On February 14, 2019, the Court of Appeals for the Federal Circuit (CAFC) issued an opinion reversing and remanding a decision by the United States District Court for the District of Delaware granting summary judgment of invalidity for lack of written description. CenTrak, Inc. v. Sonitor Techs., Inc
., —F.3d—, (Fed. Cir. Feb. 14, 2019). The CAFC ruled that there were genuine issues of material fact as to whether it was necessary to disclose in the patent specification particular implementation details to satisfy the written description requirement.
35 U.S.C. § 112 requires that a patent specification “contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art . . . to make and use the same.” This statute has been interpreted to include both a “written description” requirement and an “enablement” requirement. The former requires that the patent specification “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 and Co
., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc). The latter is a separate inquiry and addresses whether the inventor has shown that the invention works or how to make it work.
In the instant appeal, the asserted patent was directed to real-time location (RTL) systems, which allow users to locate and identify portable devices. The patent specification focused almost exclusively on infrared (IR) systems, only briefly mentioning that ultrasonic technology may also be used. The patent’s ultrasonic-disclosure consisted of two sentences:
Although IR base stations 106 are described, it is contemplated that the base stations 106 may also be configured to transmit a corresponding BS-ID by an ultrasonic signal, such that base stations 106 may represent ultrasonic base stations. Accordingly, portable devices 108 may be configured to include an ultrasonic receiver to receive the BS-ID from an ultrasonic base station.
Despite the patent’s apparent focus on IR, the patent claims all recited “ultrasonic” components. Defendant Sonitor argued that the specification’s brief reference to the use of ultrasonic communications between the base stations and portable devices was nothing more than “generic claim language appearing in ipsis verbis
” in the specification, which is insufficient to meet the written description requirement. According to Sonitor, the lack of written description was confirmed by the inventors, who admitted that the specification does not “actually describ[e]” an “ultrasonic base station” and certain other claim details. Plaintiff CenTrak countered that a skilled artisan reading the specification would understand that the inventors had possession of RTL systems that could use either IR or ultrasound, as explained by its expert.
The district court agreed with Sonitor, finding that IR and ultrasound are “fundamentally different technologies,” differing in both speed and susceptibility to interference. Per the district court, while the specification “contemplated” ultrasound, “[m]ere contemplation . . . is not sufficient to meet the written description requirement.” CenTrak, Inc. v. Sonitor Techs., Inc
., No. CV 14-183-RGA, 2017 WL 3730617, at *8 (D. Del. Aug. 30, 2017).
The CAFC reversed. According to the CAFC, genuine issues of material fact remained regarding the level of detail required to satisfy the written description requirement in view of the complexity and predictability of the relevant technology.
The CAFC determined that the district court relied too heavily on the fact that the specification only briefly mentioned ultrasonic, in
comparison to its IR focus. It also found that the district court failed to credit CenTrak’s expert testimony explaining that any differences between the embodiments were “incidental to carrying out the claimed invention,” and disclosure of such details would not necessarily be required by someone skilled in the art, given that such details were not particularly complex or unpredictable. Additionally, the CAFC found that the inventor’s testimony was not “conclusive proof,” and rather than interpreting the testimony as a legal conclusion, a reasonable fact finder could instead interpret the testimony “as an acknowledgement that the specification did not literally detail the inner workings of ultrasonic devices or identify particular examples of such devices because such details were known to skilled artisans and not part of the inventors’ inventive contribution.”
Having reversed on written-description, the CAFC declined to consider Sonitor’s alternatively raised enablement theory, an issue the district court declined to reach on summary judgment.
This case once again confirms that the written description requirement is a fact-intensive inquiry that must be judged on a sliding scale commensurate with the complexity and predictability of the technology at issue. It will be interesting to see how the district court treats the issues on remand, particularly in the context of an enabling disclosure.