How to legally build on your competitor’s patent
In a series of blog posts, Marco Coolen offers a glimpse into his work as a Dutch and European patent attorney at AOMB.
Published on June 7, 2026
Marco, a patent attorney at AOMB since 2013, shares his expertise on IO+ about patents—how they work, why they matter, and when they lose their value.
Imagine being allowed to build on your biggest competitor's patented work. No licensing fees, no lawsuit, no complicated negotiations. Just legally.
It sounds like a trick, but it is not. It is simply part of the rules of the patent system itself. Entrepreneurs sometimes see a patent as a closed gate. Something you have to avoid at all costs. A barrier that slows down your innovation. But if you look more closely, you will discover that there are openings in that gate. You just need to know where they are.
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Marco Coolen, photo © Bart van Overbeeke
Research is allowed
One of those openings is surprisingly wide. In Europe, you are allowed to use a patented invention for research and development. This means you may analyze, test, and improve a technology, as long as those activities are aimed at building knowledge. Only when you commercially launch a product that falls under the patent does a problem arise.
For R&D, then, there is often more room than entrepreneurs think. In fact, many companies already start developing while a competitor’s patent is still in force. They prepare their technology so they are ready the moment the protection expires.
Time as a strategy
A patent has a maximum term of twenty years. That may sound long, but in sectors with long development cycles, it can be surprisingly short. If you already conduct research during the term of a patent, you can build up a head start. By the time the patent expires, your product may already be ready. Without licensing fees. Without dependence on the original inventor.
The private-use exception
There is another interesting exception. In Europe, anyone who experiments without a commercial purpose is often on safe ground. After all, patent law is designed to regulate commercial exploitation. This means that at home, in a lab, or in an educational setting, you often have more freedom than many people realize.
The hidden advantage
And there is another scenario entrepreneurs sometimes forget. What if you were already working with a technology before someone else obtained a patent on it? In certain situations, you may then be able to rely on so-called prior user rights. If you can prove that you were already using the technology before the patent application was filed, you may, under certain conditions, continue doing so. The other party’s patent will then not block you completely.
From barrier to strategy
The difference, then, is not only about who owns the patent. The difference lies in who knows the rules of the game. Many companies look at patents and see a wall. But once you understand how the system works, that wall often turns into a map with strategic routes.
Research, planning, timing: that is why patents are not just legal instruments. For entrepreneurs, they are also a strategy for innovation.
The World of Patents
Every Sunday, Marco Coolen takes us into the world of IP and patents. Read more of his columns here.