Spherical Integrating Cavity for Angle-Independent Photon Density Measurement
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Solution Overview
Problem
Current methods for evaluating aerosol viral inactivation using UV-C light are inadequate as they focus on surface-based experiments, which do not accurately represent aerosolized situations, and traditional UV systems attack pathogens from limited angles, making it difficult to determine the corresponding optical power density effectively.
Innovation Solution
A photon density measuring apparatus and method that includes a substrate with a reflective layer and entrance openings to integrate and detect photons within a medium, using a photomultiplier tube to measure photon density independently of angle, allowing for effective pathogen reduction device optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional flat detector is used to measure photon density, then the detector structure is simple, but the measurement precision is poor because the detector response is a function of the angle between the detector normal and the Poynting vectors of photons
Solution Approach 1:
The patent employs a spherical integrating cavity instead of a traditional flat detector. The spherical geometry with highly reflective inner surface ensures that photons from all incident angles are uniformly distributed and integrated before reaching the detector, eliminating the angular response dependency while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent combines multiple functions into the spherical integrating cavity: it serves as both the measurement volume for photon integration and the structural housing for the detector. This merging of the integration space and detector housing reduces overall device complexity while achieving angle-independent measurement.
2Reliability
If UV-C inactivation systems attack from a singular or low number of angles, then the device structure is simple, but the inactivation effectiveness is reduced because the probability of absorption requires parallel orientation of photon electric field vector with uracil dipole transition moment
Solution Approach 1:
The patent transitions from one-dimensional or limited-angle illumination to three-dimensional omnidirectional illumination by placing the UV-C source at the center of a spherical cavity. This allows photons to attack pathogen bases from all possible angles simultaneously, maximizing the probability of absorption and inactivation.
Solution Approach 2:
The spherical cavity structure serves multiple functions: it provides omnidirectional illumination for maximum inactivation effectiveness, acts as an integrating cavity for uniform photon distribution, and maintains a relatively simple geometric form. This multi-functionality achieves high reliability without proportionally increasing complexity.
3Measurement precision
If surface-based experiments are used to evaluate viral inactivation, then the experimental setup is simple, but the measurement accuracy is poor because surface-based experiments do not represent aerosolized situations
Solution Approach 1:
The patent creates a simplified model system that copies the essential physics of aerosol inactivation without requiring complex aerosol generation equipment. By using a spherical integrating cavity with UV-C illumination, it replicates the omnidirectional photon exposure conditions that aerosolized pathogens would experience, providing accurate evaluation data with reduced apparatus complexity.
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
Enables accurate measurement of photon density within a medium, providing data for pathogen reduction system performance evaluation and ensuring sufficient UV-C levels for inactivation while preventing human exposure limits from being exceeded.
Implementation Method 1
a first reflecting layer coating at least a portion of the outer periphery of the substrate, the first reflective layer configured to integrate the photons within the volume of the substrate
Implementation Method 2
a plurality of entrance openings within the first reflective layer for diffracting the photons entering the volume
Implementation Method 3
a photon detector configured to receive the photons to detect a photon density and to produce an electrical signal representative of the detected photon density
Data Source
AI summary
An apparatus for measuring photon density, the apparatus comprising a substrate having a volume for receiving photons from within an optical radiation field, the substrate having an outer periphery, an inner periphery, and an exit aperture, a first reflecting layer coating at least a portion of the outer periphery of the substrate, the first reflective layer configured to integrate the photons within the volume of the substrate, a plurality of entrance openings within the first reflective layer for diffracting the photons entering the volume and a photon detector configured to receive the photons to detect a photon density and to produce an electrical signal representative of the detected photon density, wherein the substrate having the coating is configured such that the photons incident on the exit aperture of the volume of the substrate are at least substantially equally proportional to the photons incident on the plurality of entrance openings.