Competitive Technologies, Inc. v. Fujitsu Ltd. (333 F. Supp. 2d 858, 2004)

United States District Court for the Northern District of California 2004-07-13

Citations

Full opinion text

CORRECTED ORDER:

GRANTING DEFENDANTS’ CONSOLIDATED MOTIONS FOR SUMMARY JUDGMENT OF INVALIDITY AND NON-INFRINGEMENT OF CLAIMS OF THE ’400 PATENT [Docket No. 568], DENYING UI’S MOTION TO STRIKE IN PART THE DECLARATION OF FUJITSU’S EXPERT, DR. SILZARS [Docket No. 575], DENYING DEFENDANTS’ AND COUNTER-CLAIMANTS’ MOTION TO SHORTEN TIME [Docket No. 627], AND GRANTING IN PART AND DENYING IN PART FUJITSU’S MOTION TO STRIKE, OR IN THE ALTERNATIVE, REPLY IN SUPPORT OF EVIDENCE OBJECTIONS [Docket No. 628]

SPERO, United States Magistrate Judge.

I. INTRODUCTION

On Friday, April 2, 2004, Defendants’ Consolidated Motions for Summary Judgment of Invalidity and Non-Infringement of Claims of the ’400 Patent (“the Motion”) came on for hearing. For the reasons stated below, Fujitsu’s Motion is GRANTED. The Court further holds as follows: 1) The University of Illinois’ Motion to Strike in Part the Declaration of Fujitsu’s Expert, Dr. Aris Silzars (“UI’s Motion to Strike”) is DENIED; 2) Fujitsu’s Motion to Shorten Time is DENIED; and 3) Fujitsu’s Motion to Strike is GRANTED in part and DENIED in part.

II. BACKGROUND

In this case, which involves driver circuits for plasma display panels, UI accuses Fujitsu of infringing two of its patents— U.S. Patent No. 4,866,349 (“the ’349 Patent”) and U.S. Patent No. 5,081,400 (“the ’400 Patent”). The ’400 Patent is a continuation of the ’349 Patent, and both patents are entitled, “Power Efficient Sustain Drivers and Address Drivers for Plasma Panel.” Following a claim construction hearing, the Court issued its claim construction order on July 31, 2003. Fujitsu now brings a motion for summary judgment of invalidity and noninfringement. In the Motion, Fujitsu requests that this Court hold, as a matter of law, that: 1) claims 21-25, 27-31, 35, and 38 of the ’400 Patent are invalid as anticipated; 2) claims 21-40 of the ’400 Patent are not literally infringed; and 3) claims 26, 32-33, 36, and 39-40 of the ’400 Patent (“the Remaining Claims”) are not infringed under the doctrine of equivalents.

UI concedes that as interpreted in the Claim Construction Order, claims 21-25, 27, 35 and 38 are anticipated by Japanese Patent Publication No. 58-53344 (“Kanata-ni” or “Kanatani ’344 Publication”) and therefore are invalid. See Expert Declaration of Dr. Aris Silzars Regarding Motions for Summary Judgment (“Silzars SJ Decl.”), Ex. 39, The University’s Literal Infringement and Validity Disclosures Pursuant to Paragraphs 1 and 2 of the Court’s September 11, 2003 Scheduling Order (“UI’s September 18, 2003 Disclosures”) at 1. Accordingly, the Motion is GRANTED as to claims 21-25, 27, 35 and 38 on the basis that these claims are invalid. In addition, UI does not dispute that under the Court’s claim construction, claims 21 through 40 are not literally infringed. See id., Literal Infringement Claim Chart. Therefore, summary judgment is GRANTED on these claims with respect to the question of literal infringement. However, UI opposes the Motion as to claims 28 — 31 (on the question of invalidity) and claims 26, 32-33, 36, 39-40 (on the question of infringement under the doctrine of equivalents). These issues are addressed below.

III. ANALYSIS

A. UI’s Motion to Strike

UI brings a motion to “strike in part” the declaration of Fujitsu’s expert, Dr. Sil-zars, which was filed in support of Fujitsu’s Motion. UI argues that the declaration is improper because it includes new opinions that were not included in Dr. Silzars’ expert report and were not addressed at his deposition, in violation of this Court’s January 6, 2004 Order. However, UI fails to identify any specific opinions that are improper. Accordingly, UI’s Motion to Strike is DENIED.

B. Fujitsu’s Objections to Evidence, Motion to Strike, and Motion to Shorten Time

On February 27, 2004, Fujitsu filed, along with its Reply on the substantive Motion, Defendants’ and Counterclaim-ants’ Objections to Evidence (“Objections to Evidence”). In Fujitsu’s Objections to Evidence, it objected on numerous grounds to evidence introduced by UI in support of its Opposition. Almost three weeks later, ten days before the scheduled hearing on the Motion, UI filed The University of Illinois’ Response to Defendants’ and Counterclaimants’ Objections to Evidence (“UI Response”). The brief addressed not only Fujitsu’s evidentiary objections but also energy efficiency calculations that were presented for the first time in Fujitsu’s Reply. Six days later, on March 29, 2004 — now only four days before the scheduled hearing — Fujitsu filed a Motion to Strike or, in the Alternative, Reply in Support of Objections to Evidence (“Fujitsu’s Motion to Strike”). At the same time, Fujitsu filed a Motion to Shorten Time, requesting that the Court allow it to reply to or move to strike UI’s Response on a shortened schedule and that the Court rule on its Motion to Strike prior to taking the Motion under submission.

At the April 2, 2004 hearing, the Court declined to rule on Fujitsu’s Motion to Strike or its Motion to Shorten Time, noting that it had not had the opportunity to review any of the-late-filed briefs — UI’s Response and Fujitsu’s Motion to Strike— in detail. Rather, the Court took these motions, along with Fujitsu’s Objections to Evidence, under submission following the hearing. The Court now rules on Fujitsu’s Motion to Shorten Time, Motion to Strike, and. Objections to Evidence. First, Fujitsu’s Motion to Shorten Time is DENIED as moot. Because the Court did not consider UI’s Response or Fujitsu’s Motion to Strike at the April 2, 2004 hearing, Fujitsu was not prejudiced by its inability to respond to' UI’s late submission, making an order shortening time unnecessary.

Second, Fujitsu’s Motion to Strike is GRANTED in part and DENIED in part, as follows. The Motion to Strike is GRANTED to the extent that UI’s Re-sponse goes beyond the scope of Fujitsu’s Objections to Evidence by addressing energy efficiency calculations contained in Fujitsu’s Reply on the underlying substantive motion. Fujitsu is correct that this portion of UI’s brief is an improper sur-reply under the local rules. Therefore, section II(B)2(b) of UI’s Response shall be stricken. By the same token, the Court also does not consider the energy efficiency calculations that were introduced by Fujitsu for the first time in its Reply, at page 17, lines 4-20. See United States v. Boyce, 148 F.Supp.2d 1069, 1084 (S.D.Cal.2001) (citing to United States v. Bohn, 956 F.2d 208, 209 (9th Cir.1992) (noting that courts generally decline to consider arguments raised for the first time in a reply brief); United States v. Boggi, 74 F.3d 470, 478 (3d Cir.1996) (noting that considering arguments raised for first time in reply brief deprives opposing party of adequate opportunity to respond); Playboy Enters., Inc. v. Dumas, 960 F.Supp. 710, 720 n. 7 (S.D.N.Y.1997) (“Arguments made for the first time in a reply brief need not be considered by a court”)).

Fujitsu’s Motion to Strike is DENIED as to the remainder of UI’s Response. Although Fujitsu is correct that UI should have obtained leave of Court to file its brief, the Court declines to strike the portions that address Fujitsu’s Objections to Evidence because, had UI sought leave to file the brief, leave would have been granted. Fujitsu’s Objections to Evidence raise significant issues, to which UI is entitled to respond. Similarly, with respect to the verifications filed by UI as part of its Response — which included numerous revisions of the unverified translations that were filed by UI in support of its Opposition — UI failed to abide by local rules. Again, however, any prejudice that might have resulted from this late submission is mitigated by the fact that Defendants were given three weeks from the April 2, 2004 hearing date to bring to the Court’s attention any issues related to the Motion raised by the new translations. On April 26, 2004, Fujitsu notified the Court that the errors in the translations to which it objects do not “impact the summary judgment motions.” Therefore, in ruling on Fujitsu’s Objections to Evidence, the Court considers UI’s Response, with the exception of the portion discussed above. The Court also considers the Reply portion of Fujitsu’s Motion to Strike.

With respect to Fujitsu’s Objections to Evidence, the Court addresses Objection Nos. 1 — 3, all of which are based on Daubert v. Merrell Dow Pharm., Inc., 43 F.3d 1311 (9th Cir.1995), in the substantive portion of this Order. The Court rules as follows with respect to Fujitsu’s remaining objections.

First, as to evidence related to Fujitsu’s alleged infringement based on use of two inductors, Objection No. 4, the Court does not rely on this evidence and therefore, declines to rule on this objection.

Second, the Court overrules Objection Nos. 5 and 6, based on UI’s failure to submit the expert reports of Drs. Inan and Bitzer under penalty of perjury. Although Fujitsu is correct that these reports should have been signed under penalty of perjury, as the party opposing summary judgment, UI’s papers are “held to a less exacting standard” than those of Fujitsu. See Lodge Hall Music, Inc. v. Waco Wrangler Club, Inc., 831 F.2d 77, 80 (5th Cir.1987) (citing Charles A. Wright, Arthur R. Miller, Mary Kay Kane, Federal Practice and Procedure § 2378 at 467 (1983)). Having carefully reviewed the reports of Dr. Inan and Dr. Bitzer, the Court finds that they meet the requirements of Rule 56(e), namely, that they are “made on personal knowledge, ... set forth such facts as would be admissible in evidence, and ... show affirmatively that the affiant is competent to testify to the matters stated therein.” Fed.R.Civ.P. 56(e). Under these circumstances, the Court declines to exclude the Inan and Bitzer reports. See Shinabarger v. United Aircraft Corp., 262 F.Supp. 52, 56 (D.Conn.1966) (holding that declaration submitted in opposition to summary judgment that was signed but not sworn could be considered because “the existence of such a statement, although not presently in evidentiary form, should alert the summary judgment court to the availability at the trial of the facts contained in the statement”).

Third, the Court overrules Objection Nos. 7-8, based on Dr. Inan’s alleged lack of qualifications regarding the manufacture and design of display panels. The Court concludes that Dr. Inan possesses sufficient knowledge and expertise to satisfy the requirements of Fed.R.Evid. 702 as to the challenged opinions.

Fourth, the Court overrules Objection No. 9, based on UI’s failure to submit certifications of translations. As discussed above, UI subsequently submitted certifications and, to the extent that UI’s certifications included revisions of the translations, Fujitsu has now agreed that those revisions have no impact on its summary judgment motions.

Fifth, the Court overrules Objection No. 10 to the extent it is based on UI’s failure to submit certifications of translations for the same reason Objection No. 9 is overruled. To the extent Objection No. 10 is based on Fujitsu’s position that copying is irrelevant, the Court declines to rule on this objection because that issue is more appropriately addressed on the merits.

Sixth, the Court overrules Objection Nos. 11-13, based on the assertion that the declarations .of the inventors are irrelevant. Although Fujitsu is correct that the test for determining whether an equivalent would have been foreseeable at the time of a narrowing amendment is objective under Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki, 344 F.3d 1359, 1369 (Fed.Cir.2003), that case does not hold that the subjective knowledge of the inventors at the time of the amendment may not be considered in determining whether this objective test is met. The Court concludes that although these declarations are not dispositive of this issue, they may be considered.

Seventh, the Court declines to rule on Objection No. 14, in which Fujitsu asserts that UI’s energy' efficiency calculations contradict the patent and, therefore, should be excluded as irrelevant. This issues goes directly to the merits of the Motion and therefore, is appropriately addressed in the substantive portion of this Order rather than in an evidentiary ruling.

C. Summary Judgment Motions

1. Summary Judgment Standard

Summary judgment is appropriate “if the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, show that there is no genuine issue as to any material fact and that the moving party is entitled to judgment as a matter of law.” Fed.R.Civ.P. 56(c). In order to prevail, a party moving for summary judgment must show the absence of a genuine issue of material fact with respect to an essential element of the non-moving party’s claim, or to a defense on which the non-moving party will bear the burden persuasion at trial. Celotex Corp. v. Catrett, 477 U.S. 317, 323, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986). Once the movant has made this showing, the burden then shifts to the party opposing summary judgment to designate “specific facts showing there is a genuine issue for trial.” Id. at 323, 106 S.Ct. 2548.

In determining whether summary judgment is appropriate, the court must draw all reasonable inferences in favor of the non-moving party. Id. However, summary judgment must be supported by “facts as would be admissible in evidence.” Fed. R.Civ.P. 56(e). Scientific evidence, therefore, must meet the standards of relevance and reliability articulated in Daubert v. Merrell Dow Pharm., Inc. See Seaboard Lumber Co. v. United States, 308 F.3d 1283, 1301 (Fed.Cir.2002)(citing Daubert, 509 U.S. 579, 589, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993)). The Supreme Court in Daubert described this inquiry as follows:

Faced with a proffer of expert scientific testimony, then, the trial judge must determine ... whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue. This entails a preliminary assessment of whether the reasoning or methodology underlying the testimony is scientifically valid and of whether that reasoning or methodology properly can be applied to the facts in issue.

509 U.S. at 590, 113 S.Ct. 2786.

2. Invalidity of Claims 28-31

a. Legal Standard

A patent claim is anticipated, and therefore invalid, if a prior art reference “discloses, either expressly or inherently, all of the limitations of the claim.” EMI Group North America, Inc. v. Cypress Semiconductor Corp., 268 F.3d 1342, 1350 (Fed.Cir.2001). In the context of a means-plus-function claim, the invalidating prior art must disclose not simply a means for achieving the desired function but rather, the particular structure recited in the written description corresponding to that function. See In re Donaldson Co., Inc., 16 F.3d 1189, 1193 (Fed.Cir.1994) (holding that 35 U.S.C. § 112, paragraph 6, which limits means-plus-function claims to the structures described in the Specification and their equivalents, “applies regardless of the context in which the interpretation of means-plus-function language arises, i.e., whether as part of a patentability determination in the PTO or as part of a validity or infringement determination in a court”).

Because of the presumption of validity under 35 U.S.C. § 282, “a defendant must show invalidity by facts supported by clear and convincing evidence.” Beckson Marine, Inc. v. NFM, Inc., 292 F.3d 718, 725 (Fed.Cir.2002). On summary judgment, the court draws all reasonable factual inferences in favor of the non-movant. Id. at 722 (citing to Anderson v. Liberty Lobby Inc., 477 U.S. 242, 255, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986)). Accordingly, summary judgment on anticipation may be granted “only when the underlying factual inquiries present no lingering genuine issues.” Id.

b. The Forcing Voltage Claims (Claims 28 and 29)

i. Summary of the Arguments

Fujitsu argues that both the functions and the means of claims 28 and 29 (“the Forcing Voltage Claims”) are disclosed in the Kanatani ’344 Publication. First, Fujitsu asserts that Kanatani meets the recited function of claims 28 and 29, namely, “applying a forcing voltage which is about one-half the magnitude of the voltage level the panel capacitance reaches after charging.” According to Fujitsu, UI cannot dispute that the Kanatani prior art meets this function because it has already made a binding admission that Kanatani meets the function of method claims 22 and 23, which disclose the identical function. Silzars SJ Decl., Ex. 39, UI’s September 18, 2003 Disclosures at 1. In addition, Fujitsu points to testimony by UI’s validity expert, Dr. Bitzer, which it asserts supports the conclusions that: 1) the function of the Forcing Voltage Claims is met by Kanata-ni; and 2) one of ordinary skill in the art would have been enabled to practice the function of the Forcing Voltage Claims with the structures disclosed in Kanatani. See Silzars SJ Decl., Ex. 11, Bitzer Depo. at 525 — 533.

Second, Fujitsu argues that the means for accomplishing the forcing voltage function recited in claims 28 and 29 also is anticipated by the Kanatani prior art. In support of this contention, Fujitsu asserts that the ’400 Patent discloses several structures for applying a forcing voltage that use a connection to a power supply, as in Kanatani. Specifically, Fujitsu argues that the circuits depicted in Figures 10, 11 and 13 all apply a forcing voltage via connection to a power supply.

Figure 10 depicts an “integrated, power efficient sustain driver circuit according to the invention” in which the forcing voltage is applied using a voltage divider consisting of two external capacitors (Cssl and Css2) that are supplied on start-up by connections to power supplies (Vcc and ground). ’400 Patent, col. 15, lines 22-24, 38-42; Silzars SJ Decl. at 98, ¶ 196. Figure 11 shows an embodiment in which the forcing voltage is supplied directly from a power supply generating voltage level Vdd. Silzars SJ Decl. at 98, ¶ 197. Figure 13 depicts a circuit in which ground is used as a power supply connection to apply a forcing voltage. See Silzars SJ Decl. at 99, ¶ 198.

With respect to Figure 10, Fujitsu argues that UI’s validity expert, Dr. Bitzer, admitted during his deposition that current for charging in that figure is drawn from the power supply labeled Vcc through capacitors Cssl and Css2. See Sil-zars SJ Decl., Ex. 11, Bitzer Depo. at 545-546 (stating that “[during] the time that the inductor current is increasing, there can be and would be current through Cssl from Vcc and there will be current from Css2 as well”). Fujitsu asserts that because Figure 10, by UI’s own admission, draws current from a generic power supply to apply a forcing voltage, UI cannot now argue that the forcing voltage means excludes structures that use a direct connection to a power supply. Fujitsu further points to the Claim Construction Order, in which the Court held that Figure 10 is corresponding structure for the means for charging and discharging recited in claim 27, on which claim 28 depends. Claim Construction Order at 56. According to Fujitsu, the means for charging and discharging recited in claim 27 refers to the forcing voltage recited in claim 28.

Fujitsu argues further that the embodiment shown in Figure 11, which shows a connection to power supply Vdd without capacitor Css (or Cssl and Css2), is also corresponding structure for the Forcing Voltage Claims. In particular, citing to Dr. Bitzer’s deposition testimony, Fujitsu asserts that Vdd is the voltage across the inductor, that is, the forcing voltage, and the voltage would rise to 2 Vdd when the panel capacitance is charged. See Silzars SJ Decl., Ex. 11, Bitzer Depo. at 580 (“I’m using the term ‘forcing voltage’ here as what anybody standard in the art would have done; namely, the voltage across the inductor”), 550-551 (“Given that there’s nothing else on the output [in Figure 11], the voltage across the output would rise, as shown in Figure 12, to 2 Vdd”). Fujitsu further cites to deposition testimony by Drs. Inan and Bitzer in which both experts testified that Vdd in Figure 11 is a “power supply.” Silzars SJ Decl., Ex. 6, Inan Depo. at 133 & Ex. 11, Bitzer Depo. at 548. Finally, Fujitsu points to UI’s interrogatory responses, in which UI stated identified Figure 11 as corresponding structure for the means for applying a forcing voltage recited in claim 28. Silzars SJ Decl., Ex. 48, UI Interrogatory Responses. According to Fujitsu, because the structure shown in Figure 11 is identical to the structure used in Kanatani to apply a forcing voltage, Figure 11 provides an additional basis for concluding that the Forcing Voltage Claims are anticipated. See Sil-zars SJ Decl. at 101-102, ¶¶ 202-204 (citing to Kanatani ’344 Publication, Figures 9-10).

Similarly, Fujitsu argues that Figure 13, which shows a connection to ground as a power supply, supports its invalidity argument. Fujitsu points to the Specification, which states that Figures 11-14 are examples of “the energy recovery technique previously described in connection with the sustain circuit.” ’400 Patent, col. 15, lines 62-66. Fujitsu also points to the corresponding waveform in Figure 14, which shows charging through the inductor until the inductor current equals zero and then discharging through the inductor until the inductor current reaches zero. Fujitsu points as well to UI’s interrogatory responses, in which UI included Figure 13 as corresponding structure for the means for applying a forcing voltage recited in claim 28. Silzars SJ Decl., Ex. 48, UI Interrogatory Responses.

Finally, Fujitsu argues that UI’s position on invalidity is undermined by its allegation that Fujitsu’s TERES and TERES + driver circuits infringe the ’400 patent. According to Fujitsu, the TERES and TERES + driver circuits, like Kanata-ni, use a direct connection to a power supply to achieve a forcing voltage. Thus, Fujitsu asserts, if the Court accepts UI’s argument that a forcing voltage means using a direct connection to a power supply is not equivalent to a structure that uses Css in conjunction with a power supply, the Court should also enter summary judgment of non-infringement as to the TERES and TERES + driver .circuits.

In its Opposition, UI does not dispute that Kanatani discloses the function of the Forcing Voltage Claims. It is for this reason, UI explains, that it has conceded that method claims 22-25 are anticipated by Kanatani. UI argues, however, that the structures used to apply a forcing voltage in Kanatani are not the same as those that are disclosed in the ’400 Patent. First, UI argues that the corresponding structure for the Forcing Voltage Claims includes only the structures shown in the figures depicting sustain drivers, that is, Figures 5, 7, 9 and 10, all of which use Css or (in the case of Figure 10) Cssl and Css2, to apply the forcing voltage. Because Figures 11 and 13 depict address drivers, UI asserts, these embodiments do not disclose corresponding structure for the Forcing Voltage Claims. In support of this position, UI relies on the language in the ’400 Patent, pointing out that the term “forcing voltage” is only used in the Specification in connection with sustain circuit embodiments. See Bitzer Validity Expert Report at 4: 22-25 (citing to ’400 Patent at 10:12, 10:21, 10:35, 10:37, 11:26 and 11:50).

Second, UI asserts that there are material issues of fact with respect to whether Figure 10 — which uses power supply Vcc in conjunction with capacitors Cssl and Css2 — is equivalent to the power supply used (without capacitors) by Kanatani to apply a forcing voltage. In particular, UI cites to testimony by its expert, Dr. Bitzer, that use of a generic power supply is not equivalent to a structure that uses capacitor Css for two reasons: 1) use of Kanata-ni’s generic power supply results in higher energy losses during sustaining than use of a power supply in conjunction with capacitor Css; and 2) -the generic power supply can compensate for such losses by adding energy to the circuit, whereas Css cannot provide any additional energy. Bitzer Report at 6. In his report, Dr. Bitzer asserts that his conclusions are strengthened by Fujitsu’s own documents, which indicate that when Fujitsu tried to replace the forcing voltage capacitors in its own products with a power supply, the result was dramatically lowered energy efficiency. Bitzer Validity Expert Report at 6-7 and Ex.s I and J thereto.

UI argues further that the power supply Vcc shown in Figure 10 does not perform the forcing voltage function because the power supply in Figure 10 is at Vcc rather than the forcing voltage level Vss. See Bitzer Validity Expert Report at 5, n. 1.

UI rejects Fujitsu’s assertion that because the Court held in the Claim Construction Order that Figure 11 discloses corresponding structure for claim 27, Figure 11 must also disclose corresponding structure for the Forcing Voltage Claims. UI argues that because the Forcing Voltage Claims add limitations to claim 27, they eliminate certain embodiments, such as the one shown in Figure 11, while also requiring the inclusion of additional corresponding structure, namely, Css.

Finally, UI rejects Fujitsu’s assertion that its invalidity argument is inconsistent with’ its position that the TERES and TERES + circuits infringe the ’400 Patent. In particular, UI cites to testimony by Dr. Inan that it says supports the conclusion that while Kanatani’s generic power supply is not structurally equivalent to the embodiment shown in Figure 10, the means for applying a forcing voltage used by TERES and TERES + is equivalent to the embodiment in Figure 10. Opposition at 55 (citing Inan Report at 32-35).

ii. Discussion

In order to determine whether Fujitsu is entitled to summary judgment of invalidity as to the Forcing Voltage Claims, the Court must engage in additional claim construction, as the Forcing Voltage Claims were not expressly addressed in the Claim Construction Order. The parties are in agreement that the function of the Forcing Voltage Claims is “applying a forcing voltage which is about one-half the magnitude of the voltage level the panel capacitance reaches after charging.” Further, UI does not dispute that this function is disclosed in Kanatani. Thus, the question of whether the Forcing Voltage Claims are anticipated by Kanatani turns on corresponding structure. In particular, if Kanatani discloses the same or an equivalent corresponding structure for applying a forcing voltage as is disclosed in the ’400 Patent, there remains no genuine factual question as to anticipation. The Court concludes, based on Figure 11 of the ’400 Patent, that Kanatani discloses an identical structure for applying a forcing voltage and therefore, that the Forcing Voltage Claims are invalid.

In determining what constitutes corresponding structure, the Court looks to the Specification to determine what structures (if any) are “clearly associate[d]” with the function of a means-plus-function claim. Cardiac Pacemakers, Inc. v. St Jude Medical, Inc., 296 F.3d 1106, 1113 (Fed.Cir.2002). Neither the Forcing Voltage Claims, nor claim 27 (on which the Forcing Voltage Claims depend) are expressly limited to sustaining. Moreover, although the words “forcing voltage” are only used in the ’400 Patent in describing sustain driver circuits, UI has presented no evidence that an individual of ordinary skill in the art would have understood the term “forcing voltage” to refer only to sustaining. See Toro Co. v. White Cons.Indus., 199 F.3d 1295, 1299 (Fed.Cir.1999) (holding that there is a strong presumption that a claim term carries the ordinary and customary meaning that would be ascribed to that term by a person of ordinary skill in the field of the invention). To the contrary, UI’s expert, Dr. Bitzer, defined “forcing voltage” simply as “the voltage across the inductor.” Silzars SJ Deck, Ex. 11, Bitzer Depo. at 530. As a result, any embodiment described in the Specification that is clearly associated with the function of the Forcing Voltage Claims — whether in sustaining or addressing — may constitute corresponding structure.

UI, argues that because the words “forcing voltage” are not actually used in the Specification in describing Figures 11-13, these figures cannot constitute corresponding structure for the Forcing Voltage Claims. UI’s focus is too narrow. The inventors make clear in the Specification that the same energy efficient technique described for sustain drivers — which uses a “forcing voltage” — also can be used in address pulse generators. Indeed, the Specification makes this point at least twice. See ’400 Patent, col. 8, lines 18-21; col. 15, lines 62-65. The conclusion that Figures 11-13 are corresponding structure for the Forcing Voltage claims finds further support in the prosecution history, in which the inventors expressly stated that application claims 51-71 (claims 21—41 of the ’400 patent) “are directed to an energy efficient technique ... [which is] described throughout the application, particularly ... with reference to ... Figures 5-14.” Silzars SJ Deck, Ex. 14, ’349 Patent Application at FL062988-89.

In Figure 11, it is undisputed that the generic power supply applies a voltage Vdd across the inductor that is “about one-half the magnitude of the voltage level the panel capacitance reaches after charging.” See Silzars SJ Deck, Ex. 11, Bitzer Depo. at 551 (testifying that when switch SI is closed in Figure 12, which depicts the corresponding waveform for- Figure 11, .“the voltage across the output would rise ... to 2 Vdd”). Read in the context of the Patent as a whole, it is evident that the application of voltage Vdd depicted in Figure 11 is a “forcing voltage,” even if those words are not used in describing the figure.

Finally, the same structure is disclosed in the Kanatani ’344 Publication for applying a forcing voltage. In particular, Figures 9 and 10 show a generic power supply, labeled. “E,” which is used to apply a forcing voltage to drive a resonant circuit in a display panel, causing the voltage to reach 2E. Silzars SJ Decl. at 101-102, ¶¶ 202-204. As noted above, UI does not dispute that Kanatani meets the function of the Forcing Voltage Claims.

Because Figure 11 uses a generic power supply, which is the identical structure that is used in Kanatani to achieve the same function, the Forcing Voltage Claims are anticipated as a matter of law.

c. The Maintaining Claims (Claims 30 and 31)

i. Summary of the Arguments

Fujitsu argues that the Kanatani ’344 Publication also anticipates claims 30 and 31 (“the Maintaining Claims”) because in Figures 9 and 10 of Kanatani,. diodes D or DI and D2 are used to maintain the voltage on the panel capacitance and the ’400 Patent also discloses diodes, or their equivalent, as corresponding structure to achieve the maintaining function. Motion at 9-14. .Fujitsu makes two main arguments. First, it argues that the Claim Construction Order adopted the agreement of the parties that diodes alone can perform maintaining and therefore constitute corresponding structure. Id. at 12; see also Silzars SJ Decl. at 105, ¶212. Fujitsu notes that UI expressly argued in its Opening Claim Construction Brief that a diode-only embodiment constituted corresponding structure for the maintaining claim term and that Fujitsu agreed with UI in its responsive brief. Motion at 11; see also Silzars SJ Decl. at 105, ¶213 & Ex. 52, Opening Claim Construction Brief 43; Ex. 53, Fujitsu’s Responsive Brief at 36, 44; Ex. 54, UI Reply at 32. Similarly, the parties agreed in the Joint Claim Construction Statement that one of the embodiments that achieved the maintaining function of claim 31 used only diodes. Motion at 12 (citing Silzars SJ Decl., Ex. 32, Joint Claim Construction Statement, Claim Terms 30 and 38). Thus, Fujitsu argues, the Court’s statement that “the parties agree that diodes DI and D2 should be included as corresponding structure for the maintaining claim terms,” must be read as an acknowledgment by the Court that a diode-only embodiment is included as corresponding structure for the maintaining claim terms. Id. Under this reading of the Claim Construction Order, Fujitsu asserts, the Kanatani ’344 Publication clearly anticipates the Maintaining Claims because Kanatani discloses the exact structure that is disclosed in the ’400 patent. Id. at 9-12;

Second, Fujitsu argues, both the ’400 Patent and other prior art from the relevant time period make clear that use of one or more diodes to maintain the voltage level of the panel capacitance—as used in Kanatani—was known to be interchangeable with use of a switch/diode combination. Id. at 13. Thus, even if the Claim Construction Order excludes a diode-only embodiment and requires a diode-switch combination, the maintaining claims are invalid. In support of its contention that diodes were interchangeable with a switch/diode combination, Fujitsu points first to what it argues are binding admissions by UI that the diode-only embodiment is equivalent for performing the maintaining function. Id. In particular, Fujitsu points to the claim construction briefs and the Joint Claim Construction statement, cited above. Id. Fujitsu also points to the fact that UI has conceded that claims 24 and 25, which are method claims that describe “maintaining the panel capacitance,” are anticipated by the Ka-natani ’344 Publication. Id. Fujitsu argues that UI cannot concede that the diodes in Kanatani achieve the function of maintaining the voltage of the panel capacitance while at the same time taking the position that diodes do not perform the function of the Maintaining Claims.

UI challenges Fujitsu’s arguments on several grounds. First, UI reads the Claim Construction Order as holding that diodes constitute corresponding structure for claim 31 only when they are used in conjunction with switches and not when they are used alone. Opposition at 56. Thus, UI asserts, Kanatani only anticipates the Maintaining Claims if Kanatani’s use of diodes alone to accomplish maintaining is equivalent to a switch/diode combination. Id. Second, UI asserts based on Dr. Bitzer’s report that use of diodes alone is not equivalent to a switch/diode combination because a diode can only prevent current flow along one particular current path whereas a switch/diode combination allows a reference voltage to be added and maintained, even if there is more than one current path. Id. at 57 (citing Bitzer Validity Expert Report at 9).

In its Reply, Fujitsu’s rejects UI’s assertion that diodes are not equivalent to switches used in conjunction with diodes. Reply at 6. Fujitsu points to deposition testimony by Dr. Bitzer in which he concedes that the “stray current” problem associated with a diode only embodiment is not a problem in addressing operations but only in sustaining operations. Id. (citing Silzars SJ Deck, Ex. 11, Bitzer Depo. at 582). Thus, Fujitsu asserts, this evidence does not create a material issue of fact because nothing in claim 31 suggests that it is limited to sustaining. Id. Fujitsu also points to Figures 13 and 14 of the ’400 Patent, which depicts an address driver which uses a diode and an open switch to maintain. Id. at 8-9. Because in this embodiment maintaining does not require that a switch be closed, Fujitsu argues, these figures indicate that UI’s position that a switch is required to maintain contradicts the teachings of the patent.

ii. Discussion

UI has conceded that Kanatani meets the function requirement of the Maintaining Terms. The remaining issue to be resolved is whether the structure used by Kanatani to achieve that function, namely, diodes (without switches), is, as a matter of law, the same as the structure disclosed in the ’400 Patent for maintaining. Because the Court held in the Claim Construction Order that diodes only are corresponding structure for the Maintaining Claim, Fujitsu is entitled to summary judgment of invalidity as to these claims.

In the Claim Construction Order, the Court addressed corresponding structure for the Maintaining Terms, stating, based on the agreement of the parties, that “diodes DI and D2 should be included as corresponding structure for the maintaining claim terms, Claim Terms 30 and 39.” Claim Construction Order at 49. In the chart that summarizes the Court’s claim construction, corresponding structure for Claim Terms 30 and 39 includes “D1/S3” and “D2/S4” for Figures 5 and 7. Claim Construction Order at 58. UI asserts that the Claim Construction Order should be read as holding that corresponding structure for the. Maintaining Terms includes a switch/diode combination but does not include a diode-only embodiment. UI is incorrect.

It is true that the Court did not expressly state in the Claim Construction Order that diodes alone, without switches, are disclosed as corresponding structure for the maintaining terms in the ’400 Patent. However, this holding is conveyed in the Claim Construction Order by the use of a slash rather than the word “with” in the Court’s claim construction chart. Claim Construction Order at 58. Specifically, the Court used a slash to convey that the identified diodes and switches were alternative structures, whereas the word “with” was used when elements together constituted corresponding structure. Further, it is evident from context that the only reasonable reading of the Claim Construction Order is that diodes alone are disclosed as a corresponding structure for achieving the maintaining function. In particular, during claim construction neither UI nor Fujitsu ever suggested that diodes alone were not corresponding structure for the Maintaining Terms. To the contrary, the parties expressly agreed, both in their Joint Claim Construction Statement and in their briefs, that in Figures 5, 7, 9 and 10, maintaining could be achieved either with a diode or with a diode in combination with a switch. See Silzars SJ Decl., Ex. 32, Joint Claim Construction and Prehearing Statement; Ex. 52, The University’s Opening Claim Construction Brief at 43; Ex. 53, Fujitsu’s Responsive Brief at 36, 44; Ex. 54, UI’s Reply at 32. The parties confirmed their position on this issue at the claim construction hearing.

Nor is UI’s position supported by the Court’s statement that “switches are critical for performing the maintaining and clamping functions.” See Opposition at 56 (citing Claim Construction Order at 47). This statement addressed the question of whether switches were corresponding structure for the maintaining and clamping terms in some embodiments or rather, whether only the paths through the closed switches were part of corresponding structure. The Court was not addressing whether diodes alone were disclosed as corresponding structure for achieving the maintaining function and the statement has no bearing on that issue.

Because the Court held in the Claim Construction Order that diodes are corresponding structure for the Maintaining Terms, and in light of the fact that Kana-tani also uses diode to achieve this function, the Court concludes that the Maintaining Cláims are anticipated as a matter of law.

3. Infringement of Claims 26, 32-33, 36, and 39-40

a. Summary of the Arguments

Fujitsu argues it is entitled to summary judgment that claims 26, 32-33, 36, and 39-40 (“the Remaining Claims”) are not infringed, either literally or under the doctrine of equivalents. UI does not dispute that there is no literal infringement of these claims. See UI September 18, 2003 Disclosures, Literal Infringement Claim Chart. Thus, the issue in dispute is whether the accused devices infringe under the doctrine of equivalents. Fujitsu makes several arguments in support of its contention that the doctrine of equivalents does not apply.

First, Fujitsu argues that the changes it has made to its devices — most significantly, using clock-timed signals to clamp to an external power supply or to ground well before the current in the inductor reaches zero and the panel capacitance is fully charged or discharged — are not “insubstantial” and therefore, to apply the doctrine of equivalents to these devices is inappropriate and will result in the elimination of meaningful limitations in the claimed invention. Motion at 28-30. In particular, Fujitsu points to test results that show that its devices clamp while there is substantial current still flowing in the inductor and when the panel voltage is substantially different from the voltage level of the sustain power supply. Motion at 26-27. Fujitsu further cites to evidence that the energy efficiency of the accused devices is well below the energy efficiency projected by the inventors for those practicing the invention. Motion at 26-27. Fujitsu asserts that the early clamping used in its devices allows it to achieve significant benefits that cannot be achieved using the claimed invention, namely, better image quality, robust operating ranges and higher sustain frequencies. Motion at 23.

Second, Fujitsu argues that UI is barred from asserting as an equivalent a circuit that clamps when the inductor current is not zero under the doctrine of prosecution history estoppel, because of both a narrowing amendment made during prosecution of the patent and arguments that were made during prosecution. Motion at 31-38. As to the narrowing amendment, Fujitsu argues that: 1) the inventors narrowed the claims by amendment, adding a limitation that called for clamping when the inductor current reached zero; 2) UI has not rebutted the presumption that the narrowing amendment was made for reasons of patentability; and 3) UI has not rebutted the presumption that a device that clamps before the inductor current reaches zero is not one of the equivalents that was surrendered as a result of the amendment. Motion at 31-34.

With respect to prosecution history disclaimer, Fujitsu asserts that the inventors made numerous statements during the prosecution in which they emphasized the importance of their technique, namely, charging and discharging the panel capacitance without interruption, until the inductor current equals zero, for achieving energy efficiency. Motion at 34-38. In light of these statements, Fujitsu argues, a reasonable competitor could only conclude that UI surrendered the right to claim circuits that activate a switch to interrupt the flow of current through the inductor before the current reaches zero. Id.

Finally, Fujitsu argues that if the claims were stretched under the doctrine of equivalents to cover Fujitsu’s devices, they would also encompass prior art, thus invalidating the claims. Motion at 40^15. Specifically, both the accused devices and the circuit covered in United States Patent No. 4,707,692 (“the ’692 Patent” or “Higgins”) switch to interrupt resonant charging shortly after the inductor current reaches a maximum, according to Fujitsu. Id.

UI rejects Fujitsu’s characterization of the accused devices, arguing that UI’s test results are sufficient to establish a genuine question of fact as to whether the doctrine of equivalents applies to the accused devices. First, UI asserts that its tests show that the switches for clamping in Fujitsu’s circuits are not activated until substantially all the charging or discharging operation has been completed. Opposition at 5-6. Second, UI argues that charging and discharging in the accused devices is not interrupted until the inductor current equals zero, citing to evidence that the energy remaining in the inductor at the time of clamping continues to flow into the panel via the process of concurrent charging. Id. at 6-7.

UI also points to energy efficiency determinations by Dr. Inan showing that early clamping in Fujitsu’s devices does not result in a loss of energy efficiency and does not affect image quality, contrary to Fujitsu’s assertions. Id. at 8-12. According to UI, these results reflect the existence of a “range of clamp times within which the energy efficiency remains unchanged,” allegedly referred to by Fujitsu’s engineers as the “energy recovery saturation range.” Id. at 6-7. UI contends, further, that evidence of copying by Fujitsu’s own engineers indicates that they have long been aware that early clamping is interchangeable with clamping when the inductor current equals zero and does not affect energy efficiency or image quality. Id. at 12-13.

UI rejects Fujitsu’s reliance on the doctrine of prosecution-based estoppel, arguing that the doctrine does not apply because the Remaining Claims were not amended and nothing related to the temporal scope of the clamping limitations was surrendered during prosecution. Id. at 30-41.

Finally, UI asserts that Fujitsu’s argument that the Higgins prior art precludes application of the doctrine of equivalents fails because Fujitsu improperly focuses on individual claim limitations rather applying the “hypothetical claims” analysis required by the Federal Circuit. Id. at 41^9.

b. Doctrine of Equivalents: Legal Standard

A determination of infringement is a two-step process. Wright Medical Tech., Inc. v. Osteonics Corp., 122 F.3d 1440, 1443 (Fed.Cir.1997). The first step is claim construction, which is a question of law to be determined by the court. Id. The second step is an analysis of infringement, in which it must be determined whether a particular device infringes a properly construed claim. Id. This analysis is a question of fact. Id. A device literally infringes if each of the elements of the asserted claims is found in the accused device. Id. In the alternative, a device may infringe under the doctrine of equivalents “if every limitation of the asserted claim, or its ‘equivalent,’ is found in the accused subject matter, where an ‘equivalent’ differs from the claimed limitation only insubstantially.” Ethicon Endo-Surgery, Inc. v. United States Surgical Corp., 149 F.3d 1309, 1315 (Fed.Cir.1998).

In determining equivalence, Courts often consider “[w]hether a component in the accused subject matter performs substantially the same function as the claimed limitation in substantially the same way to achieve substantially the same result.” Id. However, “‘[equivalence ... is not the prisoner of a formula and is not an absolute to be considered in a vacuum.’” Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 24-25, 117 S.Ct. 1040, 137 L.Ed.2d 146 (1997) (quoting Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605, 609, 70 S.Ct. 854, 94 L.Ed. 1097 (1950)). In Graver Tank, the Court described the equivalence inquiry as follows:

What constitutes equivalency must be determined against the context of the patent, the prior art, and the particular circumstances of the case.... In determining equivalents, things equal to the same thing may not be equal to each other and, by the same token, things for most purposes different may sometimes be equivalents. Consideration must be given to the purpose for which an ingredient is used in a patent, the qualities it has when combined with the other ingredients, and the function which it is intended to perform. An important factor is whether persons reasonably skilled in the art would have known of the interchangeability of an ingredient not contained in the patent with one that was.

Id. (quoting Graver Tank, 339 U.S. at 609, 70 S.Ct. 854).

The doctrine of equivalents may not be applied where it would “erase ‘meaningful structural and functional limitations of the claim on which the public is entitled to rely in avoiding infringement.’” Conopco, Inc. v. May Dep’t Stores Co., 46 F.3d 1556, 1562 (Fed.Cir.1994) (quoting Pennwalt Corp. v. Durand-Wayland, Inc., 833 F.2d 931, 935 (Fed.Cir.1987)); see also Lockheed Martin Corp. v. Space Sys./ Loral, Inc., 324 F.3d 1308, 1320 (Fed.Cir.2003) (holding that “if a court determines that a finding of infringement under the doctrine of equivalents ‘would entirely vitiate a particular claim[ed] element,’ then the court should rule that there is no infringement under the doctrine of equivalents”) (quoting Bell Atlantic Network Servs., Inc. v. Covad Communications Group, Inc., 262 F.3d 1258, 1280 (Fed.Cir.2001)). Failure to meet a claim limitation, by itself, is not necessarily enough to “erase” or “vitiate” that claim element. Ethicon, 149 F.3d at 1317. As the Ethicon court noted, “any analysis of infringement under the doctrine of equivalents necessarily deals with subject matter that is ‘beyond,’ ‘ignored’ by, and not included in the literal scope of a claim.” Id. Thus, the relevant inquiry is whether the subject matter is “specifically excluded” from coverage such that its inclusion under the doctrine of equivalents is “somehow inconsistent with the language of the claim.” Id.

For example, in Moore U.S.A., Inc. v. Standard Register Co., 229 F.3d 1091, 1094 (Fed.Cir.2000), the holder of a patent for a mailer-type business form which contained a built-in envelope sued for patent infringement and argued that the accused mailer infringed under the doctrine of equivalents. One of the asserted claims called for two longitudinal strips of adhesive “extending the majority of the lengths of’ certain surfaces. Id. at 1095. The accused mailer contained adhesive strips that extended only 47.8% of the length of the surface at issue. Id. at 1097. The district court granted summary judgment on the doctrine of equivalents in favor of the defendant on the basis that 47.8% could not be “a majority.” Id. at 1098. The Federal Circuit agreed, holding that:

the applicant’s use of the term ‘majority’ is not entitled to a scope of equivalents covering a minority for at least two reasons. First, to allow what is un-disputably a minority (i.e., 47.8%) to be equivalent to a majority would vitiate the requirement that the “first and second longitudinal strips of adhesive ... extend the majority of the lengths of said longitudinal marginal portions.” ... If a minority could be equivalent to a majority, this limitation would hardly be necessary ... Second, it would defy logic to conclude that a minority—the very antithesis of a majority—could be insubstantially different from a claim limitation requiring a majority, and no reasonable juror could find otherwise.

Id. at 1106.

Similarly, in Talbert Fuel Sys. Patents Co. v. Unocal Corp., 347 F.3d 1355, 1360 (Fed.Cir.2003), the Federal Circuit affirmed summary judgment on the doctrine of equivalents where the claimed device had a boiling point no higher than 345 degrees Fahrenheit whereas the accused devices had a boiling point of between 373.8 degrees and 472.9 degrees Fahrenheit. In that case, the court held that the doctrine of prosecution history estoppel applied. Id. The court went on to hold, however, that even if there were no estoppel, summary judgment was appropriate because “no reasonable trier of fact could find only insubstantial differences between fuels having an endpoint of 345 degrees F. and fuels with the endpoints shown for the Unocal fuels.” Id.

On the other hand, in Wright Medical Tech. Inc. v. Osteonics Corp., 122 F.3d 1440, 1445 (Fed.Cir.1997), the court held that summary judgment for the defendant on the doctrine of equivalents was inappropriate because a material issue of fact remained. There, the asserted patent disclosed a medical device used to prepare the femur bone for attachment of an artificial knee. Id. at 1441. One of the asserted patent claims required an “intramedul-lary rod portion adapted to closely fit and extend through the narrowest portion of the human femur.” Id. at 1442. The court construed the claim as requiring that the rod “extend all the way through the isthmus of the femur.” Id. The accused device contained an intermedullary rod, but it did not extend all the way through the isthmus of the femur. Id. at 1444. Nonetheless, the court held that a material issue of fact remained on the question of equivalence because the plaintiff introduced testimony by the designer of the accused device that “the intramedullary rod of the [accused device] need not extend all the way through or fit tightly into the isthmus of the femur to achieve at least some of the functionality of the claimed intramedullary rod.” Id. at 1445. See also Ethicon, 149 F.3d at 1320-1321 (noting that in Wright, the difference between the claimed rod and the rod in the accused device was “not clear enough on summary judgment to conclude that no reasonable fact finder could find that the rods were equivalent ... especially ... given the patentee’s evidence suggesting that the rods performed substantially the same function in substantially the same way to achieve substantially the same result”).

Application of the doctrine of equivalents also may be limited as a result of the prosecution history of the patent. Under the doctrine of prosecution history estoppel, a patentee is barred from imposing liability for infringement by an otherwise equivalent device “when the claim scope that would have reached the accused device or method was relinquished by the patentee in order to avoid the prior art.” Pall Corp. v. Hemasure, Inc., 181 F.3d 1305, 1311 (Fed.Cir.1999). This doctrine may be applied on the basis of either arguments made during prosecution that show a clear and unmistakable surrender of subject matter, see Bayer AG v. Elan Pharm. Research Corp., 212 F.3d 1241, 1251 (Fed.Cir.2000), or where a patentee amended the application or added claims to avoid issues of patentability such as prior art. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 344 F.3d 1359, 1366 (Fed.Cir.2003) (“Festo IX”).

In the case of prosecution history estoppel based on arguments or disclaimer, the court applies an objective standard to determine whether “‘a competitor would reasonably believe that the applicant had surrendered the relevant subject matter.’” Bayer, 212 F.3d at 1251. In the case of amendment-based prosecution estoppel, the court must apply a three-step analysis, which has been summarized by the Federal Circuit as follows:

The first question in a prosecution history estoppel inquiry is whether an amendment filed in the Patent and Trademark Office (“PTO”) has narrowed the literal scope of a claim... If the amendment was not narrowing, then prosecution history estoppel does not apply. But if the accused infringer establishes that the amendment was a narrowing one, then the second question is whether the reason for that amendment was a substantial one relating to patentability.... When the prosecution history record reveals no reason for the narrowing amendment, Warner-Jenkinson presumes that the patentee had a substantial reason relating to pat-entability; consequently, the patentee must show that the reason for the amendment was not one relating to pat-entability if it is to rebut that presumption. .. a patentee’s rebuttal of the Warner-Jenkinson presumption is restricted to the evidence in the prosecution history record.... If the patentee successfully establishes that the amendment was not for a reason of patentability, then prosecution history estoppel does not apply. If, however, the court, determines that a narrowing, amendment has been made.for a substantial reason relating to patentability — whether based on a reason reflected in the prosecution history record or on the patentee’s failure to overcome the Warner-Jenkinson presumption — then the third question in a prosecution history estoppel analysis addresses the scope of the subject matter surrendered by the narrowing amendment.... At that point Festo VIII imposes the presumption that the patentee has surrendered all territory between the original claim limitation and the amended claim limitation..:. The patentee may rebut that presumption of total surrender by demonstrating that it did not surrender the particular equivalent in question according to the criteria discussed below. Finally, if the patentee fails to rebut the Festo presumption, then prosecution history estoppel bars the patentee from relying oh the doctrine of equivalents for the accused element. If the paten-tee successfully rebuts the presumption, then prosecution history estoppel does not apply and the question whether the accused element is in fact equivalent to the limitation at issue is reached on the merits.'

Festo IX, 344 F.3d at 1366-67 (citing Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. 535 U.S. 722, 740, 122 S.Ct. 1831, 152 L.Ed.2d 944 (2002) (“Festo VIII”), Warner-Jenkinson Co. v. Hilton-Davis Chem., 520 U.S. 17, 117 S.Ct. 1040, 137 L.Ed.2d 146 (1997), and Pioneer Magnetics, Inc. v. Micro Linear Corp., 330 F.3d 1352, 1356 (Fed.Cir.2003)). The application of prosecution history estoppel, including the question of whether the presumption of surrender has been rebutted, is a question of law. Festo IX, 344 F.3d at 1367.

Finally, even if the accused device-meets the test for equivalence, the doctrine of equivalents may not be applied “if the asserted scope of equivalency of what is literally claimed would encompass the prior art.” Wilson Sporting Goods Co. v. David Geoffrey and Assoc., 904 F.2d 677, 683 (Fed.Cir.1990). The rationale underlying this rule is that “a patentee should not be able to obtain, under the doctrine of equivalents, coverage which he could not lawfully have obtained from the PTO by literal claims.” Id. at 684.

In Wilson Sporting Goods, the court set forth an approach using a hypothetical claim to determine whether application of the doctrine of equivalents is precluded by-prior art. Id. at 677. The court described this approach as follows:

To simplify analysis and bring the issue onto familiar turf, it may be helpful to conceptualize the limitation on the scope of equivalents by visualizing a hypothetical patent claim, sufficient in scope to literally cover the accused product. The pertinent question then becomes whether that hypothetical claim could have been allowed by the PTO over the prior art. If not, then it would be improper to permit the patentee to obtain that coverage in an infringement suit under the doctrine of equivalents. If the hypothetical claim could have been allowed, then prior art is not a bar to infringement under the doctrine of equivalents.

Id. at 684. Hypothetical claims may broaden slightly the asserted claim but they may not narrow the claim. Streamfeeder L.L.C. v. Sure-Feed Sys., Inc., 175 F.3d 974, 983 (Fed.Cir.1999). In applying the Wilson Sporting Goods approach, once the accused infringer has come forward with evidence showing the accused device is in the prior art, the patentee bears the burden of persuasion on the question of whether the hypothetical claim ensnares the prior art. Id. at 980. While the approach in Wilson Sporting Goods is considered useful, “nothing in Wilson mandates its use as the only means of determining the extent to which the prior art restricts the scope of equivalency that the party alleging infringement under the doctrine of equivalents can assert.” Conroy v. Reebok Int’l, 14 F.3d 1570, 1576 (Fed.Cir.1994).

c. Elimination of Meaningful Limitations

Fujitsu asserts that it is entitled to summary judgment of noninfringement as to the Remaining Claims on the basis that it has presented unrebutted evidence that the accused devices differ substantially from the invention claimed in the '400 patent and further, that to apply the doctrine of equivalents to these devices would vitiate crucial claim limitations. The Court agrees.

The Remaining Claims, that is, claims 26, 32-33, 36 and 39-40, include two, closely related claim terms. First, all of the Remaining Claims contain charging/discharging limitations. As to claims 32-33, 36, and 39-40, the Court held in the Claim Construction Order that the charging/discharging limitations require that charging and discharging of the panel capacitance must be “through the inductor until all of the energy is removed from the inductor and the inductor current reaches zero.” Claim Construction Order at