Light-Emitting Device With Multi-Wavelength Fluorescent Member

Solution Overview

Problem

Conventional light-emitting devices, particularly those using blue light-emitting LEDs, pose risks to human health due to retinal damage and melatonin secretion suppression, and existing solutions fail to adequately balance luminosity and these health effects.

Innovation Solution

A light-emitting device incorporating a light-emitting element with a peak wavelength of 440-470 nm and a fluorescent member comprising multiple materials with specific peak emission wavelengths (480-520 nm, 520-600 nm, and 600-670 nm) to achieve a controlled effective radiant intensity ratio for reduced blue-light retinal damage and melatonin secretion suppression, while maintaining luminosity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If blue light-emitting LED is used to achieve high luminosity, then illumination intensity is improved, but retinal damage risk increases

Engineering Contradiction:

ImproveluminosityVSAvoidretinal damage risk

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the blue light spectrum by introducing multiple fluorescent materials with different peak emission wavelengths (480-520nm, 520-600nm, 600-670nm) that convert portions of the blue LED light into different color ranges. This segmentation reduces the concentration of harmful blue light while maintaining overall luminosity through distributed spectral emission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses composite fluorescent materials including at least one of the following: (a) a first fluorescent material having a peak light-emitting wavelength in the range of 480 nm to less than 520 nm, (b) a second fluorescent material having a peak light-emitting wavelength in the range of 520 nm to less than 600 nm, and (c) a third fluorescent material having a peak light-emitting wavelength in the range of 600 nm to 670 nm. This composite approach creates a balanced emission spectrum that reduces blue light harm while preserving luminosity.

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If blue light-emitting LED is used to achieve high luminosity, then illumination intensity is improved, but melatonin secretion suppression increases

Engineering Contradiction:

ImproveluminosityVSAvoidmelatonin secretion suppression

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the blue light spectrum by introducing multiple fluorescent materials with different peak emission wavelengths (480-520nm, 520-600nm, 600-670nm) that convert portions of the blue LED light into different color ranges. This segmentation reduces the concentration of harmful blue light while maintaining overall luminosity through distributed spectral emission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses composite fluorescent materials including at least one of the following: (a) a first fluorescent material having a peak light-emitting wavelength in the range of 480 nm to less than 520 nm, (b) a second fluorescent material having a peak light-emitting wavelength in the range of 520 nm to less than 600 nm, and (c) a third fluorescent material having a peak light-emitting wavelength in the range of 600 nm to 670 nm. This composite approach creates a balanced emission spectrum that reduces blue light harm while preserving luminosity.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If conventional fluorescent materials are used to convert blue light, then luminosity is maintained, but the ratio of effective radiant intensity for melatonin secretion suppression to blue-light retinal damage is unoptimized

Engineering Contradiction:

ImproveluminosityVSAvoideffective radiant intensity ratio control

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent precisely controls the peak emission wavelengths of fluorescent materials within specific ranges: 480-520nm for first material, 520-600nm for second material, and 600-670nm for third material. It also controls the half bandwidths and relative luminous flux ratios to achieve the target effective radiant intensity ratio range of 1.15-1.85, optimizing both luminosity and health safety.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite fluorescent materials including at least one of the following: (a) a first fluorescent material having a peak light-emitting wavelength in the range of 480 nm to less than 520 nm, (b) a second fluorescent material having a peak light-emitting wavelength in the range of 520 nm to less than 600 nm, and (c) a third fluorescent material having a peak light-emitting wavelength in the range of 600 nm to 670 nm. This composite approach creates a balanced emission spectrum that reduces blue light harm while preserving luminosity.

Inventive Principle:

Principle #40Composite materials

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

The device effectively reduces the risk of blue-light retinal damage and melatonin suppression while preserving luminosity, achieving a balanced emission spectrum that minimizes adverse health effects and enhances work efficiency.

Implementation Method 1

a fluorescent member, the fluorescent member including a first fluorescent material having a peak light-emitting wavelength in the range of 480 nm to less than 520 nm, a second fluorescent material having a peak light-emitting wavelength in the range of 520 nm to less than 600 nm, and a third fluorescent material having a peak light-emitting wavelength in the range of 600 nm to 670 nm

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS11605761B2Light-emitting device

Publication Date: 2023.03.14 NICHIA CORP

AI summary

A light-emitting device is provided. The light-emitting device includes a light-emitting element having a peak light-emitting wavelength in the range of 440 nm to 470 nm, and a fluorescent member. The fluorescent member includes a first fluorescent material having a peak light-emitting wavelength in the range of 480 nm to less than 520 nm, a second fluorescent material having a peak light-emitting wavelength in the range of 520 nm to less than 600 nm, and a third fluorescent material having a peak light-emitting wavelength in the range of 600 nm to 670 nm. The light-emitting device has a ratio of an effective radiant intensity for melatonin secretion suppression to an effective radiant intensity for blue-light retinal damage of 1.53 to 1.70 when the light-emitting device emits light with a correlated color temperature of 2700 K to less than 3500 K; 1.40 to 1.70 when the light-emitting device emits light with a correlated color temperature of 3500 K to less than 4500 K; 1.40 to 1.70 when the light-emitting device emits light with a correlated color temperature of 4500 K to less than 5700 K; and 1.35 to 1.65 when the light-emitting device emits light with a correlated color temperature of 5700 K to 7200 K.