Disavowal of Claim Scope : CAFC Alert

Prosecution history disclaimer dooms infringement case for patentee

| November 22, 2021

Traxcell Technologies, LLC v. Nokia Solutions and Networks

Decided on October 12, 2021

Prost, O’Malley, and Stoll (opinion by Prost)


Patentee’s arguments during prosecution distinguishing the claimed invention over prior art were found to be clear and unmistakable disclaimer of certain meanings of the disputed claim terms. The prosecution history disclaimer resulted in claim constructions that favored the accused infringer and compelled a determination of non-infringement.


Traxcell Technologies LLC specializes in navigation technologies. The company was founded by Mark Reed, who is also the sole inventor behind U.S. Patent Nos. 8,977,284, 9,510,320, and 9,642,024 that Traxcell accused Nokia of infringing.

The 284, 320, and 024 patents are directly related to each other as grandparent, parent, and child, respectively. The three patents are concerned with self-optimizing wireless network technology. Specifically, the patents claim systems and methods for measuring the performance and location of a wireless device (for example, a phone), in order to make “corrective actions” to or tune a wireless network to improve communications between the wireless device and the network.

The asserted claims from the three patents require a “first computer” (or in some of the asserted claims, simply “computer”) that is configured to perform several functions related to the “location” of a mobile wireless device.

Central to the parties’ dispute was the proper constructions of “first computer” and “location”.

Nokia’s accused geolocation system was undisputedly a self-optimizing network product. Nokia’s system performed similar functions as those claimed in the asserted computers, but across multiple computers. Nokia’s system also collected performance information for mobile wireless devices located within 50-meter-by-50-meter grids.

To avoid infringement, Nokia argued that the claimed “first computer” required a single computer performing the claimed functions, and that the claimed “location” required more than the use of a grid.

On the other hand, wanting to capture Nokia’s products, Traxcell argued that the claimed “first computer” encompassed embodiments in which the claimed functions were spread among multiple computers, and that the claimed “location” plainly included a grid-based location.

Unfortunately for Traxcell, their arguments did not stand a chance against the prosecution histories of the asserted patents.

The doctrine of prosecution history disclaimer “preclud[es] patentees from recapturing through claim interpretation specific meanings disclaimed during prosecution”. Omega Eng’g, Inc. v. Raytek Corp., 334 F.3d 1314, 1323 (Fed. Cir. 2003). “Prosecution disclaimer can arise from both claim amendments and arguments”. SpeedTrack, Inc. v. Amazon.com, 998 F.3d 1373, 1379 (Fed. Cir. 2021). “An applicant’s argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope even if the applicant distinguishes the reference on other grounds as well”. Id. at 1380. For there to be disclaimer, the patentee must have “clearly and unmistakably” disavowed a certain meaning of the claim.

Of the three asserted patents, the 284 patent had the most protracted prosecution, with six rounds of rejections. And it was the prosecution history of the 284 patent that provided the fodder for the district court’s claim constructions. Incidentally, the 284 patent was also the only one of the three asserted patents prosecuted by the inventor, Mark Reed, himself.

During claim construction, the district court construed the terms “first computer” and “computer” to mean a single computer that could performed the various claimed functions.

The district court first looked to the plain language of the claims. The claim language recites “a first computer” or “a computer” that performs a function, and then recites that “the first computer” or “the computer” performs several additional functions. The district court determined that the claims plainly tied the claimed functions to a single computer, and that “it would defy the concept of antecedent basis” for the claims to refer back to “the first computer” or “the computer”, if the corresponding tasks were actually performed by a different computer.

The intrinsic evidence that convinced the district court of its claim construction was, however, the prosecution history of the 284 patent.

During prosecution, in a 67-page response, Mr. Reed argued explicitly and at length, in a section titled “Single computer needed in Reed et al. [i.e., the pending application] v. additional software needed in Andersson et al. [i.e., the prior art]”, that the claimed invention requiring just one computer distinguished over the prior art system using multiple computers. The district court quoted extensively from this response as intrinsic evidence supporting its claim construction.

The Federal Circuit agreed with the district court’s claim construction, quoting still more passages from the same response as evidence that the patentee “clearly and unmistakably disclaimed the use of multiple computers”.

Next, the district court addressed the term “location”. The district court construed the term to mean a “location that is not merely a position in a grid pattern”.

Here, the district court’s claim construction relied almost exclusively on arguments that Reed made during prosecution of the 284 patent. Referring again to the same 67-page response, the district court noted that Mr. Reed explicitly argued, in a section titled “Grid pattern not required in Reed et al. v. grid pattern required in Steer et al.”, that the claimed invention distinguished over the prior art because the claimed invention operated without the limitation of a grid pattern, and that the absence of a grid pattern permitted finer tuning of the network system.

And again, the Federal Circuit agreed with the district court’s claim construction, finding that “the disclaimer here was clear and unmistakable”.

The claim constructions favored Nokia’s non-infringement arguments that its system lacked the single-computer, non-grid-pattern-based-location limitations of the asserted claims. Accordingly, the district court found, and the Federal Circuit affirmed, that Nokia’s system did not infringe the 284, 320, and 024 patents.

Traxcell made an interesting argument on appeal—specifically, the disclaimer found by the district court was too broad and a narrower disclaimer would have been enough to overcome the prior art. Traxcell seemed to be borrowing from the doctrine of prosecution history estoppel. Under that doctrine, arguments or amendments made during prosecution to obtain allowance of a patent creates prosecution history estoppel that limits the range of equivalents available under the doctrine of equivalents.

However, the Federal Circuit was unsympathetic to Traxcell’s argument, explaining that Traxcell was held “to the actual arguments made, not the arguments that could have been made”. The Federal Circuit also noted that “it frequently happens that patentees surrender more…than may have been absolutely necessary to avoid particular prior art”.

Mr. Reed’s somewhat unsophisticated prosecution of the 284 patent was in sharp contrast to the prosecution of the related 320 and 024 patents, which were handled by a patent attorney. The prosecution histories of the 320 and 024 patents said very little about the cited prior art, even less about the claimed invention. In addition, whereas Mr. Reed editorialized on various claimed features during prosecution of the 284 patent, the prosecution histories of the 320 and 024 patents rarely even paraphrased the claims.


  • Avoid gratuitous remarks that define or characterize the claimed invention or the prior art during prosecution. Quote the claim language directly and avoid paraphrasing the claim language, as the paraphrases risk being construed later as a narrowing characterization of the claimed invention.
  • Avoid claim amendments that are not necessary to distinguish over the prior art.
  • The prosecution history of a patent can affect the construction of claims in other patents in the same family, even when the claim language is not identical. Be mindful about how arguments and/or amendments made in one application may be used against other related applications.

Disavowal – Construing an element in a patent claim to require what is not recited in the claim but is described in an embodiment of the specification

| January 14, 2020

Techtronic Industries Co. Ltd. v. International Trade Commission

December 12, 2019

Lourie, Dyk, and Wallach, Circuit Judges. Court opinion by Lourie.


            The Federal Circuit reversed the Commission’s claim construction order reversing the ALJ’s construction of the term “wall console” in each of claims in the patent in suit, holding that the ALJ properly construed the term “wall console” as “wall-mounted control unit including a passive infrared detector” because each section of the specification evinces that the patent disavowed coverage of wall consoles lacking a passive infrared detector. Consequently, the Court reversed the Commission’s determination of infringement as well because the parties agreed that the appellants do not infringe the patent under the ALJ’s claim construction.


I. background

1. The Patent in Suit – U.S. Patent 7,161,319 (the “‘319 patent”)

            Intervenor Chamberlain Group Inc. (“Chamberlain”) owns the ‘319 patent, which discloses improved “movable barrier operators,” such as garage door openers. Claim 1, a representative claim, reads as follows:

            1. An improved garage door opener comprising

            a motor drive unit for opening and closing a garage door, said motor drive unit having a microcontroller

            and a wall console, said wall console having a microcontroller,

            said microcontroller of said motor drive unit being connected to the microcontroller of the wall console by means of a digital data bus.

2. Prior Proceedings

            In July 2016, Chamberlain filed a complaint at the Commission, alleging that Techtronic Industries Co. Ltd. and others (collectively, “Appellants”) violated Section 337(a)(1)(B) of the Tariff Act of 1930 by the “importation into the United States, the sale for importation, and the sale within the United States after importation” of Ryobi Garage Door Opener models that infringe the ‘319 patent.

            The only disputed term of the ‘319 patent was “wall console.” The ALJ concluded that Chamberlain had disavowed wall consoles lacking a passive infrared detector because the ‘319 patent sets forth its invention as a passive infrared detector superior to those of the prior art by virtue of its location in the wall console, rather than in the head unit, and that the only embodiment in the ‘319 patent places the passive infrared detector in the wall console as well.

            The Commission reviewed the ALJ’s order and issued a decision reversing the ALJ’s construction of “wall console” and vacating his initial determination of non-infringement.  The Commission presented following reasons for the reversal: (i) while “the [‘319] specification describes the ‘principal aspect of the present invention’ as providing an improved [passive infrared detector] for a garage door operator,” the specification discloses other aspects of the invention, and a patentee is not required to recite in each claim all features described as important in the written description; (ii) the claims of U.S. Patent 6,737,968, which issued from a parent application, expressly located the passive infrared detector in the wall console, “demonstrat[ing] the patentee’s intent to claim wall control units with and without [passive infrared detectors];” and (iii) the prosecution history of the ‘319 patent lacked “the clear prosecution history disclaimer.”

            Under the Commission’s construction, the ALJ found that Appellants infringed the ‘319 patent. Accordingly, the Commission entered the Remedial Orders against the Appellants.

            The appeal followed.

II. The Federal Circuit

            The Federal Circuit unanimously sided with the Appellants, concluding that Chamberlain disavowed coverage of wall consoles without a passive infrared detector because “the specification, in each of its sections, discloses as the invention a garage door opener improved by moving the passive infrared detector from the head unit to the wall console.”

            The court opinion authored by Judge Lourie started scrutiny of the ‘319 specification with the background section. The court opinion found that the background section discloses that the prior art taught the use of passive infrared detectors in the head unit of the garage door opener to control the garage’s lighting, but that locating the detector in the head unit was expensive, complicated, and unreliable (emphases added). The court opinion moved on to state,  [t]he ‘319 patent therefore sets out to solve the need for “a passive infrared detector for controlling illumination from a garage door operator which could be quickly and easily retrofitted to existing garage door operators with a minimum of trouble and without voiding the warranty.”

            The court opinion further stated, “[t]he remaining sections of the patent—even the abstract—disclose a straightforward solution: moving the detector to the wall console” (emphasis added).

            The court opinion dismissed the Commission’s argument that “[n]owhere does the ‘319 patent state that it is impossible or even infeasible to locate a passive infrared detector at some other location” by  pointing out, “the entire specification focuses on enabling placement of the passive infra-red detector in the wall console, which is both responsive to the prior art deficiency the ’319 patent identifies and repeatedly set forth as the objective of the invention.”

            As for the “other aspects of the invention” partially relied on by the Commission, the court opinion stated, “[t]he suggestion that the patent recites another invention—related to programming the microcontroller—in no way undermines the conclusion that the infrared detector must be on the wall unit .” More specifically, in response to Chamberlain’s and the Commission’s argument that portions of the description, particularly col. 4 l. 60–col. 7 l. 26, concern an exemplary method of programming the microcontroller to interact with the head unit by means of certain digital signaling techniques, matters not strictly related to the detector, the court opinion stated, “the entire purpose of this part of the description is to enable placement of the detector in the wall console, and it never discusses programming the microcontroller or applying digital signaling techniques for any purpose other than transmitting lighting commands from the wall console.”

            Finally, the court opinion rejected the contention of Chamberlain and the Commission that the ‘319 patent’s prosecution history is inconsistent with disavowal, by stating, “there is [n]o requirement that the prosecution history reiterate the specification’s disavowal.”

            In view of the above, the Court concluded that the ‘319 patent disavows wall consoles lacking a passive infrared detector. Accordingly, the Court reversed the Commission’s claim construction order and the determination of infringement.


· Disavowal, whether explicit or implicit, may cause a claim term to be construed narrower than an ordinary meaning of the term.

· Disavowal may be found with reference to an entire portion of the specification including an abstract and background section.

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