UV LED Development
UV LED development are playing a more and more important role at printing industry,UV coating indursty and adhesive industry. UV-LED cured applications are now technically feasible but they are still a complement to traditional arc technology.
With such a convincing case for using UVLED’s why has the technology not been more widely adopted?
• Non availability of dies (semi conductors)
• Offering sufficient light output at suitable
• Lack of shortwave radiation (below 350nm)
• Lack of suitable inks formulated to react to the outputs from UV LED light sources
But this is all starting to change……
Advances in LED technology over the past 10 years (1999 – 2009):
|Cost||$ 160/W Æ $ 6/W|
|Irradiances||1 W/cm2 Æ >10 W/cm2|
|Active Areas||100 X 100 μm2 Æ >1000X1000 μm2|
|Efficiencies||<10% Æ >50%|
LED research is being driven by the multi-billion dollar general lighting industry.
Increasing Power / Reducing Footprint
• Denser chip packing
• Driving LED’s harder
• More cooling (water cooling for high speed printing)
Current UV inks for LED curing are being formulated around either 395nm or 365nm
• 365nm offers better flexibility in formulation but the available LED dose is much lower
• 395nm LED‘s offer higher peak irradiance
• The longer wavelength has more penetration into the ink which is better for heavily pigmented inks or thick layers.
Technology convergence will continue over the next five years. UV-LED’s are adressing a wider range of existing niche applications as imaging onto very heat sensitive media, particularly where performance justifies the added value.
Mainstream graphics – eventually…