UV Sterilization Odor Control via Irradiance-Dose Constraints

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Solution Overview

Problem

The use of ultraviolet light with wavelengths between 200 nm to 235 nm for inactivating bacteria or viruses on surfaces can lead to the generation of a strange odor due to the reaction of squalene and palmitoleic acid with ultraviolet light.

Innovation Solution

Irradiating ultraviolet light in a manner that satisfies specific formulas relating irradiance (X) and integrated irradiation dose (Y) within two hours, such as 0 < Y < 10.704X - 0.373, to inactivate bacteria or viruses while minimizing odor generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultraviolet light with wavelength 200 nm to 235 nm is irradiated to inactivate bacteria or viruses, then sterilization effect is improved, but strange odor is generated due to reaction with squalene and palmitoleic acid

Engineering Contradiction:
Improvesterilization effectVSAvoidstrange odor
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the irradiance (X) and integrated irradiation dose (Y) within specific mathematical relationships. By adjusting these parameters to satisfy Y < 10.704X - 0.373, the patent achieves effective sterilization while suppressing the chemical reactions that produce odorous substances from squalene and palmitoleic acid.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs dynamic control of the ultraviolet light irradiation process by establishing a dynamic relationship between irradiance and integrated irradiation dose. The control strategy adapts the irradiation parameters in real-time based on the mathematical inequality, allowing the system to optimize sterilization effectiveness while dynamically suppressing odor generation throughout the irradiation process.

Inventive Principle:
Principle #15Dynamics

2Productivity

If high irradiance ultraviolet light is used to reduce treatment time, then productivity is improved, but odor generation is accelerated due to intensified chemical reactions

Engineering Contradiction:
Improvetreatment speedVSAvoidodor generation rate
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent resolves this contradiction by changing the irradiation parameters according to a specific mathematical relationship. Instead of using high irradiance alone, the system adjusts both irradiance (X) and integrated irradiation dose (Y) to satisfy Y < 10.704X - 0.373, achieving efficient treatment while controlling the rate of odor-generating chemical reactions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements periodic or controlled action by regulating the ultraviolet light irradiation to follow a specific temporal pattern defined by the mathematical inequality. This controlled irradiation schedule allows sufficient treatment time for sterilization while preventing the accumulation of odorous substances through controlled exposure dosing.

Inventive Principle:
Principle #19Periodic action

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

This approach effectively inactivates bacteria or viruses on surfaces while significantly suppressing the generation of strange odors, ensuring a safer and more odor-free environment.

Implementation Method 1

DNA shows the highest absorption characteristics at wavelengths around 260 nm

Methodology Applied
Scientific EffectDNA absorption of ultraviolet light: Absorption (EM radiation)

Implementation Method 2

A technique for sterilization by irradiating ultraviolet light is known

Methodology Applied
Scientific EffectUltraviolet light inactivation: Photoionisation

Implementation Method 3

Squalene, a kind of sebum, produces squalene monohydroperoxide (SQHPO) when ultraviolet light is irradiated. Here, when SQHPO and palmitoleic acid coexist, strange odorous components (odor sources) such as nonenal, hexanal, octenal, and heptanal are produced

Methodology Applied
Scientific EffectPhoto-oxidation reaction: Photo-oxidation

Data Source

PatentEP3950012B1Method for inactivating bacteria or viruses and inactivating apparatus for bacteria or viruses
Publication Date: 2025.04.09 USHIO INC
  • EP3950012B1 patent drawingFigure 1~2
  • EP3950012B1 patent drawingFigure 3
  • EP3950012B1 patent drawingFigure 4

AI summary

Provided are a method and an apparatus for inactivating bacteria or viruses attached to an object while suppressing generation of a strange odor. The method for inactivating bacteria or viruses includes a step (a) of irradiating with ultraviolet light having an optical output at a specific wavelength in a range of 200 nm to 235 nm. The step (a) is a step of irradiating with the ultraviolet light is performed so that an illuminance (X) [mW/cm2] (X &gt; 0) and an integrated irradiation dose within two hours (Y) [mJ/cm2] satisfy the following formula (1): 0&lt;Y&lt;10.704X−0.373