The Software IP Report

Indefiniteness of Software Patent Claims; Certificates of Correction

By Charles Bieneman

Categories: 35 U.S.C. § 112, Software Patents, The Software IP Report

Whether means-plus-function claims were indefinite, and the effect of a certificate of correction on correcting a patent’s priority date, were two of the interesting issues discussed by the court in Carotek, Inc. v. Event Capturing Systems, Inc., Nos. 07 Civ. 11163 (NRB), 08 Civ. 5706 (NRB) (S.D.N.Y. Nune 28, 2012).  The court held that one claim term in a patent directed to a software invention was indefinite under 35 U.S.C.  § 112, while another claim term was not.  The court also held that a certificate of correction identifying a corrected priority date was effective from the date of the certificate of correction, but not before.  (The court further discussed issues not covered in this post, including infringement and numerous state law claims.)


The court analyzed the alleged indefiniteness of two means-plus-function claim terms.  For the first term, “control means,” the court had “already determined that the specification does not adequately identify an associated structure.”  The court had previously “found, in fact, that the language in the specification purportedly disclosing the [control means] algorithm ‘simply describes the function to be performed,  not the corresponding structure’ and that the specification ‘does not even purport to describe a structure’ for many of the Patents’ claimed functions.”

The request to consider the “control means” term was procedurally improper, but the court went on to note that it was baseless on substantive grounds as well.  Prior cases had allowed functional descriptions to suffice under 35 U.S.C. § 112, sixth paragraph, where the steps of an algorithm were found “to consist of ‘known computer-implemented operations,’ which ‘are readily implemented by persons of skill in computer programming.'”  Here, one of ordinary skill in computer programming would not have known how to implement the required steps.  Moreover, the claims and the specification described the required function in almost identical language.  Therefore, claims including the term “control means” were invalid.

The court reached a different conclusion, however, concerning claims of one patent containing the word “extract.”  The patent owner pointed to several passages that allegedly described this term.  The patent specification described a “method of extraction,” including “a specific process by which extraction may occur,” and also provided “certain criteria by which to determine whether data has been extracted or, rather, simply deleted.”  The description of the word “extract” resembled precedent in which “the Federal Circuit found that ‘one of ordinary skill in the art would understand how to implement’ a relatively minimal description of a component of a means-plus-function patent.”  Thus, claim terms including the word” extract” were not invalid.

Certificate of Correction

The three patents-in-suit all “relate[d] to a system for monitoring a continuous manufacturing process.”  Before U.S. 5,821,990 issued, the patent owner, based on the application for the ’990 patent, filed a continuing prosecution application (CPA), a predecessor to the modern request for continuing examination (RCE).  After the ’990 patent issued, the patent owner petitioned the PTO to modify the CPA application to make it a divisional of the application for the ’990 patent, which in turn was a divisional of the application for U.S. 5,717,456.  After granting the petition, the PTO required the patent owner to submit a new inventors’ declaration claiming priority to the application for the ’456 patent.  U.S. 6,211,905 issued claiming priority only to the ’990 patent application, and not the ’456 patent.  Following issuance of ’905 patent, the patent owner “requested a certificate of correction ‘noting the correct priority date’ ‘in the above-captioned patent.’”

These filing dates and the chain of priority were of much more than academic interest.  The ’905 patent would be anticipated, and therefore invalid, unless it obtained the benefit of the filing date of the ’456 patent.

The patent owner argued that it was the PTO’s fault that the priority chain for the ’990 patent was incorrect.  The court disagreed.  It was the patent owner who had erroneously filed a CPA rather than a divisional.  When the patent owner asked to correct this error, the PTO granted the request.  There was no reason why the PTO should have assumed that the priority claim for ’905 patent’s application should have included the application for ’456 patent in addition to the ’990 patent’s application.  Further, it was not clear that a CPA should have received the benefit of all parent applications in a priority chain.

The patent owner also argued that the inventors’ declaration filed with the application for the ’905 patent included a priority claim to the application for the ’456 patent.  However, as the court pointed out, 35 U.S.C. § 120 states that “[n]o application shall be entitled to the benefit of an earlier filed application under this section unless an amendment containing the specific reference to the earlier filed application is submitted at such time during the pendency of the application as required by the Director.”

Based on the court’s reasoning, ’905 patent would be invalid unless the certificate of correction entitled it to the priority date for the ’456 patent.  The plaintiffs argued that, because 35 U.S.C. § 120 requires that an application be amended to obtain a priority date, and the certificate of correction amended only the patent, that the correction was ineffective to allow the patentee to obtain ’456 patent priority date.  However, the court noted that the Federal Circuit had urged “lenity” in this area, and that the certificate of correction was adequate to fulfill the function of providing notice of the ’905 patent’s priority date.  Therefore, while the ’905 patent was invalid when it was issued, it became valid as of the date of the certificate of correction.