The Patent Light

In a previous post, I explained that when courts usually interpret or “construe” claim terms, they first look to the plain and ordinary meaning of the claims, then they look to the specification for unique definitions or use of the terms, they also look to the prosecution history, and finally they review extrinsic sources, such as technical dictionaries used in the field of the invention.

One exception to this procedure occurs when courts interpret what is called a “means plus function” claim or claim element.  This type of claim element is “statutory” meaning that it is governed by a provision in the patent statute.  It also called a “112, Paragraph 6” claim term under the older pre-AIA scheme.  After the AIA revisions to the Patent Act, the paragraphs in section 112 were numbered.  So, now patent attorneys refer to this paragraph as Section 112(f) or 35 U.S.C. 112(f).  Thus, when patent attorneys refer to “means plus function” claim, Section 112, Paragraph 6 claim, or Section 112(f) claim, they are referring to the same type of claim or claim element.

The current section 112(f) statute reads as follows:

(f) Element in Claim for a Combination.—

An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.

35 U.S.C. 112(f)

When courts construe “means plus function” clauses, they first identify the claimed function.  After identifying the claimed function, courts then determine what structure, if any, is disclosed in the specification that corresponds to the claimed function.

The very real danger when using this type of claim language is that if there is no corresponding structure in the specification, the claim element (and the entire claim) is deemed indefinite, and hence, invalid.

In order to qualify as “corresponding,” the structure disclosed in the specification must not only perform the claimed function, but the specification must clearly associate the structure with performance of the function.  This association must be clear to a “person of ordinary skill in the art” or what we call a “POSITA.”  In other words, would a POSITA be able to readily associate the structure in the specification to the claimed function?  If not, then the claim is invalid for failure to satisfy the definiteness requirement of another patent statute.

In some circumstances, the specification can provide adequate structure to support a means-plus-function limitation by calling out standard electronic components, even without detailing the component’s internal circuitry or operation. See, for instance, S3 Inc. v. NVIDIA Corp., 259 F.3d 1364, 1370 (Fed. Cir. 2001). In S3, the claims recited a “means. . . for selectively receiving.” Id. The specification disclosed a “selector” as the corresponding structure without providing any information about the selector’s circuitry or operation. Id. The patentee, however, “presented evidence that a selector is a standard electronic component whose structure is well known in this art, and that such standard components are usually represented in the manner shown.” Id. Accordingly, the Federal Circuit found that the selector provided adequate structure for the “means for selectively receiving.” Id. at 1371.

By contrast, reciting a generic term for an electronic component is insufficient if an ordinary artisan would not associate the claimed component with a specific, well-known structure. Ergo Licensing v. Carefusion 303, 673 F.3d 1361, 1365 (Fed. Cir. 2012).  In Ergo Licensing, the patent claimed a “programmable control means having data fields describing metering properties of individual fluid flows.” Id. at 1363. The patent disclosed a “control device” as the corresponding structure, without any additional details about its design or circuitry. Id. Importantly, the control device in Ergo Licensing could have been one of “at least three different types of control devices commonly available and used at the time to control adjusting means.” Id. at 1364.  In this instance, the Federal Circuit held that “[t]he recitation of `control device’ provides no more structure than the term `control means’ itself, rather it merely replaces the word `means’ with the generic term `device.'” Id. at 1363-64. Thus, an ordinary artisan would not associate the “control device” with a specific electronic component. Id.

Means-plus-function claiming involves a quid pro quo. When a patentee desires the convenience to express claims in terms of function, he or she then has a duty to clearly link or associate structure with the claimed function.  If the specification is not clear as to the structure that the patentee intends to correspond to the claimed function, then the patentee has not paid that price associated with the convenience of using a means plus function claim element.

Thus, a means-plus-function clause is indefinite if a POSITA would be unable to recognize the structure in the specification and associate it with the corresponding function in the claim.” All-Voice Computing PLC v. Nuance Commc’ns., Inc., 504 F.3d 1236, 1241 (Fed. Cir.2007) (citing Atmel Corp. v. Info. Storage Devices, Inc., 198 F.3d 1374, 1381-82 (Fed.Cir.1999)).