The opinion of the court was delivered by: GERSHON
GERSHON, United States District Judge:
This patent infringement action alleges that Schenck Corporation ("Schenck") has infringed two patents held by Acrison, Inc. ("Acrison") for a type of "loss-in-weight" feeder system. Basically, a loss-in-weight feeder system is a mechanism for discharging a liquid or powder from a hopper at a steady rate. The systems are particularly useful in the pharmaceutical industry, where small, but precise, amounts of a substance must be combined with other ingredients. Asserting non-infringement, Schenck now moves for summary judgment.
Prior to the invention of the microprocessor circuitry at issue here, a principal problem in the operation of loss-in-weight systems arose from the fact that external disturbances, which are common in an industrial plant setting, can disrupt steady outflow from the hopper. Because disturbances, such as a gust of air or a worker dropping a tool on the hopper, are arbitrary in both duration and amplitude, it was difficult, if not impossible, to anticipate them or to correct for their effects. The patented microprocessor circuitry at issue here was developed to solve this problem.
Acrison has two patents for loss-in-weight circuitry systems sold under the trade name "Acrilok": 1) Reissue Patent No. 32,102 (expired October 18, 1994) and 2) Reissue Patent No. 30, 967 (expired June 17, 1992). The only significant difference between the two systems is that Patent No. 32,102 ("the 102 patent") employs digital circuitry and Patent No. 30,967 ("the 967 patent") employs analog circuitry.
Schenck has its own patent for a loss-in-weight system, Patent No. 4,977,526, issued December 11, 1990, which carries the trade name "Multicont."
A patent document contains two distinct parts:
First, it contains a specification describing the invention "in such full, clear, concise, and exact terms as to enable any person skilled in the art. . .to make and use the same." 35 U.S.C. § 112. . .Second, a patent includes one or more "claims," which "particularly point out and distinctly claim the subject matter which the applicant regards as his invention." 35 U.S.C. § 112.
Markman v. Westview Instruments, Inc., 517 U.S. 370, 116 S. Ct. 1384, 1387-88, 134 L. Ed. 2d 577 (1996) (citations omitted). It is the claims section that sets forth the novelty of the invention and, thus, the scope of possible infringement. 116 S. Ct. at 1388 The interpretation of claims language is "purely within the province of the court." Id. at 1387.
The claims of the 102 patent are written in "means-plus-function" language. See 35 U.S.C. § 112, P 6. ("an element in a claim . . . may be expressed as a means for performing a specified function"). In the case of a claim so expressed, infringement is found if the accused device "employ[s] means identical or equivalent to the structures, material, or acts described in the patent specification. The accused device must also perform the identical function as specified in the claims." King Instruments Corp. v. Perego, 65 F.3d 941, 945-46 (Fed. Cir. 1995) (citation omitted), cert. denied, 134 L. Ed. 2d 778, 116 S. Ct. 1675 (1996).
The focal point of the dispute between the parties is Element H of Claim 1 of the 102 patent. The text of Element H is set forth below:
Plaintiff's Ex. A at col. 17, lines 38-49. The parties disagree sharply in their interpretation of this language. Based upon its interpretation of Element H, Schenck argues that in two respects its product is as a matter of law non-infringing; the first relates to the comparison of signals which measure the flow of material, and the second relates to how the systems respond to signals which indicate a disturbance.
The Comparison of Signals.
The Acrilok system is a means for measuring material outflow at successive time intervals and comparing the weight data obtained at those intervals. Using a microprocessor, a signal is derived from at least one weight sample taken during a first time interval (T1) and compared with a signal derived from at least one weight sample taken during a later time interval (T2). The system continues to make these comparisons through T3, T4, and so on.
It is undisputed that the Schenck system also uses a microprocessor to compare signals derived at successive time intervals based upon weight data. However, in the Schenck system, readings at successive time intervals are compared not, as in the Acrison system, with readings from prior time intervals, but with a previously derived predicted weight for the particular time interval. As set forth in the patent for the Schenck system, a signal derived from at least one weight sample taken during a first time interval is used to produce a signal that ...