by Dennis Crouch
CenTrak v. Sonitor Tech (Fed. Cir. 2019) is a quirky case that basically stands for the (wrongheaded) proposition that the Written Description Requirement does not usually require a description of how to make the invention actually work. Here, largely the court relied on the broad language of Alcon Research Ltd. v. Barr Labs., Inc., 745 F.3d 1180, 1191 (Fed. Cir. 2014) (“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 district court dismissed this infringement lawsuit on summary judgment — finding the asserted claims invalid for lack of written description or not infringed (or both). On appeal the Federal Circuit reversed that determination — finding both issues ripe with “genuine disputes of material fact.”
The patent at issue here claims the use of ultrasound signals to track location of a mobile device (typically a patient in a hospital). U.S. Patent 8,604,909. There are several reasons why ultrasound can be a better option than WIFI or infrared (IR) signals for location detection within a small area. For example, the steeper proximity decay makes it much less likely that a distant base-station would pick-up the signal. Thus, location can be discovered and without needing triangulation or highly precise equipment. Both the patentee and accused infringer deal in ultrasonic location equipment.
All the claims are directed to the ultrasound approach. However, it does not appear that the inventor initially cared much about the ultrasound approach. Rather, the original provisional application does not mention ultrasound at all . While the subsequent priority non-provisional application also focuses primarily on the use of IR and RF signals, it does does include two-sentences disclosing ultrasound signalling:
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.
The original priority filing also included one claim directed to ultrasonic detection. That claim was the subject of a restriction requirement and withdrawn. The patent at issue is the resulting divisional application filed with a set of 25 claims all directed to ultrasonic detection.
At trial, the inventor admitted that the invention did not describe an ultrasonic portable device:
Q. But there’s no ultrasonic portable device that is actually described in the ’909 patent; right?
A. This is correct, yeah.
But, the inventor indicated (supported by expert testimony) that a person of skill in the art would have little trouble adapting the disclosure to build the ultrasound system.
[To make the invention] You have to understand how to drive an ultrasonic transmitter, how to receive an ultrasonic signal, and how to process them. But this is known art to people who are knowing ultrasound.
In its invalidity decision, the district court focused on the testimony of no example device and concluded that the mere mention of ultrasonic techniques was not sufficient to satisfy the written description requirement. The court explained, for instance, that the claims include timing synchronization elements that were explained for IR, but that timing could be quite different for ultrasound of speed (speed of light vs speed of sound) and reflection differences.
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The written description requirement is a test of for sufficiency of disclosure — The disclosure must “reasonably convey . . . that the inventor had possession of the claimed subject matter as of the filing date.” Ariad. The basic question is whether the specification as originally filed provides evidence that that the inventor actually invented what is being claimed.
In looking at the evidence on appeal, the Federal Circuit found a “genuine issues of material fact” as to whether “disclosure of the implementation details” is necessary to satisfy the written description requirement. According to the court, written description does not demand examples, or actual reduction to practice. Rather, the law only requires “identif[ication] of the claimed invention . . . in a definite way” quoting Ariad.
Here, the court concluded, “the specification at least mentions base stations and receivers that use ultrasound,” and in many cases such a mention is sufficient to satisfy WD. One question that arises from Ariad is the level of detail required. In that case, the court explained that “the level of detail required to satisfy the written description requirement varies depending on the nature and cope of the claims and on the complexity and predictability of the relevant technology.” Here, the court concluded that the level of complexity and predictability is a factual issue in dispute and thus that it should go to trial rather than be decided on summary judgment.
In this process, the court noted that on remand, the district court should also consider the separate doctrine enablement that may bear more teeth in this type of situation.
On infringement, the district court also dismissed the case for lack of infringement. The claims require use of wireless computer network, including a backbone, Wi-Fi access points, and server hardware. The accused infringer does not supply this material but instead piggy-backs its systems as an add-on to the already existent network. The district court found that no single entity had “made” the system and so Sonitor could not be liable as a direct infringer.
On appeal, the Federal Circuit rejected that analysis — finding material evidence that Sonitor was the “final assembler” of the system and thus could be held liable for “making” the invention. I’ll note here that the hospitals themselves could be held liable, but the patentee would rather extract rents from its direct competitor rather than its potential clients.