DCT

1:25-cv-23725

Voltstar Tech Inc v. Linxiangzhi

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-23725, S.D. Fla., 08/19/2025
  • Venue Allegations: Venue is based on the allegation that the defendant is not a resident of the United States and has committed acts of infringement within the district.
  • Core Dispute: Plaintiff alleges that Defendant’s wall chargers, sold online, infringe a patent related to the compact size and physical configuration of electrical charger plugs designed to avoid obstructing adjacent outlets.
  • Technical Context: The technology concerns the mechanical design and packaging of AC-to-DC power adapters for consumer electronics, where compact size and non-interference with other plugs are significant usability features.
  • Key Procedural History: The patent-in-suit is a reissue of U.S. Patent No. 9,024,581. During the reissue process, the independent claim was narrowed by changing a length limitation from "equal to or less than 2.0 inches" to strictly "less than 2.0 inches," and by adding a new width limitation of "less than 1.75 inches." This narrowing of the claim scope may be a central issue in the litigation.

Case Timeline

Date Event
2008-05-21 Priority Date for U.S. Patent No. 9,024,581
2015-05-05 Issue Date of U.S. Patent No. 9,024,581
2021-10-26 Issue Date of Reissue Patent No. RE48,794 E
2025-08-19 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Reissue Patent No. RE48,794 E - Charger Plug With Improved Package

  • Patent Identification: U.S. Reissue Patent No. RE48,794 E, "Charger Plug With Improved Package," issued October 26, 2021 (the "’794 Patent"). (Compl. ¶7).

The Invention Explained

  • Problem Addressed: The patent describes issues with prior art charger plugs being bulky, which often results in the plug blocking access to adjacent electrical outlets (’794 Patent, col. 1:41-48). Additionally, conventional manufacturing methods involving insert-molding electrical blades and manually soldering connections were described as costly, time-consuming, and contributing to the larger size (’794 Patent, col. 2:1-32).
  • The Patented Solution: The invention discloses a charger plug with a reduced package size and a simplified construction that avoids interference with adjacent outlets (’794 Patent, col. 4:66-67). The design uses blades that can be slidably inserted into the housing and connected to the internal circuitry via solder-less spring contacts, which is intended to reduce manufacturing complexity and overall product dimensions (’794 Patent, Abstract; col. 3:9-17).
  • Technical Importance: This design approach sought to decrease manufacturing costs and time while creating a more compact and consumer-friendly charger that could be used without impeding access to other outlets on a power strip or wall receptacle (’794 Patent, col. 2:44-48).

Key Claims at a Glance

  • The complaint asserts infringement of at least independent Claim 1 of the ’794 Patent (Compl. ¶29).
  • The essential elements of asserted independent Claim 1 include:
    • A charger plug for converting 120V input power to DC output power.
    • A housing containing separate blade members with prongs extending from a front wall.
    • A DC connector for a power cord.
    • A specific size limitation, wherein the housing has "a longitudinal length extending between the front wall and the rear end and the longitudinal length is less than 2.0 inches."
    • A specific width limitation, wherein "a width of the housing outer profile being less than 1.75 inches."
    • A functional limitation, wherein "the outer profile having no interference with an adjacent receptacle of the power source."
  • The complaint does not explicitly reserve the right to assert other claims but focuses its allegations on Claim 1.

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are numerous "charger products" sold by Defendant under the "Love your yy" brand on Amazon.com (Compl. ¶21). The complaint identifies these products by name and Amazon Standard Identification Number (ASIN) in a multi-page table (Compl. ¶21, pp. 5-14).

Functionality and Market Context

  • The complaint alleges the accused products are chargers designed to connect between an AC power source, such as a wall outlet, and an electronic device requiring DC power for charging (Compl. ¶22). The complaint provides a table listing the accused products, such as the "Replacement Fast Charger Adapter For kindle Paperwhite 7-13" (ASIN B0CF7351VT), which identifies specific instrumentalities at issue (Compl. ¶21, p. 5).
  • A central allegation is that the accused chargers "employ a reduced plug-size" which prevents them from blocking or interfering with the use of adjacent outlets (Compl. ¶23).
  • The complaint further alleges that the size and shape of the chargers permit easy insertion and removal of a power cord without needing to unplug the charger from the wall outlet (Compl. ¶24). The products are marketed and sold to consumers throughout the United States via e-commerce platforms (Compl. ¶18).

IV. Analysis of Infringement Allegations

The complaint references an infringement claim chart in its "Exhibit 3," which was not included with the provided filing (Compl. ¶25, ¶29). The infringement theory is therefore based on the narrative allegations in the complaint body.

The complaint alleges that Defendant’s chargers directly infringe at least Claim 1 of the ’794 Patent (Compl. ¶28-¶29). The narrative alleges that the accused products are chargers that connect to an AC power source and have a "reduced plug-size" (Compl. ¶22, ¶23). This reduced size is alleged to satisfy the claim limitation of not blocking or interfering with adjacent outlets (Compl. ¶23). These allegations directly map to the core size and non-interference limitations recited in Claim 1 of the ’794 Patent.

  • Identified Points of Contention:
    • Scope Questions: The reissue history, which narrowed the dimensional limitations of Claim 1, will be a central focus (Compl. ¶12, fn. 1). Any attempt by the plaintiff to argue for a scope of protection that covers dimensions equivalent to, but not literally within, the claimed "less than 2.0 inches" length and "less than 1.75 inches" width could raise questions of prosecution history estoppel. The interpretation of "no interference with an adjacent receptacle" will also be critical: does this require zero physical overlap with the space of an adjacent outlet, or a more functional standard where another plug must simply remain usable?
    • Technical Questions: The complaint makes broad allegations across dozens of products but does not provide specific measurements for any of them (Compl. ¶21). A primary technical question will be whether discovery and testing show that the accused products literally meet the precise dimensional limitations recited in the asserted claim. Evidence will be required to demonstrate how, and under what test conditions, the accused products exhibit "no interference."

V. Key Claim Terms for Construction

  • The Term: "outer profile having no interference with an adjacent receptacle" (’794 Patent, col. 14:49-51).

    • Context and Importance: This functional limitation is at the heart of the invention's stated purpose. Its construction will likely be dispositive, as it defines the boundary between a permissible compact design and an infringing one.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent specification describes a goal of providing "little or no interference with use of an adjacent receptacle," which may support an interpretation where minor physical encroachment is allowed so long as the adjacent outlet remains functional (’794 Patent, col. 1:46-48).
      • Evidence for a Narrower Interpretation: The claim language itself uses the absolute term "no interference." A defendant may argue this imposes a strict standard requiring zero physical conflict with the space needed for any standard plug in an adjacent receptacle, as supported by the summary of the invention that mentions the plug is "sized so as not to impede access to or use of an adjacent outlet" (’794 Patent, col. 4:66-67).

  • The Term: "longitudinal length... is less than 2.0 inches" and "width of the housing outer profile being less than 1.75 inches" (’794 Patent, col. 14:43-48).

    • Context and Importance: These precise dimensions were finalized during reissue, making them critical limitations. Practitioners may focus on the proper methodology for measuring these dimensions on charger housings that may have curved, tapered, or irregular shapes.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent does not provide an explicit definition or figure dictating the exact measurement points for "width" or "length" on a potentially non-rectangular housing body, which could create ambiguity allowing for different measurement approaches (’794 Patent, Fig. 1).
      • Evidence for a Narrower Interpretation: A defendant will likely argue that "outer profile" requires measuring the maximum dimensions of the housing at its widest and longest points, excluding the electrical prongs. The specificity of the numbers, added during reissue to overcome prior art, suggests they were intended to be strictly applied (’794 Patent, col. 14:45-48; Compl. ¶12, fn. 1).

VI. Other Allegations

  • Willful Infringement: The complaint alleges on "information and belief" that the defendant had "actual or constructive knowledge" of the plaintiff's rights (Compl. ¶20). The prayer for relief requests a finding of willful infringement and a corresponding enhancement of damages (Prayer for Relief ¶C). However, the complaint does not plead specific facts supporting pre-suit knowledge, such as prior correspondence or citation of the patent.

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of dimensional compliance: Will the accused products, upon physical measurement according to a construed definition of "width" and "length," fall strictly within the numerical limits of Claim 1, especially in light of the claim-narrowing reissue proceeding?
  • A second core issue will be one of functional scope: How will the court define "no interference"? Will it be a strict, geometric test of non-encroachment on an adjacent outlet's physical space, or a functional test requiring only that the adjacent outlet remains usable by a standard plug?
  • A key evidentiary question will be one of proof: How will the plaintiff establish, on a product-by-product basis for the dozens of accused chargers, that each instrumentality meets every limitation of the asserted claim, particularly the precise dimensional and non-interference requirements?