Multi-Directional LED Illumination for Museum Exhibit Preservation

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Solution Overview

Problem

Current illumination systems for art galleries and museums struggle to faithfully reproduce original colors and enhance three-dimensional effects while avoiding damage to exhibits, as conventional light sources often include harmful ultraviolet light and lack the nuanced color rendering of natural light.

Innovation Solution

An illumination system comprising multiple white light sources with different color temperatures, arranged to irradiate light from various directions, which approximates the spectral distribution of natural light by satisfying specific relationships between their emission spectra and spectral luminous efficiency, thereby improving color and boundary discriminability and maintaining a natural texture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If solar light is used for illumination, then all colors existing in the natural world can be reproduced as original colors, but the light emission characteristics change from moment to moment and cannot be artificially managed

Engineering Contradiction:
Improvecolor rendering qualityVSAvoidlight emission stability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent copies the spectral characteristics of solar light by using multiple LEDs with different peak wavelengths (violet, blue, blue-green, green, yellow-green, yellow, orange, red) combined with phosphors to reproduce the continuous spectrum of solar light, while maintaining stable and controllable light emission characteristics through artificial light sources

Inventive Principle:
Principle #26Copying

2Illumination intensity

If solar light is used for illumination, then all wavelength components of visible light are included, but harmful ultraviolet light and infrared light are also included which can damage exhibits

Engineering Contradiction:
Improvespectral completenessVSAvoidultraviolet and infrared damage
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts only the beneficial visible light wavelength components (400-780nm) needed for color rendering while deliberately excluding the harmful ultraviolet and infrared components by using LEDs that emit only in the visible range, thus protecting exhibits from light-induced damage

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the limitation of LED technology (inability to produce continuous spectrum like solar light) into an advantage by selectively emitting only beneficial visible wavelengths without harmful UV and IR components, turning a technical constraint into a protective feature for exhibit preservation

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

3Loss of energy

If conventional LED illumination combining blue LED and yellow phosphor is used, then energy saving and long lifespan are achieved, but only unnatural white color lacking warmth can be reproduced

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcolor rendering quality
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent uses a composite approach by combining 8 different types of LEDs (violet LED + blue phosphor, blue LED + yellow phosphor, blue-green LED + green phosphor, green LED + yellow-green phosphor, yellow-green LED + yellow phosphor, yellow LED + orange phosphor, orange LED + red phosphor, red LED) to create a composite light source that maintains LED energy efficiency while achieving solar light-like color rendering

Inventive Principle:
Principle #40Composite materials

4Illumination intensity

If illumination intensity is increased to highlight exhibits, then color rendering and three-dimensional effect are improved, but damage to exhibits from light irradiation is accelerated

Engineering Contradiction:
Improvebrightness and color vividnessVSAvoidlight-induced deterioration
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the spectral parameters of the illumination light by using a multi-LED system with specific peak wavelengths and phosphor combinations to achieve high color rendering quality, allowing for lower overall illumination intensity while maintaining visual effectiveness, thus reducing cumulative light damage to exhibits

Inventive Principle:
Principle #35Parameter changes

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 enhances the vividness and three-dimensional appearance of exhibits by improving color rendering and reducing the risk of damage from ultraviolet light, achieving a more natural and effective illumination that highlights the original texture and intent of the artwork.

Implementation Method 1

a first white light source 51 and a second white light source 52, and in which emission spectra P1(λ) and P2(λ) of the white light sources satisfy a relationship of

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

B(λ) is an emission spectrum of black body radiation having a corresponding color temperature

Methodology Applied
Scientific EffectBlack body radiation: Thermal Radiation

Data Source

PatentEP3276679B1Illumination system and illumination method
Publication Date: 2021.03.03 TOSHIBA MATERIALS CO LTD
  • EP3276679B1 patent drawingFigure 1~2
  • EP3276679B1 patent drawingFigure 3~4
  • EP3276679B1 patent drawingFigure 5~6

AI summary

The illumination system according to an embodiment of the invention has a plurality of white light sources satisfying the relationship -0.2 ≤ [(P(λ) × V(λ))/(P(λmax1) × V(λmax1)) - (B(λ) × V(λ))/(B(λmax2) × V(λmax2))] ≤ +0.2. where P(λ) is the emission spectrum of a white light source having a specific correlated color temperature on a black body radiation trajectory, B(λ) is the emission spectrum of a black body radiation of the corresponding color temperature, V(λ) is the spectrum of the spectral lumin-ous efficiency, λmax1 is the wavelength at which P(λ) × V(λ) is maximum, and λmax2 is the wavelength at which B(λ) × V(λ) is maximum. Each of the white light sources is a while light source of different color temperature, and constituted in such a manner that the light from each of the white light sources is irradiated from a different direction onto an object to be illuminated.