality by providing different optical characteristics in different portions of the housing. The housing includes transparent or translucent portions that allow uncontrolled direct light transmission, reflective portions that provide controlled light redirection, and openings that enable light emission. This local differentiation allows the system to maintain beam control in regions where it is needed while permitting uncontrolled light paths in regions where optical efficiency is prioritized.

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 hybrid reflector system enhances color uniformity and optical efficiency by allowing uncontrolled light to pass without additional bounces and redirecting light at higher angles, resulting in a tighter beam with improved color mixing and reduced optical loss.

Implementation Method 1

an intermediate reflector disposed inside the bowl and proximate to the light source. The reflectors are arranged to interact with the light emitted from the source

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a bowl-shaped outer reflector and an intermediate reflector disposed inside the bowl

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

blue emitting LEDs have been used to generate white light by surrounding the blue LED with a yellow phosphor... The surrounding phosphor material 'downconverts' some of the blue light, changing it to yellow light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP2494268B1Hybrid reflector system for lighting device
Publication Date: 2017.04.19 WOLFSPEED INC
  • EP2494268B1 patent drawingFigure 1
  • EP2494268B1 patent drawingFigure 2~3
  • EP2494268B1 patent drawingFigure 4~8

AI summary

A hybrid reflector system for use in lighting application. The system is particularly well-suited for use with solid state light sources, such as light emitting diodes (LEDs). Embodiments of the system include a bowl-shaped outer reflector and an intermediate reflector disposed inside the bowl and proximate to the light source. The reflectors are arranged to interact with the light emitted from the source to produce a beam having desired characteristics. Some of the light passes through the system without interacting with any of the reflector surfaces. This uncontrolled light, which is already emitting in a useful direction, does not experience optical loss normally associated with one or more reflective bounces. Some of the light emanating from the source at higher angles that would not be emitted within the desired beam angle is reflected by one or both of the reflectors, redirecting that light to achieve a tighter beam.