Full opinion text
OPINION SWEET, District Judge. In this patent infringement action, defendant Lansa, Inc. (“Lansa”) has moved for partial summary judgment pursuant to Rule 56 of the Federal Rules of Civil Procedure on the ground that U.S. Patent No. 6,295,075 (the “’075 Patent”) is. invalid, and plaintiff ResQNet.com, Inc. (“Re-sQNet”) has cross-moved to strike Lansa’s invalidity defense. ResQNet subsequently brought its own motion for partial summary judgment pursuant to Rule 56 on the ground that the newlook software distributed by Lansa infringes the ’075 Patent, and Lansa cross-moved for partial summary judgment of non-infriñgement of the ’075 Patent and moved separately for partial summary judgment on the ground of non-infringement of U.S. Patent No. 5,831,608 (the “ ’608 Patent”). Lansa has also moved for leave to amend its answer and counterclaims pursuant to Rules 9 and 15(a) of the Federal Rules of Civil Procedure, with respect to which motion ResQNet has moved for leave to file a surreply. Finally, Lansa has moved for sanctions against ResQNet pursuant to Rule 11 of the Federal Rules of Civil Procedure, and ResQNet has cross-moved for similar sanctions against Lansa -as well as for the revocation of the pro hac vice admission of Lansa’s counsel, James H. Hulme, Esq'. (“Hulme”). For the reasons set forth below, Lan-sa’s motion for partial summary judgment of invalidity of the ’075 Patent is denied, ResQNet’s motion to strike the invalidity defense as to- the -’075 Patent is denied, ResQNet’s motion for partial summary judgment of infringement of the ’075 Patent is denied, Lansa’s motion for partial summary judgment of non-infringement of the ’075 Patent is denied, Lansa’s motion for partial summary judgment of non-infringement of the ’608 Patent is denied, ResQNet’s motion for-leave to file a surre-ply is granted, Lansa’s motion for leave to amend its answer and counterclaims is granted, Lansa’s motion for • sanctions 'is granted in part and otherwise denied, and ResQNet’s motion for sanctions and to revoke the pro hac vice status of Lansa’s counsel is denied. Prior Proceedings This action was commenced on April 27, 2001. According to the complaint filed on that date, Lansa was producing, offering for sale and selling various products alleged to infringe four patents held by Re-sQNet, namely, U.S. Patent No. 5,530,961 (the “ ’961 Patent”), U.S. Patent No. 5,792,659 (the “ ’659 Patent”), U.S. Patent No. 5,812,127 (the “127 Patent”), and the ’608 Patent. An amended complaint was filed on December 4, 2001, alleging infringement of the same four patents previously named as well as the ’075 Patent. Discovery with respect to claim construction issues proceeded, ResQNet withdrew its allegations of infringement concerning the ’659 Patent and the 127 Patent, and a Markman hearing was held on June 12, 2002 with regard to the remaining patents-in-suit. The opinion of the Court construing certain claims of the ’961 Patent, the ’608 Patent and the ’075 Patent was rendered in September 2002. See ResQNet.com v. Lansa, Inc., No. 01 Civ. 3578(RWS), 2002 WL 31002811 (S.D.N.Y. Sept.5, 2002) (“ResQNet I”). On November 4, 2002 the •parties entered into a consent judgment acknowledging the withdrawal by Re-sQNet of all allegations that newlook infringed the patents named in the amended complaint with the exception of one claim each from the ’961 Patent, the ’608 Patent, and the ’075 Patent, and stipulating that Lansa’s systems would not infringe these remaining claims in light of the holding of ResQNet I. On October 16, 2003, the U.S. Court of Appeals for the Federal Circuit affirmed this Court’s construction of the ’961 Patent’s claim and reversed in part the construction of claim 1 of the ’608 Patent and claim 1 of the ’075 Patent. See ResQNet.com v. Lansa, Inc., 346 F.3d 1374 (Fed.Cir.2003) (“ResQNet II”). Familiarity with ResQNet I and ResQNet II is assumed. Discovery resumed, and on April 27, 2004, Lansa filed its first motion for partial summary judgment on the ’075 Patent, asserting the invalidity of the ’075 Patent. ResQNet cross-moved to strike Lansa’s invalidity defense as insufficient. Oral arguments on both motions were heard on May 19, 2004, after which ResQNet submitted a letter brief to which Lansa responded on May 24, 2004. While these motions were pending, Lan-sa’s subpoena issued to the third-party witness and counsel to ResQNet, Jeffrey I. Kaplan, was quashed in July 2004. See ResQNet.com v. Lansa, Inc., No. 01 Civ. 3578(RWS), 2004 WL 1627170 (S.D.N.Y. July 21, 2004) (“ResQNet III”). In light of certain of the conclusions reached in ResQNet III, Lansa moved to amend its answer and counterclaims on August 4, 2004. Following briefing, including a letter motion by ResQNet for leave to file a surreply, Lansa’s motion and ResQNet’s letter motion were deemed fully submitted without oral argument on August 25, 2004. In the interim, ResQNet filed a motion for partial summary judgment on the ’075 Patent on August 20, 2004, claiming infringement of the ’075 Patent. Lansa cross-moved for partial summary judgment of non-infringement as to the ’075 Patent on August 23, 2004 and interposed a separate motion for summary judgment of non-infringement with respect to the ’608 Patent. Following further briefing, as well as the submission by Lansa of certain supplemental materials with respect to its earlier motion for partial summary judgment on the ’075 Patent and the submission by ResQNet of a response to Lansa’s supplemental submission, oral arguments were heard on September 29, 2004, at which time these motions too were deemed fully submitted. Prior to oral arguments on the partial summary judgment motions on September 29, 2004, Lansa filed a motion pursuant to Rule 11, Fed.R.Civ.P., seeking sanctions on the ground, inter alia, that ResQNet had failed to conduct an adequate pre-filing investigation before commencing this litigation. ResQNet filed a cross-motion for Rule 11 sanctions and for the revocation of the pro hac vice admission of Lan-sa’s counsel, Hulme, on October 18, 2004. Following further briefing, the submission of a surreply memorandum by Lansa and the submission by ResQNet of a declaration in response to the surreply, oral arguments were heard on these latest motions on October 27, 2004, at which time they were deemed fully submitted. The Patents-In-Suit As a result of the withdrawal by Re-sQNet of its allegations of infringement concerning the ’659 Patent and the ’127 Patent and the subsequent affirmance of this Court’s construction of the relevant claim of the ’961 Patent by the Federal Circuit, see ResQNet II, 346 F.3d at 1378-82, only one claim each from the two remaining patents are at issue here: claim 1 of the ’608 Patent and claim 1 of the ’075 Patent. Both of the remaining patents-in-suit “claim, in relevant part, ‘screen recognition’ and terminal emulation — processes that download a screen of information from a remote mainframe computer onto a local personal computer (PC).” Id. at 1375. As the Federal Circuit explained in ResQNet II, by way of general background, Mainframe computers permit multiple users to simultaneously access one central computer. Before the widespread use of PCs, each user would connect to the mainframe using a so-called “dumb terminal.” ... A dumb terminal, as its name implies, did not process or reformat the data received from the mainframe. Rather, the dumb terminal simply displayed the information from the mainframe. Symmetrically, the dumb terminal sent all data entry back to the mainframe for processing. Because a dumb terminal’s monitor generally was a monochromatic green, the display was called a “green screen.” Gradually, PCs replaced dumb terminals. Unlike a dumb terminal, a PC does not merely send and receive information. Rather, a PC uses software to facilitate communication to and from the mainframe. With that software, a PC does not simply mimic a dumb terminal, but processes the information into a graphical user interface (GUI) format, which is much more user-friendly. Although the GUI format displays and receives information to and from the user, the PC still sends and receives information only in the manner understood by the mainframe, i.e., as if a dumb terminal were connected to the mainframe. In relevant part, the asserted patents specifically facilitate recognition of the information that the mainframe sends to the PC. Id. at 1375-76; see also ResQNet I, 2002 WL 31002811, at *1 (noting the parties’ agreement “that the technology at issue in this case relates to ‘screen recognition’ software that translates between the GUI world of the PC and the plain text, green-screen world of the legacy mainframe system”). A graphical user interface (“GUI”) format includes “icons, windows, help menus, and other features that represent the standard well-known interfaces in today’s modern PCs.” Id. The ’608 Patent contains a single claim with limitations written in a means-plus-function form, as follows: Apparatus for implementing a computer terminal to be connected to a remote computer, said apparatus comprising: means for identifying a particular user logged on to said remote computer through said computer terminal; means for identifying, based upon a position, length and type of each of a plurality of fields, a particular screen to be displayed to said user; and a plurality of special function keys, each key performing a specified function, the specified function performed for each key being determined by the particular user logged on and the particular screen identified to be displayed. (’608 Patent, col. 4,11. 38-49.) The claimed function of the ’608 Patent is “ ‘identifying ... a particular screen to be displayed to said user.’ ” ResQNet II, 346 F.3d at 1382 (citation omitted). The specification, as the Federal Circuit observed in ResQNet II, “sets forth the corresponding structure: ‘Upon a screen of information being downloaded to a personal computer 103, the personal computer analyzes the screen with respect to the location of particular fields, and other attributes thereof, in order to recognize the particular screen downloaded.’ ” Id. (citation omitted). Thus, [Similar to the ’961 patent, the structure is an algorithm for analyzing the downloaded information to generate a screen ID. Further similar to the ’961 patent, neither the function nor its corresponding structure alone resolves the claim construction issue because that issue depends on which fields the algorithm employs in “identifying ... a particular screen to be displayed to said user.” ’608 patent, col. 4, 11. 42-44. These similarities reflect the parentage of the ’608 patent, which is a continuation-in-part (CIP) of the ’961 patent. Id. The Federal Circuit resolved the claim construction issue of “which fields the algorithm employs” by construing “each of a plurality of fields” as recited in claim 1 to mean “each of at least two fields.” See id. at 1382-83. The Federal Circuit did not disturb this Court’s prior ruling that the algorithm at issue in claim 1 of the ’608 Patent “is dependent on three parameters for identifying a screen: position, length, and type.” ResQNet I, 2002 WL 31002811, at *7. Unlike the ’608 Patent, claim 1 of the ’075 Patent “is a pure method claim.” ResQNet II, 346 F.3d at 1383. Claim 1 of the ’075 Patent is as follows: The method of communicating between a host computer and a remote terminal over a data network comprising steps of: establishing a first communication session between said terminal and a communications server via a first communications channel; downloading, from said server to said terminal, communications software for communicating between said terminal and said host and a plurality of specific screen identifying information; utilizing said communications software to implement a second communications session between said terminal and said host via a second communications channel independent of said server; receiving a screen from said host to said terminal; if said received screen matches one of the plurality of specific screen identifying information, displaying a customized GUI screen; and if said received screen does not match one of the plurality of specific screen identifying information, displaying a default GUI screen. (’075 Patent, col. 4, 11. 65-67; col. 5, 11. 1-19.) While claim 1 of the ’075 Patent requires an algorithm, see ResQNet II, 346 F.3d at 1377 (“The asserted claims — claim 2 of the ’961 patent, claim 1 of the ’608 patent, and claim 1 of the ’075 patent — each require an algorithm that recognizes the screen based on the information downloaded from the mainframe to the PC.”), the particular algorithm need not be of the type described in the ’961 Patent. See ResQNet II, 346 F.3d at 1383-84. As employed in claim 1 of the ’075 Patent, the phrase “ ‘a plurality of specific screen identifying information’ ” means “at least two pieces of specific screen identifying information.” Id. at 1383. According to the Federal Circuit, “the presence of ‘specific’ connotes selected or particular. This phrase does not equate to ‘all.’ ” Id. The Facts The facts are derived from the parties’ eight initial and responsive Statements of Facts made pursuant to Local Civil Rule 56.1, as well as from the supporting materials submitted by the parties, to the extent that such materials were provided. The facts are undisputed except as noted and do not constitute findings of fact by this Court. Patent Speciñcations And Prosecution History According to Lansa, the ’075 Patent specification shows that the language of claim 1 regarding the steps of matching the received screen to one of the plurality of specific screen identifying information, and displaying a customized or default GUI screen requires an algorithm that generates a unique screen identification (“ID”) number. ResQNet disputes this point as contrary to the Federal Circuit’s decision in ResQNet II and to the language of the ’075 Patent. ResQNet raises similar objections to Lansa’s assertion that the prosecution history of the ’075 Patent confirms that the correct interpretation of the steps of matching one of the plurality of specific screen identifying information and displaying a GUI is through an algorithm that generates a unique screen ID number. According to Lansa, the steps for “receiving a screen from said host to said terminal; if said received screen matches one of the plurality of specific screen identifying information, displaying a customized GUI screen; and if said received screen does not match one of the plurality of specific screen identifying information, displaying a default GUI screen” were added as a limitation during the prosecution history of the ’075 Patent. (’075 Patent, col. 5, 11. 13-19.) ResQNet disputes this point as irrelevant. The language “means for identifying, based upon a position, length and type of each of a plurality of fields, a particular screen to be displayed to said user” was a limitation that was added to claim 1 of the ’608 Patent during its prosecution history. (’608 Patent, col. 4,11. 42-44.) Prior Sale The ’075 Patent was filed on July 10, 1997 and issued on September 25, 2001. One year prior to the filing date of the ’075 Patent (the “critical date”) is July 10, 1996. ResQNet is the owner of the ’075 Patent. The only asserted claim of the ’075 Patent is claim 1, which ResQNet alleges is infringed by Lansa’s newlook product. The newlook product is one of many computer programs available worldwide that facilitates terminal emulation. The product is designed to “graphically enable” existing computer applications. The new-look software allows storage of selected information as a record in a repository. According to Lansa, Look Software Pty Ltd. (“Look Software”) of Australia commenced development of the newlook software product in January 1995. ResQNet contests this point, asserting that there is no admissible evidence from which to ascertain what was done in 1995 or what features or functions any such system included. ResQNet further disputes Lansa’s assertion that newlook is a comprehensive application program that allows terminal users to display green screen data from a host in GUI formats by enhancing the screen data, a process known as terminal emulation. According to ResQNet, it is unclear which version of newlook is being described and as of what date. Moreover, ResQNet asserts that the testimony of Marcus Dee of Look Software (“Dee”), offered by Lansa is support of these points, is inadmissible and uncorroborated. Finally, ResQNet asserts that the newlook software referenced in 1995 is drastically different from the newlook software at issue in this case. ResQNet cites no evidence on the record in support of this position. Lansa asserts that the newlook software currently sold is the same software, and has operated in the same manner, as the software that was first offered for sale in the United States in 1996, including its use of dynamic recognition technology to display graphical screens and its ability to make customizations using the “Identify” tool which are applied when a “Screen ID” is matched. Lansa further asserts that newlook has remained the same product since its release in early 1996 but has been enhanced with additional features such as the “designer” feature, which allows a customer to add his or her own objects and images to a screen. ResQNet disputes that the newlook software sold in 1996 and the software presently sold are the same, and asserts that Lansa’s testimony concerning what was sold in 1996 is inadmissible hearsay. ResQNet disputes Lansa’s assertion that the newlook product was advertised in the Asia/Pacific region in a publication entitled “News/4You” in March 1996 on the ground that there is no admissible evidence that sets forth the features or functions of the product advertised in 1996. According to Lansa, the March 1996 “News/4You” publication advertised that “NewLook DYNAMICALLY generates sophisticated, consistent Windows GUIs.” (Declaration of Marcus Dee, dated Apr. 5, 2004 (“Dee Decl.”), at ¶ ll.) The same publication, according to Lansa, included a working demonstration diskette containing the newlook program and encouraged the reader to “Install and run the NewLook demonstration to see samples of the varying screen styles NewLook supports.” (Id.) ResQNet disputes this point, asserting that the publication in question contains no evidence as to whether the product contained the limitations of the claim in issue and that there is no admissible evidence as to the features present in any system advertised in 1996. Similar objections are raised to Lansa’s assertion that the newlook software was offered for sale and sold in the Asia/Pacific region as early as March 1996 and that a copy of newlook was sold to Aspect Computing Pty Ltd in March 1996. According to Dee, he offered the new-look software for sale to Steve Abbott, President and Chief Technical Officer of Speciality Insurance Services in Orange, California (“Abbott”) on or around June 24, 1996. ResQNet disputes this point on the same grounds raised with relation to the Asia/Pacific advertisements and sales asserted by Lansa and further asserts that Dee’s declaration is inadmissible, as Dee is an interested witness. In a facsimile dated June 24, 1996, Dee asked Abbott to “please confirm [the order] by fax and send us a check for $US350.” (Dee Deck, at ¶ 18 & Exh. F.) Included in the facsimile of June 24, 1996 was a ten-page overview of the newlook software which describes dynamic GUI generation, various alternatives to create GUIs for green screen applications, and the advantages of newlook software’s technique for dynamic GUI generation, including reference to “an approach that reliably and instantly generates the user interface at runtime.” (Dee Deck, at ¶ 20 & Exh. F.) The overview also describes the “Identify” and “Filters” features of the program that are used, according to Larisa, to define and apply customizations. As explained in the facsimile of June 24, 1996, dynamic GUI generation describes the way newlook software changes green screens into GUIs. ResQNet asserts that the details set forth in the facsimile and overview fail to show the steps in the claim at issue and thus do not anticipate the claim. ResQNet also asserts that it is unknown what was sold to Abbott. Abbott responded to Dee by facsimile dated July 1, 1996, requesting that Dee send a copy of newlook to him as soon as possible. Abbott also wrote that his company was working on three very large opportunities with insurance companies and that a good GUI would enhance his company’s position and could result in “many 100s of seats for NEWLOOK.” (Dee Deck, at ¶ 24 & Exh. G.) On August 20, 1996, Speciality Insurance Services rendered a check for a single-user license for the newlook product. ResQNet disputes the relevance of these facts. The Operation Of Newlook ResQNet disputes Lansa’s assertion that newlook applies instantaneous analysis of green screen information and instantaneous generation of the GUI, resulting in dynamic and automatic, “on the fly” recognition and GUI format generation. Likewise, ResQNet disputes Lansa’s assertion that, with newlook, any changes made to existing green screens are instantly reflected in the “just in time” generated GUI format on the end-user’s PC and that new-look is not a static process, where a batch process is run before displaying GUI from a green screen. According to Lansa, there is no batch process run before displaying GUI from a green screen with the newlook product. ResQNet disputes this point as irrelevant and asserts that unspecified newlook documents establish that a batch process is run before the green screen is displayed in order to determine which fields will be utilized to identify the screen. According to Lansa, newlook operates using existing IBM standards and/or through a person manually selecting a field. ResQNet disputes this point and asserts that Lansa’s documents and testimony establish that the system evaluates the position, length and type of predetermined fields in order to identify the screen after generating a screen ID. ResQNet cites no specific record evidence in support of its interpretation. ResQNet further asserts that the manual operation referred to by newlook is simply setting up the algorithm to be used by the computer in advance and that even the system in the ’608 Patent requires such a process. ResQNet cites no record evidence in its Local Civil Rule 56.1 Statement in support of its interpretation. According to Lansa, with the newlook product a received green screen is merely read to see if there is a match. In other words, newlook looks at a screen for a predetermined field on which to identify a field, and then makes a comparison between the field found and the defined override profile. Certain of the evidence cited by Lansa in support of this proposition is not in the record. ResQNet disputes Lan-sa’s assertion that the received green screen is merely read to see if there is a match and suggests that the received screen is checked to determine the location and types of particular fields that have been preselected in order to uniquely identify the screen. ResQNet cites no specific record evidence in support of its interpretation. According to Lansa, newlook does not employ an algorithm to generate a unique screen identification number. Certain of the evidence cited by Lansa in support of this proposition is not in the record. Re-sQNet, in turn, disputes this point, but cites no record evidence in support of its own interpretation. Discussion I. The Motions for Partial Summary Judgment A. The Summary Judgment Standard Summary judgment is granted only if there is no genuine issue of material fact and the moving party is entitled to judgment as a matter of law. See Fed.R.Civ.P. 56(c); Celotex Corp. v. Catrett, 477 U.S. 317, 322-23, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986); SCS Communications, Inc. v. Herrick Co., Inc., 360 F.3d 329, 338 (2d Cir.2004). The court will not try issues of fact on a motion for summary judgment, but, rather, will determine “whether the evidence presents a sufficient disagreement to require submission to a jury or whether it is so one-sided that one party must prevail as a matter of law.” Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 251-52, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986). Summary judgment is appropriate where the moving party has shown that “little or no evidence may be found in support of the nonmoving party’s case. When no rational jury could find in favor of the nonmoving party because the evidence to support its case is so slight, there is no genuine issue of material fact and a grant of summary judgment is proper.” Gallo v. Prudential Residential Servs., Ltd. P’ship, 22 F.3d 1219, 1223-24 (2d Cir.1994) (internal citations omitted). If, however, “ ‘as to the issue on which summary judgment is sought, there is any evidence in the record from which a reasonable inference could be drawn in favor of the opposing party, summary judgment is improper.’” Security Ins. Co. of Hartford v. Old Dominion Freight Line Inc., 391 F.3d 77, 82-83 (2d Cir.2004) (quoting Gummo v. Village of Depew, 75 F.3d 98, 107 (2d Cir.1996)). “The party seeking summary judgment bears the burden of establishing that no genuine issue of material fact exists and that the undisputed facts establish her right to judgment as a matter of law.” Rodriguez v. City of New York, 72 F.3d 1051, 1060-61 (2d Cir.1995). This burden may be satisfied “by showing — that is pointing out to the district court — that there is an absence of evidence to support the nonmoving party’s case.” PepsiCo, Inc. v. Coca-Cola Co., 315 F.3d 101, 105 (2d Cir.2002) (internal quotation marks and citations omitted); accord Goenaga v. March of Dimes Birth Defects Found., 51 F.3d 14, 18 (2d Cir.1995) (“In moving for summary judgment against a party who will bear the ultimate burden of proof at trial, the movant’s burden will be satisfied if he can point to an absence of evidence to support an essential element of the non-moving party’s claim.”). In order to defeat a motion for summary judgment, the non-moving party must offer sufficient evidence to enable a reasonable jury to return a verdict in its favor. See Anderson, 477 U.S. at 248, 106 S.Ct. 2505; Byrnie v. Town of Cromwell, Bd. of Educ., 243 F.3d 93, 101 (2d Cir.2001); Scotto v. Almenas, 143 F.3d 105, 114 (2d Cir.1998). In other words, the non-moving party “may not rely simply on conclusory statements or on contentions that the affidavits supporting the motion are not credible.” Ying Jing Gan v. City of New York, 996 F.2d 522, 532 (2d Cir.1993); see also Scotto, 143 F.3d at 114-15. A material fact is one that would “affect the outcome of the suit under the governing law,” and a dispute about a genuine issue of material fact occurs if the evidence is such that “a reasonable jury could return a verdict for the nonmoving party.” Anderson, 477 U.S. at 248, 106 S.Ct. 2505; see also R.B. Ventures, Ltd. v. Shane, 112 F.3d 54, 57 (2d Cir.1997). Thus, “[ojnly disputes over facts that might affect the outcome of the suit under the governing law will properly preclude the entry of summary judgment.” Anderson, 477 U.S. at 248, 106 S.Ct. 2505; see also Quarles v. Gen. Motors Corp., 758 F.2d 839, 840 (2d Cir.1985) (“[T]he mere existence of factual issues — where those issues are not material to the claims before the court — will not suffice to defeat a motion for summary judgment.”). In determining whether a genuine issue of material fact exists, a court must resolve all ambiguities and draw all reasonable inferences against the moving party. See Matsushita Elec. Indus. Co. v. Zenith Radio Corp., 475 U.S. 574, 587, 106 S.Ct. 1348, 89 L.Ed.2d 538 (1986); Gibbs-Alfano v. Burton, 281 F.3d 12, 18 (2d Cir.2002). B. Lansa’s Motion for Partial Summary Judgment of Invalidity And ResQNet’s Motion To Strike The Invalidity Defense Are Denied Lansa has moved for partial summary judgment as, to the ’075 Patent on the ground that the ’075 Patent is invalid under 35 U.S.C. § 102(b). Lansa contends that undisputed facts show that newlook was on sale in the United States prior to the ’075 Patent’s critical date, July 10, 1996, thus rendering the ’075 Patent invalid. Solely for purposes of this motion relating to the “on-sale” defense, Lansa has conceded infringement of the ’075 Patent. See Vanmoor v. Wal-Mart Stores, Inc., 201 F.3d 1363, 1366 (Fed.Cir.2000). ResQNet has contended that the prior art does not include the limitations of the claim at issue. ResQNet has also cross-moved to strike the invalidity defense asserted by Lansa as to the ’075 Patent on the ground that a patent may not be deemed invalid based merely upon the uncorroborated testimony of an interested witness. According to ResQNet, Dee, upon whose testimony Lansa has relied in support of its argument for invalidity, should be precluded from testifying at trial, as Dee’s testimony is the “sole proof’ offered as to the nature of the purported prior art and permitting his uncorroborated testimony would “merely cause confusion.” (PI. Apr. 27, 2004 Mem. at 9.) Under 35 U.S.C. § 102(b), a patent is invalid if the purported invention it describes was in public use and on sale more than one year prior to the filing of the patent application, a date known as the critical date. See Scaltech, Inc. v. Retec/Tetra, L.L.C., 269 F.3d 1321, 1327-28 (Fed.Cir.2001) (explaining the nature of a critical date). Thus, prior to the critical date, (1) “the product must be the subject of a commercial offer for sale” and (2) “the invention must be ready for patenting.” Pfaff v. Wells Elecs., Inc., 525 U.S. 55, 67, 119 S.Ct. 304, 142 L.Ed.2d 261 (1998). With respect to this first condition, “[a]n offer which rises to the level of a commercial offer for sale, one which the other party could make into a binding contract by simple acceptance (assuming consideration), constitutes an offer for sale under § 102(b).” Group One, Ltd. v. Hallmark Cards, 254 F.3d 1041, 1048 (Fed.Cir.2001), cert. denied, 534 U.S. 1127, 122 S.Ct. 1063, 151 L.Ed.2d 967 (2002). As to the second condition, an invention is considered “ready for patenting” when it has been reduced to practice prior to the critical date, or there are specifications or other descriptions of the invention that enable a person of skill in the art to practice the invention. See Pfaff, 525 U.S. at 67-68, 119 S.Ct. 304; see also Vanmoor, 201 F.3d at 1366. A party challenging the validity of a patent pursuant to § 102(b) must demonstrate the applicability of the on-sale bar with clear and convincing evidence. See Poly-America, L.P. v. GSE Lining Tech, Inc., 383 F.3d 1303, 1308 (Fed.Cir.2004); Abbott Labs. v. Geneva Pharms., Inc., 182 F.3d 1315, 1318 (Fed.Cir.1999). In general, an accused infringer bears the burden of proving that the device sold prior to the critical date in question anticipated the patent claim. See Poly-America, 383 F.3d at 1309; Abbott Labs., 182 F.3d at 1318; Evans Cooling Sys., Inc. v. General Motors Corp., 125 F.3d 1448, 1451 (Fed.Cir.1997). Where, however, the pat-entee has alleged that the device in question infringed its patent and the accused infringer has conceded that infringement for purposes of a § 102(b) defense, the accused infringer’s burden is satisfied. See Vanmoor, 201 F.3d at 1366; Evans Cooling Sys., 125 F.3d at 1451. There is no dispute that a product was offered for sale under the name “newlook” prior to the critical date of the ’075 Patent. Relying on the rule articulated in Evans Cooling Systems and Vanmoor, Lansa argues that it has satisfied its burden of demonstrating that the newlook software sold in 1996 anticipates claim 1 of the ’075 Patent because ResQNet has alleged that newlook infringes the ’075 Patent. Thus, according to Lansa, it need not show that one using the newlook software would practice each step in claim 1 of the ’075 Patent in order to establish its on-sale defense. ResQNet argues that there is nothing beyond Dee’s testimony to establish that the newlook product offered for sale prior to the ’075 Patent’s critical date is the same product that is alleged to infringe the ’075 Patent. In both Evans Cooling Systems and Vanmoor, the products on sale prior to the critical date were the same as the products alleged to infringe the plaintiffs’ patents. As one court has recently explained, the plaintiffs in Evans Cooling Systems and Vanmoor “held no viable causes of action for infringement unless they could prove infringement of devices that were on sale before the respective critical dates;” in sum, “the substance of their allegations implicated only prior art.” IXYS Corp. v. Advanced Power Tech., Inc., No. 02 Civ. 3942(MHP), 2004 WL 540513, at *6 (N.D.Cal. Mar.18, 2004) (concluding that “[t]he logical nexus that existed between infringement and invalidity in Evans Cooling” was not present where the plaintiff patentee could succeed on its claim without proving that the product alleged to be on sale prior to the critical date itself infringes the patent). By contrast, the amended complaint in this action alleges that Lansa began producing, offering for sale and selling various items that infringe ResQNet’s patents “[l]ong after” ResQNet invented and applied for patent protection as to its technologies. (Am. Compl. at ¶ 8.) Although ResQNet has alleged that Lansa’s “infringing products are believed to include at least those sold under the name Newlook” (Am. Compl. at ¶ 9), there is no allegation that the newlook product alleged to infringe “[l]ong after” ResQNet’s application for patent protection is the same product assertedly on sale prior to the ’075 Patent’s critical date. As a result, the amended complaint, on its own, provides an insufficient basis from which to conclude that Lansa has satisfied its burden of proving that the use of the newlook software offered for sale in 1996 anticipates claim 1 of the ’075 Patent. Notwithstanding this conclusion, however, if there is no genuine issue of material fact as to whether the newlook product offered for sale in 1996 is the same as the newlook product alleged to infringe the ’075 Patent, the application of the rule set forth in Evans Cooling Systems and Vanmoor would appear mandated. Simply put, to prevail on its motion for partial summary judgment as to the invalidity of the ’075 Patent, Lansa must demonstrate that no genuine issue of material fact exists as to whether the accused version of newlook is materially identical to that offered for sale in 1996. Dee has testified that the newlook software currently sold is the same software and operates in the same manner as the newlook software offered for sale in the United States in 1996. In addition, Lansa points to documents describing how the newlook software presently available operates and to the description of the newlook software included in the facsimile dated June 24, 1996 sent by Dee to Abbott as further demonstrating that the software alleged to infringe and that offered for sale in 1996 are materially identical. Although certain similarities between the 1996 and accused versions of newlook are apparent based on a comparison of the documentary evidence submitted, the record does not clearly demonstrate that the newlook product offered for sale in 1996 is materially identical to the newlook product accused by ResQNet. For instance, and notwithstanding the documentary evidence submitted by Lansa in a supplemental filing in September 2004, it is not evident whether the 1996 incarnation of newlook employed a server or communications channels in the same manner as the accused version of newlook, material features in view of the three computer host-server-terminal arrangement recited in the claim of the ’075 Patent allegedly infringed by the present version of newlook. Drawing all reasonable inferences in ResQNet’s favor, see Gibbs-Alfano, 281 F.3d at 18, it may not be determined based upon the current record that the newlook product offered for sale in 1996 is materially identical to the newlook product accused by ResQNet. Accordingly, Lansa’s motion for partial summary judgment as to the invalidity of the ’075 Patent must be denied based on the presence of genuine issues of material fact as to whether the product offered for sale by Lansa in 1996 is materially identical to the product sold in 2001 and alleged to infringe the ’075 Patent. ResQNet’s motion to strike the invalidity defense and preclude Dee from testifying about the defense at trial is likewise denied. As ResQNet correctly notes, under the law of the Federal Circuit, a party may not establish an on-sale bar solely by reliance on uncorroborated testimony. See Finnigan Corp. v. Int’l Trade Comm’n, 180 F.3d 1354, 1367 (Fed.Cir.1999); Woodland Trust v. Flowertree Nursery, Inc., 148 F.3d 1368, 1371 (Fed.Cir.1998). In accordance with this principle, oral testimony offered in support of a § 102(b) argument may be excluded if it is offered without any corroborating evidence. See, e.g., Texas Digital Sys., Inc. v. Telegenix, Inc., 308 F.3d 1193, 1217-18 (Fed.Cir.2002) (holding that, “[i]n the absence of further contemporaneous corroborating evidence, we are unable to conclude that the district court abused its discretion in refusing to admit Brown’s testimony for lack of corroboration”), cert. denied, 538 U.S. 1058, 123 S.Ct. 2230, 155 L.Ed.2d 1108 (2003). Lansa has not relied solely on Dee’s testimony but has also invoked certain contemporaneous documentary evidence in support of its argument for invalidity of the ’075 Patent. ResQNet argues that the documentary evidence proffered is insufficient to corroborate Dee’s testimony, as the documents proffered by Lansa fail to set forth the presence of the first three limitations of claim 1 in the 1996 newlook product. Because ResQNet’s motion does not address the documentary evidence contained in Lansa’s supplemental submission filed on September 28, 2004, ResQNet’s motion is denied at this time, with leave granted to renew the motion as an in limine motion prior to trial. C. Material Facts Preclude Summary Judgment As To Whether Lansa’s Newlook Product Infringes the ’075 Patent ResQNet has moved for partial summary judgment of liability on the ground that Lansa’s newlook product infringes claim 1 of the ’075 Patent. ResQNet argues that Lansa has failed to identify any single claim limitation absent from its product. In response, Lansa has cross-moved for partial summary judgment of non-infringement of thé ’075 Patent, arguing that Lansa’s newlook product neither literally infringes claim 1 of the ’075 Patent nor infringes claim 1 under the doctrine of equivalents. Both motions hinge on whether an algorithm that generates a unique screen identification number is an essential element of ResQNet’s invention and whether such an algorithm is employed by Lansa’s newlook product. “Determination of patent infringement requires a two-step analysis: (1) the scope of the claims must be construed; and (2) the allegedly infringing device must be compared to the construed claims.” Mars, Inc. v. H.J. Heinz Co., 377 F.3d 1369, 1373 (Fed.Cir.2004); accord PSC Computer Prods., Inc. v. Foxconn Int'l Inc., 355 F.3d 1353, 1357 (Fed.Cir.2004). In construing claims, a court looks first to intrinsic evidence, including the words of the claims themselves, the patent specification, and the prosecution history of the patent. See W.E. Hall Co. v. Atl. Corrugating, LLC, 370 F.3d 1343, 1350 (Fed.Cir.2004) (citing Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed.Cir.1996)). Intrinsic evidence should be examined first, as it is “the most significant source of the legally operative meaning of disputed claim language.” Vitron- ics, 90 F.3d at 1582. In this regard, a patent’s specification is usually “ ‘disposi-tive’ ” where the language of a claim is in dispute, as the specification “ ‘is the single best guide to the meaning of a disputed term.’ ” Bell Atl. Network Servs., Inc. v. Covad Communications Group, Inc., 262 F.3d 1258, 1268 (Fed.Cir.2001) (quoting Vitronics, 90 F.3d at 1582). Reliance on extrinsic evidence, including expert testimony, is only appropriate when the intrinsic evidence does not resolve an ambiguity in a disputed claim term or when the court requires assistance in learning the technical aspects of the relevant art. See DeMarini Sports, Inc. v. Worth, Inc., 239 F.3d 1314, 1323 (Fed.Cir.2001); EMI Group N. Am., Inc. v. Intel Corp., 157 F.3d 887, 892 (Fed.Cir.1998); Bell & Howell Document Mgmt. Prods. Co. v. Altek Sys., 132 F.3d 701, 706 (Fed.Cir.1997). Lansa argues that partial summary judgment of non-infringement is appropriate both for want of literal infringement and under the doctrine of equivalents. With regard to the first argument, summary judgment as to literal infringement is appropriate only “when no genuine issue of material fact exists, in particular, when no reasonable jury could find that every limitation recited in the properly construed claim either is or is not found in the accused device.” Bai v. L & L Wings, Inc., 160 F.3d 1350, 1353 (Fed.Cir.1998). As to Lansa’s second argument, “[i]nfringement under the doctrine of equivalents requires that the accused product contain each limitation of the claim or its equivalent.” Leggett & Platt, Inc. v. Hickory Springs Mfg. Co., 285 F.3d 1353, 1358-59 (Fed.Cir.2002) (citing Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 40, 117 S.Ct. 1040, 137 L.Ed.2d 146 (1997)). “A claim element is equivalently present in an accused device if only ‘insubstantial differences’ distinguish the missing claim element from the corresponding aspects of the accused device.” Sage Prods., Inc. v. Devon Indus., Inc., 126 F.3d 1420, 1423 (Fed.Cir.1997). Thus, under the doctrine of equivalents, summary judgment of noninfringement is proper where “no reasonable jury could determine two elements to be equivalent.” Leggett & Platt, 285 F.3d at 1360 (quoting Warner-Jenkinson, 520 U.S. at 39 n. 8, 117 S.Ct. 1040). The Federal Circuit reversed the construction of claim 1 of the ’075 Patent from ResQNet I, but only “to the extent that it required the claimed method to include more than ‘a plurality of specific screen identifying information.’ ” ResQNet II, 346 F.3d at 1384. The Federal Circuit otherwise made clear that “[t]he asserted claims” — including claim 1 of the ’075 Patent — “each require an algorithm that recognizes the screen based on the information downloaded from the mainframe to the PC.” Id. at 1373. In so ruling, the Federal Circuit appears to have implicitly construed claim 1 of the ’075 Patent by reference to the specification, since the term “algorithm” is not included in the element language of claim l. The relevant intrinsic evidence as well as ResQNet’s own representations and admissions support this construction, and demonstrate that an algorithm is required by the “match[ing]” process described in the fifth limitation of claim 1, which limitation explains the result where “said received screen matches one of the plurality of specific screen identifying information.” (’075 Patent, col. 5, 11. 14-15 (emphasis supplied).) Thus, the summary of the invention, part of the written description of the ’075 Patent, sets forth the matching process as follows: [A]s host screens are downloaded to the terminal emulator, the terminal emulator performs the screen recognition algorithm, and sends the results to the server. The server then returns to the terminal emulator the appropriate parameters for displaying the screen in GUI format. (’075 Patent, col. 2,11. 28-32.) The matching process is described in somewhat more detail elsewhere in the specification, once again underscoring the role played by an algorithm to make possible the match in question: Once the communications connection is established, screens of information, depending upon the particular application being run, will be downloaded from host 102 to NC terminal 104. These screens of information are waited for at block 205 by the NC terminal 204. The screen of information is then placed into a presentation space of operation box 206 and it is recognized using a screen recognition procedure at block 207. The particular screen recognition algorithm used is not critical to the present invention but may be of the type described in the ’961 patent. After the screen is recognized and a screen ID is generated, the decision point 208 determines whether or not such screen is contained in the screen table at the server. (’075 Patent, col. 4, 11. 1-13.) ResQNet itself has acknowledged that an algorithm is called for by claim 1, explaining in opposition to Lansa’s motion that “a simple matching algorithm ... will suffice to meet the language of the claim....” (PL Sept. 17, 2004 Opp. Mem. at 2.) While an algorithm may be integral to claim 1 of the ’075 Patent, ResQNet nonetheless argues that the language of claim 1 does not call for an algorithm that generates a screen identification number, as Lansa has suggested. The language of the specification belies this conclusion. In particular, the specification teaches that, whichever algorithm is employed, the application of that algorithm invariably produces a unique identification number: During the implementation of a particular application, host 102 downloads a variety of different screens. These green screens, as they are called, are processed through screen recognition algorithms such as that described in the previously incorporated ’961 patent and ’583 application. The processing of each screen generates a unique identification number. (’075 Patent, col. 3, 11. 39-45 (emphasis supplied).) Following the generation of a unique identification number by the processing of each screen by a screen-recognition algorithm, a table of unique identification numbers previously downloaded from the server is “utilized to ascertain the tag from the unique identifier.” (’075 Patent, col. 3,11. 45-46 (emphasis supplied).) This table, as the specification elsewhere notes, contains “the unique identification numbers which will be generated by each screen downloaded from the host when the screen recognition algorithms of the ’961 Patent, or other such screen recognition algorithms, are executed.” (’075 Patent, col. 3,11. 13-17 (emphasis supplied).) Simply put, the execution of the screen-recognition algorithms required by claim 1 generates unique identification numbers, and this description of the algorithm’s function limits the scope of claim 1. See Alloc, Inc. v. Int’l Trade Comm’n, 342 F.3d 1361, 1370 (Fed.Cir.2003) (stating that, “where the specification makes clear at various points that the claimed invention is narrower than the claim language might imply,” such as where “the specification read as a whole suggests that the very character of the invention requires the limitation be a part of every embodiment,” it is “entirely permissible and proper to limit the claims”). The prosecution history for the ’075 Patent does not suggest a contrary conclusion. As originally filed, the application for what later became the ’075 Patent initially contained claims directed to a “three-way” communications system among a terminal, server and a remote host, as a part of which system the terminal would download different screens of information from the host and, upon receiving the screen, according to the applicants’ description, “either read[ ] a screen ID sent by the host or generated its own screen ID” subsequently transmitted to the server. (Affidavit of James H. Hulme, sworn to Sept. 17, 2004 (“Sept. 17 Hulme Aff.”), Exh. B, at ZEP 12846 (explaining that the server would then send the terminal information “indicative of how to display the information downloaded from the host”).) Upon initial examination by the United States Patent and Trademark Office (the “PTO”), all of the claims were rejected as being anticipated by U.S. Patent No. 5,754,830 (the “ ’830 Patent”). The applicants subsequently sought to distinguish their proposed claims from the ’830 Patent, once again offering a brief review of the invention claimed: Applicant’s invention relates to a technique of utilizing a remote server in order to assist in presenting a graphical user interface (GUI) to a user. In operation, software from a communications server is downloaded to a terminal. The software is specifically designed to allow communications between the terminal and a remote host. A second communications channel is then established between the terminal and the remote host.... In claim 3, the server is also used in order to assist in presentation of the information downloaded from the server. For example, the screen ID which is generated at the terminal in response to receiving a screen of information is decoded and sent to the server. The server then interprets the particular screen ID, utilizes a table lookup or other mechanism in order to determine how to present the screen of information as a graphical user interface, and then sends the presentation information to the terminal. (Sept. 17 Hulme Aff., Exh. B, at ZEP 12872-73 (emphasis supplied).) The applicants argued that the ’830 Patent did not teach the decoding of each screen of information at the terminal and the subsequent transmittal of the “decoded scree[n] ID to a remote server in order to have the remote server specify the GUI presentation for each screen.” (Sept. 17 Hulme Aff., Exh. B., at ZEP 12874.) The PTO once again rejected the proposed claims, noting that the applicants had not claimed the limitation of decoding screen information at the terminal and transmitting a decoded screen ID in order to specify a particular GUI. Subsequent amendments setting forth the limitation of decoding screen information, including decoding screen ID information, at the terminal were likewise rejected by the examiner. It was only upon adding the final three limitations of present claim 1 that the application was allowed. As the applicants explained upon presenting the new limitations, The amendment to the claims has added limitations directed to a selection of a GUI screen that may be customized in the circumstance that the screen received from the host matches one of a plurality of screen identifying information, or, alternatively may be a default GUI screen if the received screen from the host does not so match. This unique limitation derives from the specification at page 7 line 23 through page 8, line 26, which describes the flowchart of figure 2 of the application. (Sept. 17 Hulme Aff., Exh. B, at ZEP 12922-23 (emphasis supplied).) The portions of the specification to which the applicants referred and from which the “unique limitation derives” are the same portions of the specification, previously described, which set forth the use of an algorithm to perform a “screen recognition procedure,” upon the performance of which “a screen ID is generated.” (’075 Patent, col. 4,11.1-13.) Thus, the prosecution history of the ’075 Patent provides further confirmation that claim 1 and, in particular, the matching process claimed therein are to be construed to require use of an algorithm that generates screen IDs. ResQNet argues that this construction runs contrary to the holding of ResQNet II, insofar as the Federal Circuit ruled that claim 1 of the ’075 Patent does not require that the particular screen-recognition algorithm employed be of the type described in the ’961 Patent. This argument must be rejected. According to the Federal Circuit, the ’961 Patent requires an algorithm which evaluates all of the fields of an incoming screen of data in order to uniquely identify the incoming screen. See ResQNet II, 346 F.3d at 1379-82. In other words, the ’961 Patent does not simply describe an algorithm that generates unique screen IDs, but one that “requires use of every field in the information downloaded from the mainframe to the PC in determining a screen ID.” Id. at 1382 (emphasis supplied). To construe claim 1 of the ’075 Patent to require an algorithm that generates a unique screen ID, without regard to how that screen ID is generated or from what data it is derived, does not, therefore, run contrary to the Federal Circuit’s holding that the ’075 Patent need not employ the type of algorithm described in the ’961 Patent. Nor, for that matter, does this construction contradict ResQNet’s argument that even a prior art algorithm could be employed by the method claimed in the ’075 Patent. ResQNet has also argued that construing claim 1 to require an algorithm that generates a unique screen ID would render the language “generating a screen ID” superfluous in the claims in which it is contained, such as the claims of the ’961 Patent, and would impermissibly read limitations of the ’961 Patent into the ’075 Patent. As there is “no reason to construe the ’075 claims as identical to similar claim terms in the other two patents,” including the ’961 Patent, ResQNet II, 346 F.3d at 1383, ResQNet’s argument concerning superfluity and parallel construction is unconvincing. Furthermore, for the reasons set forth above, the requirements of claim 1 of the ’075 Patent described herein are not being read into the claim from the ’961 Patent but, rather, are required in light of the ruling of the Federal Circuit, the specification and the relevant prosecution history. As claim 1 requires an algorithm that generates a screen ID in order to perform the “match[]” described in the fifth limitation to the claim, the next question is whether Lansa’s newlook product infringes the claim so construed. According to ResQNet, the newlook product contains each of the limitations of claim 1, including, as ResQNet argues in the alternative, the requirement of an algorithm that generates screen IDs. ResQNet cites the testimony of Lansa’s technical witness for the proposition that newlook employs so-called rules to generate GUIs, and points to a variety of documentary evidence concerning newlook which make reference to screen IDs. Lansa, in turn, has cited both documentary and testimonial evidence for the proposition that newlook does not generate a unique screen ID as required by the claim. Drawing necessary inferences against the moving party as to each of the two motions, see Gibbs-Alfano, 281 F.3d at 18, and in view of the incompleteness of the record, both motions for partial summary judgment as to the ’075 Patent are denied. The existence of genuine issues of material fact as to whether newlook infringes the ’075 Patent by, inter alia, employing an algorithm to generate screen IDs precludes judgment as a matter of law. D. Lansa’s Motion for Partial Summary Judgment of Non-Infringement of the ’608 Patent Is Denied Lansa has moved for partial summary judgment of non-infringement of the ’608 Patent on the ground that the ’608 Patent, and in particular the second limitation of claim 1 of the ’608 Patent, is properly construed as employing an algorithm to generate a screen identification number, and newlook does not generate such a screen identification number. Accordingly, Lansa contends that newlook does not infringe the ’608 Patent. ResQNet does not dispute Lansa’s characterization of the ’608 Patent but argues that the testimony of Lansa’s witnesses demonstrates that newlook generates a screen ID by operation of a pattern-matching algorithm. Claim 1 of the ’608 Patent, which is a continuation-in-part of the ’961 Patent, “require[s] an algorithm that recognizes the screen based on the information downloaded from the mainframe to the PC.” Re-sQNet II, 346 F.3d at 1376. As the Federal Circuit has explained, Similar to claim 1 of the ’961 patent, claim 1 of the ’608 patent contains limitations in means-plus-function format. The claimed function is “identifying ... a particular screen to be displayed to said user.” ’608 patent, col. 4, 11. 42-44. The specification sets forth the corresponding structure: “Upon a screen of information being downloaded to a personal computer 103, the personal computer analyzes the screen with respect to the location of particular fields, and other attributes thereof, in order to recognize the particular screen downloaded.” Id. at col. 2,11. 51-55. Thus, similar to the ’961 patent, the structure is an algorithm for analyzing the downloaded information to generate a screen ID. Id. at 1382. The generation of a screen ID by the algorithm in question requires “use of a plurality of specific individual fields, i.e., at least two fields.” Id. at 1383, 1384 (reversing this Court’s construction of claim 1 of the ’608 Patent “to the extent that it required the algorithm to use more than ‘each of a plurality of fields’ ”). As was explained in ResQNet I, “the language of the claim itself makes clear that, unlike the ’961 patent, the algorithm is dependent on three parameters for identifying a screen: position, length, and type.” Re-sQNet I, 2002 WL 31002811, at *7. For a means-plus-function claim such as claim 1 of the ’608 Patent, literal infringement generally requires that the relevant structure in the accused device perform the identical function recited in the claim and be identical or equivalent to the corresponding structure in the specification. See, e.g., Ishida Co., Ltd. v. Taylor, 221 F.3d 1310, 1316 (Fed.Cir.2000) (“Literal infringement of a claim with a means-plus-function clause requires that the accused device perform a function identical to that identified in the means clause.”); Valmont Indus., Inc. v. Reinke Mfg. Co., 983 F.2d 1039, 1042 (Fed.Cir.1993) (“In sum, for a means-plus-function limitation to read on an accused device, the accused device must employ means identical to or the equivalent of the structures, material, or acts described in the patent specification. The accused device must also perform the identical function as specified in the claims.”). Where, however, a dependent claim was rewritten into independent form and the original independent claims were cancelled, surrendering subject matter that was originally claimed for reasons related to patentability, the resulting narrowing amendment gives rise to a rebuttable presumption of surrender of equivalents and to prosecution history es-toppel. See generally Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 733-41, 122 S.Ct. 1831, 152 L.Ed.2d 944 (2002); Honeywell Int’l Inc. v. Hamilton Sundstrand Corp., 370 F.3d 1131, 1139-44 (Fed.Cir.2004), petition for cert. filed, 73 U.S.L.W. 3146, 2004 WL 1950434 (U.S.2004) (No. 04-293). “Whether a patentee is presumptively estopped from asserting equivalents for an amended claim element is a question of law....” Honeywell Int’l, 370 F.3d at 1139. The “surrendered subject matter is defined by the cancellation of independent claims that do not include a particular limitation and the rewriting into independent form of dependent claims that do include that limitation.” Id. at 1144. Equivalents, as the Federal Circuit has stated, “are presumptively not available with respect to that added limitation.” Id.; see also Toro Co. v. White Consol. Indus. Inc., 383 F.3d 1326, 1331 (Fed.Cir.2004) (explaining that, under the doctrine of prosecution history estoppel, “resort to the doctrine of equivalents is precluded based on actions of the patentee during prosecution evincing a surrender ... of subject matter”). Thus, in Ranbaxy Pharmaceuticals, Inc. v. Apotex, Inc., 350 F.3d 1235 (Fed.Cir.2003), the Federal Circuit concluded that there had been a narrowing amendment giving rise to a presumptive surrendering of equivalents, explaining that: While Apotex was merely rewriting a dependent claim into independent form, the effect on the subject matter was substantial. The dependent claims that were redrafted into independent form did more than simply add an additional limitation; they further defined and