The Federal Circuit has held that functional language in a software claim should be given patentable weight. In re Jasinski, No. 2012-1482 (Feb. 15, 2013). Accordingly, the Court reversed the U.S. Patent and Trademark Office's rejection of claims as allegedly anticipated. If applied to claims in other software patents and patent applications, this decision, although designated non-precedential, could be significant.
Specifically, the patent examiner had contended, and the Board of Patent Appeals and Interferences agreed, that certain recitations were merely statements of intended use, and not to be given patentable weight. These include recitations in a claim preamble of "a method for verifying the accuracy of logical-to-physical mapping software designed for testing memory devices," and a recitation in the claim body of:
[d] comparing said fail memory locations derived by said logical-to-physical mapping software to said various predetermined memory locations to verify the accuracy of said logical-to-physical mapping software.
The Federal Circuit Panel, in an opinion authored by Judge Moore, and joined by Judges Prost and Clevenger, agreed with the patent applicant that
[n]ot only does the “to verify/verifying” language refer to the “essence of the invention,” it also provides the criteria by which the previously-recited comparing limitation is analyzed. We thus conclude that the “to verify/verifying” language is limiting. See Vizio, Inc. v. Int’l Trade Comm’n, 605 F.3d 1330, 1341 (Fed. Cir. 2010) (“[T]he ‘for decoding’ language . . . is properly construed as a limitation, and not merely a statement of purpose or intended use for the invention,because ‘decoding’ is the essence or a fundamental characteristic of the claimed invention.”). The Court then reversed the Board's affirmance of the examiner because the Court agreed that the primary reference did not anticipate the claims.
Editorial comment: this could, as stated above, be a significant decision. Anyone who has prosecuted software patent applications has felt the frustration of the patent examiner asserting that seemingly meaty claim language merely recited a "non-structural or functional limitation" and thus was not entitled to patentable weight. This decision will be a good weapon against rejections that use such reasoning. (And even if patent examiners are not persuaded, this is a case to be cited in appeal briefs.)
The PatentlyO blog suggests that this decision will likely result in "continued growth in the use of functional claim language." Perhaps so, and one cannot deny that functional language, especially if not interpreted under the rubric of 35 U.S.C. 112, can be very broad. Nonetheless, I believe that a claim drafter should avoid functional claim language wherever possible.
Often functional language cannot be avoided; you will certainly see it in many claims I have drafted. However, I will not start using it more because of this decision. Instead, good software claims (like good mechanical or any other patent claims) should, wherever possible, recite a clear structure that is not dependent on a particular purpose or use. I say this for many reasons: to promote clear claim constructions, to keep prosecution clean and simple, and because one never knows what future courts will do.