Phosphor Substrate Layout for LED Color Tuning and Light Extraction

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Solution Overview

Problem

Existing light emitting substrates cannot adjust the emitted light color to be different from the light emitted by the light emitting elements, limiting color flexibility and efficiency.

Innovation Solution

A light emitting substrate with a phosphor substrate and multiple light emitting elements, where a phosphor layer is applied to cover the elements, allowing for wavelength conversion and adjusting the emitted light color by using a second phosphor with a different correlated color temperature, and strategically positioning the phosphor layer to cover at least 80% of the substrate's front face.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a reflective material is provided on the substrate surface, then light emitting efficiency is improved, but the emitted light color cannot be adjusted to be different from the light emitted by the light emitting element

Engineering Contradiction:
Improvelight emitting efficiencyVSAvoidlight color adjustability
Core Design Contradiction:
Loss of energyVSAdaptability or versatility

Solution Approach 1:

The patent applies wavelength converting materials (phosphors) with different emission characteristics to convert the light wavelength from the LED. By selecting phosphors with specific emission peaks and characteristics, the emitted light color can be adjusted independently from the LED's emission spectrum while maintaining high light extraction efficiency through the reflective substrate

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines reflective materials with wavelength converting materials (phosphors) to create a composite light emitting structure. The reflective substrate extracts light efficiently while the phosphor layer converts the wavelength, achieving both high efficiency and color adjustability simultaneously

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If wavelength converting materials are used to adjust light color, then light emission color can be changed, but light extraction efficiency may be reduced due to additional optical interfaces

Engineering Contradiction:
Improvelight color adjustabilityVSAvoidlight extraction efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent applies wavelength converting materials in specific patterns or regions on the substrate surface, allowing different areas to have different optical functions. This localized approach optimizes both light extraction and wavelength conversion efficiency by placing phosphors where they are most effective

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The reflective substrate acts as an intermediary that first extracts light from the LED with high efficiency, then the phosphor layer converts the wavelength of this extracted light. This two-stage process separates the light extraction function from the wavelength conversion function, optimizing both

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables adjustment of emitted light color, reduces glare, and alleviates chromaticity variations, while enhancing light emission efficiency by using a phosphor layer that covers a significant portion of the substrate.

Implementation Method 1

a phosphor layer which is disposed on the front face of the insulating substrate to form the front face of the phosphor substrate and includes a second phosphor in which a light emission peak wavelength, in a case where light emitted by the light emitting element is used as excitation light

Methodology Applied
Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentEP3905349B1Light-emitting substrate, and lighting device
Publication Date: 2024.02.07 DENKA CO LTD
  • EP3905349B1 patent drawingFigure 1A
  • EP3905349B1 patent drawingFigure 1B
  • EP3905349B1 patent drawingFigure 1C

AI summary

A phosphor substrate of the invention having at least one light emitting element mounted on one surface, includes an insulating substrate, at least one electrode pair disposed on one surface of the insulating substrate and bonded to the light emitting element, and a phosphor layer which is disposed on one surface of the insulating substrate and includes a phosphor in which a light emission peak wavelength, in a case where light emitted by the light emitting element is used as excitation light, is in a visible light region, in which a bonded surface of a surface of the at least one electrode pair facing an outer side in a thickness direction of the insulating substrate, the bonded surface being bonded to the light emitting element, is positioned further on the outer side in the thickness direction than a non-bonded surface which is a surface other than the bonded surface, and at least a part of the phosphor layer is disposed around the bonded surface of the one surface.