Dielectric Multilayer Optical Filter for Angle-Tolerant UV Inactivation
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Solution Overview
Problem
Existing ultraviolet sterilization devices using interference filters with dielectric multilayer films face issues with incident angle dependence, leading to inefficient light usage and limited effective irradiation area due to blocking or attenuating light at large angles, which complicates the use of ultraviolet light for microbe inactivation on or in the human body without damaging human cells.
Innovation Solution
An optical filter using a dielectric multilayer film with SiO2 and Al2O3 layers or HfO2 and SiO2 layers is designed to transmit ultraviolet light within the range of 190 to 237 nm, allowing efficient use of light at various incident angles and preventing damage to human cells, while blocking light outside this range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an interference filter with dielectric multilayer film is used to block ultraviolet light outside the 190-230 nm range, then human cell damage is prevented, but light at large incident angles is blocked or attenuated, reducing effective irradiation area
Solution Approach 1:
The patent extends the transmission wavelength range from the conventional 190-230 nm to 190-237 nm by adjusting the optical filter characteristics. This parameter change allows light at large incident angles to pass through while maintaining the blocking of harmful UV wavelengths, thereby increasing the effective irradiation area without compromising human cell safety.
2Reliability
If an interference filter with dielectric multilayer film is used to transmit light within 190-230 nm, then microbe inactivation is achieved, but light usage efficiency is reduced due to blocking at large incident angles
Solution Approach 1:
By extending the transmission wavelength range to 190-237 nm, the optical filter allows more light from the source to pass through, including light at large incident angles. This reduces energy loss while maintaining effective microbe inactivation, as the extended range still falls within the germicidal spectrum.
3Reliability
If ultraviolet light is applied for sterilization, then microbe inactivation is achieved, but human cells are damaged due to DNA destruction
Solution Approach 1:
The patent applies selective wavelength transmission by designing the optical filter to transmit only specific ultraviolet wavelengths (190-237 nm) that are effective for microbe inactivation. This local quality approach ensures that harmful wavelengths outside this range are blocked, protecting human cells while maintaining sterilization effectiveness.
Solution Approach 2:
The patent converts the potential harm of broad-spectrum ultraviolet radiation into a benefit by using an optical filter to selectively transmit only the germicidal wavelengths (190-237 nm). This transforms the harmful full UV spectrum into a beneficial narrow band that inactivates microbes while sparing human cells.
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 optical filter enables effective microbe inactivation with a large irradiation area by transmitting light at large angles, reducing power requirements and preventing human cell damage, and allows for efficient cell activation processing.
Implementation Method 1
an interference filter having a dielectric multilayer film made of SiO2/Al2O3 or SiO2/MgF2 is used as an optical filter in order to transmit light having a wavelength within a wavelength range of 190 to 230 nm
Implementation Method 2
the interference filter blocks or significantly attenuates light that is incident on the interference filter at a large incident angle
Implementation Method 3
the ultraviolet light absorbed by the DNA inside the cells destroys a genetic code of the DNA, and so the target organisms are inactivated
Data Source
AI summary
An optical filter which is used in an inactivation processing device that performs inactivation processing on a processing target microorganism. The optical filter, when discharge light from a light source in which the center wavelength of the discharge light is between 190 nm and 237 nm is incident at an incident angle 0°, transmits at least a portion of the ultraviolet ray equal to or greater than 190 nm and equal to or less than 230 nm and at least a portion of the ultraviolet ray greater than 230 nm and equal to or less than 237 nm, and attenuates the light intensity between 200 and 280 nm not including a wavelength region equal to or greater than 190 nm and equal to or less than 237 nm.