TIR Extractor Light-Emitting Device for White LED Efficiency

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Solution Overview

Problem

Conventional white LEDs with phosphor-based light-emitting devices face challenges such as light-energy losses, phosphor self-heating, and degradation due to overheating, humidity, and chemical changes, which affect the efficiency and longevity of the lighting devices.

Innovation Solution

The implementation of a light-emitting device with a total internal reflection (TIR) extractor element, which includes a scattering element and an extractor element configured to provide total internal reflection, optimizing light propagation and reducing losses by redirecting scattered light back into the scattering element for recycling and enhancing chromaticity and luminance isotropy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphor-based light-emitting devices are used to generate white light, then light conversion efficiency is improved, but light-energy losses and phosphor self-heating occur

Engineering Contradiction:

Improvelight conversion efficiencyVSAvoidlight-energy losses

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent extracts the phosphor material from direct contact with the LED chip by introducing a reflective layer between them. This separation allows the phosphor to be positioned optimally for light conversion while preventing energy loss through direct thermal coupling, thus maintaining high conversion efficiency while reducing energy losses.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

A reflective layer is introduced as an intermediary between the LED chip and phosphor material. This intermediary layer redirects light that would otherwise be absorbed or scattered, improving light extraction efficiency and reducing energy losses while maintaining effective phosphor excitation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If phosphor-based light-emitting devices are used, then white light generation is achieved, but phosphor degradation from overheating and chemical changes occurs

Engineering Contradiction:

Improvewhite light generationVSAvoidphosphor degradation

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The phosphor is extracted from direct thermal contact with the heat-generating LED chip by positioning it on a reflective layer. This spatial separation maintains the phosphor's functional proximity to the light source for effective white light generation while thermally isolating it to prevent degradation from overheating and chemical changes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates a protective environment for the phosphor by using a reflective layer that prevents direct exposure to harmful factors such as moisture and oxygen, while maintaining optimal conditions for photoluminescence. This protective configuration reduces degradation from chemical changes while preserving white light generation capabilities.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Illumination intensity

If conventional light-emitting structures are used, then light emission is achieved, but optical reflection losses occur

Engineering Contradiction:

Improvelight emissionVSAvoidoptical reflection losses

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The patent converts harmful reflected light that would normally be lost into beneficial illumination by implementing a reflective layer. This layer captures light that would otherwise be reflected away or absorbed, redirecting it back through the phosphor layer to generate additional white light, thus converting energy loss into useful output.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The reflective layer recovers light energy that would otherwise be discarded through reflection or absorption. By redirecting this light back through the optical system, the patent recovers energy that would be lost, improving overall system efficiency while maintaining light emission performance.

Inventive Principle:

Principle #34Discarding and recovering

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 improves the efficiency of light emission by minimizing optical reflection losses and ensuring directional control of light, leading to enhanced luminance and chromaticity uniformity within specific solid angle ranges.

Implementation Method 1

an extractor element (130) having side surfaces (138) shaped to provide total internal reflection (TIR) of light from the scattering element (120)

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a scattering element (120) having an input surface (115) spaced apart from the light-emitting element (110) and positioned to receive light emitted from the light-emitting element (110)

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentEP3044626B1Light-emitting device with total internal reflection (TIR) extractor

Publication Date: 2023.07.26 QUARKSTAR LLC

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AI summary

A variety of light-emitting devices are disclosed that are configured to output light provided by a light source. In general, embodiments of the light-emitting devices feature a light source and an extractor element coupled to the light source, where the extractor element includes, at least in part, a total internal reflection (TIR) surface. Luminaires incorporating light-emitting devices of this type are also disclosed.