DCT

1:25-cv-23507

Voltstar Tech Inc v. Sun Zhongyuan

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-23507, S.D. Fla., 08/05/2025
  • Venue Allegations: Venue is asserted on the basis 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 line of USB wall chargers infringes a reissue patent related to the specific dimensions and physical configuration of compact power adapters.
  • Technical Context: The technology concerns the design of small-form-factor electrical chargers intended to avoid obstructing adjacent wall outlets, a common issue with consumer electronics accessories.
  • Key Procedural History: The patent-in-suit, RE48,794, is a reissue of U.S. Patent No. 9,024,581. The complaint notes that during reissue, the key independent claim was narrowed to require a longitudinal length "less than 2.0 inches" (previously "equal to or less than 2.0 inches") and to add a new width limitation of "less than 1.75 inches." This amendment suggests a deliberate narrowing of claim scope, which will likely be a central issue in claim construction and infringement analysis. The complaint also mentions that the plaintiff has entered into licensing agreements with third parties for its patent.

Case Timeline

Date Event
2008-05-21 Priority Date for U.S. Patent No. 9,024,581 (RE48,794 E)
2015-05-05 Issue Date for U.S. Patent No. 9,024,581
2021-10-26 Issue Date for Reissue Patent No. RE48,794 E
2025-08-05 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 Invention Explained

  • Problem Addressed: The patent's background describes issues with prior art electrical chargers, which are often bulky enough to interfere with the use of adjacent electrical outlets (RE48,794 E, col. 1:42-48). Additionally, conventional manufacturing methods, such as insert-molding electrical blades and hand-soldering connections, are described as expensive, time-consuming, and contributors to a larger physical package (RE48,794 E, col. 2:11-40).
  • The Patented Solution: The invention is a compact charger plug with specific dimensional limitations designed to ensure it does not block adjacent receptacles. The patent discloses a charger with a housing that has a "longitudinal length ... less than 2.0 inches" and a "width ... less than 1.75 inches" (RE48,794 E, col. 13:51-56). The design also proposes an improved assembly method using slidably mounted blades and solder-less spring contacts to connect to the internal printed circuit board (PCB), simplifying manufacturing and reducing the overall size (RE48,794 E, Abstract; col. 4:45-56).
  • Technical Importance: This approach addresses the persistent consumer demand for smaller, more convenient charging accessories that do not monopolize wall outlet space, a significant design constraint for high-volume consumer electronics.

Key Claims at a Glance

  • The complaint asserts infringement of at least Claim 1 (Compl. ¶29).
  • Independent Claim 1 requires, in essence:
    • A charger plug with a housing and separate blade members secured within.
    • A DC connector for a removable power cord.
    • A specific housing configuration with a front face, an outer profile, and a rear end.
    • A sizing limitation where the housing’s longitudinal length is less than 2.0 inches and its width is less than 1.75 inches.
    • A functional limitation where the outer profile has "no interference with an adjacent receptacle."
  • The complaint does not explicitly reserve the right to assert dependent claims but alleges infringement of "at least one of the claims" (Compl. ¶26).

III. The Accused Instrumentality

Product Identification

The accused products are a series of "SZYSK Direct" branded chargers, including the "USB-C Fast Charger for New Kindle Fire Tablets," "15W Fast Charger for New and Old Kindle Fire Tablets," "MacBook Air Charger," and others sold on Amazon.com (Compl. ¶21).

Functionality and Market Context

The complaint alleges the accused products are electrical chargers that connect between an AC power source (like a wall outlet) and a device to be charged (Compl. ¶22). It specifically alleges that the chargers employ a "reduced plug-size" design so that they do not block or interfere with adjacent outlets (Compl. ¶23). The complaint further alleges that the size and shape of the chargers allow for a power cord to be easily inserted and removed while the charger remains plugged into the wall (Compl. ¶24).

IV. Analysis of Infringement Allegations

The complaint references a claim chart in its Exhibit 3 purporting to show infringement of Claim 1; however, this exhibit was not attached to the publicly filed complaint (Compl. ¶25, ¶29). In the absence of the chart, the infringement theory must be inferred from the complaint's narrative allegations.

The core of the plaintiff's infringement theory is that the accused chargers are specifically designed to be compact in a way that directly maps onto the benefits and dimensional limitations described in the ’794 Patent. The complaint alleges the accused products have a "reduced plug-size" that, when plugged in, "do not block or interfere with the use of adjacent outlets," directly mirroring the language and purpose of asserted Claim 1 (Compl. ¶23). The infringement case appears to rest on the factual assertion that the physical dimensions and non-interfering profile of the accused chargers fall within the specific limitations recited in the patent's claims.

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

"outer profile having no interference with an adjacent receptacle"

  • Context and Importance: This functional limitation is at the heart of the invention's stated purpose. The definition of "interference" and the scope of "adjacent receptacle" will be critical. Practitioners may focus on this term because its construction will determine the standard of proof for infringement. A dispute may arise over whether this limitation requires non-interference with all possible standard NEMA outlet configurations or only the most common ones.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language "no interference with an adjacent receptacle of the power source located on all sides" could be argued to set a high, absolute standard, covering any standard adjacent plug (RE48,794 E, col. 13:59-14:2).
    • Evidence for a Narrower Interpretation: A defendant might argue the term should be limited by the embodiments and figures shown in the patent, which illustrate a specific type of duplex outlet (RE48,794 E, Fig. 20). The patent also repeatedly emphasizes the benefit in the context of standard wall outlets, potentially limiting its scope.

"longitudinal length... less than 2.0 inches, a width... less than 1.75 inches"

  • Context and Importance: These precise dimensional limitations were added during the reissue proceeding that led to the ’794 Patent (Compl. ¶12 & fn. 1). Infringement of this element will be a matter of factual measurement, but the claim construction question is how and where to measure. The patent defines "longitudinal length" as extending "between the front wall and the rear end" (RE48,794 E, col. 13:51-53), but the exact boundaries of these features on a curved or complex housing could be debated.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent provides general definitions, such as "charger plug face area defined by the front wall" (RE48,794 E, col. 13:38-39), which a party might argue should be interpreted expansively to include any forward-facing surface.
    • Evidence for a Narrower Interpretation: The figures, such as Figure 1 and Figure 10, provide specific visual examples of a "front wall" (102) and "rear end" (40), which could be used to argue for a more constrained definition tied to the specific geometry disclosed.

VI. Other Allegations

  • Indirect Infringement: The complaint does not contain a count for indirect infringement.
  • Willful Infringement: The complaint alleges that the defendant had "actual or constructive knowledge" of the plaintiff's intellectual property rights (Compl. ¶20). The prayer for relief requests a finding that infringement was "willful, wanton, and deliberate" to support an award of enhanced damages (Compl., Prayer for Relief ¶C). The complaint does not specify the basis for this alleged knowledge, such as a pre-suit notification letter.

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

  1. A central issue will be one of factual proof: do the accused "SZYSK Direct" chargers literally meet the dimensional requirements of Claim 1, specifically a length of "less than 2.0 inches" and a width of "less than 1.75 inches"? The case may turn on a straightforward evidentiary showing of product measurements.

  2. A key legal question will be the scope of functional language: how will the court construe the term "no interference with an adjacent receptacle"? The outcome will depend on whether this requires absolute non-interference with every possible configuration of a standard power source or is limited by the patent's examples and ordinary context.

  3. A critical factor in claim construction will be the impact of the reissue proceeding: why were the dimensional limitations narrowed and added during reissue? The prosecution history of the ’794 Patent will likely contain arguments or disclaimers made by the patentee to secure the reissue, which could significantly constrain the interpretation of the asserted claims.