Federal Circuit Deems Written Description Requirement Satisfied if Specification Identifies the Claimed Invention in a Definite Way

The United States Court of Appeals for the Federal Circuit recently issued a ruling reversing a district court’s grant of summary judgment of non-infringement and invalidity for failure to satisfy the written description requirement. See CenTrak, Inc. v. Sonitor Techs., Inc., 2019 U.S. App. LEXIS 4442 (Fed. Cir. Feb. 14, 2019) (Before Reyna, Taranto, and Chen, Circuit Judges) (Opinion for the Court, Chen, Circuit Judge).

CenTrak, Inc. (CenTrak) sued Sonitor Technologies, Inc. (Sonitor) for infringement of U.S. Patent No. 8,604,909, which claims systems for locating and identifying portable devices using ultrasonic base stations. The district court granted summary judgment of non-infringement, holding that a defendant must be the actor who assembles the entire claimed system to be liable for direct infringement, but CenTrak had not submitted proof that Sonitor personnel had made an infringing assembly. Regarding invalidity, the district court ruled that while the specification “contemplated” ultrasonic components, “[m]ere contemplation . . . is not sufficient to meet the written description requirement.”

Written Description Requirements

In reversing the district court, the Federal Circuit began by reciting the test for sufficiency of a patent’s written description, i.e., “whether the disclosure of the application relied upon reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.” Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010). CenTrak argued that the district court’s written description ruling fell more in line with an enablement theory than written description in that the district court seemed to be effectively requiring the specification to disclose basic, routine implementation details for how a portable device can receive location and timing synchronization information from a neighboring base station using an ultrasound signal. The Court pointed out that:

“written description is about whether the skilled reader of the patent disclosure can recognize that what was claimed corresponds to what was described; it is not about whether the patentee has proven to the skilled reader that the invention works, or how to make it work, which is an enablement issue.”

The Court ultimately concluded that genuine issues of material fact remained as to whether disclosure of the implementation details that the district court identified were necessary to satisfy the written description requirement. The Court cited its previous decision in ScriptPro LLC v. Innovation Associates, Inc., 833 F.3d 1336, 1341 (Fed. Cir. 2016), for the proposition that “a specification’s focus on one particular embodiment or purpose cannot limit the described invention where that specification expressly contemplates other embodiments or purposes.”  The Court went on to explain that “the fact that the bulk of the specification discusses a system with infrared components does not necessarily mean that the inventors did not also constructively reduce to practice a system with ultrasonic components.” Instead, the written description requirement may be satisfied if the specification identifies the claimed invention in a definite way.

Therefore, the question here was the level of detail that the ’909 patent’s specification must contain, beyond disclosing that ultrasonic signals can be used, to adequately convey to a skilled artisan that the inventors possessed an ultrasonic embodiment. The parties disputed the complexity and predictability of ultrasonic real-time location (“RTL”) systems, and the district court erred by not sufficiently crediting testimony from CenTrak’s expert that the differences between infrared and ultrasound, when used to transmit small amounts of data over short distances, are incidental to carrying out the claimed invention. The testimony from CenTrak’s expert suggested that those details were not particularly complex or unpredictable, and Sonitor did not explain why a person of ordinary skill in the art would need to see such details in the specification to find that the named inventors actually invented the claimed system. Thus, the district court erred in granting summary judgment on this issue.

Infringement Analysis

Next, the Court analyzed the district court’s holding that CenTrak did not present sufficient evidence to raise a triable issue of fact as to whether Sonitor makes infringing systems. It was undisputed that Sonitor does not provide certain claimed elements in the accused systems, such as a backbone network, Wi-Fi access points, or server hardware. The district court and Sonitor therefore relied on Centillion Data Sys., LLC v. Qwest Commc’ns Int’l, Inc., 631 F.3d 1279 (Fed. Cir. 2011) for the proposition that to “make” a system, a single entity must assemble the entire system itself. CenTrak argued, however, that admissible evidence that Sonitor is the “final assembler” raised a triable issue of fact on infringement even though Sonitor does not “make” each of the claimed components of the accused systems. Part of CenTrak’s infringement theory was that Sonitor “integrat[es] the entire system into the customer’s network.” An “integration agreement” could constitute circumstantial evidence that Sonitor hired a contractor to build at least part of an infringing system. Furthermore, CenTrak argued that even if a third party who does not work for Sonitor installed all claimed hardware, Sonitor would still infringe by configuring the Sonitor ultrasonic location transmitters to integrate with the customer’s network and by entering location codes into the Sonitor server software to associate location transmitters with locations in the facility. According to CenTrak, the accused system is not an operable assembly until it is configured.

The Court agreed with CenTrak, explaining that a final assembler can be liable for making an infringing combination, even if it does not make each individual component element. A reasonable jury could therefore find that before an accused Sonitor system goes online, Sonitor personnel complete at least a portion of the final system configuration and software setup necessary to make the system work. In other words, Sonitor makes a combination of hardware and software that is “configured” to infringe. Thus, the district court erred in ruling that there were no genuine issues of material fact that Sonitor was entitled to summary judgment on the issue of “making.”