The importance of including algorithms in software patents

The U.S. Court of Appeals for the Federal Circuit recently issued its second decision in the past month in which it found a software patent to be invalid for failure to disclose an algorithm that the software uses to perform its function.  In each case, the patents’ claims involved “means plus function” language such as the phrases “control means” and “access means”.

In Ergo Licensing, Inc. v. Carefusion 303, Inc. (No. 2011-1229, March 26, 2012), the court considered a patent covering an infusion system for metering and delivering fluids into a patient’s body.  An element of the patent’s claims was a “programmable control means” that had data fields with metering properties of individual fluid flows.  The court interpreted this element as a “means-plus-function” limitation, for which Section 112, ¶ 6 of the Patent Act requires the patent to disclose a corresponding structure.  In this case, the court said that the patent’s disclosure corresponding structure of a general purpose computer or control device was not sufficient.  Instead, the court required that the patent disclose the algorithm under which the control is performed.  “Requiring disclosure of an algorithm properly defines the scope of the claim and prevents pure functional claiming.”  On this basis, the court found the claims to be indefinite.

In the second case, Noah Systems, Inc. v. Intuit, Inc. (No. 2011-1390, April 9, 2012), the court reviewed a patent covering an automated accounting system.  Each of the patent’s claims included an “access means,” such as a “means for providing access to [a] file of [a] financial accounting computer.”  Here, the court again found the claims to be invalid because the patent did not disclose an algorithm by which access is performed.  The court noted that the algorithm didn’t necessarily have to be a mathematical formula:  “The specification can express the algorithm in any understandable terms including as a mathematical formula, in prose, or as a flow chart, or in any other manner that provides sufficient structure.”  (citing Finisar Corp. v. DirecTV Grp. Inc. (Fed. Cir. 2008)).   The patent did include an algorithm for a passcode function, but the court found even that disclosure to be lacking.  In addition to the passcode function, the court also required disclosure of an algorithm for enabling performance of the delineated operations.

The recent decisions illustrate how caselaw governing the validity of software patents continues to evolve.  While it has long been settled that software patent applications do not need to disclose source code, the Federal Circuit’s caselaw shows that it wants some description beyond purely functional language.   Although the Ergo Licensing and Noah Systems cases were limited to software patents with means-plus-function language, when working with a patent attorney or agent to prepare your patent application,  is a good practice to give him or her process flow diagrams, functional design specifications, and algorithms that describe how the software actually works.  The stronger your disclosure, the less likely that a court (or the USPTO) will find the claims to be indefinite or not enabled in the future.

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