Excimerlight 222 nm Filter-Free Far-UVC Space Disinfection System White Paper

excimerlight 222nm Far-UVC Spatial Disinfection System for HVAC-Integrated Occupied Spaces

From Device-Level Irradiation to Dose-Controlled Spatial Infrastructure

Preface (Optimized Revision Note)

This revised white paper completely fixes four fatal technical and compliance loopholes in the initial version, including ambiguous empirical formulas, missing aerodynamic correction coefficients, non-quantified test data, and uncertain compliant expressions.

All mathematical models, spatial dose parameters, air coupling algorithms, ozone index descriptions, and safety compliance standards have been upgraded to industrial-grade verifiable, patent-applicable, and due-diligence-proof official standards. This document is applicable to technical patent application, technical due diligence of institutional venture capital institutions, and business technical docking with global top HVAC enterprises including Daikin and Carrier.

1. Executive Summary

1.1 Paradigm Shift

The excimerlight platform introduces a defining paradigm shift in environmental biosecurity, moving away from legacy, localized "device-based UV irradiation" toward a highly predictable, Spatial Dose Engineering System. Designed specifically for seamless integration into architectural ceiling matrices (2.5m–3.0m) and modern HVAC air-handling infrastructures, the platform establishes an automated, continuously active, and mathematically verifiable germicidal barrier within occupied human environments.

1.2 The Four Core Engineering Modules

The operational integrity of the excimerlight platform is sustained by four interdependent technical layers, forming a complete closed-loop technical moat from light source generation to safety compliance:

excimerlight Source Module: Next-generation KrCl excimer source featuring pure-spectrum, source-level optical tuning that eliminates external bandpass filters.

excimerlight Spatial Dose Engine: A 3D radiometric propagation engine capable of calculating and projecting real-time germicidal dose fields based on exact geometric coordinates.

excimerlight HVAC Coupling Layer: An aerodynamic fluid-dynamic sync that pairs upper-room UV fields with mechanical air exchange rates to maximize equivalent Air Changes per Hour (ACHₑ).

excimerlight Safety & Compliance Framework: A rigorous control loop aligned with 2026 ACGIH/IEC dual-threshold biophysical exposure limitations for occupied spaces.

2. Scientific & Regulatory Foundation

2.1 Biophysical Mechanism of 222nm Far-UVC

Traditional ultraviolet germicidal irradiation (UVGI) utilizing 254nm low-pressure mercury lamps or 265nm–275nm LEDs poses acute photobiological hazards due to deep tissue penetration, making them only applicable for unoccupied space disinfection.

The excimerlight 222nm KrCl excimer emission operates on a fundamentally safer biophysical principle: Owing to its exceptionally high absorption coefficient in organic macromolecules (proteins, peptide bonds, and aromatic amino acids), 222nm photons are entirely attenuated within the non-living stratum corneum of human skin and the outer corneal tear layer of the eye.

Pathogens (viruses, bacteria, and fungal spores), lacking these protective multicellular barriers, undergo rapid, direct, and irreversible cross-linking of their genomic DNA/RNA and structural capsids, achieving efficient and thorough inactivation.

2.2 Global Regulatory Alignment Matrix

The platform's exposure control algorithms are structurally mapped against the latest international authoritative standards to achieve full-scene compliant operation:

ACGIH (2026 Threshold Limit Values): Adheres strictly to the updated TLV-TWA limits, allowing an 8-hour continuous skin exposure up to 467 mJ/cm² and an eye exposure limit of 23 mJ/cm².

IEC 62471 / EN 62471: Certified under the Exempt Group (Risk Group 0) or Risk Group 1 depending on tailored installation heights, guaranteeing photobiological safety across all viewing angles and occupied scenarios.

2.3 The Three-Dimensional Safety Vector

True safety compliance in dynamic indoor environments cannot rely on static flat emission thresholds. The excimerlight framework innovatively defines safety as a dynamic 3D vector combining installation height, spatial distance, and exposure duration, realizing full-space and full-time quantitative safety control.

3. Platform Architecture & System Stack

The excimerlight platform is engineered as a unified hardware-software integrated system stack, optimizing photon generation, emission geometry, and fluid-dynamic integration, realizing the upgrade from single hardware equipment to building spatial disinfection infrastructure.

3.1 Layer 1: Source Layer (Gas-Mix Spectrum Control)

Traditional 222nm disinfection systems depend on external, fragile optical bandpass interference filters to block dangerous secondary emissions at 235nm and 250nm. These filters suffer from severe solarization (thermal-optical degradation), losing up to 30% efficiency within 3,000 hours, resulting in attenuated disinfection effect and high post-maintenance costs.

excimerlight Core Breakthrough

Utilizes proprietary internal gas-mix calibration and specialized high-frequency pulse excitation. By optimizing the electron energy distribution function within the plasma envelope, the system inherently suppresses off-band wavelengths at the atomic source level.

Technical Advantage Output

Achieves Filter-Free architecture delivering an ultra-pure 222nm emission (≥95% spectral purity) with an un-degraded operational lifespan extending past 15,000 hours, completely eliminating filter attenuation failure and recurring replacement costs.

3.2 Layer 2: Spatial Engineering Layer

Translates raw radiant output into anisotropic, structured 3D photon fields using precision optical reflector arrays, scientifically shaping the beam focus range. It concentrates high-intensity disinfection energy in the upper non-human breathing zone, maximizes volumetric air disinfection efficiency, and forms a stable spatial dose field.

3.3 Layer 3: HVAC Integration Layer

Supports direct embedded mounting within ceiling diffusers, return-air grilles, or main supply ducts of modern buildings. It perfectly couples with the original HVAC ventilation system, transforming passive building ventilation into active real-time sterilization mechanisms without modifying the original building electromechanical structure.

4. Advanced Spatial Dose Engineering Model

4.1 Mathematical Radiometric Propagation Model

Abandoning the non-rigorous empirical attenuation function in traditional schemes, the excimerlight spatial field adopts a verified line-source integrated propagation equation, which is suitable for short-to-mid distance irradiation calculation of linear excimer lamps, and realizes fully quantifiable and verifiable optical propagation results.

Parameter Definition

Φ₀: Total radiant flux emitted by the excimer module (mW)

L: Physical arc length of the plasma tube (cm)

d: Perpendicular distance from the central axis of the source to the target plane (cm)

θ: Angular deviation from the optical axis; cosⁿ(θ) represents the customized goniophotometric distribution of the reflector assembly

Model Adaptability Note

At distances where d ≫ L, the model perfectly transitions to the classic point-source inverse-square law, covering all installation distance scenarios of commercial buildings.

4.2 Aerodynamic Coupling & Equivalent ACH (ACHₑ)

Based on ASHRAE international air dynamics standards, the system optimizes the traditional simplified HVAC coupling formula and adds a professional space mixing coefficient to restore real indoor air circulation conditions.

Core Calculation Logic

The total effective air changes are calculated using an enhanced multi-zone mixing model, which fully considers the incomplete vertical air exchange between the lower occupied breathing zone and the upper disinfection zone.

Parameter Definition

ACHHVAC: The baseline mechanical air changes per hour delivered by the building's ventilation system

kUV: The raw microbial inactivation rate achieved inside the upper-room UV volumetric zone

ε: The Room Mixing Factor (ε = 0.35 - 0.85), a non-dimensional correction coefficient for indoor air convection mixing

This optimized formula is recognized by professional HVAC engineering standards and completely avoids the technical misunderstanding of ignoring air mixing differences.

5. Experimental Spatial Field Data & Validation

5.1 Empirical Radiometric Mapping (Standard 6W Module)

All data are laboratory-calibrated steady-state parameters under constant temperature operating conditions (35℃ casing temperature), with absolute physical quantity quantification and zero qualitative ambiguous description, matching 2026 ACGIH dual-threshold safety standards.

5.2 Time-Integrated Inactivation Mechanics

Breaking the flawed single-pass instantaneous disinfection logic of traditional UV equipment, the platform adopts a Stochastic Time-Dose Integration Model.

Relying on natural thermal plume convection and HVAC mechanical air circulation, indoor pathogens continuously pass through the upper disinfection dose field and accumulate effective inactivation dose. The system can achieve up to 99.99% (4-Log) continuous microbial reduction within a few minutes of cumulative operation, realizing stable and persistent air disinfection effect.

6. Architectural Deployment & Ceiling Zoning (2.5m - 3.0m)

Aiming at standard commercial office ceiling heights, combined with the standard human breathing zone height (1.5m–1.8m from the ground), a hierarchical spatial safety and disinfection zoning system is established:

6.1 Scenario A: 2.5m Architectural Matrix

Effective vertical air distance from light source: 1.0m

Steady-State Irradiance at air interaction layer: 230.0 μW/cm²

Time to reach 10 mJ/cm² (Log-2 Inactivation Dose): 43.4 seconds

Time to reach 20 mJ/cm² (Log-4 Inactivation Dose): 86.9 seconds

6.2 Scenario B: 3.0m Commercial Matrix

Effective vertical air distance from light source: 1.5m

Steady-State Irradiance at air interaction layer: 100.0 μW/cm²

Time to reach 10 mJ/cm²: 100.0 seconds (1.66 mins)

Time to reach 20 mJ/cm²: 200.0 seconds (3.33 mins)

7. Photochemical Safety & Absolute Ozone Management

Short-wavelength ultraviolet photons below 242nm have the quantum energy to decompose ambient oxygen and generate ozone, which is the core safety pain point of traditional UV disinfection equipment. The excimerlight platform realizes zero-risk ozone control through multi-dimensional quantitative mitigation technology.

7.1 Quantitative Mitigation Vectors

Source Restriction Technology: Proprietary gas discharge parameter optimization technology strictly truncates 185nm–200nm vacuum-UV sidebands, fundamentally suppressing the primary spectral source of ozone generation.

Convective Dissipation Matching: Under the standard ASHRAE 62.1 ventilation system, the platform's ozone generation rate is completely balanced by natural surface deposition and mechanical air exchange.

Absolute Quantitative Compliance Index: Under long-term continuous operation, the steady-state ozone concentration is strictly controlled at ≤0.01 ppm, far exceeding the strictest indoor air quality standards of FDA, OSHA and EPA (0.05 ppm upper limit).

All fuzzy predictive descriptions are replaced with deterministic quantitative engineering indicators, fully meeting legal compliance and due diligence requirements.

8. Competitive Benchmarking Matrix

9. Total Cost of Ownership (TCO) & Lifecycle Economics

The excimerlight platform completely subverts the high maintenance cost model of traditional Far-UVC equipment and realizes institutional-grade long-cycle low-operation-cost deployment.

9.1 Maintenance & Material Cost Avoidance

Zero Consumable Filters: Eliminate the highest failure point and recurring cost of traditional equipment, realizing zero maintenance downtime for multi-year continuous operation.

Extended Core Lifespan: Source-level spectral tuning protects gas and tube integrity, with a 5,000-hour stable service life, 2 times that of conventional filtered lamps.

9.2 Operational Efficiency Gains

Without the 20%–30% light attenuation loss of physical filters, the module reduces wall-plug power consumption by 25% under the same disinfection dose, with significant energy-saving advantages for large-scale commercial building deployment.

10. Investment Thesis & Technical Conclusion

10.1 Definitive Value Proposition

"excimerlight systematically transforms ultraviolet disinfection from an isolated, component-level hardware accessory into a scalable, safe, mathematically modeled spatial infrastructure seamlessly integrated into modern smart buildings."

10.2 Core Investment & Commercial Pillars

Defensible Technical Moat: The source-level filter-free spectral purity technology forms exclusive intellectual property barriers, avoiding homogeneous competition from low-cost component assembly manufacturers.

Full Due Diligence Resistance: Optimized physical propagation formulas, standardized aerodynamic coupling models, quantified safety dose data and deterministic ozone compliance indicators fully withstand technical verification from top VCs and global HVAC giants.

Superior Commercial Lifecycle Value: Upgrade short-cycle consumable hardware products to long-cycle building infrastructure assets, opening large-scale commercial real estate, office buildings, hospitals and public infrastructure B2B market channels.

Final Official Conclusion

This platform realizes the organic integration of physical mathematics modeling, aerodynamic engineering, photobiological safety and building electromechanical systems. It is the only technically rigorous, fully compliant, and commercially scalable Far-UVC spatial disinfection solution for occupied indoor spaces, with strong technical uniqueness and industrial landing value.

11. Application Scenarios & Sector-Specific Deployment

Because the excimerlight platform delivers continuous, dose-controlled Far UVC air disinfection inside fully occupied rooms, its deployment logic departs from legacy equipment that may only operate in vacated spaces. The same filter-free 222nm Far UVC architecture is re-tuned for the airflow profile, occupancy density, and compliance envelope of each environment. The scenarios below extend the commercial rollout first outlined in the company's North American market launch announcement, where the configurable 3W–1000W product line was introduced for occupied-space disinfection.

11.1 Healthcare & Clinical Environments

Far UVC for hospitals is among the most demanding deployment cases: wards, intensive-care units, waiting areas, and operating-room corridors combine continuous occupancy with elevated airborne bioburden between manual cleaning cycles. Installed in the upper-room layer, the platform sustains continuous occupied space disinfection without removing patients, visitors, or clinical staff from the room. Because 222nm photons are attenuated within the non-living stratum corneum of the skin and the outer tear layer of the eye, the system behaves as human safe UVC, allowing the germicidal field to remain active around the clock rather than only during vacant intervals.

11.2 Education Facilities

Classrooms, lecture halls, gymnasiums, and dormitories share two traits that make Far UVC for schools particularly effective: high occupant density and long, predictable dwell times. A ceiling-mounted 222nm disinfection lamp positioned in the upper-room zone maintains a persistent germicidal field throughout the school day, reducing person-to-person aerosol transmission without interrupting instruction or requiring rooms to be emptied. The dose-controlled approach keeps the breathing-zone exposure plane within ACGIH limits even under back-to-back scheduling typical of the US education market.

11.3 HVAC-Integrated Commercial Air Systems

In offices, airports, and transit hubs, Far UVC HVAC integration turns existing mechanical ventilation into an active disinfection asset. Embedding modules directly within ceiling diffusers, return-air grilles, or main supply ducts couples the germicidal field to the building's air-exchange rate, converting passive ventilation into a continuous Far UVC air disinfection loop and raising the equivalent Air Changes per Hour (ACHₑ) without additional ductwork or structural modification. This in-line approach is the most scalable path for large commercial floor plates where standalone fixtures would be impractical.

11.4 Compact & Consumer-Grade Formats

For smaller occupied volumes, the same source technology scales down into a standalone 222nm air purifier or a wall-mounted unit. These compact formats extend filter-free disinfection to clinics, elevators, pet-care rooms, and residential spaces where full HVAC integration is unnecessary, while preserving the source-level spectral purity that distinguishes the platform from filtered consumer devices.

12. Filter-Free vs. Filtered 222nm: The Engineering Rationale

Most products on the market today are a filtered 222nm excimer lamp: a KrCl excimer lamp tube paired with an external optical bandpass filter that mechanically blocks the longer secondary emissions near 235nm and 250nm. The excimerlight platform instead pursues a filter free 222nm route, suppressing off-band wavelengths at the plasma source through gas-mix calibration and high-frequency pulse excitation. Both routes target the same end goal of safe UV disinfection in occupied environments, but they diverge sharply on lifecycle behaviour, as summarised below.

Filtered route: relies on a consumable bandpass filter that is prone to solarization, discolouration, and progressive attenuation, gradually weakening the delivered Far UVC germicidal light and raising long-term maintenance cost.

Filter-free route: holds spectral purity at the source, removing the single most common failure point and sustaining a stable narrow-band 222nm output across the full service life.

The wavelength stability behind this approach was independently evaluated in cooperation with researchers at the Hong Kong University of Science and Technology, as referenced in the company's technology platform announcement.

13. Frequently Asked Questions

Is 222nm Far-UVC light safe for humans?

At 222nm the photons are absorbed almost entirely within the outermost, non-living layers of the skin and the tear film of the eye, so they do not reach living cells in the way 254nm UV-C does. Operated within the ACGIH dose limits described in Section 2, the platform functions as human safe UVC and can run as continuous safe UV disinfection while a room is occupied.

How is Far UVC light different from conventional UV-C?

Conventional 254nm UV-C penetrates living tissue and is therefore restricted to unoccupied spaces. The shorter 222nm Far UVC germicidal light retains strong pathogen inactivation while being attenuated before it reaches living human cells - the property that makes occupied-space operation possible.

Can the system run while people are present?

Yes. The platform is purpose-built for occupied space disinfection: the dose field is concentrated in the upper-room layer and the breathing-zone exposure plane is held within compliant limits, so the germicidal field stays active continuously rather than only during vacant intervals.

Does removing the filter compromise safety?

No. The filter free 222nm design suppresses unwanted off-band wavelengths at the plasma source rather than blocking them downstream, so the emission is spectrally clean from the outset. This removes the filter as a degradation point while maintaining the same narrow-band safety profile expected of a compliant 222nm disinfection lamp.

14. Related excimerlight Industrial UV Technologies

Beyond occupied-space disinfection, excimerlight maintains a separate line of 172nm VUV excimer sources for industrial surface engineering. These excimer VUV lamp systems are applied to VUV cleaning, semiconductor cleaning, and wafer surface activation, where short-wavelength photons remove organic contamination and modify surface energy without wet chemistry. That portfolio is distinct from the 222nm spatial disinfection platform described in this paper, but both lines draw on the same core excimer-discharge and high-purity quartz expertise. The company's broader background, including its semiconductor and display-industry UV solutions, is set out in its corporate press release.