Summary
concluding that the court need not address the reverse doctrine of equivalents because the court rejected the proposed claim construction
Summary of this case from Amgen, Inc. v. Hoechst Marion Roussel, Inc.Opinion
01-CV-10207-PBS.
January 3, 2003
MEMORANDUM AND ORDER
INTRODUCTION
Plaintiff VLT, Inc. ("VLT") claims that the power converters made by Power-One, Inc. ("Power-One") literally infringe U.S. Patent No. Re. 36,098 ("the `098 patent"). VLT moves for summary judgment on its infringement claim. Power-One brings a cross-motion for summary judgment of non-infringement on the ground that the claim is barred by the doctrine of judicial estoppel and by the reverse doctrine of equivalents. After hearing, VLT's motion is DENIED and Power-One's Motion is DENIED.
BACKGROUND
The complicated technology at issue in this case is discussed in detail in VLT Corp. v. Unitrode Corp., 130 F. Supp.2d 178 (D.Mass. 2001) ("Unitrode"), and the Memorandum and Order in VLT, Inc. v. Lucent Tech., Inc., 00-CV-11049-PBS, (D.Mass. October 18, 2001) ("Lucent"). This case is also related to VLT, Inc. v. Lambda Electronics, Inc. (No. 01-CV-10957-PBS) and VLT, Inc. v. Artesyn Technologies, Inc. (No. 01-CV-10238-PBS). Familiarity with opinions in these cases is assumed.
Claim One of the '098 patent provides:
1. In a single ended forward converter in which energy is transferred from a primary winding to a secondary winding of a transformer during the ON period of a primary switch, circuitry for recycling the magnetizing energy stored in said transformer to reset it during the OFF period of said primary switch, compromising:
a storage capacitor;
an auxiliary switch connected in series with said storage capacitor;
a switch control circuit operating said auxiliary switch in accordance with a control logic such that (a) said auxiliary switch is opened prior the ON period [sic] of said primary switch, (b) said auxiliary switch remains open throughout the ON period of said primary switch, (c) said auxiliary switch is closed after the ON period of said primary switch.
The specification states:
[A] delay between the opening of the auxiliary switch and the closing of the primary switch represents dead time. For this reason it is efficient to keep such a delay to a minimum, consistent with the requirement to avoid an overlap between switches. However, a small delay is useful to allow the magnetizing current to charge and discharge parasitic capacitances associated with the switches and windings.
Col. 7, ll. 2-11 (emphasis added). In Unitrode and Lucent, I construed the term "ON period" of a switch as the time in which the switch is enabled to conduct current that it could otherwise block, and explained as to the word "prior":
By its usage of the word "prior," Claim 1 requires some delay between the "ON period" of the auxiliary switch and the "ON period" of the primary switch. The claim does not, however, specify the length of the delay.
Unitrode, 130 F. Supp.2d at 191 (emphasis in original).
The Court also considered the reference to the word "useful" in the specification:
If there is a residual capacitance in the switch and winding, it will ultimately be discharged in one manner or another. It either can be discharged as heat (i.e., dissipatively), or it can be discharged as energy flowing into the transformer core (i.e., non-dissipatively). Only the latter result, however, could be considered "useful" as required by the specification. Col. 7, lines 4-11.
Unitrode, 130 F. Supp.2d at 189. While the specification does not specify the length of the delay, it does state that the delay must be "useful." The Court has never addressed whether there should be a functional definition of delay.
Power-One produces and markets single ended forward converters that employ an active reset comprising an auxiliary switch and a capacitor in series, to reset the core of the transformer. There is a period of time prior to, and after, the ON period of the primary switch during which neither the primary nor auxiliary switch is enabled to conduct current that it could otherwise block. The converters do not employ zero voltage switching, and the parasitic capacitance is discharged with heat loss in all of Power-One's converters.
LEGAL ANALYSIS
"A literal patent infringement analysis involves two steps: the proper construction of the asserted claim and a determination as to whether the accused method or product infringes the claim as properly construed." Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1581-82 (Fed. Cir. 1996).
At step one, Power-One asks the Court to construe Claim One by holding that the switch-timing architecture requires zero-voltage switching and/or requires a useful switching delay in which magnetizing current non-dissipatively discharges parasitic capacitance without heat loss.
A. Judicial Estoppel
1. The argument
Power-One asserts that the doctrine of judicial estoppel precludes VLT from taking the position that the `098 patent claims any switch timing delay. Power One points out that in the Unitrode patent litigation, VLT argued to the jury that the patent was valid (and nonobvious) because the invention involved a special switching delay in which magnetizing current non-dissipatively discharged parasitic capacitance, i.e., discharged it without heat loss. According to Power-One, its converters are designed with so little magnetizing current that they discharge parasitic capacitance dissipatively with significant heat loss.
Furthermore, Power-One argues that in the Unitrode trial, VLT equated their invention with zero-voltage switching. Power-One's converters do not exhibit zero-voltage switching. Rather, in the accused converters, the energy stored in the parasitic capacitance of the main switch is dissipatively discharged as heat after the switch starts to conduct. VLT denies that it ever took the position, in the Unitrode litigation or elsewhere, that its patent claimed only zero-voltage switching.
2. The doctrine
The Supreme Court has recently addressed the doctrine of judicial estoppel:
`[W]here a party assumes a certain position in a legal proceeding, and succeeds in maintaining that position, he may not thereafter, simply because his interests have changed, assume a contrary position, especially if it be to the prejudice of the party who has acquiesced in the position formerly taken by him.' . . . This rule, known as judicial estoppel, `generally prevents a party from prevailing in one phase of a case on an argument and then relying on a contradictory argument to prevail in another phase.'
New Hampshire v. Maine, 532 U.S. 742, 749, 121 S.Ct. 1808, 1814 (2001) (internal citations omitted). It establishes a three-pronged approach to analyzing judicial estoppel claims:
First, a party's later position must be `clearly inconsistent' with its earlier position. . . . Second, courts regularly inquire whether the party has succeeded in persuading a court to accept that party's earlier position, so that judicial acceptance of an inconsistent position in a later proceeding would create `the perception that either the first or the second was misled,' . . . A third consideration is whether the party seeking to assert an inconsistent position would derive an unfair advantage or impose an unfair detriment on the opposing party if not estopped.
Id. at 750-51.
The doctrine of judicial estoppel is applicable in patent suits, see Key Pharmaceuticals v. Hercon Laboratories Corp., 161 F.3d 709, 715-16 (Fed. Cir. 1999), and the case law of the First Circuit governs. See Wang Laboratories v. Applied Computer Sciences Inc., 958 F.2d 355, 358 (Fed. Cir. 1992) (applying First Circuit law on judicial estoppel).
The First Circuit has held that "judicial estoppel `precludes a party from asserting a position in one legal proceeding which is contrary to a position it has already asserted in another.'" Lydon v. Boston Sand Gravel Company, 175 F.3d 6, 12 (1st Cir. 1999), quoting Patriot Cinemas, Inc. v. General Cinema Corp., 834 F.2d 208, 212 (1st Cir. 1987). The doctrine "should be employed when a litigant is `playing fast and loose with the courts,' and when `intentional self-contradiction is being used as a means of obtaining unfair advantage . . . .'" Patriot Cinemas, 834 F.2d. at 212 (citation omitted). "[A]pplication of the doctrine requires that the party being estopped have succeeded previously with a position directly inconsistent with the one it currently espouses." Lydon, 175 F.3d at 13. Where "there is no indication of deliberate dishonesty . . . nor . . . prejudice to judicial proceedings or the position of the opposing party," estoppel is not proper. Desjardins v. Van Buren Community Hospital, 37 F.3d 21, 23 (1st Cir. 1994).
3. The Unitrode Litigation
The issue in the Unitrode litigation was whether the claims of the patent were obvious in light of prior art, not whether the accused devices infringed the claims. VLT strenuously argued that the genius of the invention was the switch timing architecture which enabled the converter to operate at high frequency, and therefore to be miniaturized, and to discharge parasitic capacitance non-dissipatively, rather than as heat. Throughout the trial, VLT witnesses described the benefits of zero-voltage switching, the name given to the concept of closing the switch only after the voltage across it has been discharged to zero. At various times, VLT equated zero-voltage switching with the invention. For example, the inventor, Patrizio Vinciarelli, testified:
Q. What benefits are obtained from zero-voltage switching, the '098 patented invention?
A. It eliminates all of the switching losses or greatly reduces.
Unitrode Trial Day 6, at 39.
In staving off the obviousness defense, VLT emphasized the non-dissipative discharge of parasitic capacitance. For example, plaintiffs' expert Dr. Paul Horowitz stated:
Q: Now, is it the case that what Dr. Vinciarelli did was merely patenting the delay?
A. I certainly wouldn't think of it that way at all. Dr. Vinciarelli invented the following thing: the combination of active rest of a forward converter. . . .combined with the timing architecture . . . [for] removal of stored charge in parasitic capacitances, thereby enabling efficient use of the switches and the elimination or greatly reduced, if not elimination, of dissipative loss of this energy in the switches.
Unitrode, Day 4, p. 41, lines 4-17. However, VLT never took the position that the claim was limited to zero-voltage switching. Dr. Horowitz testified:
Q. And the result was that [VLT] did not have both switches on at the same time, as was the case in Mr. Carsten's converters, right?
A. Let me say that that would satisfy the claim language, although additional guidance is given as to how long that delay should be.
Unitrode Trial Day 4, at 139-140.
4. Zero-voltage switching
The doctrine of judicial estoppel does not mandate a claim construction that the switching architecture is limited only to zero-voltage switching for two reasons. First, VLT's position in the Unitrode trial was not "clearly inconsistent" with the position it is taking now. New Hampshire, 532 U.S. at 750. While zero-voltage switching was one embodiment of the patent, VLT never took an inconsistent position in Unitrode that the claim required zero-voltage switching. Further, in the Lucent litigation, Vicor stated: "While, as Lucent acknowledges, the '098 patent has been referred to as the `zero voltage switching patent,' actual zero voltage switching is not required by claim one." (Docket No. 60, at 10. n 1b). While the term zero-voltage switching was equated with the invention at times during the Unitrode trial, that factor is not dispositive because the Unitrode devices at issue there employed zero-voltage switching.
Second, it is far from "crystal clear" that VLT's victory before the jury in Unitrode "depended conceptually on proof" that the `098 patent claimed only zero-voltage switching. See Franco v. Selective Insurance Company, 184 F.3d 4, 9 (1st Cir. 1999). Put differently, there is no evidence that VLT actually succeeded in convincing the jury that the invention was non-obvious because of zero-voltage switching. Any possible confusion was dispelled by the jury instructions, which do not mention zero-voltage switching:
I instruct you that Claim 1 of the `098 patent teaches some delay between the ON period of the auxiliary switch and the ON period of the primary switch. The question for you is whether it would have been obvious for someone of ordinary skill in the field of power supply electronics in February, 1982, to have created this switch timing delay in combination with all the other elements specified in Claim 1 of the `098 patent.
Unitrode Trial Transcript, Day 8, at 76.
Urging a claim construction that requires zero-voltage switching, Power-One's expert, Rudy Severns, an electrical engineer, states: "Discharge of the capacitance without heat dissipation means that the voltage across the capacitance is at or near zero when the switch closes." (See Non-Infringement Report, Docket No. 57, ¶ 32). However, extrinsic evidence of claim construction is disfavored, as is limiting a claim to one embodiment of an invention. See VLT, Inc. v. Lambda Electronics, Inc., Civ. Action No. 00-10238-PBS, Memorandum and Order, dated December 31, 2002, at pp. 4-6. I reject Power-One's request that Claim One be limited to zero-voltage switching.
5. Delay
The more difficult issue is Power-One's request that Claim One be construed to require a useful switching delay that eliminates or greatly reduces heat dissipation. I am troubled by VLT's argument that Claim One includes non-useful delay not only because that position is inconsistent with its prior argument in Unitrode, and Lucent, but also because it is inconsistent with the specification itself. As Dr. Horowitz testified, the patent provides guidance as to how long the delay should be. Specifically, the specification states "a small delay is useful to allow the magnetizing current to charge and discharge parasitic capacitances associated with the switches and windings." Col. 7, ll. 2-11. The inventor, Patrizio Vinciarelli, Dr. Horowitz, and both parties agree that useful delay includes delay that eliminates or greatly reduces heat loss. Indeed, that is the claim construction urged by Power-One (Docket No. 60). Exxon Research and Engineering Company v. United States, 265 F.3d 1371, 1381 (Fed. Cir. 2001) (permitting functional definitions).
This is a different issue from whether delay must be "purposeful," which seems to hinge on the state of mind of the maker of an accused device. VLT abandoned this requested claim construction.
The Court thus construes the word "prior" in Claim One as requiring a useful small delay that allows the magnetizing current to charge and discharge non dissipatively parasitic capacitances associated with the switches and windings. Delay includes delay that eliminates or greatly reduces heat loss. It does not require zero-voltage switching.
Because the Court rejects Vicor's claim construction that any delay suffices, the Court need not address the reverse doctrine of equivalents.
B. Infringement
The Court has an inadequate record for determining whether there is literal infringement of any of Power-One's converters under the Court's claim construction requiring useful delay.
ORDER
VLT's motion for summary judgment of infringement (Docket No. 54) is DENIED, and Power-One's motion for summary judgment of non-infringement (Docket No. 51) is DENIED. The Court orders the parties not to re-file motions for summary judgment on the infringement issue. The Court will determine validity first.