Light-emitting device with segmented reflective members and air layer

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Solution Overview

Problem

Existing light-emitting devices have limitations in light extraction efficiency, particularly when a light-transmissive member is disposed over a wavelength conversion member via an air layer.

Innovation Solution

A light-emitting device configuration with a first portion including a light-emitting element and a wavelength conversion member covered by a reflective member, and a second portion with a light-transmissive member above the wavelength conversion member via an air layer, where the air layer extends between reflective surfaces, allowing repeated reflections and wavelength conversions for enhanced light extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a light-transmissive member is disposed over a wavelength conversion member via an air layer, then light extraction is enabled, but light extraction efficiency is insufficient

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidlight energy loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The reflective member is divided into a first reflective member covering the light-emitting element and wavelength conversion member, and a second reflective member disposed around the light-transmissive member. This segmentation creates multiple reflection paths and surfaces that work together to extract light more efficiently from the wavelength conversion member.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The air layer is extended to fill the space between the first reflective member and the second reflective member, creating a three-dimensional light extraction pathway. This dimensional extension allows light to undergo multiple reflections and wavelength conversions before extraction, significantly improving light extraction efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Productivity

If excessive wavelength conversion substances are used, then wavelength conversion is enhanced, but device complexity and material usage increase

Engineering Contradiction:

Improvewavelength conversion efficiencyVSAvoidwavelength conversion substance quantity

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

Light undergoes continuous wavelength conversion through multiple passes between the first and second reflective members. The air layer enables repeated reflections that allow the wavelength conversion substance to be illuminated multiple times, maintaining continuous useful action and improving conversion efficiency without requiring excessive amounts of material.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent changes the optical path length and reflection parameters by introducing the air layer between reflective members. This parameter change allows light to traverse the wavelength conversion member multiple times, enhancing conversion efficiency while using reduced quantities of wavelength conversion substance.

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

This configuration significantly improves light extraction efficiency by facilitating repeated reflections and wavelength conversions, reducing the need for excessive wavelength conversion substances while enhancing overall light output.

Implementation Method 1

a first reflective member covering a lateral surface of the light-emitting element and a lateral surface of the wavelength conversion member... a second reflective member disposed around the light-transmissive member... The air layer extends in a region between the first upper surface of the first reflective member and the first lower surface of the second reflective member

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a wavelength conversion member disposed on an upper surface of the light-emitting element... facilitating repeated reflections and wavelength conversions for enhanced light extraction

Methodology Applied

Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentUS20250207757A1Light-emitting device

Publication Date: 2025.06.26 NICHIA CORP

AI summary

A light-emitting device includes first and second portions. The first portion includes a light-emitting element, a wavelength conversion member, and a first reflective member covering lateral surfaces of the light-emitting element and the wavelength conversion member. The second portion includes a light-transmissive member disposed above the wavelength conversion member via an air layer, and a second reflective member disposed around the light-transmissive member. An upper surface of the first reflective member has a first upper surface disposed around the wavelength conversion member and a second upper surface disposed outwardly of the first upper surface. A lower surface of the second reflective member has a first lower surface disposed around the light-transmissive member and a second lower surface disposed outwardly of the first lower surface. The air layer extends between the first upper surface of the first reflective member and the first lower surface of the second reflective member.