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Disclosing An Algorithm in a Patent Application

Posted Wednesday, November 16, 2011 by Mike Gibbons

On November 4, 2011, the Court of Appeals for the Federal Circuit (CAFC) issued an opinion in Typhoon Technologies v. Dell, in which the Court found that disclosing an algorithm in prosaic form was permissible.

The Typhoon Technologies patents at issue included “means-plus function” claims, in which the patentee describes structure for carrying out the claim in the specification portion of the patent application. The patent claims included “means for cross-referencing” functions, and then provided two textual descriptions of the technique of cross-referencing.

For example, one section of the specification read, “Cross-referencing entails the matching of entered responses with a library of possible responses, and, if a match is encountered, displaying the fact of the match, otherwise alerting the user, or displaying information stored in memory fields associated with that library entry.”

At the District Court level, the patent had been invalidated for indefiniteness in the claims reciting the “means for cross-referencing.” Previous CAFC holdings, including Aristocrat Technologies v. IGT (2008), have required that when a means-plus function claim recites an algorithm, that algorithm must be disclosed in the specification. In Aristocrat, the patent claim at issue was a “game control means arranged to control images displayed on the display means,” but the specification disclosed only “appropriate programming” to actually control the images. The CAFC had ruled “appropriate programming” was indefinite, and stated the disclosure of an actual algorithm to carry out the programming would have been required for the claim to be definite.

Returning to Typhoon Technologies, the District Court relied on the Aristocrat Technologies holding to invalidate the “means for cross-referencing” claim. But the CAFC held that the portions of the specification discussing cross-referencing (including the above excerpt) sufficiently disclosed an algorithm. The discussion recited more than just “appropriate programming.” The CAFC reminds us that Aristocrat doesn’t require that a specification have a listing of source code or a highly detailed description of the algorithm. All that is needed is to disclose enough information such that one with skill in the art reading the specification would know how to make the invention.

Here, the CAFC ruled that the descriptions within Typhoon Technologies’ patents were adequately detailed for one with skill in the art to understand how to implement the cross-referencing function. The prosaic form chosen by the patent attorney to express the function of the cross-referencing aspect of the invention was suitable.

The lower court decision as to the invalidity of the Typhoon Technologies patent on the grounds that these claims were indefinite was thus reversed.

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