Federal Circuit Archives - Page 16 of 75

Federal Circuit

Prior Art Coherency and Cache Incoherency: “Known-Technique” Rationale for Motivation to Combine

by Jake B. Vallen | Mar 23, 2023 | Patents

The US Court of Appeals for the Federal Circuit, addressing the issue of whether certain factual and legal conclusions relating to obviousness were supported by substantial evidence, held that the Patent Trial & Appeal Board improperly rejected evidence of “known-technique” rationale to provide a motivation to combine. Intel Corp. v. PACT XPP Schweiz AG, Case No. 22-1037 (Fed. Cir. Mar. 13, 2023) (Newman, Prost, Hughes, JJ.)

PACT owns a patent that “relates to multiprocessor systems and how processors in those systems access data.” The claimed multiprocessor system addressed cache incoherency, a problem associated with the use of multiple cache memories to store data, particularly local copies of the same data stored on multiple processors. Cache incoherency (i.e., inconsistencies among different cache processors) “may arise if one processor changes its local copy of the data and that change isn’t propagated to the other copies of that data.”

Intel petitioned for inter partes review of claims 4 and 5 of the patent, relying on two prior art references, Kabemoto and Bauman. Kabemoto and Bauman both address the problem of cache incoherency. As the Federal Circuit explained, Kabemoto maintains cache coherency “by ‘snooping’ along a shared ‘bus,’” while Bauman “us[es] a global, segmented secondary cache.”

The Board upheld the patentability of the challenged claims, concluding that “Intel failed to prove the obviousness of each limitation of [independent] claim 4,” from which claim 5 depended. Intel had contended that a person of ordinary skill in the art would combine Kabemoto and Bauman to teach all limitations in claim 4 by “replac[ing] Kabemoto’s secondary caches” with “Bauman’s segmented global [secondary cache],” which is a separate cache. PACT did not dispute that the combination of Kabemoto and Bauman taught each limitation of claim 4 but argued that Intel failed to demonstrate a motivation to combine Kabemoto and Bauman.

The Board nevertheless found that Intel failed to demonstrate that the prior art disclosed the segment-to-segment limitation and concluded that Intel failed to show that a person of ordinary skill in the art would have been motivated to combine the teachings of Kabemoto and Bauman. Intel appealed.

The Federal Circuit first addressed Intel’s contention “that substantial evidence d[id] not support the Board’s determination that the prior art fails to disclose the segment-by-segment limitation” of claim 4. The Court found that “Bauman’s Figure 6 teaches—if not plainly illustrates—the segment-to-segment limitation of the claims interconnect system” and reversed the Board’s contrary conclusion.

Next, the Federal Circuit addressed Intel’s contention that the Board’s determination that there was no motivation to combine Kabemoto and Bauman was not supported by substantial evidence. On this issue, the Court reasoned that under KSR, it was “enough for Intel to show that there was a known problem of cache incoherency in the art, that Bauman’s secondary cache helped address that issue, and that combining the teachings of Kabemoto and Bauman wasn’t beyond the skill of an ordinary artisan.” As the Court put it, “[n]othing more is required to show a motivation to combine under KSR.”

Explaining [...]

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Actual or Potential Consumers in Related Goods Context Doesn’t Require PURE Overlap

by Benjamin Ediger, Ph.D. | Mar 23, 2023 | Trademarks

The US Court of Appeals for the Federal Circuit reminded us that, in the context of related goods, the likelihood of confusion analysis does not require that actual or potential consumers of the goods be the same, but only that there be sufficient overlap. In re Oxiteno S.A. Industria e Comercio, Case No. 22-1213 (Fed. Cir. Mar. 9, 2023) (Dyk, Bryson, Prost, JJ.)

Oxiteno filed an intent-to-use trademark application for OXIPURITY, with its goods and services statement ultimately amended to include dozens of chemical products “for use in the pharmaceutical, veterinary, flavor and fragrance, and cosmetic fields.” The application was refused on likelihood of confusion grounds in view of FMC Corporation’s registered OXYPURE mark, largely because the hydrogen peroxide products covered by the OXYPURE registration moved through the same channels of trade as products recited in the Oxiteno application.

Oxiteno appealed the refusal to the Trademark Trial & Appeal Board. The Board analyzed likelihood of confusion using the DuPont factors and found the first four factors most relevant:

Factor 1: The similarity of OXIPURITY and OXYPURE. The Board concluded (as had the Examiner) that the two marks were “similar in sound, meaning and commercial impression,” and found that this factor strongly favored a likelihood of confusion.

Factor 2: The similarity of the covered goods. The Board agreed with the Examiner that the respective goods, while not the same, were sufficiently related to favor a likelihood of confusion finding.

Factor 3: The similarity of channels of trade. The Board reviewed the third-party websites that the Examiner considered particularly dispositive. The websites sold hydrogen peroxide goods covered by the OXYPURE mark and the chemicals Oxiteno intended to sell under the OXIPURITY mark. The Board concluded that the same sources manufactured FMC’s established products and Oxiteno’s intent-too-use products, and directly sold these products to largely overlapping industries.

Factor 4: “[t]he conditions under which and buyers to whom sales are made.” Of the four most relevant factors in this case, this was the only factor that the Board found to favor registration. The Board concluded that the consumers of the established and intent-to-use products would be sophisticated and not act on impulse.

Despite the potential consumers’ presumed sophistication, the Board found that factors 1 through 3 “rendered confusion likely” and thus affirmed the Examiner’s refusal. Oxiteno appealed.

Oxiteno argued that likelihood of confusion could not be found when the actual or potential consumers of the respective products covered by two marks were not the same, as with the relevant products here.

The Federal Circuit affirmed the Board, noting statements made by a company selling Oxiteno’s products that explained why almost every business is a potential purchaser of FMC’s OXYPURE hydrogen peroxide products. The Court also noted that FMC’s brochures stated that it sold its hydrogen peroxide products under OXYPURE and other brand names to the same key industries to which Oxiteno sold its products. The Court, therefore, concluded that substantial evidence supported that at least some [...]

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Show Your Work: PTO Director’s Procedure for Issuing Instructions Is Reviewable

by Rodney Swartz, PhD | Mar 23, 2023 | Patents

The US Court of Appeals for the Federal Circuit affirmed the district court’s finding under the Administrative Procedure Act (APA) that the substance of the US Patent & Trademark Office (PTO) Director’s instructions is unreviewable but reversed the finding that the cloak of unreviewability extended to the procedure used in issuing the instructions. Apple v. Vidal, Case No. 22-1249 (Fed. Cir. Mar. 13, 2023) (Lourie, Taranto, Stoll, JJ.)

The creation of the inter partes review (IPR) program opened new avenues for reviewing the validity of patents following issuance. Since the program’s inception, Congress has recognized that there is a possibility of parallel proceedings at the Patent Trial & Appeal Board and in the district court, that such proceedings could result in conflicting decisions and reduced efficiency in the system. However, Congress left it to the discretion of the two branches to work out such situations among themselves.

As one lever to overcome these issues, Congress provided the Director with unreviewable discretion in deciding whether to institute an IPR. Recently, the Director attempted to leverage this power to increase efficiencies and reduce gamesmanship by instructing the Board on what to consider when instituting an IPR.

Apple and four other companies challenged these instructions in the district court. Apple argued that the Director’s instructions violated the APA by being contrary to the IPR provisions, arbitrary and capricious, and issued without the notice-and-comment rulemaking required under the APA.

Following a motion to dismiss, the district court concluded that Apple’s challenges were directed at the Director’s actions, making them unreviewable by the court. Apple appealed.

On appeal, the Federal Circuit considered all three of Apple’s APA challenges to the instructions, along with whether Apple had standing to bring the suit. The Court agreed with the district court that the question of whether an instruction violates the APA by being contrary to the IPR provisions or by being arbitrary and capricious is directed to the substance of the Director’s action and is not reviewable: “§ 314(a) invests the Director with discretion on the question whether to institute review . . . : The determination by the Director whether to institute an inter partes review . . . shall be final and nonappealable.” As the Federal Circuit noted, this conclusion rests on the well-supported need for the PTO Director to give guidance to delegatees on how to make institution determinations.

The Federal Circuit disagreed that the announcement procedure the Director used for issuing the instructions to the Board was unreviewable, however. As the Court noted, the procedure employed by an agency to announce guidelines is “quite apart” from the substance of those guidelines. Given this distinction, the Court concluded that the procedure the Director used to announce the instructions was reviewable: “The government here has not shown that anything in § 314(d) or elsewhere in the IPR statute supplies clear and convincing evidence that there was to be no judicial review of the choice of announcement procedure, a matter for which generally applicable standards exist.”

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Transfer Motions Take Priority Regardless of Target District

by Jodi Benassi | Mar 16, 2023 | Patents

The US Court of Appeals for the Federal Circuit granted a writ of mandamus and ordered the district court to decide a motion for intra-district transfer before proceeding to further substantive matters, explaining that both intra-district and inter-district transfer motions must be prioritized. In re: Apple Inc., Case No. 23-120 (Fed. Cir. Mar. 6, 2023) (per curiam) (nonprecedential).

SpaceTime3D sued Apple for patent infringement in February 2022 in the Western District of Texas, Waco Division. In July 2022, Apple moved to transfer the action within the Western District to Austin. The motion was fully briefed by the parties on November 7, 2022. The claim construction hearing was scheduled for November 17, 2022, based on an agreement between the parties. The day before the hearing, Apple moved to stay the hearing and all other proceedings until the district court ruled on Apple’s pending motion to transfer. The district court deferred claim construction, then denied Apple’s stay motion. The district court acknowledged that it was required to prioritize a motion for inter-district transfer but stated that “it does not have to stay the proceedings or decide whether to transfer the case intra-district until closer to trial.” Apple filed a writ of mandamus with the Federal Circuit.

The Federal Circuit noted that although the remedy of mandamus is drastic and should be invoked only in extraordinary situations, it has previously granted mandamus “to correct a clearly arbitrary refusal to act on a longstanding pending transfer motion.” The Federal Circuit stated that under Fifth Circuit law, precedent entitles parties to have their transfer motions prioritized. The Federal Circuit was not swayed by the trial court’s reliance on a statement in an unpublished, nonprecedential Fifth Circuit decision in Sundell v. Cisco Systems, Inc., because the Fifth Circuit did not suggest any discretion in the prioritization of transfer motions based on the type of transfer. The Federal Circuit explained that the Fifth Circuit does not require that inter-district transfer motions be prioritized to the exclusion of intra-district transfer motions. The Federal Circuit granted Apple’s petition for mandamus and ordered the district court to timely decide the transfer motion before proceeding with further substantive matters beyond the claim construction hearing.

A Maze-Like Path and Laundry List Don’t Provide Written Description

by Cecilia Choy, Ph.D. | Mar 16, 2023 | Patents

The US Court of Appeals for the Federal Circuit affirmed a Patent Trial & Appeal Board (Board) decision that there was insufficient written description in the asserted priority applications to support a genus claim because of a lack of ipsis verbis disclosure and insufficient blaze marks. The Court concluded that the priority applications did not support an early priority date. Regents of the University of Minnesota v. Gilead Sciences, Inc., Case No. 21-2168 (Fed. Cir. March 6, 2023) (Lourie, Dyk, Stoll, JJ.)

Gilead filed a petition for inter partes review (IPR) challenging Minnesota’s patent directed to phosphoramidate prodrugs preventing virus reproduction or cancerous tumor growth. Gilead’s US Food & Drug Administration-approved drug, sofosbuvir, is marketed by Gilead to treat chronic hepatitis C infections and falls within claim 1 of the patent.

The 2014 application that issued as the challenged patent claimed priority to four applications. In the IPR, Gilead argued that the claims were anticipated by a Gilead-owned patent publication (Sofia). The publications used in the decision are as follows:

NP3 and NP2 have the same disclosure. NP2 and P1 contain similar disclosures, which the Board called NP2-P1. The broader claim in NP2-P1 has a relationship of genus to the narrower subgenus claims in the patent at issue. There was no dispute that Sofia disclosed every limitation of each challenged claim. The Board held that NP2-P1 failed to provide a sufficient written description to support the asserted priority date of the challenged claims, which were therefore found to be anticipated by Sofia. Minnesota appealed.

Minnesota argued the following to the Federal Circuit:

The Board erred in holding that the NP2-P1 applications have insufficient written description.
The Board ran afoul of Administrative Procedure Act (APA) requirements.
Minnesota is a sovereign state entity immune from IPR.

35 U.S.C. § 120 sets forth requirements for a patent application to benefit from a filing date of an earlier application. Minnesota asserted that the NP2-P1 priority applications literally described or provided blaze marks to the challenged subgenus claims. The Federal Circuit disagreed, explaining that written description for a genus claim of chemical compounds raises “particular issues,” requiring a description of the outer limits of the genus and either a representative number of members or structural features common to the members of the genus. The Court found that the asserted priority applications (NP2-P1) did not provide such description and the challenged claims were not entitled to the filing dates of those applications.

The Federal Circuit found that the asserted priority applications did not provide ipsis verbis disclosure of the challenged subgenus claim. The Court quoted an oft-noted saying associated with Yogi Berra, a catcher for the New York Yankees some 50 years ago, about a notable failure to provide direction: “when one comes to a fork in the road, take it.” The Court also cited its 1996 decision in [...]

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Patent Law Principles Apply to Claim Scope: Orange Book Delisting and Listing and Regulations

by Benjamin Ediger, Ph.D. | Mar 9, 2023 | Patents

The US Court of Appeals for the Federal Circuit ordered that the only Orange Book patent asserted in a lawsuit must be delisted since its claims were directed to the computer-implemented distribution system and not a method of use. Jazz Pharms., Inc. v. Avadel CNS Pharms., LLC, Case No. 23-1186 (Fed. Cir. Feb. 24, 2023) (Lourie, Reyna, Taranto, JJ.)

Jazz Pharmaceuticals holds a new drug application (NDA) for Xyrem, an oral sodium oxybate solution prescribed to help those with certain narcolepsies manage cataplexy. Sodium oxybate itself is no longer covered by patents because it has been used in relation to narcolepsy since the 1960s. For this reason, Jazz built its patent portfolio around Xyrem’s formulation, use and distribution.

Jazz uses a single-pharmacy distribution system for Xyrem, known as a risk evaluation mitigation strategy (REMS). Implementing REMS was a condition of Xyrem’s US Food & Drug Administration (FDA) approval because it mitigates safety risks of dangerous active pharmaceutical ingredients such as sodium oxybate. One of Jazz’s patents is directed to this REMS distribution system. Abbreviated New Drug Application (ANDA) 505(b)(2) NDA (Hybrid NDA) approval is similarly conditioned on implementing a REMS that is sufficiently comparable to any that the NDA holder must implement. The FDA eventually determined that single-pharmacy systems were unnecessary for Xyrem and potentially detrimental.

Avadel submitted a hybrid NDA for a drug that requires only a single nightly dose, unlike Xyrem, which requires a patient to wake up during the night to ingest a second dose. Avadel’s application also proposed a more lenient REMS that utilizes multiple pharmacies. In view of these differences, Avadel believed that it could avoid a lengthy FDA approval process because all of Jazz’s Xyrem Orange-Book-listed patents seemed addressable without making any Paragraph IV certifications. As for the REMS patent, Avadel filed a statement under 21 U.S.C. § 355(b)(2)(B) because the patent was listed as claiming a method of use and Avadel was not seeking approval for the REMS system to which that patent’s claims were directed.

Jazz sued Avadel asserting seven patents, of which the REMS patent was the only Orange-Book-listed patent. Avadel asserted a counterclaim requesting that the district court order Jazz to delist the REMS patent from the Orange Book. The district court subsequently held a Markman hearing finding that the REMS patent’s claims were directed to a system and not a method. The district court granted Avadel’s motion for judgment on the pleadings, finding that the REMS patent did not claim “the drug for which the application was approved” and thus had to be delisted from the Orange Book. Jazz appealed.

Jazz argued that because the FDA permitted the REMS patent to be Orange Book listed, Avadel was prohibited from availing itself of the statutory delisting provision. The Federal Circuit disagreed, concluding that the language of the delisting provision was only concerned with whether a listed patent met the provisions’ conditions at the time of the triggering litigation.

Jazz also argued that there was no evidence that Congress imported patent-law [...]

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Free Speech Shines Bright, Illuminates Patent Owner’s Right to Allege Infringement

by Anisa Noorassa | Mar 2, 2023 | Patents

The US Court of Appeals for the Federal Circuit reversed a district court’s preliminary injunction prohibiting a patent owner from communicating its view that a competitor infringed, finding that the speech restriction was improper because the infringement assertions were not objectively baseless. Lite-Netics, LLC v. Nu Tsai Capital LLC, Case No. 23-1146 (Fed. Cir. Feb. 17, 2023) (Lourie, Taranto, Stark, JJ.)

Lite-Netics and Nu Tsai Capital d/b/a Holiday Bright Lights (HBL) compete in the market for holiday string lights. Both companies use similar magnetic mechanisms that allow users to secure the end of the lights. Lite-Netics owns several patents that describe and claim magnetically secured decorative lights. In June 2017, Lite-Netics sent a cease-and-desist letter to HBL demanding that it stop selling lights alleged to infringe Lite-Netics’s patents. After remaining silent for five years, Lite-Netics sent another cease-and-desist letter in April 2022 demanding that HBL either explain why its products did not infringe the Lite-Netics patents or stop selling the products.

When HBL refused to stop selling the allegedly infringing products, Lite-Netics sent communications to HBL’s customers notifying them of their infringement claim and threatening “all legal rights and remedies” to stop the sale of HBL’s products. Lite-Netics then filed a lawsuit against HBL for infringement of the patents. HBL asserted counterclaims, including tortious interference with business relationships, defamation under Nebraska law and bad faith patent-infringement communications. HBL also sought a preliminary injunction to prevent Lite-Netics from publishing further accusatory statements. Finding that HBL would likely succeed on its tortious interference and defamation claims and that Lite-Netics’ infringement allegations were “objectively baseless,” the district court granted the preliminary injunction. Lite-Netics appealed.

The Federal Circuit reversed the district court, finding that in cases where an injunction restricts a party’s rights to First Amendment protected speech about its federal patent rights, federal law preempts state tort law. The Court explained that federal law requires a higher “bad faith” standard of proof for a preliminary injunction that would impinge on those federal rights. The Court found that HBL had failed to show that Lite-Netics’s allegations and the publication of its allegations were made in bad faith or that those allegations were objectively baseless. The Court therefore reversed and remanded to the district court for further proceedings.

The Alice Eligibility Two-Step Dance Continues

by Kavya Rallabhandi | Mar 2, 2023 | Patents

The US Court of Appeals for the Federal Circuit affirmed a district court’s dismissal of a Fed. R. Civ. P. 12(b)(6) motion, holding that patent claims directed to abstract ideas and lacking inventive steps that transform abstract ideas into patent-eligible inventions fail the Alice two-step test and are not patent eligible under 35 U.S.C. § 101. Hawk Tech. Sys., LLC v. Castle Retail, LLC, Case No. 22-1222 (Fed. Cir. Feb. 17, 2023) (Reyna, Hughes, Cunningham, JJ.)

35 U.S.C. § 101 states that laws of nature, natural phenomena and abstract ideas are not patentable. The Supreme Court of the United States in Alice v. CLS Bank Int’l (2014) articulated a two-step test for examining patent eligibility: a patent claim falls outside § 101 if it is directed to a patent-ineligible concept such as an abstract idea and lacks elements sufficient to transform the claim into a patent-eligible application.

Hawk Technology sued Castle Retail alleging infringement of its patent directed to security surveillance video operations in Castle Retail’s grocery stores. The patent relates to a method of viewing multiple simultaneously displayed and stored video images on a remote viewing device of a video surveillance system using result-based functional language. Castle Retail moved to dismiss on the basis that the claims were not patent eligible under § 101. After conducting a technology briefing, the district court granted the motion. The district court ruled that the claims were abstract because surveillance monitoring is a common business practice and the claims recited little more than taking video surveillance and digitizing it for display and storage in a conventional computer system, and the claims did not limit the abstract idea to a new technological improvement in video storage/display that could transform the abstract idea into a patent-eligible invention. Hawk Technology appealed.

The Federal Circuit, reviewing de novo, affirmed. Addressing Alice step one, the Court found that the patent’s required functional results of receiving/digitizing video images, converting images to selected format and storing/displaying/transmitting the images were similar to claims that the Court previously ruled as abstract. The results-oriented claim language failed to concretely recite how the claimed invention improved the functionality of video surveillance systems and was therefore abstract. Regarding Alice step two, the Court analyzed the claim elements, both individually and as an ordered combination in light of the specification, for transformative elements. The Court explained that although the claims recited the purported inventive solution and referenced specific tools/parameters, they neither showed how monitoring and storage was improved nor required anything other than off-the-shelf, conventional computer, network and display technology for gathering, sending and presenting the specified information.

Procedurally, the Federal Circuit found that the motion to dismiss was not decided prematurely because the technology briefing was purely a procedural step conducted in each patent case and there was no evidence that the district court’s decision hinged on new facts constituting matters beyond the pleadings. Hawk had argued that because the district court considered Castle’s testimony and evidence, it was required to convert the [...]

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DC Circuit to Disputes Ancillary to Patent Matters: “You Can’t Sit with Us”

by Jake B. Vallen | Mar 2, 2023 | Patents

For the first time, the US Court of Appeals for the District of Columbia Circuit addressed whether appeals of discovery orders ancillary to a patent suit are within the exclusive jurisdiction of the US Court of Appeals for the Federal Circuit. The DC Circuit joined its sister circuits and held in the affirmative. Fraunhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E.V. v. Sirius XM Radio Inc., Case No. 22-7001 (DC Cir. Feb. 17, 2023) (Srinivasan, Henderson, JJ., Edwards, Sr. J.)

In February 2017, Fraunhofer-Gesellschaft Zur Förderung commenced a civil action for patent infringement against Sirius XM Radio in the District of Delaware. During discovery, Fraunhofer subpoenaed for deposition Sirius XM’s former Chief of Marketing Officer, My-Chau Nguyen, a resident of Washington, DC.

After Nguyen failed to appear for her deposition, she filed a motion in the US District Court for the District of Columbia to quash the subpoena. Fraunhofer responded with a cross-motion to compel Nguyen’s deposition and a motion for sanctions. The DC district court denied Nguyen’s motion to quash, ordered her to sit for deposition, found her in contempt for failing to appear for deposition in the first instance, and expressed an intent to award sanctions upon Fraunhofer’s submission of documentation reflecting fees and costs. Fraunhofer appealed to the DC Circuit.

The DC Circuit first addressed whether it had jurisdiction to consider Nguyen’s challenge to the district court’s order compelling her deposition in light of the fact that Nguyen’s deposition had already been taken at the time of appeal. The Court held that Nguyen’s challenge was moot because “[n]umerous courts have held that an appeal from enforcement of a subpoena becomes moot once the party has complied with the subpoena.” Therefore, the Court reasoned that it lacked jurisdiction to consider Nguyen’s subpoena challenge because she had already complied with the subpoena at the time of the appeal.

Next, the Court addressed whether it had jurisdiction to assess the merits of Nguyen’s challenge to the district court’s finding of contempt and intent to award sanctions. The Court determined that it did not have subject matter jurisdiction to consider these issues. The Court explained that because “the underlying litigation between Fraunhofer and Sirius XM in the District of Delaware arises under an Act of Congress relating to patents[,]” Nguyen’s discovery dispute in the DC district court was “ancillary to a patent suit.” The DC Circuit reasoned that only the Federal Circuit is vested with jurisdiction over appeals “arising under . . . any Act of Congress related to patents[.]” (28 U.S.C. § 1295(a)(1).) Holding similarly to other circuits, the Court concluded that because Nguyen’s discovery dispute was ancillary to a patent matter, the ability to decide the merits of her appeal was solely within the province of the Federal Circuit.

The DC Circuit found that it did not have the authority to transfer Nguyen’s challenges to the Federal Circuit, however. The DC Circuit concluded that it was forced to dismiss rather than transfer because “this appeal could not have been brought [...]

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When It Comes to Claim Construction, Prosecution History and Specification Rule

by Thomas DaMario | Feb 23, 2023 | Patents

Addressing claim constructions across two patents that ultimately led to noninfringement findings by a district court, the US Court of Appeals for the Federal Circuit affirmed one construction because it was supported by the prosecution history but reversed another because it was unsupported by the specification. SSI Techs., LLC v. Dongguan Zhengyang Elec. Mech. Ltd., Case Nos. 21-2345, 22-1039 (Fed. Cir. Feb. 13, 2023) (Reyna, Bryson, Cunningham, JJ.)

SSI owns two patents directed to sensors for determining the characteristics of fluid in a container such as a fuel tank. One patent, referred to as the transducer patent, describes an exemplary sensor system containing a “level” transducer and a “quality” transducer. The two transducers use ultrasonic sound waves and time of flight to determine both a level of fluid in a given tank and a quality (i.e., concentration of diesel exhaust fluid). The other patent, referred to as the filter patent, describes a similar system but attempts to address the problem of erratic measurement results that may occur because of air bubbles embedded in the fluid. This patent claims a “filter” covering the sensing area that substantially prohibits gas bubbles from entering the sensing area.

Dongguan Zhengyang Electronic Mechanical (DZEM) produces systems that determine the quality and volume of diesel exhaust fluid that are used in emission-reduction systems for diesel truck engines. SSI accused DZEM of infringing both patents. In the district court action, DZEM brought a motion for summary judgment of noninfringement based on the court’s construction of certain terms that appear in the asserted claims. With reference to the transducer patent, the claims recite the need to “determine whether a contaminant exists in the fluid based on . . . a dilution of the fluid [] detected while the measured volume of the fluid decreases.” The district court determined that this claim element required that the contaminant determination actually consider the measured volume of the fluid. The district court predicated its determination on the prosecution history, having found that this term was amended to include the disputed term and that the applicant’s intention was to incorporate the specific error-detection capability recited in the specification. The parties had previously agreed that the DZEM products did not base the contamination determination on any consideration of the measured volume. As a result, the district court granted DZEM’s motion for summary judgment of noninfringement on the transducer patent.

Regarding the filter patent, the district court adopted DZEM’s construction of the term “filter,” which was “a porous structure defining openings, and configured to remove impurities larger than said openings from a liquid or gas passing through the structure.” DZEM’s accused sensors includes a rubber cover with four apertures. The district court found that the rubber cover was not “porous” because the apertures were “relatively large” when compared with the disclosed embodiments in the specification. As a result, the court granted DZEM’s motion for summary judgment of noninfringement on the filter patent. SSI appealed.

SSI challenged both constructions. Regarding the transducer patent, SSI argued that [...]

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