FAQ & Glossary

Frequently asked questions and UV Curing technical glossary

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FAQ & Glossary

Frequently asked questions and UV Curing technical glossary

The world of UV LED curing is a rapidly growing, ever-changing environment. Below are frequently asked questions about the company and marketplace as well as technical glossary. If there are questions of definitions you would like covered, please contact Phoseon.

Frequently Asked Questions (FAQs)

Who is Phoseon Technology?
Phoseon Technology has pioneered Semiconductor Light Matrix (SLM)™ technology utilizing high power UV LED technology to manufacture the environmentally cleanest, coolest operating, highly efficient ultraviolet curing products on the market. Phoseon is a venture-funded, privately-held corporation founded in 2002 headquartered in Hillsboro, Oregon.

What is ultraviolet LED?
Ultraviolet (UV) LED stands for ultraviolet light emitting diode. A UV LED is an electronic light source with electromagnetic radiation that has a wavelength shorter than that of visible light but longer than x-rays.

What is Ultraviolet curing?
Ultraviolet curing is the polymerization of UV sensitive materials, rather than drying through the evaporation of solvents.

Where did the name Phoseon come from?
The etymology of “Phoseon” references “long-lasting light,” conveying reliability, endurance, and our long-term commitment to deliver to the world bright, industrial light sources characterized by insignificant energy consumption or environmental impact.

What is the Semiconductor Light Matrix (SLM) Technology? 
SLM is a unique technology for producing UV light. Forty years ago, mercury-based arc lamps were the only UV light source available to initiate the UV curing process. New bulb-based light sources such as Excimer bulbs, microwave sources have been introduced, but the basic technology remains the same. Phoseon Technology has developed a “bulbless” Semiconductor Light Matrix (SLM) technology to produce UV light for curing applications. The future of high intensity UV technology is small, cool and clean, with no bulb replacement required.
Phoseon’s Semiconductor Light Matrix (SLM) technology combines a dense array of light emitting semiconductor devices, with micro optics and advanced thermal technology in a cost-effective MOEMS (micro opto electro-mechanical system) package. The result is a high intensity UV light system that offers an efficient, scalable, safe, long-life, and environmentally friendly alternative to traditional UV sources.

What is an Arc lamp?
An arc lamp or arc light is the general term for a class of lamps that produce light by an electric arc. An arc lamp is also called a discharge lamp, or an arc discharge lamp. The type of lamp is often named by the gas contained in the bulb; including neon, argon, xenon, krypton, sodium, metal halide, and mercury. The common fluorescent lamp is actually a low-pressure mercury arc lamp.

What application markets does Phoseon support? 
Phoseon’s ultraviolet curing products are currently used in production applications for ultraviolet curing of printing, coatings, and adhesives. In addition to printing, coatings and adhesives, there are many other applications for implementing Phoseon’s technology.

How is the SLM technology different than other UV LED solutions available on the market? 
Phoseon’s proprietary Semiconductor Light Matrix (SLM) technology is a breakthrough in high power light applications. It uses a tightly-integrated array of high-intensity light-emitting semiconductor devices. Ultraviolet SLM arrays produce significantly higher intensity light than other LED ultraviolet curing technologies. The light produced by traditional UV LEDs is limited by the discretely packaged design. Phoseon’s SLM approach is to use proprietary packaging, optics, and thermal design to optimize the output.

What is the difference between traditional UV lamps and UV LED sources?
Traditional Arc lamps use an electric arc inside a mercury gas to excite atoms, which then decay, emitting photons. Microwave lamps excite the gas via microwave emission. Xenon lamps use Xenon gas (no mercury) but can only be “flashed.”
UV LED Semiconductors (UV LED) emit a narrow bandwidth of light at the junction where doped semiconductor positive holes join with negative electrons when voltage is applied.

What is unique about Phoseon’s products?
Phoseon is the original inventor of patented SLM™ technology. None of the Phoseon products use bulbs or contain mercury.
SLM technology offers the following benefits compared to arc lamps:

  1. More reliable.
  2. High speed curing <1 sec for inks.
  3. Pinning and full cure of inks and coatings.
  4. Special technology for surface curing.
  5. No heat damage, <20 degree temperature increase during curing.
  6.  No shutters, no ozone, no mercury, no safety issues, less heat exhaust, less power consumption.

Glossary

Arc lamp
An arc lamp or arc light is the general term for a class of lamps that produce light by an electric arc. An arc lamp is also called a discharge lamp, or an arc discharge lamp. The type of lamp is often named by the gas contained in the bulb; including neon, argon, xenon, krypton, sodium, metal halide, and mercury. The common fluorescent lamp is actually a low-pressure mercury arc lamp.

Binders (for UV printing inks)
Momomers, prepolymers – usually acrylate compounds. With the help of the photoinitiators, the liquid acrylate compounds react under the influence of UV light to form a solid plastic film. Binders are produced synthetically.

Dose
Energy absorbed per unit mass.

Drop-On-Demand (DoD)
A drop-on-demand inkjet printhead differs from the continuous ones in that a physical process is manipulated to momentarily overcome the surface tension forces and emit a drop cluster of drops. The supply is not sufficiently pressurized to form a continuous stream of fluid. Printhead systems utilizing piezoelectric technology and thermal technology operate in drop-on-demand mode.

Inkjet
Printing process which bings the ink with nozzles to the surface of the material. The color output works piezoelectric or thermal. Using up to six colors is possible. The printing unit uses more than one hundred nozzles. The quality is comparable with four color printing.

Irradiance
Irradiance is radiant power arriving at the surface from all forward angles. It is usually expressed in watts or milliwatts per square centimeter (W/cm² or mW/cm²). The energy (expressed in J/cm² or mJ/cm²) delivered to the substrate depends on the line speed and the irradiance.

LED UV curing
Ultraviolet electronic light source that utilizes LEDs (light emitting diodes) used for drying inks, coatings, adhesives and other UV sensitive materials through polymerization instead of evaporation.

Nanometer (nm)
a metric unit of length equal to one billionth of a meter. It is the most common unit used to describe the manufacturing technology used in the semiconductor industry. It is the most common unit to describe the wavelength of light, with visible light falling in the region of 400–700 nm.

Peak Irradiance
Peak Irradiance is the intense peak of the focused power directly under the lamp. This is the maximum point of the irradiance profile measured in W/cm² or mW/cm².

Photoinitiator
Additive for UV curing printing inks and varnishes through absorption of UV light, photoinitiators form reactive products (radicals), leading to cross-linkage with the molecules in the binder.

Photometer
An instrument for measuring visible light, usually filtered or corrected to match the human eye response.

Piezoelectric Drop-on-Demand Inkjet (PIJ)
An inkjet design, whose prime mover is a piezoelectric material.

Polymerization
a chemical process that combines several monomers to form a polymer or polymeric compound.

Pinning
Inkjet “pinning” allows the ink to be partially cured immediately after being jetted to reduce dot gain and provide a sharper more vibrant image on an inkjet printer.

Radiometer
A device that senses irradiance incident on its sensor element. Its construction may incorporate either a thermal detector or a photonic detector. The instantaneous signal output will usually have a linear proportionally to radiant flux, and will depend on incident wavelengths. The resulting characteristic response to irradiance versus wavelength is called responsivity.

Semiconductor Light Matrix (SLM) Technology
SLM is a unique technology invented by Phoseon Technology for producing UV light. Forty years ago, mercury-based arc lamps were the only UV light source available to initiate the UV curing process. New bulb-based light sources such as Excimer bulbs, microwave sources have been introduced, but the basic technology remains the same. Phoseon Technology has developed a “bulbless” Semiconductor Light Matrix (SLM) technology to produce UV light for UV curing applications. The future of high intensity UV curing technology is small, cool and clean, with no bulb replacement required.
Phoseon’s Semiconductor Light Matrix (SLM) technology combines a dense array of light emitting semiconductor devices, with micro optics and advanced thermal technology in a cost-effective MOEMS (micro opto electro-mechanical system) package. The result is a high intensity UV light system that offers an efficient, scalable, safe, long-life, and environmentally friendly alternative to traditional UV sources.

Solvent Inks
Inks whose carrier is an organic, usually volatile solvent.

Spectral Output
The radiant output of a lamp versus wavelength. It is displayed in a variety of ways, but commonly a graph or chart of output watts plotted against wavelength. The appearance of the plot will vary dramatically, depending on the wavelength resolution used.

Thermal Inkjet (TIJ)
The Thermal Inkjet incorporates a heater located in the floor of an ink channel near the exit nozzle. A liquid-to-vapor-transition results in a volume expansion of the heated liquid.

Total UV Power
The sum of the UV energy emitted over the area of the emitting window.

Ultraviolet
(UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3eV to 124 eV. It is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet.

UV
Abbreviation for ultraviolet.

UV coating
Refers to surface treatments which are either cured by ultraviolet radiation, or protect the underlying material from its harmful effects.

VUV, UVA, UVB, UVC
Designations of UV wavelength ranges, originally for distinction of physiological effects of UV, and establishment of safe exposure limits. The generally accepted ranges are:

  • VUV: 100-200 nm
  • UVC: 200-280 nm
  • UVB: 280-315 nm
  • UVA: 315-400 nm

UVA is commonly referred to as long UV wavelengths, while UVC is considered short UV wavelengths.

UV Curable Inks
Inks which cure via treatment with ultraviolet light. These inks produce hard, durable images and are less media-sensitive than solvent or aqueous inks.

UV Curing
The polymerization of UV sensitive materials, rather than drying through the evaporation of solvents.

UV Lamp
Lamp which radiates UV light to cure the UV curable ink. The UV lamp can happen as an arc lamp or as an UV LED.

UV LED
A UV LED (ultraviolet light emitting diode) is an electronic light source with electromagnetic radiation that has a wavelength shorter than that of visible light but longer than x-rays.

UV Printing
Printing with ink visible only under ultraviolet light.

UV Printing inks
Systems ready for energy UV curing, which are activated by UV radiation. They consist of pigments, a blend of liquid acrylic esters (binders, reactive diluents) or their prepolymers, and photoinitiatitors.

Wavelength
A fundamental descriptor of electromagnetic energy, including light. It is the distance between corresponding points of a propogated wave. It is the velocity of light divided by equivalent frequency of oscillation associated with a photon. UV wavelengths are currently measured in nanometers.