A
Absorption – When a material captures UV energy as it passes through or reflects off its surface.
Additive lamp (bulb) – A mercury vapour lamp containing added metals like gallium or iron, altering the spectral output to suit specific curing needs. Also known as metal halide or doped lamps.
Adhesion – The strength of bond between a cured UV coating and its surface (substrate), influenced by material type and cure quality.
Anode – The positive side of an LED; where electrical current enters and light emission begins.
Arc lamp – A mercury vapor lamp where UV is produced by an electric arc between two electrodes.
Arc length – The distance between electrodes in a quartz lamp, representing the length over which UV is effectively generated.
ASTM D3359 – A standardised test for assessing coating adhesion using a cut-and-peel tape method.
B
Ballast – An electrical component that regulates the current in an arc lamp to keep output steady.
Bandwidth – The range of UV wavelengths a lamp emits, measured in nanometres.
Binning – The process of grouping UV LEDs based on wavelength, irradiance, and voltage to ensure consistent performance.
Black light – A UV light source primarily emitting UVA with minimal visible light.
Borosilicate – Durable, heat-resistant glass that transmits more UV than standard glass. Used in UV optics.
Bulb (lamp) – A quartz tube containing mercury and gas. When energised, it emits UV light. The term 'lamp' is more common in Europe.
Burn-in period – Initial run time for a UV lamp/system to stabilise after start-up or during quality testing.
C
Capacitor – Optimises electrical efficiency by correcting power factor in the UV system.
Cassette / cartridge / cradle – Mounting structures that support the UV lamp and reflector inside the lamphead; designed for easy removal and servicing.
Cathode – The negative terminal of an LED.
Cationic chemistry / cationic curing – A curing method that continues after initial UV exposure, ideal where full light access isn’t possible.
Chip – The semiconductor component of an LED, made from materials like gallium nitride.
Choke – Another term for ballast; controls current in an arc lamp.
Cold mirror – A UV reflector coating that directs UV toward the cure surface while filtering out infrared heat.
Coolant – A fluid that removes heat from UV systems, keeping components at safe temperatures.
Cross-cut / cross hatch test for measuring adhesion – A standardised method used to evaluate how well a UV-cured coating adheres to a substrate. A grid pattern is cut into the coating and tape is applied to see how much material lifts away. This test is widely used in quality control for UV coatings.
Crosslinking – Chemical bonding that creates strong, durable polymers during UV curing.
Cure length – The effective length of a UV lamp or LED array that delivers consistent irradiance for curing. It determines the maximum width of substrate that can be fully cured in a single pass under the lamp.
Cure / curing / cured – The process of hardening or setting UV-reactive materials through polymerisation.
D
DC power supply – Provides constant voltage to power LEDs and other components.
Depletion zone – The boundary layer in an LED’s semiconductor where charge carriers are absent.
Devitrification – A change in quartz due to prolonged heat/UV exposure, making it opaque.
Dichroic – A coating that reflects UV and transmits heat, improving curing efficiency.
Die / diode – Semiconductor layers in an LED chip. Also referred to as a chip.
Doped lamp (bulb) – A UV mercury arc lamp infused with metal additives—such as gallium, iron, or indium—to shift and enhance specific wavelengths. Also referred to as an additive or metal halide lamp, it tailors spectral output for different photoinitiators.
Doped LED – An LED made with intentional impurities to alter its electrical and optical properties.
Dose (dosage) – The UV energy absorbed per unit mass. Not to be confused with energy density.
Dose rate – Another term for irradiance, measured in W/cm².
Dose test strip – A disposable strip that visually indicates UV energy exposure by changing colour. Commonly used to validate UV curing performance during setup, production, or system verification.
Driver / driver board – Regulates and distributes voltage to LED arrays, similar to how a ballast works for arc lamps.
Dual cure – A chemistry that cures under both UV LED and mercury arc sources.
Duty cycle – The proportion of ON time during LED pulsing. Affects energy density but not irradiance.
Dynamic exposure – UV exposure that varies over time due to lamp or substrate movement.
Dynamic range – The span of irradiance a radiometer can accurately measure.
E
Effective cure length – The length of a UV lamp that delivers uniform and optimal output.
Electrode – The current-carrying terminals in arc lamps. Also used to describe lamp types.
Electrodeless – UV lamps (e.g. microwave) that do not use electrodes.
Electroluminescence – Light emitted when electric current passes through a semiconductor.
Electromagnetic spectrum – The full range of radiation, including UV, visible, and infrared light.
Emitting window – The quartz or glass part of a lamphead that allows UV output while protecting internal components.
Encapsulate – A protective coating around LEDs to guard against moisture and dust.
Energy density – Total UV energy delivered per unit area (J/cm²). Often called dose.
Energy density test strip – A tool used to measure the cumulative UV energy (in J/cm²) delivered to a surface. These strips provide a simple, visual indication of whether a surface has received sufficient dose for proper cure.
Excimer lamp – A UV source emitting narrow-band light, useful for specific curing or surface processes.
F
Flood – A UV light output that is wide and unfocused, useful for large-area exposure.
Focal distance (length) – The optimal distance from a focused lamp to the cure surface for peak UV output.
Focus – The area where UV energy is most concentrated from a reflector system.
Forward bias – The condition that allows current to flow through an LED.
Forward voltage – Voltage drop across an LED during operation.
Free radical chemistry / free radical curing – A UV-curing method that relies on continuous exposure. Rapid cure times.
Frequency – Number of wave cycles per second, measured in Hertz (Hz).
G
Gallium (Ga) – A metal additive in UV lamps that shifts output toward longer wavelengths.
Germicidal – UV light, particularly UVC, used to deactivate bacteria and viruses.
H
Human Machine Interface (HMI) – User control interface, typically touchscreen, for UV systems.
I
Igniter – Starts the arc in electrode-based lamps.
Indium (In) – A metal used in doped lamps to extend output past 400 nm.
Infrared – Part of the spectrum that emits heat. Managed by filters and cooling in UV systems.
Integral blower – A built-in fan used to cool the lamphead.
Integral shutter – A mechanical system inside a lamphead to block UV output when not curing.
Integrating sphere / Ulbricht sphere – A lab tool that measures total UV output by evenly scattering light inside a coated sphere.
Intensity – Common but imprecise term. Often used in place of irradiance.
Interlock – A safety mechanism that shuts off UV if unsafe conditions are detected.
Irradiance – The UV power hitting a surface per unit area (W/cm²).
Irradiance profile – A time- or area-based view of irradiance from a lamp or system.
Irradiator – Another term for a complete UV lamphead or light engine, typically including the lamp, reflector, housing, and cooling system. It is responsible for delivering UV energy to the curing surface.
ISO 2409 Standard – An international test for assessing adhesion using a cross-hatch tape method.
J
Joule – A unit of energy. One joule equals one watt-second.
L
Lambert’s cosine law – Describes how radiant intensity decreases with angle from a surface.
Lambertian – A surface that emits evenly in all directions.
Lambertian source – A light source, like an LED, that approximates even brightness across angles.
Lamp (bulb) – A sealed quartz UV source, powered by electrodes or microwaves.
Lamphead – The full UV assembly including lamp, housing, cooling, and optics.
LED (light emitting diode) – A semiconductor light source used in modern UV curing systems.
LED array – A group of LEDs configured to provide uniform UV coverage.
LED lamphead / head / lamp / irradiator / light source / dryer / light engine – Terms used to describe complete LED UV assemblies.
LED module / package – A component-level assembly of one or more LEDs with wiring and optics.
Lens – Shapes UV output from a lamp or LED.
Liquid chiller (cooler) – Circulates fluid to manage heat in some UV systems.
Louvre – UV-blocking slats that allow airflow for cooling.
M
Magnetron – Generates microwaves to power electrodeless UV lamps.
Mercury – A key element in traditional UV lamps that emits strong UV when vaporised.
Mercury arc lamp – An electrode-driven lamp that emits UV from vaporised mercury.
Mercury plus (H+) – Microwave lamps designed for higher UVC output.
Mercury vapour lamp – A UV lamp that operates via mercury vaporisation.
Metal halide – A type of mercury arc lamp doped with metals such as gallium or iron to modify spectral output. It provides a broader UV spectrum than standard mercury lamps and is particularly effective for curing thicker or pigmented materials.
Micrometre – A unit of length equal to one millionth of a metre (µm).
Microwave – Both a method of energising UV lamps and part of the EM spectrum.
Monochromatic – Emitting light at a single wavelength.
Monomer – A low-weight resin molecule that forms polymers during UV curing.
N
Nanometre – A unit of measurement for light wavelengths (nm).
Negative cooling – Cooling method where air is pulled into the lamphead.
Nitrogen inerting / blanketing – Flooding a curing surface with nitrogen to prevent oxygen inhibition.
O
Oligomer – A larger molecule than a monomer, forming the backbone of cured resins.
Optical device – Used to control or shape UV output.
Out-of-focus – When the lamp is too near or far from the focal point, reducing curing effectiveness.
Oxidising – When oxygen interferes with UV curing by reacting with free radicals.
Oxygen inhibition – Slows or impedes cure at the surface due to oxygen exposure.
Ozone (O3) – Created when UV below 240 nm interacts with oxygen. Managed by ozone-free lamp designs.
Ozone inhibiting / ozone free bulbs – Lamps that block ozone-producing wavelengths.
P
Parts per million (PPM) – A concentration measurement often used in safety and chemical analysis.
Peak irradiance / peak power density – The highest UV output recorded over a given time or surface.
Photoinitiator – A chemical that absorbs UV and starts the curing reaction.
Photopolymerisation – UV-triggered chemical process that forms solid polymers.
Pinning – A partial UV cure used in printing to stabilise ink before final curing.
Planar shutter – An external shutter system that moves across the lamphead face.
Polychromatic or polychromic – UV sources that emit across many wavelengths.
Polymer – A large molecule formed from repeated subunits (monomers/oligomers).
Positive cooling – Air is pushed through the lamphead to provide cooling.
Positive-negative junction (p-n junction) – The structure within an LED where light emission occurs.
Post cure – Further reactions or exposures after initial UV cure.
Power – Electrical input per lamp length, usually in watts per cm or inch.
Power density – Often used interchangeably with irradiance.
Power supply / power supply unit (PSU) – Supplies power to UV systems and may include controls.
Pulse width modulation (PWM) – A method of controlling UV output by adjusting ON/OFF times.
Q
Quartz filter – A UV-transparent water-cooled tube that reduces infrared heat.
Quartz plate / quartz window – Transparent barrier protecting internal lamphead components.
Quartz tube – Either the main body of a UV lamp or a protective sleeve.
R
Radiant power – Total UV energy output over time.
Radiometer – Device that measures UV irradiance or energy.
Reflector – Directs UV energy toward the substrate. Comes in parabolic or elliptical designs.
Remote blower – A cooling fan system located away from the lamphead.
RF – Radio frequency used in microwave UV systems.
RF detector – Monitors RF emissions and ensures safety in microwave systems.
RF screen – Allows UV through while containing RF in microwave lampheads.
S
Semiconductor – Material used in LEDs that can both conduct and insulate electricity.
Shutter – Used to block UV light temporarily without powering off the system.
Solarisation – The clouding of quartz after prolonged UV and heat exposure.
Solid-state electronics – Components without moving parts, used in LED systems.
Spectral output – A graph showing the intensity of UV energy across different wavelengths.
Starter – Applies high voltage to start electrode-based UV lamps.
Starter bulb – Used in microwave systems to ignite UV lamps.
Static exposure – Constant UV exposure over a fixed time.
Striking – The act of starting a UV lamp.
Surface cure – The top layer cure of a coating.
T
Tape test for measuring adhesion – A general term for adhesion tests involving adhesive tape, including ASTM D3359 and ISO 2409. These tests determine how well a cured UV coating adheres to a substrate by applying tape over a cut grid or pattern and checking for film removal.
Threshold Limit Value (TLV) – Maximum allowable concentration of a substance in workplace air.
Through cure – Full depth cure down to the substrate.
Time Weighted Average (TWA) – An occupational exposure metric representing the average level of UV (or any hazardous factor) a worker is exposed to over a standard 8-hour shift. Used in safety compliance to evaluate long-term UV exposure risks.
Total energy – The total amount of UV energy received by a surface during exposure, measured in joules per square centimetre (J/cm²). Also referred to as UV dose or energy density, it’s a critical factor for achieving a complete and effective cure.
Total power / total radiant power – Overall UV energy output, measured in watts.
Transmittance – Ratio of UV energy passing through a material to the total energy hitting it.
U
Ultraviolet (UV) – Part of the light spectrum beyond visible violet (approx. 100–450 nm).
UV energy density test strip – A strip that changes colour based on total UV exposure.
UVA (315 – 400 nm) – Longwave UV, commonly used in curing.
UVB (280 – 315 nm) – Medium-wave UV.
UVC (200 – 280 nm) – Short-wave UV, germicidal.
UVV (400 – 450 nm) – Overlaps visible light; sometimes included in UV discussions.
V
Vacuum UV – UV between 100–200 nm; doesn’t transmit in air.
Viscosity (dynamic) – A measure of fluid thickness, affecting how inks and coatings flow.
Vitrification – The process of turning quartz to glass.
W
Watt – Unit of power. 1 watt = 1 joule per second.
Watt density – Power output per unit area.
Waveguide – Directs microwave energy to the lamp in electrodeless systems.
Wavelength – The distance between wave peaks. Used to define UV light characteristics.
Wire bond – Electrical connection in LED packages.