Certificate of Correction

Heightened Written Description Requirement for Negative Claim Limitations?

Negative patent claim limitations were once disfavored by the USPTO.  This is because defining claim scope by exclusion was considered less precise relative to more traditional, positive claim scope recitations.  Over the years, the USPTO has been guided to accept negative limitations as in some cases it may be the only way to adequately claim a given invention.  Yet, in assessing written description support for such claim features, the USPTO explains that “the mere absence of a positive recitation in a patent specification is not a basis for exclusion consistent with written description requirements.” MPEP 2173.05(i) 

In some cases, examiners have been known to require explicit support for a negative claim limitation. The degree of specification support necessary to support a negative claim limitation was analyzed last week by the Federal Circuit.

Inphi Corporation (“Inphi”) filed a request for inter partes reexamination of Netlist, Inc.’s (“Netlist”) U.S. Patent No. 7,532,537 (“the ‘537 patent”) directed to computer system memory modules comprising memory chips.  Numerous claims were rejected as obvious.  In overcoming the rejection, Netlist amended its claims, narrowing them and adding a negative limitation.  The negative claim limitation excluded three particular types of memory chip selection signals. 

Inphi appealed to the Board arguing in pertinent part that Netlist’s negative claim limitation failed to satisfy the written description requirement.  The Board affirmed the Examiner’s final decision and denied Inphi’s subsequent request for rehearing.

The question posed to the CAFC was whether Netlist’s negative claim limitation was supported by the specification or constituted impermissible new matter. That is, whether or not the disclosure of alternative implementations was enough, or whether a particular advantage disadvantage of one option to the exclusion of another, was required. 

The CAFC affirmed the Board, holding that simply describing alternative features without articulating advantages or disadvantages of each feature can support a negative limitation. (here)

The parties’ dispute centered on interpreting the key language in Santarus, Inc. v. Par Pharm, Inc.:

Negative claim limitations are adequately supported when the specification describes a reason to exclude the relevant limitation.  Such written description support need not rise to the level of disclaimer.  In fact, it is possible for the patentee to support both the inclusion and exclusion of the same material.

694 F.3d 1344, 1351 (Fed. Cir. 2012).  Inphi argued that the specification in Santarus clearly differentiated between an advantageous option and a disadvantageous alternative, and this was necessary to support a negative limitation directed to the disadvantageous alternative.  The ‘537 patent lacked such clear differentiation, but the Board pointed to three parts of the specification where the chip signaling alternatives were distinguished:  in a standards publication for memory devices that was incorporated by reference, in a table where these three types of chips were listed separately, and in a figure where these three types of chips were displayed on different signal lines.  The Court held that this constituted substantial evidence supporting the Board’s finding, emphasizing that “Santarus did not create a heightened written description standard for negative claim limitations and that properly described, alternative features are sufficient to satisfy the written description standard of § 112, paragraph 1 for negative claim limitations.”

Retroactive Correction of Patent ClaimsBack in March, I discussed the degree of change that can be secured from the USPTO via a Certificate of Correction (COC). As a reminder, one of the more limited methods to address errors in an issued patent is via COC as defined by 35 U.S.C. § 255. The statue provides that mistakes of a clerical or typographical nature, or of minor character may be corrected upon request. Such mistakes must have been made in good faith, and not constitute new matter or require reexamination.Once issued, a valid COC is only effective prospectively. For this reason, such certificates are best secured at the earliest possible date.Of course until claims are very closely scrutinized, the need for minor correction may not be so apparent. In cases where the COC is not secured for years, is there a mechanism available to retroactively correct a patent claim as to such minor errors?This issue was recently explored in Fujitsu Limited v. Tellabs Operations Inc., and Telllabs Inc. (NDIL).In Fujitsu U.S. Patent 5,386,418 was at issue. Claim 1 recited the language “and flag data;” this was a mistake. Claim 1 should have recited “a flag data.”Although the ‘418 Patent originally issued in 1995, a COC was not obtained until 2007, immediately prior to the Tellabs litigation.With respect to the claim language issue, Tellabs advanced two theories on summary judgment: (1) The COC was invalid for broadening the claims; and (2) claim 1, as issued, was indefinite.In ruling on these motions, the court explained that the COC corrected a minor issue, thus the COC was valid. For similar reasoning the court rejected argument (2).Fujitsu also sought summary judgment of its own, arguing that that the claim correction should be made retroactively, based on the doctrine of judicial correction. Tellalbs argued that the combination of a COC and judicial correction for the same patent was improper. The court agreed with Fujitsu, explaining, (full decision here):Although a valid certificate of correction is only effective prospectively, Southwest Software, Inc. v. Harlequin Inc., 226 F.3d 1280, 1295 (Fed. Cir. 2000) (“[F]or causes arising before its issuance, the certificate of correction is not effective.”), the district court can retroactively correct certain errors in a patent’s claims if “(1) the correction is not subject to reasonable debate based on consideration of the claim language and the specification and (2) the prosecution history does not suggest a different interpretation of the claims.” Novo Indus., L.P. v. Micro Molds Corp., 350 F.3d 1348, 1354, 1357 (Fed. Cir. 2003). These “determinations must be made from the point of view of one skilled in the art.” Ultimax Cement Mfg. v. CTS Cement Mfg., 587 F.3d 1339, 1353 (Fed. Cir. 2009).  .           .           .           .           .           .           .           .           .           . Neither Hoffer nor Ultimax suggests that the district court’s authority to correct a patent is constrained by the presence of a certificate of correction, and the court declines to impose such a proscription against judicial correction in this case. Consequently, the court agrees with Fujitsu that the Novo standard is the controlling standard for judicial correction, and the ‘418 Patent’s Certificate of Correction does not prevent this court from correcting the same error in claim 1.           .           .           .           .           .           .           .           .           . Patents provide an important notice function to the public and, as a result, post-issuance judicial corrections which have a retroactive effect must be carefully scrutinized. In this case, viewing the intrinsic evidence from the perspective of one of ordinary skill in the art, as the court must in determining whether a judicial correction is supported under Novo, this court finds that the only reasonable correction of claim 1 replaces “and flag bit data” with “a flag bit data.” A person of ordinary skill in the art, having reviewed the specification, drawings, and prosecution history, would have immediately recognized this error and understood what was claimed. The court accordingly corrects claim 1 of the ‘418 Patent to replace “and flag bit data” with “a flag bit data.”This case was brought to my attention by the great Docket Navigator.

Back in March, I discussed the degree of change that can be secured from the USPTO via a Certificate of Correction (COC). As a reminder, one of the more limited methods to address errors in an issued patent is via COC as defined by 35 U.S.C. § 255. The statue provides that mistakes of a clerical or typographical nature, or of minor character may be corrected upon request. Such mistakes must have been made in good faith, and not constitute new matter or require reexamination.

Once issued, a valid COC is only effective prospectively. For this reason, such certificates are best secured at the earliest possible date.

Of course until claims are very closely scrutinized, the need for minor correction may not be so apparent. In cases where the COC is not secured for years, is there a mechanism available to retroactively correct a patent claim as to such minor errors?

This issue was recently explored in Fujitsu Limited v. Tellabs Operations Inc., and Telllabs Inc. (NDIL).

In Fujitsu U.S. Patent 5,386,418 was at issue. Claim 1 recited the language “and flag data;” this was a mistake. Claim 1 should have recited “a flag data.”

Although the ‘418 Patent originally issued in 1995, a COC was not obtained until 2007, immediately prior to the Tellabs litigation.

With respect to the claim language issue, Tellabs advanced two theories on summary judgment: (1) The COC was invalid for broadening the claims; and (2) claim 1, as issued, was indefinite.

In ruling on these motions, the court explained that the COC corrected a minor issue, thus the COC was valid. For similar reasoning the court rejected argument (2).

Fujitsu also sought summary judgment of its own, arguing that that the claim correction should be made retroactively, based on the doctrine of judicial correction. Tellalbs argued that the combination of a COC and judicial correction for the same patent was improper. The court agreed with Fujitsu, explaining, (full decision here):

Although a valid certificate of correction is only effective prospectively, Southwest Software, Inc. v. Harlequin Inc., 226 F.3d 1280, 1295 (Fed. Cir. 2000) (“[F]or causes arising before its issuance, the certificate of correction is not effective.”), the district court can retroactively correct certain errors in a patent’s claims if “(1) the correction is not subject to reasonable debate based on consideration of the claim language and the specification and (2) the prosecution history does not suggest a different interpretation of the claims.” Novo Indus., L.P. v. Micro Molds Corp., 350 F.3d 1348, 1354, 1357 (Fed. Cir. 2003). These “determinations must be made from the point of view of one skilled in the art.” Ultimax Cement Mfg. v. CTS Cement Mfg., 587 F.3d 1339, 1353 (Fed. Cir. 2009).  

.           .           .           .           .           .           .           .           .           . 

Neither Hoffer nor Ultimax suggests that the district court’s authority to correct a patent is constrained by the presence of a certificate of correction, and the court declines to impose such a proscription against judicial correction in this case. Consequently, the court agrees with Fujitsu that the Novo standard is the controlling standard for judicial correction, and the ‘418 Patent’s Certificate of Correction does not prevent this court from correcting the same error in claim 1

.           .           .           .           .           .           .           .           .           . 

Patents provide an important notice function to the public and, as a result, post-issuance judicial corrections which have a retroactive effect must be carefully scrutinized. In this case, viewing the intrinsic evidence from the perspective of one of ordinary skill in the art, as the court must in determining whether a judicial correction is supported under Novo, this court finds that the only reasonable correction of claim 1 replaces “and flag bit data” with “a flag bit data.” A person of ordinary skill in the art, having reviewed the specification, drawings, and prosecution history, would have immediately recognized this error and understood what was claimed. The court accordingly corrects claim 1 of the ‘418 Patent to replace “and flag bit data” with “a flag bit data.”

This case was brought to my attention by the great Docket Navigator.