Patent demand letters are stressful. Before responding or ignoring, evaluate infringement, patent prosecution history, ownership, and litigation history.
Has your startup received a “demand” letter asserting that you are infringing on a patent? Real infringement of valid patents does occur, and some of these patent demand letters are legitimate. However, many patent demand letters are sent in less than 100% good faith. For example, the sender of the letter may not be worrying about the actual merits. Rather, they may be betting that the startup will settle quickly to avoid litigation costs.
Don’t immediately contact the sender, and don’t ignore the letter either. Instead, calm down and evaluate the facts, preferably with the help of a patent attorney. Is there a plausible infringement problem or not? How to tell the difference? I discuss a few common methods below.
To start, get: 1) a copy of the issued patents discussed in the demand letter, 2) the USPTO prosecution history of these patents, and 3) information about the allegedly infringing product.
Warning: If the letter doesn’t provide actual issued patent numbers, or if the letter only cites patent application numbers, the probability that the letter is bogus becomes higher.
Look at the independent claims for each patent (claim 1 is not always the broadest claim). See if your allegedly infringing product infringes the entire wording of any independent claim. If so, look at the relevant dependent claims for more detail. If the letter argues contributory infringement, combine your product with the other accused product for this analysis. Check if your marketing literature is promoting this combination. If so, you might want to change it. Claim chart analysis can help here.
Do your homework
The patent prosecution history for the patents in question is usually downloadable from the USPTO. It can be very relevant. You will see any previous litigation. You will also see any previous USPTO reexaminations or Patent Trial and Appeal Board (PTAB) challenges. Finally, the history will tell you if the patent applicant had to make significant concessions during the patent prosecution history.
You can use the patent’s USPTO assignment records to better understand the relationship between the sender and the actual patent owner of record. This is not always clear. What is this relationship, and is the purported patent owner the real patent owner?
If there is a history of litigation, check it out. Patent litigation usually takes place in Federal Courts. This is usually available through PACER (Public Access to Court Electronic Records) and a number of other sources. Has the patent owner been filing a lot of lawsuits and then settling before the court reaches a decision. Alternatively, does the patent owner usually win?
There are many other issues that can be explored as well, but this type of information can help you and your attorney better evaluate what your next steps should be.