Ssi Technologies, LLC v. Dongguan Zhengyang Electronic Mechanical Ltd.

59 F.4th 1328
Court of Appeals for the Federal Circuit·Decided February 13, 2023·No. 21-2345·Published·Cited by 7 cases

Opinion

United States Court of Appeals for the Federal Circuit

SSI TECHNOLOGIES, LLC,

Plaintiff-Appellant

v.

DONGGUAN ZHENGYANG ELECTRONIC MECHANICAL LTD., Defendant-Cross-Appellant

2021-2345, 2022-1039

Appeals from the United States District Court for the Western District of Wisconsin in No. 3:20-cv-00019-jdp, Judge James D. Peterson.

Decided: February 13, 2023

SHANE A. BRUNNER, Michael Best & Friedrich, LLP, Madison, WI, argued for plaintiff-appellant. Also represented by MICHAEL BESS, Chicago, IL; J. RYAN GRAY, Raleigh , NC; MELANIE J. REICHENBERGER, Milwaukee, WI; DEREK C. STETTNER, Menomonee Falls, WI.

JOSEPH KUO, Saul Ewing Arnstein & Lehr LLP, Chicago , IL, argued for defendant-cross-appellant. Also represented by ELIZABETH A. THOMPSON.

2 SSI TECHNOLOGIES, LLC v.

DONGGUAN ZHENGYANG ELECTRONIC MECHANICAL LTD.

Before REYNA, BRYSON, and CUNNINGHAM, Circuit Judges. BRYSON, Circuit Judge.

Appellant SSI Technologies, LLC, (“SSI”) brought this action against appellee Dongguan Zhengyang Electronic Mechanical LTD (“DZEM”), alleging that DZEM infringes two of SSI’s patents. DZEM asserted counterclaims for invalidity of the asserted patents and for tortious interference with prospective business relations. The district court granted summary judgment to DZEM on the infringement claims and dismissed DZEM’s invalidity counterclaims. The court also granted summary judgment to SSI on the tortious interference counterclaim. We affirm in part, reverse in part, vacate in part, and remand.

I

A

SSI has asserted U.S. Patent Nos. 8,733,153 (“the ’153 patent”) and 9,535,038 (“the ’038 patent”) against DZEM in this case. The patents are generally directed to sensors for determining the characteristics of fluid in a container, such as a fuel tank. SSI’s commercial embodiments of the asserted patents and DZEM’s accused products are systems that determine the quality and volume of diesel exhaust fluid (“DEF”) that is used in emission-reduction systems for diesel truck engines.

1

Claim 1 is generally representative of the five asserted claims of the ’153 patent for purposes of this appeal. It recites :

1. A system for determining a quality of a fluid in a tank, the system comprising: a transducer configured to generate a sound wave and to detect an echo of the sound wave, the transducer positioned near the bottom of the tank such that the sound wave travels toward a fixed object,

SSI TECHNOLOGIES, LLC v. 3 DONGGUAN ZHENGYANG ELECTRONIC MECHANICAL LTD.

the fixed object positioned a known distance away from the transducer; a temperature sensor configured to detect a temperature of the fluid; and a controller configured to produce a signal to drive the transducer to produce the sound wave, receive an indication of the detected echo from the transducer, receive an indication of the temperature of the fluid from the temperature sensor, and determine whether a contaminant exists in the fluid based on the temperature of the fluid, a time period from when the sound wave is produced to when the echo is detected , and at least one of the group of a) whether a measured volume is out of range and b) a dilution of the fluid is detected while the measured volume of the fluid decreases .

’153 patent, cl. 1 (emphasis on disputed limitation).

The specification of the ’153 patent describes an exemplary sensor system containing two transducers, a “level” transducer and a “quality” transducer. Id. at col. 6, ll. 5–12. The level transducer is positioned at the bottom of the tank and emits ultrasonic sound waves upward toward the surface of the fluid. Id. at Fig. 3 & col. 6, ll. 10–12. The quality transducer is positioned at the bottom of the tank and emits ultrasonic sound waves toward a reflector that is also positioned at the bottom of the tank. Id. at Fig. 3 & col. 6, ll. 8–10. Based on the time of flight of the sound wave emitted from the level transducer to the surface of the fluid, the system can calculate the volume of the fluid in the tank. Id. at col. 10, line 40, through col. 11, line 9.

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Similarly, the system can determine the quality of the fluid (i.e., the concentration of the DEF) by using the time of flight of the sound wave, which is the elapsed time for the sound wave emitted from the quality transducer to travel to and back from the reflector. Id. at col. 9, ll. 17–50.

The ’153 patent also discloses an error-detection mechanism by which the system can “detect failures of various components of the system.” Id. at col. 12, ll. 38–40. First, the system can determine that an error exists “when it detects the concentration level of the [DEF] decreasing (i.e., becoming diluted) at the same time as the level of the [DEF] is decreasing.” Id. at col. 12, ll. 40–43. Such conditions indicate an error “[b]ecause the [DEF] cannot become diluted when the level of the [DEF] is decreasing.” Id. at col. 12, ll. 51–53. Second, the system can determine that an error exists when “the calculated level [of DEF] will exceed the known actual maximum level” of the tank. 1 Id. at col. 12, ll. 57–60.

2

Claim 9 of the ’038 patent, the main claim of that patent that is at issue in this appeal, recites:

1 The specification of the ’153 patent uses the terms “measured” and “calculated” interchangeably. At one point, the specification discloses that the controller can perform a “plausibility check” by “comparing the calculated level against the absolute physical capacity for the tank 110.” ’153 patent, col. 11, ll. 34–38. In the following sentence , the specification notes that “[t]he controller 400 generates a diagnostic output . . . whenever the measured level exceeds the capacity of the [DEF] tank.” Id. at col. 11, ll. 39–41. Those two sentences describe the same functionality , and we therefore interpret the term “calculated,” as used in the ’153 patent, to be equivalent to the term “measured .”

SSI TECHNOLOGIES, LLC v. 5 DONGGUAN ZHENGYANG ELECTRONIC MECHANICAL LTD.

9. A sensor operable to sense a characteristic of a fluid, the sensor comprising: a sensing area configured to contain the fluid; a chimney configured to exhaust entrapped air from the sensing area; and a filter covering the sensing area, the filter configured to allow a liquid portion of the fluid to enter the sensing area, and substantially prohibit one or more gas bubbles of the fluid from entering the sensing area; and a transducer configured to output a pulse of sound through the liquid portion of the fluid contained within the sensing area, receive the reflected pulse of sound, and output a characteristic of the fluid based on the received pulse of sound.

’038 patent, cl. 9 (emphasis on disputed limitation).

Like the system disclosed in the ’153 patent, the sensor of the ’038 patent operates by measuring the time of flight of an “ultrasonic pulse wave [that] travel[s] the distance of the sensing area and return[s] to the output point.” Id. at col. 2, ll. 10–12. The invention of the ’038 patent seeks to address the problem of “erratic measurement results” that may occur due to “air bubbles [that] are embedded in the fluid.” Id. at col. 2, ll. 13–18. Accordingly, the specification of the ’038 patent discloses a sensor having a filter that “blocks, or inhibits, air bubbles from entering a sensing area of the fluid sensor.” Id. at col. 2, ll. 4–7.

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B

1

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Ssi Technologies, LLC v. Dongguan Zhengyang Electronic Mechanical Ltd., 59 F.4th 1328 (Fed. Cir. 2023).

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