Single-sided Illuminated Luminescent Rod with Cerium Gradient

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Solution Overview

Problem

Existing lighting systems face challenges in achieving high brightness, efficiency, and reliable thermal management, particularly in high lumen density devices with limited cooling options and cerium concentration issues in luminescent rods, leading to thermal and optical problems.

Innovation Solution

A lighting system featuring a luminescent concentrator with a garnet type A3B5O12 material doped with trivalent cerium, utilizing single-sided illumination and three-sided cooling, along with a reflector to enhance light absorption and thermal management, allowing for improved efficiency and reduced cerium concentration to prevent detrimental effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If two-sided illumination is used in high lumen density devices, then light output is improved, but cooling options are limited and thermal management becomes difficult

Engineering Contradiction:
Improvelight outputVSAvoidthermal management
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The luminescent rod is segmented into regions with different cerium concentrations: a first region with higher cerium concentration for efficient light absorption and conversion, and a second region with lower cerium concentration for better thermal management and reduced thermal quenching. This segmentation allows the device to achieve high light output while managing thermal effects in different zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the luminescent rod are given different properties through varying cerium concentrations. The first region has high cerium concentration for optimal optical performance, while the second region has low cerium concentration for reduced thermal quenching and improved cooling efficiency. This local differentiation resolves the contradiction between light output and thermal management.

Inventive Principle:
Principle #3Local quality

2Use of energy by moving object

If high cerium concentration is used in luminescent rods, then light conversion efficiency is improved, but thermal quenching and detrimental effects increase

Engineering Contradiction:
Improvelight conversion efficiencyVSAvoidthermal quenching
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The luminescent rod is divided into two regions with different cerium concentrations. The first region uses high cerium concentration to maximize light conversion efficiency, while the second region uses low cerium concentration to minimize thermal quenching and maintain reliability. This segmentation allows both high efficiency and low thermal quenching to coexist.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cerium concentration is optimized locally in different regions of the luminescent rod. High concentration in the first region for optimal optical conversion, low concentration in the second region for reduced thermal quenching. This local optimization resolves the contradiction between conversion efficiency and thermal reliability.

Inventive Principle:
Principle #3Local quality

3Temperature

If single-sided illumination is used, then cooling is improved, but light absorption may be reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidlight absorption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The luminescent rod features a first region with high cerium concentration positioned to receive incident light for efficient absorption and conversion, and a second region with low cerium concentration positioned to benefit from improved cooling. This local differentiation allows single-sided illumination to provide both effective light absorption and enhanced cooling efficiency.

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 system achieves increased intensity and efficiency, better thermal management, and reliability by optimizing cerium concentration and cooling, enabling higher output flux while maintaining the luminescent rod below its critical quenching temperature.

Implementation Method 1

a garnet type A3B5O12 luminescent material configured to convert the light source light into converter light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

the converter light can be split into two parts. A first part consists of first types of light rays that will hit the side walls of the bar under angles larger than the critical angle of reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3775680B1Single-sided illumination of high lumen density lamps
Publication Date: 2021.12.01 SIGNIFY HOLDING BV
  • EP3775680B1 patent drawingFigure 1A~1B
  • EP3775680B1 patent drawingFigure 1C
  • EP3775680B1 patent drawingFigure 1D~1E

AI summary

The invention provides a lighting system (1) comprising: - a light source (10) configured to provide light source light (11); - an elongated luminescent body (100) having a length (L), the elongated luminescent body (100) comprising: - a plurality of side faces (140) over at least part of the length (L), wherein the side faces (140) comprise a first side face (143), comprising a radiation input face (111), and a second side face (144) configured parallel to the first side face (143), wherein the side faces (143, 144) define a height (H), wherein the elongated luminescent body (100) further comprises a radiation exit window (112) bridging at least part of the height (H) between the first side face (143) and the second side face (144); - a garnet type A3B5O12 luminescent material (120) comprising trivalent cerium, with a height dependent concentration selected from a concentration range defined by a minimum concentration ymin = 0.036*x-1 and a maximum concentration ymax = 0.17*x-1, wherein y is the trivalent cerium concentration in % relative to the A element, and wherein h is the height (H) in mm, wherein the garnet type A3B5O12 luminescent material (120) is configured to convert at least part of the light source light (11) into converter light (101); - one or more heat transfer elements (200) in thermal contact with one or more side faces (140); and - a reflector (2100) configured at the second side face (144) and configured to reflect light source light (11) escaping from the elongated luminescent body (100) via second face (144) back into the elongated luminescent body (100).