There are many reasons software patents cause so much trouble. The Patent Office does not do a good job reviewing software patent applications to see if they are claiming something new. And these patents often describe the purported invention with highly vague and ambiguous language. Software patents also tend to claim every way to solve a problem, rather than the particular solution developed by the applicant. This is known as functional claiming. While it may seem like an arcane legal dispute, functional claiming is a key feature of overbroad software patents.

The Patent Act already contains a provision that is supposed to limit the scope of functional claims. If a claim describes an invention functionally, its scope is supposed to be limited to the structure the applicant actually discloses in the patent. Unfortunately, the Federal Circuit has interpreted this law narrowly and makes it far too easy for patent applicants to avoid it. Essentially, as long as a patent applicant avoids using some magic words, then the court will not apply the law.

Today EFF filed an amicus brief on this issue in a case called Williamson v. Citrix. The key claim language in this case is as follows:

a distributed learning control module for receiving communications transmitted between the presenter and the audience member computer systems and for relaying the communications to an intended receiving computer system and for coordinating the operation of the streaming data module.

As you can see, this claim describes the invention in terms of what it does rather than how it does it. But the Federal Circuit did not treat this as a functional claim. Instead, the court applied a “strong presumption” that where an applicant does not use the magic words “means for” then the claim will not be treated as a functional claim. This allows the patent applicant to skirt the law.

The defendants have asked the Federal Circuit to rehear this case en banc and reject the “strong presumption.” We agree. Our brief argues that courts must analyze the substance of the patent claim rather than looking to whether or not the applicant used certain magic words. If an applicant describes the invention in terms of what it does, then the Patent Act’s restrictions on functional claiming must be applied.

Restrictions on functional claiming will not solve all problems with software patents. But they will make it harder for applicants to come up with one way to solve a problem and then monopolize all ways to solve that problem. This has been a major reason why software patents are so useful to patent trolls. We urge the Federal Circuit to hear this case en banc and restore the Patent Act’s prohibition of overbroad functional claims.