Where Is Direct Imaging Headed?

Estimated reading time: 5 minutes

At the 2026 EIPC Summer Conference in Lithuania, Dennis Pusch, sales and business development manager for direct imaging at Schmoll Maschinen, examined the latest developments in UV light source technologies and the real-world trade-offs manufacturers must consider. If you're evaluating an imaging system upgrade or simply want to understand where the technology is headed, this interview is well worth your time.

Marcy LaRont: Dennis, in your presentation, you asked, "If I offered you a UV light source with twice the output power, would you expect your direct imaging process to perform better?" What did you hope would be the response?

Dennis Pusch: I hoped they would say, “Yes, of course. I would expect the exposure time to be much shorter. More power equals faster exposure time.” I wanted to highlight that more power does not necessarily mean everything is better.

LaRont: So, what is the answer to that question?

Pusch: From an application perspective, certain factors that influence the exposure result need to be considered, such as matching wavelengths, material thickness, and overall conditions of the panel. From a cost perspective, it is not guaranteed that a high-power light source will be low-maintenance. Most people may think that a stronger light source has a bigger form factor, which can assume a higher price tag, or, practically speaking, make maintenance work more challenging. But it does not have to be like this always, which I tried to address in my presentation.

LaRont: You also asked, "Why do companies invest in direct imaging to begin with?" Tell me more about some of those technical and economic trade-offs.

Pusch: PCB manufacturers invest in direct imaging for a variety of reasons, from replacing outdated technology to moving from an analog process with phototools to a fully digital process with direct imaging. DI systems have become more capable as they’ve evolved from single- to multi-wavelength systems, offering more flexibility and usability for different applications such as photoresist or solder mask exposure.

Older equipment is more limited in this perspective and generally have higher running costs, and service and spare parts are harder to get, which leads to increased downtime. Any time a machine isn’t producing, it’s not making any money. Other reasons for PCB manufacturers to invest in new DI systems can simply be to add capacity, while for others this investment can be seen as a technological upgrade or an enabler for tomorrow’s requirements.

LaRont: Earlier, you alluded to the idea that while technology is better for finer features and denser designs. But the throughput speaks to cost. Do you necessarily want to replace your old imaging process?

Pusch: There are good reasons to keep working with the existing systems, but I emphasized making the correct choice when considering investment in a new technology. The correct choice can affect capabilities: finer feature sizes, higher accuracy, and so on. It will also affect the cost side.

What is the optimal machine configuration? Do I need a manual machine, or maybe a fully automated machine? In direct imaging, we talk about light engines; the number of light engines directly impacts throughput. For example, do I need to equip the machine with three or five photoheads? This impacts both the initial equipment investment as well as long-term service and maintenance cost.

LaRont: Does that also dictate whether you go with a standard LDI machine, or opt for three or five heads, which is quite sophisticated.

Pusch: Yes. Initially, LDI systems had single wavelengths from the lower UV spectrum, dedicated to resist exposure. Then, shortly after, solder mask exposure became more relevant, and multi-wavelength systems became available. At Schmoll, we have been promoting our multi-wavelength systems for the past decade.

I highlighted that a single-wavelength system, when configured correctly, can deliver significant benefits. Light sources have developed over time. Now we can configure a tool that operates at a single wavelength and works equally well for certain applications, while allowing us to achieve much higher output power. That means a much faster exposure time. Moreover, if this allows you to use fewer photo heads than before, it lowers the final cost of such a tool.

As a result, the investment becomes more attractive while maintaining high performance, perhaps providing features to address today's applications even better. I’m thinking about better exposure for very thick materials, which we are seeing more of, and about optical depths of focus, which play a big role because panels aren't always flat once you stack them into large multilayers.

Putting all of this together, there are three major pillars: resolution, throughput, and optical depths of focus. Schmoll has developed a solution that effectively addresses these three requirements, enabling us to offer customers a range of options tailored to their production needs. These range from compact, versatile systems suitable for both photoresist and solder mask exposure with a lower initial investment, to fully automated in-line solutions designed for high-volume manufacturing and maximum throughput.

LaRont: Can your customers retrofit existing Schmoll machines with some of this new technology, or are they simply looking at a capabilities upgrade in their next system purchase?

Pusch: Schmoll always has possibilities, and we are known for finding solutions. In many cases, a retrofit may be possible, but it’s a case-by-case decision because we are continuously expanding our product portfolio. Our “Monobeams,” which are photohead systems with a single wavelength, are super powerful and deliver excellent performance. The Monobeam follows the exact design of our normal multi-wavelength photohead. We continue to be flexible with our modular systems, but most often the new capabilities come in the new equipment. A retrofit will need to be a case-by-case decision.

LaRont: With the newer LDI machines, whether it's a single image wavelength or multiple, what is the cost argument for purchasing a more automated solution vs. a less automated solution?

Pusch: For customers, it has to do with the restrictions in their existing environment, infrastructure, and the room itself. Cleanroom space is expensive and usually space is restricted. If there are none of these issues present, today's DI machines can be integrated with automation systems available from Schmoll or a third-party.

What benefit is the customer aiming for with automation? What are the conditions they want to automate in their process? If our customer is doing a lot of prototyping or high-mix, low-volume production, then panel sizes can vary quite often. If, for example, you’re doing a variety of applications: inner layers, outer layers, solder mask, all on the same machine, then this obviously brings a different degree of challenge to automating the process: a dedicated inline system for inner layers, and a dedicated inline system for outer layers, optimized for a specific panel size, certainly makes the automation easier.

LaRont: That makes sense. What did you hope the audience would take away from your presentation?

Pusch: Selecting a proper direct imaging tool requires thorough preparation and research into available options. Although they may appear quite similar, not every LDI system is the same. The technology may appear the same on the surface, but the difference lies in the details. At Schmoll, we develop solutions tailored to customer needs. With current trends in miniaturization, we focus on those three pillars I mentioned: resolution, throughput and depth of focus. But we want to have this at a very attractive level of performance, so exposure speed stays very relevant.

LaRont: Dennis, thank you so much for your time. I enjoyed your presentation yesterday, and safe travels on your return.

Pusch: Thank you.