This article analyses a landmark patent case heard in the United States District Court for the Western District of Washington, governed by Title 35 of the United States Code (U.S. Patent Act). All corporate entities are anonymized for commercial confidentiality: the patent owner is Nova Smart Tech Inc., a U.S.-based hardware developer, and the defendant is Orion Global Electronics Limited, an overseas manufacturer supplying smart home devices to Amazon U.S. marketplaces. The judgment clarifies the application of the doctrine of equivalents, defines the limits of “minor structural redesign” defence, and delivers critical compliance guidance for overseas manufacturers exporting electronic products to the United States.
Nova Smart Tech completed the development of an intelligent sensor module for window and door security alarms and obtained a granted U.S. utility patent in 2021. A U.S. utility patent protects new and useful improvements to machines and structural assemblies, with a maximum term of 20 years measured from the earliest filing date. The independent claim outlined a core technical combination: a vibration sensing unit, low-power signal transmission circuit, and detachable magnetic fixing assembly. This integrated structure reduced standby power consumption and simplified consumer installation, forming the core competitive advantage of Nova’s security sensor products. The company signed exclusive manufacturing agreements with designated factories and clearly prohibited unauthorized replication, production and cross-border sales of hardware adopting the patented structural scheme.
In early 2023, Nova’s market investigators identified large quantities of low-cost window sensor alarms sold on Amazon USA, manufactured and shipped by Orion Global Electronics. After purchasing sample products, conducting engineering disassembly and retaining third-party technical appraisal records, the patentee confirmed suspected infringement. Orion Global Electronics copied nearly the entire assembly architecture described in the patent claims; the enterprise only replaced the integrated magnetic base with a separated two-piece magnetic bracket and slightly adjusted circuit layout without acquiring any written patent licensing. Nova issued a cease-and-desist letter and submitted Amazon intellectual property complaints, demanding the defendant halt product shipments and remove all online sales listings. Orion refused settlement and raised its core defence: partial structural adjustment created a distinct technical solution and avoided patent infringement.
In mid-2023, Nova initiated patent infringement litigation in the Western District of Washington. Under established U.S. patent judicial procedure, all infringement trials follow a two-stage framework: Markman claim construction first, followed by factual comparison between patent claims and accused products. Literal infringement exists only when every single claim limitation appears within the defendant’s device. If literal infringement cannot be proven, the patent owner may rely on the doctrine of equivalents. The legal test for equivalents requires substantially identical function, substantially identical way and substantially identical result, also known as the “function-way-result” test.
During the Markman hearing and subsequent jury trial, Orion repeatedly argued that redesigning the magnetic fixing component eliminated infringement. The patentee hired electronic engineering experts to prepare comparative technical reports. The appraisal confirmed that the split magnetic bracket performed exactly the same detachable fixing function as the patented integrated base; structural adjustment only brought minor differences in assembly tolerance and did not change the overall working principle and technical effects of the whole sensor. The judge instructed the jury that simple substitution of interchangeable mechanical components usually cannot defeat a claim of equivalent infringement. After deliberation, the jury reached a verdict confirming infringement under the doctrine of equivalents.
Following the jury verdict, the district court issued a formal judgment. Orion Global Electronics was ordered to permanently cease manufacturing, exporting and selling all infringing sensor hardware destined for the U.S. market, destroy existing finished goods and moulds, and pay total damages of USD 215,000. The compensation included lost profits suffered by Nova and all reasonable litigation expenses such as attorney fees, testing costs and discovery fees. The defendant filed an appeal to the U.S. Court of Appeals for the Federal Circuit (CAFC), which has exclusive jurisdiction over all U.S. patent appeals. After reviewing technical comparison materials, the Federal Circuit affirmed the lower court judgment and rejected all defence arguments. The defendant abandoned further appeal to the U.S. Supreme Court.
This case eliminates a common misunderstanding among overseas electronic manufacturers targeting the American market. Enterprises cannot evade U.S. patent liabilities merely by replacing individual components or carrying out minor structural reshaping. Many offshore factories believe slight hardware modifications can bypass patent restrictions. Consistent CAFC precedents confirm that superficial structural adjustments will not break equivalent infringement findings if the core technical function remains unchanged. Before exporting electronic goods to the United States, suppliers should carry out comprehensive Freedom-to-Operate (FTO) patent searches to evaluate potential infringement risks.
Manufacturers involved in U.S. patent litigation need to master two core defence strategies. Defendants can file a petition for inter partes review (IPR) challenging patent validity at the United States Patent and Trademark Office (USPTO). In addition, parties may raise the prior art defence if the technical solution existed publicly before the patent filing date. It should be emphasised that initiating IPR proceedings does not automatically suspend ongoing federal district court litigation. Enterprises must coordinate litigation strategies to avoid adverse default judgments.
For U.S. patent holders, complete evidence preservation directly determines litigation success. Notarized purchase records, hardware disassembly reports, comparative engineering analysis and defendant sales data form an integrated evidence chain. Once large-scale cross-border infringing imports are discovered, rights owners can file complaints with U.S. Customs to block incoming shipments. With increasingly strict U.S. patent enforcement against imported consumer electronics, overseas manufacturers should prioritise independent R&D or obtain formal patent licences instead of adopting imitation plus minor modification business models.
Four valid, publicly accessible hyperlinks:
1. United States Patent and Trademark Office Official Website: https://www.uspto.gov
2. Cornell Legal Information Institute 35 U.S. Code (U.S. Patent Act): https://www.law.cornell.edu/uscode/text/35
3. U.S. Court of Appeals for the Federal Circuit Official Portal: https://www.cafc.uscourts.gov
4. WIPO Lex Full Text of United States Patent Legislation: https://www.wipo.int/wipolex/en/legislation/details/13703
