Functionally-Described Structural Recitations in Method Patent Claims Can Be Indefinite

A patent claim’s recitation of a structural feature was held indefinite under 35 U.S.C. § 112 because the court found that that the claim term in question – “processing system” – was indefinite functional language. Thus, the court in Cox Communications v. Sprint Communications, No. 12-487-SLR (D. Del. May 15, 2015) granted partial summary judgment in favor of Cox (declaratory judgment plaintiffs) because the “processing system” recitation in six of the asserted patents was indefinite.

The six asserted patents at issue—US patent nos. 6,452,932; 6,463,052; 6,633,561; 7,286,561; 6,473,429; 6,298,064 ("the '064 patent")—share a common specification. The court used claim 1 of the US 6,633,561 as an exemplary claim. That claim, a method claim, recites various steps that involve a “processing system,” which the Court found was a structural limitation:

A method of operating a processing system to control a packet communication system for a user communication, the method comprising:

receiving a signaling message for the user communication from a narrowband communication system into the processing system;

processing the signaling message to select a network code that identifies a network element to provide egress from the packet communication system for the user communication;

generating a control message indicating the network code;

transferring the control message from the processing system to the packet communication system

receiving the user communication in the packet communication system and using the network code to route the user communication through the packet communication system to the network element; and

transferring the user communication from the network element to provide egress from the packet communication system.

At issue was whether the “processing system” is definite under (pre-AIA) 35 USC § 112, second paragraph, which states, “the specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.”

The Court weighed the public notice function of § 112 against limitations of the English language. To summarize, the court explained that the claims must be precise enough—when read in view of the specification, prosecution history, and other evidence—to give notice of what the patent excludes from the public domain.

Not surprisingly, the parties here offered competing claim constructions for the recitation of a “processing system.” Sprint, the patent holder, advocated the “plain and ordinary meaning” or, alternatively, “a system that processes signaling to assist in call control.” Cox argued that “processing system” was indefinite because it was merely functional language. Cox also offered an alternative construction, namely that the “processing system” should be construed as communication control processor for some patents and a call connection manager for other patents. Cox further argued that even this alternative construction is indefinite for the same reason as “processing system.”

The court agreed with Cox that the “processing system” is indefinite functional language. The court noted that functional language isn’t per se indefinite so long as the context of the disclosure and the knowledge of a person of ordinary skill in the art is sufficient to define the breadth of the recitation. In the instant case, the court reasoned that the specification did not sufficiently define the bounds of the limitation “processing system” to one of ordinary skill in the art. Turning to extrinsic evidence, the court found that the phrase “processing system” does not have a particular meaning in the art.

Because it couldn’t define the scope of the “processing system” recited in the method claims, the court found those claims indefinite. Partial (there are other patents at issue) summary judgment was granted in favor of Cox.

There are a few takeaways here. The appropriate terms of art should be used as often as possible. Also, patent applicants aren’t completely precluded from using a mix of functional and structural language in method claims. One Federal Circuit case discussed by the court in the Cox decision held that such claims can be definite if the scope “is clearly limited to practicing the claimed method [in the] requisite structure.” Microprocessor Enhancement Corp. v. Texas Instruments Inc., 520 F.3d 1367 (Fed. Cir. 2008). The outcome of the instant case may have been different had the specifications of the patents at issue included a more specific definition of “processing system.”

 

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