Phosphor-Converted White Light Source for Sunlight-Like Color Rendering

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Solution Overview

Problem

Conventional artificial light sources fail to accurately reproduce the subtle variations in sunlight, including color temperature, radiation rate, and turbidity, which are essential for authentic illumination of artworks and human environments, leading to inadequate color representation and potential damage to sensitive materials.

Innovation Solution

A white light source system that replicates sunlight by combining LED modules with phosphor layers, using a database to control light emission intensities based on measured sunlight spectra, and incorporating a phosphor layer to absorb UV light, reducing harmful emissions and achieving a correlated color temperature with minimal deviation from blackbody radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional LED illumination combines blue LED and yellow phosphor to achieve energy saving, then energy efficiency is improved, but color rendering accuracy deteriorates

Engineering Contradiction:

Improveenergy efficiencyVSAvoidcolor rendering accuracy

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent combines multiple LED types (violet, blue, cyan) with multiple phosphor materials (yellow, orange, red) to create a composite light source that reproduces the full sunlight spectrum while maintaining LED energy efficiency. This merging of multiple light sources and phosphors resolves the contradiction by achieving both energy savings and accurate color rendering.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention uses composite phosphor materials including yellow phosphor, orange phosphor, and red phosphor in specific combinations to achieve a spectral power distribution that closely matches sunlight. This composite approach enables accurate color rendering while maintaining the energy efficiency of LED technology.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If sunlight is used for illumination, then color rendering is improved, but harmful UV exposure increases

Engineering Contradiction:

Improvecolor reproduction accuracyVSAvoidultraviolet damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts only the beneficial visible spectrum components of sunlight (380-780nm) while deliberately excluding the harmful ultraviolet portion. The LED-based system reproduces sunlight's spectral characteristics in the visible range without generating UV radiation, thus achieving accurate color rendering without artwork damage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the limitation of LEDs (inability to naturally produce UV) into a benefit by designing a system that mimics sunlight's visible spectrum while inherently avoiding UV damage. This transforms what could be seen as a deficiency into a protective feature for illuminated objects.

Inventive Principle:

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

3Device complexity

If LED combinations are simplified to reduce complexity, then device complexity is reduced, but spectral accuracy deteriorates

Engineering Contradiction:

Improvestructure complexityVSAvoidspectral distribution accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by assigning specific functions to different LED-phosphor combinations: violet/blue LEDs with yellow phosphor for the blue-green region, cyan LEDs with orange phosphor for the yellow-orange region, and additional red phosphor for the red region. Each combination is optimized for its specific spectral region, achieving overall spectral accuracy without excessive complexity.

Inventive Principle:

Principle #3Local quality

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 system provides a natural and accurate reproduction of sunlight variations, enhancing color rendering indices and reducing UV and blue light intensity, thus preserving artworks and being gentle on human bodies while mimicking the dynamic changes of natural sunlight.

Implementation Method 1

incorporating a phosphor layer to absorb UV light, reducing harmful emissions

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

combining LED modules with phosphor layers

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS11978726B2White light source system

Publication Date: 2024.05.07 SEOUL SEMICONDUCTOR

AI summary

A light emitting device including a substrate, a first light emitter to emit light having a first color temperature, and a second light emitter to emit light having a second color temperature, in which the first light emitter has a first converter including first phosphors and a first resin, each first phosphor having different half-value widths, the second light emitter has a second converter including second phosphors and a second resin, each second phosphor having different peak wavelengths, at least one phosphor of the first converter has a half-value width of 33 nm to 110 nm, a distance between peak wavelengths of at least two phosphors of the second converter is 150 nm or less, and at least one phosphor of the first converter has a particle size of 5 um to 50 um.