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Written by: Danielle Burke on Aug 3rd, 2017
The optical design of UV LED curing systems is critical to their performance for curing of inks, coatings and adhesives. This post will explain the importance of optical design and provide examples of optical options available.
Optical design of UV LED curing systems is important to ensure that your system works efficiently and that all of the output generated by the UV LED system reaches the target material and cures the correct surface area. If the optical design of the UV lamp is not optimized, under-curing or over-curing can occur. Poorly designed optics placed in a UV LED curing system can result in unnecessarily high intensity causing over-curing of the target. Over-curing of target materials affects the quality of the final product. For example, in print applications, if the ink is over-cured, the process results could be banding and other issues. Conversely, inefficient design or poorly fitted optics can result in a significantly reduced light output onto the target area resulting in under-curing of the target material.
Greater intensity is not always the goal with UV LED curing systems, but the direction of light and dose (energy density) are critical. As a result, it is important to have the optimum optical design for your application and to ensure that you work with a reputable lamp supplier with a rigorous quality management system in place.
Achieving the optimum energy density in each application is a challenge for UV LED curing systems designers. If energy density is too high the material will be over-cured, too low and the material will not cure consistently if at all. For system designers, the first step is to determine the optimum energy density for your application.
A further challenge in optical design is in material selection. Exposure to such high levels of UV light can degrade traditional materials over time, reducing optical output. ProPhotonix has over 10 years of experience in supplying UV LED based systems and has a well-established, reliable supply chain. Our extensive quality control, lifetime testing and burn-in facilities ensure repeatable, quality UV solutions.
Optical requirements can differ from one application to another. For this reason, ProPhotonix has built flexibility into the design of our UV LED systems. Each product in the COBRA Cure FX series is configurable allowing users to select the optimum optical set-up for their application.
The COBRA Cure FX series is available in highly collimated, angle reduced and natural emission profile configurations. The highly collimated version is typically a zero degree option. This configuration has a narrow illumination angle, which ensures low risk of curing at the print head. However, this configuration is not suitable for applications that require a wide curing profile.
An angle reduced profile is the second option. This configuration provides an optical output angle of forty degrees. While still a relatively narrow illumination angle ensuring low risk of curing at the print head, this option produces high dose levels and is suited to applications requiring a wide curing profile. The angle reduced profile is a popular option, as it provides a tighter angle than many systems, which results in reduced reflections in the system and significantly reducing the risk of unintended curing. As this configuration maintains high intensity levels, especially over wide working distance ranges, it is ideal for applications such as inkjet printing.
The final option is a natural emission profile which offers a sixty degree angle. This configuration has the highest level of dose at short working distances (<5mm) of the options presented in this post, but dose reduces significantly past 5mm. With a wider illumination angle there is an increased risk of curing at the print head. The type of system can be used in industrial applications such as ink curing, counterfeit detection and medical applications.
ProPhotonix has over 15 years of experience working with UV LEDs. As an experienced LED system manufacturer, ProPhotonix is expert in working with complex requirements to provide the optimum solution for your system’s needs. Custom solutions are also available where we can adapt many of our existing systems to meet your specific requirements. For these types of applications, ProPhotonix has an in-house optical engineering team that can develop an optimized illumination system to satisfy your requirements. Contact us at firstname.lastname@example.org to find out more.