The scope of protection of a Patents is determined by the claims and their interpretation based on the description. If the claim only defines a function without structure, the description is used to determine the scope of protection under US patent law in accordance with 35 USC 112 para. 6. In a new decision, the CAFC has revised its 10-year jurisprudence according to which the use of the word “means” was decisive.

The Court of Appeals for the Federal Circuit (CAFC) has taken the case of Williamson v. Citrix as an opportunity to revise its recent jurisprudence on means-plus-function claims. claims has been revised. It has returned to the previous principle that claims must be examined on a case-by-case basis for the applicability of 35 USC §112 para. 6.

Williamson had obtained a patent for a “virtual classroom”. In detail, the claim defined the functions of the teacher computer and the student computers, which could communicate with each other via a server over the Internet so that each student could contact both the teacher and fellow students.

One of the features of the claim was: “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 a streaming data module”. The court of first instance had interpreted this claim as “means-plus-function” within the meaning of §112 para. 6. Since the description did not contain an algorithm for implementing all the functions mentioned, the court declared the claim invalid due to lack of disclosure.

On appeal, the CAFC affirms this judgment, correcting the principles of its more recent jurisprudence.

About 10 years ago, the CAFC established a new standard when considering the applicability of §112 para. 6. It said that the absence of the word “means” created a strong and not easily overcome presumption that §112 para. 6 was not applicable. He had confirmed and even tended to reinforce this standard of review in several subsequent decisions.

In the present decision, he throws this strict, formalistic standard overboard. It sees no reason to attach such great weight to the word “means”. The standard of review should now (again) be whether the claim wording in question means a sufficiently definite structure for the skilled person. Thus, if the word “means” is used, there is a rebuttable presumption that §112 para. 6 is applicable. If it can be shown that the claim does not define a sufficiently definite structure, Sec. 112 para. 6 is applicable. Conversely, the absence of the word “means” does not exclude the applicability of Sec. 112 para. 6 if there are reasons to do so.

In this specific case, the CAFC assesses the word “module” as an empty placeholder, such as “means”, “element”, “mechanism” or “device”. Thus, the claim is to be read as “means-plus-function”. The fact that a person skilled in the art is readily able to program the function on the basis of the claimed function does not mean that a sufficiently defined structure is disclosed. It does not say how exactly the module interacts with the other parts of the system.

Furthermore, the CAFC did not find an algorithm or the like in the description which explains by means of a mathematical formula, a method or a flow chart how the module realizes the specified functions. Thus, the claim is indefinite and therefore invalid.

This judgment returns to the correct standard. The formality of whether the word “means” appears or not is again subordinated to the substantive question of whether only a function or also a structure is revealed.

In practice, this means that if the Applicant tries to formulate the patent as broadly as possible and therefore only mentions functions in the claim but not specific means, then, according to U.S. jurisprudence, it must be examined whether §112 para. 6 is applicable. This limits the protection of the claimed function to the specific “structures” and their equivalents mentioned in the description. This means that the claim is much narrower than it may appear at first glance. If the Applicant then tries to avoid this restriction in the description by not naming a specific structure, the claim is indefinite and therefore invalid.

Left: www.cafc.uscourts.gov/sites/default/files/opinions-orders/13-1130.Order.6-11-2015.1.PDF