Lighting Apparatus Light Extraction via Segmented Reflector

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Solution Overview

Problem

The existing fiber light source apparatus has a low light extraction efficiency due to self-absorption by the wavelength converting member, which reduces the amount of wavelength-converted light that can be effectively outputted.

Innovation Solution

A lighting apparatus design that includes a light guiding member, a wavelength converting unit with a holder and a wavelength converting member, where the holder has a through hole with a reflecting portion and a wavelength-converted light propagating area, allowing for improved light extraction by isolating the wavelength converting member from the inner surface of the holder and using a light transmitting member to transmit both excitation and wavelength-converted light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the wavelength converting member is placed to cover the entire opening of the spacer, then the light path is extended through the converting member, but the self-absorption increases and reduces the extraction efficiency of wavelength-converted light

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidself-absorption loss

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The opening of the spacer is divided into two distinct regions: a first opening that allows transmitted light to pass through, and a second opening that receives reflected light. This segmentation enables different light paths to be optimized independently, reducing self-absorption while maintaining effective light utilization

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A reflecting member is introduced as an intermediary element to redirect light that has transmitted through the wavelength converting member back toward the conversion region. This mediator extends the effective light path without requiring the converting member to cover the entire opening, thereby reducing self-absorption losses

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the wavelength converting member covers the entire opening, then more light is subjected to wavelength conversion, but the amount of wavelength-converted light output is reduced due to self-absorption

Engineering Contradiction:

Improvewavelength conversion amountVSAvoidwavelength-converted light output

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The reflecting member creates a continuous light circulation path where unconverted light is repeatedly directed back through the wavelength converting member. This continuous action increases the probability of wavelength conversion without requiring a larger converting member area, thus maintaining high conversion productivity while reducing self-absorption

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The spacer opening is differentiated into regions with different functions: the first opening optimized for transmitted light passage and the second opening optimized for reflected light reception. This local quality differentiation allows each region to contribute optimally to either conversion quantity or light output

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

This design enhances the light extraction efficiency of wavelength-converted light by reducing self-absorption and redirecting light through a reflecting portion, resulting in a higher proportion of wavelength-converted light being outputted effectively.

Implementation Method 1

reflect by a reflecting portion made of the metallic thin film 950a provided on the surface of the spacer 950 the light launched toward the light guiding member 920 is returned to the wavelength converting member 940

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a wavelength converting member (a fluorescent substance) 940 is installed at a front end of the light guiding member 920... converts to a light of different wavelength

Methodology Applied

Scientific EffectWavelength conversion: Fluorescence

Implementation Method 3

since the wavelength converting member 940 has a self-absorbing property, the wavelength converting member 940 absorbs a part of the light subjected to wavelength conversion by the wavelength converting member 940

Methodology Applied

Scientific EffectSelf-absorption: Absorption (EM radiation)

Data Source

PatentUS8358067B2Lighting apparatus having an improved light extraction efficiency

Publication Date: 2013.01.22 OLYMPUS CORPORATION(JP)

AI summary

In a lighting apparatus which emits light of a desired wavelength by irradiating excitation light from a light source to a wavelength converting member, a structure is such that a part of wavelength-converted light which is launched from the wavelength converting member is made to launch from an irradiated-light emerging area without making the light incidence again to the wavelength converting member.