Commercial Division Blog

Posted: January 7, 2016 / Categories Intellectual Property, Client Q & A

Client Q&A: I think someone is infringing my patent. What should I do?

I think someone is infringing my patent. What should I do?

By John M. Lundin

A patent does not give you the right to make the patented invention, it gives you the right to prevent others from making, using, selling or offering to sell the patented invention. But if someone is infringing your rights under your patent, how do you enforce them?


The short answer is that you can enforce your rights as a patent holder by suing the infringer in federal court. However, there are several considerations you should evaluate before doing so.

Evaluate the Potentially Infringing Product

The first thing you should do is determine whether the product actually infringes your patent. This is a question that may involve both technical expertise--something you may have if you are the inventor--and legal expertise. So, you might need to hire patent counsel to help you evaluate the potentially-infringing product. It is natural to want to avoid the cost of counsel or a technical expert before complaining about possible infringement of your patent, but it is often worth it. A patent infringement lawsuit can be very expensive. And, if things go wrong, you could end up having your patent invalidated. So, look before you leap.

In general, a product infringes the patent if it does the things described in the patent's claims. Patents typically are written as broadly as possible. For that reason, a product might be covered by your patent even though it is not what you envisioned when you created the invention. And, if the product you now make incorporates the invention, the patent might cover products that look quite different from your product. Just because it does not look like your product, it does not mean that a competing product does not infringe your patent.

At the same time, just because someone's product looks similar to your product does not mean that it infringes your patent. Someone needs to compare the potentially-infringing product to your patent's claims.

Cease and Desist Letter

A common next step is to send a cease and desist letter to the infringer. This serves several purposes, including putting them on notice of your patent in case your product is not labeled as patented, making them liable for enhanced damages if they continue to infringe, and possibly even inducing them to stop the infringement and/or take a license to your patent.

There is a downside to a cease and desist letter. It might cause the alleged infringer to bring a lawsuit for a declaration that they do not infringe (or even that your patent is not valid) in a court that is convenient for them but inconvenient for you.

You can write a cease and desist letter yourself, but if at all possible, you should have a lawyer draft it. It is an important document with legal consequences. Beyond that, the fact that you engaged counsel to research and send the letter shows that you take your claim seriously and have the means and intentions to go forward with litigation if the cease and desist letter gets no results.

Sometimes, a patent dispute need go no further than the cease and desist letter: the infringer agrees to stop the infringement, to pay for future use and/or to pay for a license for future use of the invention.


If the cease and desist letter gets no results, the next step is to sue for patent infringement.
Patent infringement suits often are expensive. They usually require technical experts and a lot of lawyer hours. This can be a big impediment, particularly if you are suing a large company that more easily can bear the legal fees. Sometimes, though, you can get outside litigation funding in exchange for a share of your recovery.

One danger in patent litigation is that a common defense to a claim for patent infringement is to attack the validity or enforceability of the patent. Recent changes in the patent law permit these challenges to take place both in litigation and before the US Patent Office.

Still, if you want to enforce your patent, sometimes there is no alternative to fighting to protect it.

What is Your Remedy

A patent infringement lawsuit normally asks a court to prevent the defendant from using the patented invention and to pay damages for past infringement. As a practical matter, the goal is to get the infringer to pay for past use and to pay you a license fee for future use of the invention.


We can advise you on how to protect your rights as a patent holder, including the options for using litigation finance to fund a patent infringement lawsuit. And, if you need a specialized patent attorney who is admitted to practice before the US Patent and Trademark Office, we can refer you to one.