Embedded Phosphor Reflector Structure for Low-Loss Lighting

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Solution Overview

Problem

Remote phosphor devices in lighting apparatuses suffer from optical losses due to reflection and acceptance losses caused by the gap between the phosphor wheel and the transmitting member, leading to inefficient wavelength conversion and heat management.

Innovation Solution

Embedding the phosphor layer in a reflecting member with a transmitting member in direct contact, utilizing an immersion layer, and incorporating reflective surfaces on the reflecting member to minimize optical losses and enhance heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a gap is kept between the phosphor wheel and the transmitting member to facilitate heat removal, then heat dissipation is improved, but optical losses increase due to reflection and acceptance losses

Engineering Contradiction:
Improveheat dissipationVSAvoidoptical losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

A cooling plate is introduced as an intermediary component between the phosphor layer and the transmitting member. The cooling plate serves dual functions: it provides efficient heat removal from the phosphor layer through thermal contact, and simultaneously maintains optical coupling by being in direct contact with the transmitting member, thereby eliminating air gaps and reducing reflection and acceptance losses.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooling plate performs multiple functions simultaneously: it acts as a heat sink for thermal management, provides structural support for the phosphor layer, and serves as an optical interface element that maintains contact with the transmitting member to minimize optical losses. This multi-functional design resolves the contradiction between heat dissipation and optical efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Temperature

If the phosphor layer is made thinner to reduce heat generation, then heat impact is reduced, but wavelength conversion efficiency decreases

Engineering Contradiction:
Improveheat impactVSAvoidwavelength conversion efficiency
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The cooling plate acts as a thermal intermediary that actively removes heat from the phosphor layer during operation. This allows the phosphor layer to be kept thin for efficient heat removal while maintaining optimal thickness for wavelength conversion, as the cooling plate prevents heat accumulation that would otherwise limit phosphor layer thickness.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the thermal parameter of the system by introducing active cooling through the cooling plate. This enables the phosphor layer thickness to be optimized for wavelength conversion efficiency without being constrained by heat buildup, as the cooling plate dynamically manages the thermal parameter during operation.

Inventive Principle:
Principle #35Parameter changes

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

Significantly improves optical efficiency by reducing reflection and acceptance losses, allowing for thinner phosphor layers and more effective heat removal, thereby enhancing the overall performance of the lighting apparatus.

Implementation Method 1

The phosphor is designed to convert blue or UV light (e.g. 450 nm, 405 nm or shorter wavelengths) into visible light or near infra-red light with longer wavelengths than the exciting light

Methodology Applied
Scientific EffectWavelength conversion: Photoluminescence

Implementation Method 2

The bottom portion as well as the side surface portion of the reflecting member reflect wavelength-converted light rays back thereby increasing the optical efficiency of the phosphor device

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

The index of refraction of the immersion material is preferably less than the index of refraction of the transmitting member

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 4

the carrier member is made from a material with suitable cooling properties, e.g. a metal such as copper, aluminum or the like, facilitating dissipation of the heat generated by the exciting light when impinging on the phosphor layer

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2525703B1Phosphor device and lighting apparatus comprising the same
Publication Date: 2016.06.22 OSRAM GMBH
  • EP2525703B1 patent drawingFigure 1a~2
  • EP2525703B1 patent drawingFigure 3~5

AI summary

A phosphor device (21) comprises a carrier member (1), a reflecting member (2) being arranged at the upper face of the carrier member (1), a phosphor layer (3) being embedded in the reflecting member (2) and a transmitting member (4) being arranged on the phosphor layer (3). Exciting light entering the transmitting member (4) and impinging on the phosphor layer (3) is effectively wavelength-converted, reflected by the reflecting member (2) and extracted through the transmitting member (4).