Strategy ® LAW JOURNAL NEWSLETTERS &Management Volume 5, Number 1 • May 2004 Prosecution History : Beware of What You Clearly and Unambiguously Say

By Jonathan S. Caplan expressly stated in the claim, and the response to a rejection in and Benu Mehra result can play out at the level of a which the patentee argued that a prior literal infringement analysis. Thus, an art reference that disclosed the use of atent prosecutors typically are accused infringer should closely metallic copper did not teach the cautious when making argu- examine prosecution history state- “copper ion” feature in the claim. In Pments that distinguish their ments, not only as a source of argu- particular, the patentee stated that client’s from the . ments to limit the patentee’s range of metallic copper was “outside [the] This caution was traditionally based equivalents, but also as a source of claims.” Id. at 453. The Federal Circuit on the concern that later, when the potentially determinative evidence for took note of these positions by the client enforced its patent rights against a favorable claim construction to patentee and stated “[b]y making this a potential infringer, these arguments avoid literal infringement. Similarly, disclaimer or concession, [the patent- may provide the basis for restricting patent prosecutors should carefully ee] surrendered any interpretation of the range of equivalents available phrase the arguments made during its claim that would include metallic to the patentee under the doctrine prosecution so as to avoid unneces- copper catalysts.” Id. of prosecution history estoppel. sarily emphasizing arguments or dis- Ten years later, the Federal Circuit Prosecution history estoppel normally tinctions in order to obtain allowance continued to apply this disclaimer limits the range of equivalent elements of claims, thereby limiting the oppor- doctrine in Southwall Technologies, that are available to satisfy a claim ele- tunity of a future alleged infringer to Inc. v. Cardinal IG Co., 54 F.3d 1570 ment under a doctrine of equivalents successfully invoke the doctrine of (Fed. Cir. 1995). In this case, the court analysis (ie, when there is no literal prosecution history disclaimer. construed “sputter-deposited dielec- infringement of that claim element). tric” used in an improved heat mirror Recent decisions by the Federal Circuit THE FEDERAL CIRCUIT’S EARLY to require formation of the dielectric not only reaffirm the significance of HISTORY OF ‘DISCLAIMER’ by a one-step reactive sputtering statements made during prosecution; For years, the Federal Circuit has process, even though such a one-step they also extend their impact to a lit- relied on “disclaiming” statements process was not expressly stated in the eral infringement analysis. A patentee made in the prosecution history to claim term at issue. Id. at 1576-77. who during prosecution “clearly and construe claims, even though the During prosecution, the patentee unequivocally” disavows the prior art phrase “prosecution history dis- stated that its sputter-deposited (or even defines the invention) may claimer” was not used. For example, in dielectric “can be laid down directly” affect the literal scope of the claims. Standard Oil Co. v. American by a reactive sputtering process and This doctrine is now regularly referred Cyanamid Co., 774 F.2d 448 (Fed. Cir. then “directly connected to the oxide.” to as prosecution history disclaimer. 1985), the claim term “copper ion,” in The Federal Circuit treated this prose- Under this doctrine, a claim term the context of a process for hydroliz- cution history as a clear and unam- may receive a “gloss” that limits the ing a nitrite that required the “pres- biguous statement disclaiming a claim to a particular feature that is not ence of copper ion,” was construed to two-step process of depositing a metal Jonathan S. Caplan is a partner at not include metallic copper catalysts, and then oxidizing the metal. Id. Kramer Levin Naftalis & Frankel LLP. His even though there was no such By the mid-1990s, the Federal practice focuses on patent litigation, express limitation in the claim. Id. at Circuit was clearly recognizing the patent prosecution and counseling. Benu 452-53. This construction was based doctrine of prosecution history dis- Mehra is an associate at Kramer Levin on a statement in the specification that claimer as a claim limiting principle, Naftalis & Frankel LLP. Her practice the use of metallic copper alone was noting that “[p]rosecution history focuses on patent litigation. not effective, as well as a statement in serves as a limit on the scope of claims LJN – PATENT STRATEGY & MANAGEMENT MAY 2004 by excluding any interpretation of the appreciable heat from entering the energy rotating said lamp” used in a claim for a claim language that would permit the zone and affecting the temperature of the wireless, remote-controlled portable patentee to assert a meaning for the zone), resulted in a “deliberate surrender searchlight. Defendant Wal-Mart argued claim that was disclaimed or disavowed of claim scope, unmistakable in its effect that the claims at issue were limited to during the prosecution in order to because it is not suitable to multiple lamps capable of 360° rotation, even obtain claim allowance.” See Zenith interpretations.” Id. Accordingly, the court though there was no such express Labs, Inc. v. Bristol-Myers Squibb Co., 19 limited the claim term “to visibly outline” limitation in the claim. Id. at 1332. F.3d 1418 (Fed. Cir. 1994) (finding no to a function that did not add heat in the Wal-Mart based its contention on a disclaimer); Southwall, 54 F.3d 1570; manner distinguished by the patentee statement in the specification of the York Prods., Inc. v. Central Tractor during the prosecution history. Id. at 1328. that described the Farm & Family Center, 99 F.3d 1568 Another recent decision applying pros- ability of the lamp to have 360° rotation, (Fed. Cir. 1996) (finding no disclaimer). ecution history disclaimer is Microsoft as well as several statements made Corp. v. Multi-Tech, 357 F.3d 1340 (Fed. during prosecution. For example, in RECENT FEDERAL CIRCUIT Cir. 2004). In Microsoft, the technology at response to a Patent Office rejection, the DECISIONS ON DISCLAIMER issue was personal computer-based patentee argued: 1) that a prior art The prosecution disclaimer doctrine systems for simultaneously transmitting reference was distinguished because it has been refined and more frequently voice and data to a remote site over a “would not be rotatable so as to be able invoked in the last couple of years, with telephone line. The Federal Circuit relied to sweep through 360° or greater as the Federal Circuit developing a stan- on prosecution history disclaimer to limit achieved by applicants’ invention”; 2) dard for evaluating the nature of the claim terms “sending,” “transmitting,” that the claims at issue in the Patent potentially disclaiming statements. For and “receiving” data packets to the direct Office rejection were amended to recite example, statements that can be charac- transmission of data packets over a rotation through at least 360° to avoid terized as clear, deliberate, unequivocal, telephone line, even though no such prior art; and 3) that the claims recited and/or unmistakable can give rise to a limitation was expressly stated in the “separate horizontal and vertical drive disclaimer, whereas vague or ambigu- asserted claims. Id. at 1350-51. The court means for tilting and rotating as well ous statements generally cannot. In noted Multi-Tech’s repeated and consis- through 360°” to carry out two different Omega Eng’g, Inc. v. Raytek Corp., 334 tent description of its invention in the types of adjustments, tilting and rotation. F.3d 1314 (Fed. Cir. 2003), the court set specification as communicating directly Id. at 1333. forth a standard for applying the prose- over a telephone line, including about The Federal Circuit noted that there cution disclaimer doctrine and the two dozen references in the specification were dependent claims that expressly policy basis for the standard. The court to data transmission “over” or “through” recited the 360° limitation argued explained that the disclaimer doctrine a telephone line. Id. at 1347-48. The during prosecution, but the 360° limita- attaches when a patentee makes a state- Federal Circuit also noted Multi-Tech’s tion was not expressly recited in the ment of “unequivocal[ ] disavow[al],” response to an in which it asserted independent claim. As a result, and where the statements are “clear argued that a “standard telephone line” the court did not apply the disclaimer and unmistakable.” Id. at 1324-26. The established the point-to-point connection doctrine to either the specification court found that this standard struck the between telephone equipment on each statement or the prosecution history balance between the public notice func- end of the line used in the invention. Id. statements because the statements tion of prosecution history and the right at 1349. The Federal Circuit found that did not rise to the level of “clear dis- of patentees to pursue broad patent Multi-Tech’s specification statements avowal.” Id. coverage. Id. at 1325. and prosecution history statements The technology in Omega concerned a describing its invention in the context of CONCLUSION laser sighting system for use on infrared telephone line transmission “unambigu- The doctrine of prosecution history thermometers. The patentee argued in ously” demonstrated Multi-Tech’s under- disclaimer can be used to characterize prosecution, on several occasions, that the standing of its as limited to the statements in the prosecution history as claimed method for outlining an energy transmission of data packets directly over “clear and unambiguous” or “unmistak- zone (which recited the claim term “to a telephone line. Id. able” which, if accepted, can limit the visibly outline”) distinguished the prior art The prosecution disclaimer doctrine meaning of claim terms in a literal because it did not add appreciable heat to was not applied, however, by the Federal infringement analysis, even if the the energy zone so as to affect the accu- Circuit in a recent 2004 case in which the limited meaning is not expressly racy of the temperature measurement. Id. disclaimer argument was raised. In provided in the claims. Patent prosecu- at 1327. The Federal Circuit noted that the Golight, Inc. v. Wal-Mart Stores, Inc., 355 tors and litigators must consider this patentee’s repeated statements of what its F.3d 1327 (Fed. Cir. 2004), the claim term doctrine in creating and evaluating invention “could not be” (ie, precluding at issue was “horizontal drive means for prosecution histories.

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