559 F.Supp.3d 821
W.D. Wis.2021Background
- SSI Technologies sued Dongguan Zhengyang Electronic Mechanical Ltd. (DZEM) for infringing two patents on diesel exhaust fluid (DEF) sonic sensors: U.S. Patent No. 8,733,153 (time-of-flight measurement + temperature; includes measured-volume error-detection language) and U.S. Patent No. 9,535,038 (adds a filter to keep gas bubbles out of the sensing area).
- Both parties make competing DEF contamination sensors; the accused DZEM device uses a rubber cover with large intake holes and side slits that deflect/vent bubbles rather than straining fluid through a porous medium.
- SSI moved for summary judgment on DZEM’s tortious-interference counterclaim and other matters; DZEM moved for partial summary judgment of noninfringement and related relief. Several discovery/evidentiary motions were also pending.
- Claim-construction disputes centered on: (1) the ’153 claim phrase requiring the controller to determine contamination “based on” temperature, time-of-flight, and at least one of (a) measured-volume out-of-range or (b) a dilution detected while the measured volume decreases; and (2) the meaning of “filter” in the ’038 patent (mesh/porous structure vs. functional device).
- Prosecution history for the ’153 patent showed the measured-volume language was added to overcome an obviousness rejection (Marcovecchio), and the specification ties measured-volume/dilution language to an error-detection feature.
- DZEM pleaded noninfringement, invalidity, and tortious interference; the court resolved claim construction and infringement on summary judgment, dismissed invalidity counterclaims without prejudice, and rejected the tortious-interference claim.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Infringement of ’153 — scope of "based on" / "measured volume" | SSI: phrase requires only that the determination occur while volume decreases (i.e., during use); does not require controller to consider measured volume | DZEM: requires controller be configured to consider measured volume (or out-of-range volume) when determining dilution; prosecution history and spec support measured-volume/ error-detection limitation | Held: Court adopts DZEM's reading — claim requires controller to consider measured volume; DZEM sensor lacks this, so no infringement of ’153 claims |
| Infringement of ’038 — meaning of "filter" | SSI: "filter" can be defined functionally as device that blocks/separates air bubbles; broader construction would capture DZEM cover | DZEM: "filter" = porous structure with openings that removes impurities larger than pore size (consistent with mesh embodiments) | Held: Court construes "filter" as a porous structure that strains out particles/bubbles; DZEM rubber cover is a baffle/vent, not a porous filter, so no infringement of ’038 claims |
| DZEM invalidity counterclaims | SSI: patents need not be adjudicated if no ongoing threat; court may dismiss invalidity once noninfringement determined | DZEM: sought adjudication of invalidity (and argued §112/enabling issues re: transducer limitation) | Held: Court dismisses invalidity counterclaims without prejudice as moot because patents were not infringed and no evidence of future enforcement risk |
| DZEM tortious-interference counterclaim (Noerr‑Pennington / sham lit.) | SSI: communications alleging infringement are protected petitioning activity; suit not objectively baseless so Noerr-Pennington applies | DZEM: SSI knew claims were meritless; communications were anticompetitive and some targeted foreign companies where SSI lacks patents | Held: Court rejects sham exception (SSI positions supported by expert opinion); Noerr-Pennington protects SSI’s communications regarding protected patents; DZEM also failed to show definite prospective contracts with foreign third parties — tortious-interference claim dismissed |
Key Cases Cited
- Phillips v. AWH Corp., 415 F.3d 1303 (en banc) (framework for claim construction; ordinary meaning and specification focus)
- O2 Micro Int’l Ltd. v. Beyond Innovation Tech. Co., Ltd., 521 F.3d 1351 (claim-construction principles and reliance on intrinsic evidence)
- Kemco Sales, Inc. v. Control Papers Co., 208 F.3d 1352 (two-step infringement analysis: claim construction then comparison)
- E.R.R. Presidents Conference v. Noerr Motor Freight, Inc., 365 U.S. 127 (Noerr‑Pennington doctrine protecting petitioning activity)
- United Mine Workers of Am. v. Pennington, 381 U.S. 657 (extension of Noerr principles)
- Prof. Real Estate Inv’rs v. Columbia Pictures Indus., 508 U.S. 49 (sham‑litigation exception: objectively baseless + misuse of process as anticompetitive weapon)
- Havoco of Am., Ltd. v. Hollobow, 702 F.2d 643 (7th Cir.) (Noerr protection extended to tortious‑interference claims)
- Edgewell Personal Care Brands, LLC v. Munchkin, Inc., 998 F.3d 917 (doctrine of equivalents standard: function/way/result test)
- Flexuspine, Inc. v. Globus Medical, Inc., 879 F.3d 1369 (district court may dismiss invalidity claims when patent not infringed)