Before Rich, Michel, and Lourie, Circuit Judges.
The opinion of the court was delivered by: Lourie, Circuit Judge.
Appealed from: United States International Trade Commission
Finnigan Corporation appeals from the final determination of the United States International Trade Commission that claims 1-4, 8, 12, 14, and 17 of U.S. Patent 4,540,884 were not literally infringed and that claims 1-4 and 8 were anticipated under 35 U.S.C. § 102(b). See In re Certain Ion Trap Mass Spectrometers and Components Thereof, USITC Inv. No. 337-TA-393 (Dep't Commerce Feb. 25, 1998) ("Initial Determination"); Certain Ion Trap Mass Spectrometers and Components Thereof; Notice of Final Commission Determination of No Violation of Section 337 of the Tariff Act of 1930, 62 Fed. Reg. 19946 (Dep't Commerce Apr. 13, 1998) ("Final Determination"). Because the Commission did not err in its construction of the claims and its determination that those claims were not literally infringed, but did err in its Conclusion that the claims were anticipated, we affirm-in-part and reverse-in-part.
A. The Patented Technology
Finnigan is the assignee of the `884 patent, which pertains to a method for using a "quadrupole ion trap" to generate a mass spectrum of a trapped sample for purposes of analysis. The disclosed "quadrupole" ion trap is depicted in Figure 1 of the patent:
The ion trap generally works as follows: The sample to be analyzed is ionized to impart an electrical charge to the atoms or molecules of the sample. The ionized sample is then subjected to an electric field, called a "quadrupole field" or "trapping field," which is generated by applying a radio-frequency (RF), alternating-current (AC) voltage to electrode ring 11. The magnitude of this AC voltage is denoted as "V" in the patent and its angular frequency is denoted as "(" (the Greek letter "omega"). A direct-current (DC) voltage "U" may be added to the AC voltage. The quadrupole field causes certain ions to orbit within the storage region of the trap, which is bounded by the electrode ring and end caps 12 and 13. The extent of the orbit of a given ion depends upon its mass-to-charge (m/e) ratio.
The disclosed ion trap can be used as a mass spectrometer by changing or "scanning" the parameters that define the quadrupole field, viz., U, V or (, such that the trajectories of certain trapped ions are no longer sustainable within and leave the field where they are detected. The specification sets forth the process as follows:
"DC and RF voltage (U, and V cos (t) are applied to a three-dimensional electrode structure such that ions over the entire specific mass range of interest are simultaneously trapped within the field imposed by the electrodes. Ions are then created or introduced into the quadrupole field area by any one of a variety of well known techniques. After this storage period, the DC voltage, U, the RF voltage[,] V, and the RF frequency, (, are changed, either in combination or singly so that trapped ions of consecutive specific masses become successively unstable. As each trapped ionic species becomes unstable, all such ions develop trajectories that exceed the boundaries of the trapping field. These ions pass out of the trapping field through perforations in the field imposing electrode structure and impinge on a detector such as an electron multiplier or a Faraday collector. The detected ion current signal intensity as [a] function of time corresponds to a mass spectr[um] of the ions that were initially trapped." `884 patent, col. 4, ll. 28-48.
The specification identifies the ion species that are trappable in a given quadrupole field by reference to a "Mathieu Stability Diagram," an example of which is shown in Figure 4 of the patent:
The physics giving rise to the bounded area of this diagram is complicated; fortunately a detailed understanding is unnecessary to resolve the controversy presented here. Simply stated, if a given ion in a given quadrupole field maps within the boundaries of the diagram, it is trappable; if a given ion maps outside the boundaries of the diagram, it is not trappable. In the words of the patent specification:
"If [the] scanning parameters combine to map inside the stability envelope[,] then the given particle has a stable trajectory in the defined field. A charge[d] particle having a stable trajectory in a three[-]dimensional quadrupole field is constrained to an aperiodic orbit about the center of the field. Such particles can be thought of as trapped by the field. If for a particle m/e, U, V, ro and ( combine to map outside the stability envelop on the stability diagram, then the given particle has an unstable trajectory in the defined field. Particles having unstable trajectories in a three[-]dimensional field attain displacements from the center of the field which approach infinity over time. Such particles can be thought of as escaping the field and are consequently considered untrappable." `884 patent, col. 3, l. 56 to col. 4, l. 2.
The foregoing aspects of the written description are reflected in independent claim 1, with the disputed claim language emphasized:
"1. The method of mass analyzing a sample which comprises the steps of defining a three dimensional quadrupole field in which sample ions over the entire mass range of interest can be simultaneously trapped introducing or creating sample ions into the quadrupole field whereby ions within the range of interest are simultaneously trapped changing the three dimensional trapping field so that the simultaneously trapped ions of consecutive specific masses become sequentially unstable and leave the trapping field and detecting the sequential unstable ions as they leave the trapping field and providing an output signal indicative of the ion mass."
Independent claims 8 and 17 are similar to claim 1. The language in those claims corresponding to the disputed limitation in claim 1 reads as follows:
"scanning one or more of U, V and ( between predetermined limits so that the trapped ions of specific mass become sequentially and selectively unstable and sequentially exit from the ion trap (claim 8)"
"sequentially selecting by ejecting ion[s] of different mass values by scanning the three dimensional quadrupole field (claim 17)"
B. The Accused Device and Technique
Bruker's ESQUIRE-LC spectrometer operates in a manner similar to the disclosed embodiment of the `884 patent in all material respects, except in the manner in which ions are ejected from the trapping field for detection. As previously mentioned, the patented embodiment ejects ions from the trap by changing or "scanning" the quadrupole field to render trapped ions unstable with respect thereto, i.e., by transferring previously trapped ions outside of the stability diagram. In addition, the end caps 12 and 13 of the patented embodiment are grounded. See Figure 1 supra. The ESQUIRE device, in contrast, ejects ions without transferring the ions outside of the stability diagram. Instead, the trapped ions are ejected by applying a "supplementary" AC voltage to one of the end caps. This arrangement is depicted in Bruker's "Primer" on the operation of the ESQUIRE machine, with the supplementary AC voltage labeled "auxiliary dipolar amplitude": Joint App. at A3300.
In the Bruker technique, certain ions are trapped in the storage area, just as in the patented embodiment. Each of these ions orbits within the trap with a "secular" frequency, which is dependent on the quadrupole scanning parameters. During analysis, one of these parameters (usually V) is changed to bring the secular frequency of a given ion into parity with the fixed frequency of the supplementary voltage (or a harmonic thereof). When this happens, the field produced by the supplementary voltage and the ion are in "resonance." Resonance causes the ion to gain kinetic energy from the supplementary field, "just as a parent can impart additional energy to a child on a swing by pushing the child at the same moment on each `orbit' of the swing. As the ion gains energy, its trajectory, like that of the swinging child, will increase over time, until the ion exits the trap . . . and strikes a detector." Commissioner's Brief at 7. Eventually, as scanning continues, the secular frequency of another ion species is brought into parity with the fixed supplemental voltage frequency and is ejected, and so on. The important point is that, in contradistinction to the patented embodiment, the ions ejected from the trapping field are stable from the standpoint of the stability diagram.
Because the Bruker technique involves principles of resonance, it is referred to in the literature as "resonance ejection," whereas the patented embodiment employs a form of "nonresonance ejection."
C. The Proceedings Before the Commission
Finnigan filed a complaint at the Commission asserting that the Intervenors *fn1 were importing the ESQUIRE systems in violation of 19 U.S.C. § 1337(a) (1994) ("Section 337") because these systems infringed, inter alia, its `884 patent. See 19 U.S.C. § 1337(a)(1)(B) (prescribing that importation of articles that "infringe a valid and enforceable United States patent" is an unlawful trade practice). In response, the Commission instituted an investigation on February 20, 1997, see Certain Ion Trap Mass Spectrometers and Components Thereof; Notice of Investigation, 62 Fed. Reg. 8774 (1996), which culminated in a 309-page Initial Determination in which the Administrative Law Judge (ALJ) recommended that the Commission conclude that Section 337 had not been violated. As relevant here, the ALJ determined that claims 1-4, 8, 12, 14, and 17 were not literally infringed *fn2 and that claims 1-4 and 8 were anticipated and therefore invalid under § 102(b). These determinations were adopted by the Commission. *fn3
The ALJ's noninfringement determination followed from his Conclusion that the claims did not cover the resonance ejection technique practiced by the Bruker device. Much of the ALJ's Discussion of claim construction focused on the interpretation of the term "unstable," which appears in independent claims 1 and 8. The ALJ found it "significant" that the specification makes "use of the terms `stable' and `unstable' with specific reference to the curves of the [Mathieu] stability diagram . . . ." Initial Determination at 26. The ALJ also found significant the specification's Discussion of the prior art, ...