YOYO-UV designs, manufactures and sells UVC flashlights for shortwave fluorescent mineral observation, lab examination, scientific research, sensitive materials inspection and other professional controlled applications.
Hand-held UVC light sources are offered with wavelengths of 254nm, 265nm and 275nm, with options for custom UV LED, optical filter, reflector, battery, driver and housing for OEM products.
Compact and high-output shortwave UVC flashlights are manufactured for distributors, laboratories, mineral suppliers and UV equipment manufacturers. OEM & ODM services are provided for design, optical evaluation, prototype production and batch manufacturing.
What Is a UVC Flashlight?
UVC flashlight is a portable light source producing ultraviolet radiation within the UVC wavelength range.
UVC normally refers to the wavelength range below 280nm. Available UVC LED flashlights include 254nm, 255nm, 265nm and 275nm.
Compared with conventional 365nm UVA blacklight flashlight, a UVC flashlight produces a much shorter wavelength UV radiation.
This makes UVC flashlight useful for special purposes, including:
Shortwave fluorescent mineral analysis
Lab inspection
Scientific study
Phosphor analysis
Sensitive materials examination
Optics testing
Professional UVC studies
UVC is invisible or near-invisible light for the human eye and can be harmful to eyes and skin. This kind of product should be used as professional UV tool instead of ordinary flashlight.
254nm & 255nm Shortwave UVC Flashlights
254nm and 255nm UVC flashlights are typically used as hand-held shortwave UV sources.
A conventional low-pressure mercury lamp has a characteristic emission line at 253.7nm, which is often called 254nm.
Modern UVC LEDs can be designed at 255nm, depending on the LED series and wavelength bin.
When discussing shortwave fluorescence application, both of these terms are commonly used in the market.
It is always necessary to check the exact peak wavelength and wavelength range when designing a UVC flashlight precisely.
UVC Flashlights for Fluorescent Minerals
Shortwave UV is widely used by fluorescent minerals enthusiasts, geologists and laboratories.
Some fluorescent minerals show very strong fluorescence reactions under 254nm or 255nm UVC, whereas they have weak reactions or other fluorescence colors when illuminated with the ordinary 365nm longwave UVA.
Some shortwave UV responsive minerals include:
Willemite
Calcite
Scheelite
Hardystonite
Fluorapatite
Feldspar
Other fluorescent minerals
It depends on the actual mineral composition, activators and specimen.
To conduct serious mineral examination, shortwave UVC is able to be used along with midwave UVB and longwave UVA for comparison of fluorescence reactions at different UV wavelengths.
254nm vs 265nm vs 275nm UVC Flashlights
The best UVC wavelength for any application depends on the target material.
254nm / 255nm
254nm and 255nm are particularly important for:
Shortwave fluorescent minerals
Phosphor inspection
Observation
Scientific examination
Lab testing
Inspection of UV-sensitive material
265nm
265nm can be used for:
UVC research
Optical testing
Examination
Materials study
Germicidal system testing
275nm
275nm is used in:
UVC research
Laboratory optics testing
Material study
OEM UVC equipment design
Controlled microbial system study
No wavelength is necessarily the best choice for all applications.
For OEM projects, the wavelength should be selected depending on the target material or study.
Shortwave vs Midwave vs Longwave UV
Users of ultraviolet flashlights, especially fluorescent minerals enthusiasts, divide UV light into shortwave, midwave and longwave bands.
A typical division is:
Shortwave: about 254/255nm UVC
Midwave: about 310nm UVB
Longwave: about 365nm UVA
Different minerals may react differently to each band.
For example, a specimen can give a bright reaction under 365nm but give another color or show a weaker reaction under 254nm.
That is why professional examination of fluorescent minerals requires more than one UV wavelength.
Electrical Power vs UVC Radiant Power
Electrical wattage and radiant power of the UVC flashlight are different specifications.
For example, a flashlight may have a 15W-class UVC LED system but deliver a significantly lower UVC radiant power.
Electrical power describes the energy consumption of the system.
UVC radiant power, normally given in milliwatts or watts, describes the optical UV output.
For comparison of UVC flashlights for professional purposes, the following should be taken into account:
Peak wavelength
Radiant power
Electrical power
Irradiance
Distance from the flashlight to the measurement point
Beam diameter
Current
Thermal condition
UVC flashlights cannot be compared in terms of electrical wattage alone.
Radiant Power vs Irradiance
Radiant power and irradiance are different parameters.
UVC radiant power is the total UVC optical output of the source.
Irradiance is the UV power, delivered per one square centimeter to a certain surface.
It is normally given in mW/cm² units.
For example,
10 mW/cm² at 10 cm
provides more useful information than
10 mW/cm²
since the distance directly influences the UV energy delivery.
Beam angle, reflector and spot diameter can also influence the irradiance value.
Beam Angle, Spot Size & Working Distance
Optical system influences the way UVC energy is delivered.
A narrow beam is capable of concentrating a higher UVC energy on a small spot and can be used for examining individual mineral specimen or laboratory samples.
A wide beam allows illuminating a large area.
It is important to specify the following characteristics:
Beam angle
Reflector diameter
Spot diameter
Working distance
Irradiance at the target area
For OEM projects, it is necessary to specify the required working distance and the target area in order to select proper reflector and optical structure.
UV Filters for UVC Flashlights
A professional shortwave UVC flashlight can use an optical filter for eliminating non-useful visible light and out-of-band radiation.
UV filters, such as ZWB-series filter glasses and other technologies can be used for certain wavelengths.
Filters do not increase the output power of LEDs.
Instead, filters change the output spectrum, allowing only a certain range of wavelengths to pass through.
Main parameters of a filter include:
Wavelength transmission
Visible light rejection
Out-of-band rejection
Filter thickness
Resistance to temperature
Filter diameter
Any optical filter will inevitably introduce transmission loss.
That is why the whole optical system, consisting of LED, reflector and filter, should be considered as one component.
ZWB3 Filtered UVC Flashlights
Certain models of YOYO-UV UVC flashlights use black ZWB3 filter glass.
The purpose of the filter is to eliminate non-UV light for improving the optical background of shortwave fluorescence observation.
This allows seeing the fluorescence response better in dark environment.
However, filter selection should be done based on the exact spectral characteristics of the filter.
For custom OEM products, alternative filter systems can be considered taking into account the wavelength and optical requirements.
Thermal Management for High-Power UVC Flashlights
High-power UVC LEDs produce a lot of heat.
A part of electricity is converted to UV light; however, most of the energy is converted to the heat of the LED, PCB and flashlight body.
A professional thermal system includes the following elements:
LED copper or aluminum PCB
Aluminum flashlight housing
Thermal interface material
Heat transferring areas
Temperature monitoring
Automatic current reduction
Low voltage protection
Maximum output right after turning on the flashlight does not necessarily equal to sustainable output after the flashlight reaches its operating temperature.
For professional applications, stable output within the operating period can be more important than peak power output.
Rechargeable UVC Flashlights
Rechargeable UVC flashlights may use the following batteries:
18650
21700
26650
Custom battery pack
The correct type of battery depends on LED voltage, drive current, runtime and flashlight dimensions.
Battery capacity alone does not define the runtime.
Runtime depends on:
LED power
Driver efficiency
Thermal management
Operating mode
Battery state
Ambient temperature
For high-output UVC flashlights, the battery, driver and thermal management system should be designed together.
UVC Flashlights for Laboratory & Research Purposes
Portable UVC light source is useful when the laboratory or engineering team needs a portable controlled UV source at a certain shortwave wavelength.
Typical applications are:
Fluorescence observation
Phosphor testing
Optical testing
Materials examination
Laboratory research
UV-sensitive coatings
Scientific instrument
Controlled UVC testing
In professional applications, wavelength precision, output stability and conditions of measurement are usually more important than electrical wattage.
The required wavelength should be selected depending on the test protocol and the target material.
UVC Flashlights for Germicidal Testing
UVC radiation is used in microbial control applications; however, a UVC flashlight is not able to ensure a certain level of disinfection automatically.
Disinfection effect depends on the following parameters:
UVC wavelength
Delivered irradiance
Exposure time
UV dose
Working distance
Beam uniformity
Microorganism
Surface condition
Shadowing
Treatment geometry
That is why it is necessary to test the system under defined conditions and measure the resulting microorganisms reduction percentage.
For OEM germicidal system development, it is necessary to measure the UVC dose and validate the treatment protocol.
Hand-held UVC products should not be promoted as household sanitizer tools without proper safety engineering and performance testing.
How to Test UVC Flashlights
It is necessary to use instruments suitable for the required wavelength for the testing of UVC flashlight performance.
Depending on the requirements of the project, the following characteristics can be measured:
Peak wavelength
Spectral distribution
Radiant power
Irradiance
Beam diameter
Working distance
Surface temperature
Runtime
Output stability
It is necessary to use the UV meter with the proper sensitivity for 254nm, 265nm or 275nm wavelengths.
A spectrometer or spectroradiometer can be used when detailed spectral characteristics are required.
It is always necessary to record the distance from the light source and operating conditions when measuring irradiance.
UVC Flashlight Safety
UVC radiation is hazardous to the eyes and skin.
Never stare at UVC LED or beam, even briefly.
Never aim a UVC flashlight at living persons or animals.
For professional operation:
Use UV-protective eyewear
Protect your skin
Aim the beam only at the target
Do not allow reflections
Control access to the operating area
Keep the product out of reach of children
Add warning labels
Use controlled activation if necessary
For professional purposes:
UVC-protected eyewear should be used
Skin should be protected
The beam should be aimed only at the target
Reflective objects should be avoided
Access to the operating area should be controlled
The product should be kept out of reach of children
Warning labels should be added
Controlled activation should be provided if necessary
Custom OEM & ODM UVC Flashlights
For OEM and ODM projects, YOYO-UV provides OEM and ODM UVC flashlight manufacturing services for distributors, laboratories, UV equipment companies, fluorescent minerals suppliers and professional product developers.
Customization options can include:
254nm UVC
255nm UVC
265nm UVC
275nm UVC
Custom UVC wavelength
LED brand & model
Radiant output
Quantity of LEDs
Optical filter
Reflector
Beam angle
Spot diameter
Working distance
LED PCB
Driver current
Thermal management
Battery
Charging system
Aluminum housing
Switch & operating mode
Waterproof structure
Logo
Packaging
Design and optical evaluation services are provided from LED selection and prototype assembly to batch manufacturing.
What Information Do We Need For a Custom UVC Flashlight?
For OEM UVC flashlight project, the following information is useful:
Required wavelength
Application
Required radiant output
Required irradiance, if any
Working distance
Target spot diameter
Optical filter requirement
Battery type
Required runtime
Flashlight dimensions
Operating mode
Environmental requirements
Order quantity
If the specifications are unknown yet, it is necessary to specify the target material and application.
Our engineers can recommend the proper UVC LED, filter, reflector, driver and thermal system for prototype development.
Whether you need a 254nm shortwave UV flashlight for fluorescent minerals, 265nm hand-held UVC light source, 275nm UVC research flashlight or completely customized professional shortwave UV torch, YOYO-UV is able to provide OEM and ODM development from prototype production to batch manufacturing.
