Broadband LED Fluorescent Emitter for Stable Visible-IR Output

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Solution Overview

Problem

Conventional light sources, such as halogen lamps, have short lifespans and require frequent maintenance, while existing LED light sources lack a wideband wavelength component from the visible region to the infrared region, leading to potential decreases in analysis precision over time in sorting machines.

Innovation Solution

A light emitting element is developed that uses a single LED element with a specific peak wavelength, combined with a fluorescent body that generates wideband light emission from the visible region to 1050 nm, minimizing changes in the light emission spectrum over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If halogen lamps are used as light sources, then wideband light emission is achieved, but the lifespan is short and maintenance is frequent

Engineering Contradiction:
ImprovelifespanVSAvoidmaintenance frequency
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent changes the fundamental parameters of the light source by transitioning from thermal radiation (halogen lamp) to electroluminescence (LED). This parameter change enables the use of LED elements with inherently longer lifespans while achieving wideband emission through fluorescent conversion, thereby resolving the contradiction between lifespan and maintenance frequency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical/thermal system of halogen lamps with an optical/electrical system using LED elements combined with fluorescent bodies. This substitution eliminates the short lifespan issue of halogen lamps while maintaining wideband light emission capability, thus improving reliability and reducing maintenance frequency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Duration of action of stationary object

If conventional LED elements are used, then long lifespan is achieved, but wideband wavelength coverage from visible to infrared is insufficient

Engineering Contradiction:
ImprovelifespanVSAvoidwavelength coverage
Core Design Contradiction:
Duration of action of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent merges LED elements with fluorescent bodies to create a composite light source. The LED provides efficient, long-lived excitation light, while the fluorescent body converts this to wideband emission covering visible and infrared regions. This merging resolves the contradiction by combining the lifespan advantage of LEDs with the wavelength coverage capability of fluorescent materials.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite material systems combining LED semiconductors with fluorescent phosphors. This composite approach enables the light source to exhibit both the durability of LED technology and the broad spectral emission characteristics of fluorescent materials, thereby achieving both long lifespan and wideband wavelength coverage.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If multiple LED elements with different peak wavelengths are combined, then wideband emission is achieved, but spectral changes occur over time

Engineering Contradiction:
Improvewavelength coverageVSAvoidspectral stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent extracts the wavelength diversity function from multiple LED elements and concentrates it into a single LED element combined with a multi-wavelength fluorescent body. This extraction simplifies the system to a single LED source while maintaining wideband emission, thereby eliminating the spectral instability caused by combining multiple LED elements with different characteristics.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces the fluorescent body as an intermediary between the single LED element and the final wideband emission. The fluorescent body acts as a mediator that converts the narrowband LED emission into wideband output, achieving wavelength diversity without the spectral instability associated with directly combining multiple LED elements.

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

The solution provides a stable wideband light emission with minimal spectral changes over time, ensuring high analysis precision in sorting machines by maintaining consistent wavelength distribution.

Implementation Method 1

an LED element (3) that emits light (L0) having a peak wavelength (λ1) in the range of greater than or equal to 380 nm and less than or equal to 500 nm

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

a fluorescent body (5) that generates, when the light (L0) emitted by the LED element (3) enters, fluorescence (L1) having a wavelength longer than that of the light (L0)

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3799138B1Light emitting element
Publication Date: 2025.04.16 USHIO INC
  • EP3799138B1 patent drawingFigure 1~2A
  • EP3799138B1 patent drawingFigure 2B~2C
  • EP3799138B1 patent drawingFigure 3A~3B

AI summary

Provided is a light emitting element which emits broadband light, and in which there is little tendency for a light emission intensity spectrum to change over time. This light emitting element is provided with: an LED element which emits excitation light having a single peak wavelength in a range of 380-500 nm; a fluorescent body to which at least a portion of the excitation light is incident, and which emits fluorescent light having a wavelength greater than the excitation light; and a light extraction surface, from which the output light, in which the excitation light and the fluorescent light are superimposed on each other, is output. The output light shows emission of light in a range from at least the peak wavelength of the excitation light to 1050 nm, and shows light emission intensities, all of which are not less than the light emission intensity at 1050 nm, in a range from at least the peak wavelength of the excitation light to 1050 nm.