by Dennis Crouch
In a major 2014 decision, the Supreme Court raised the standard of definiteness under 35 U.S.C. 112(b) – now requiring that the scope of patent claims be “reasonably certain” to one of skill in the art. Nautilus v. Biosig. Historically, “reasonably certain” is a high standard and has been linked with the beyond-a-reasonable-doubt standard in criminal law. I.e., claim scope that is reasonably certain may also be seen as having its scope defined beyond a reasonable doubt. The higher standard can also be contrasted with the prior Federal Circuit that only invalidated ambiguous claims that were both insolubly ambiguous and not amenable to construction.
Despite the dramatic potential of Nautilus, the Federal Circuit has largely muted its impact.
The one area where patent-challengers see continued success is when means-plus-function claims lack appropriate structural support in the underlying patent document. 35 U.S.C. 112(f) allows a patentee to claim a “means” for accomplishing a specified function without reciting the actual structure of the mechanism or material used to accomplish the function. However, as a rule of construction, the statute indicates that the “means” will be construed to “cover the corresponding structure, material, or acts described in the specification and equivalents thereof.” The impact is that, although the claim appears to broadly cover a “function” it will be construed to be much more limited. When an applicant follows this claiming approach, but fails to specify any corresponding structure within the specification then the claim is deemed invalid as indefinite.
In Eon Corp v. AT&T (Fed. Cir. 2015), the Federal Circuit has affirmed that Eon’s asserted patent claims are invalid for failing to specify the structure associated with a purely functional claim element.
Eon’s U.S. Patent No. 5,663,757 covers a data processing station that facilitates instant purchases while watching a television program. The patent was written back when the wort “means” was still popular among patent drafters. Here, the district court found that eight separate “means” claims were directed to “complex” computer software such as “causing selected themes to automatically display a second menu.” Based upon that undisturbed complexity fact-finding, the appellate court found that a structure in the form of the software algorithm should have been disclosed. Because no software algrithms were disclosed, the software means claims failed and were properly held invalid as indefinite.
Of interest here, the Federal Circuit reasoned that the algorithm is necessary to “avoid pure functional claiming.” Quoting Aristocrat Techs. Austl. Pty Ltd. v. Int’l Game Tech., 521 F.3d 1328 (Fed. Cir. 2008).
A general purpose computer is flexible—it can do anything it is programmed to do. Therefore, the disclosure of a general purpose computer or a microprocessor as corresponding structure for a software function does nothing to limit the scope of the claim and “avoid pure functional claiming.” Aristocrat. As such, when a patentee invokes means-plus-function claiming to recite a software function, it accedes to the reciprocal obligation of disclosing a sufficient algorithm as corresponding structure.
Although the court here highlights the doctrinal point of “pure” functional claiming — claiming function with no limiting structure — the actual facts are that the disclosed microprocessor and does provide some amount of structure. As with abstract-idea analysis, it seems here that the question is not so black-and-white, but rather whether some magical threshold has been crossed.
The case also offers some hints to the ongoing debate over subject matter eligibility of computer implemented inventions. In particular, the court reiterated its prior statements that a “the general purpose computer becomes a special purpose computer when loaded with the special programming.”