DCT
1:25-cv-23730
Voltstar Tech Inc v. Liu Zhenwen
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Voltstar Technologies, Inc. (Illinois)
- Defendant: Liu Zhenwen a/k/a Sxsllslso (China)
- Plaintiff’s Counsel: Sriplaw PLLC
- Case Identification: 1:25-cv-23730, S.D. Fla., 08/19/2025
- 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 in the district.
- Core Dispute: Plaintiff alleges that Defendant’s USB wall chargers infringe a patent related to the dimensional and functional characteristics of compact power adapters.
- Technical Context: The technology concerns the design of small-form-factor AC-to-DC power adapters, which are ubiquitous for charging consumer electronics, where physical size and non-interference with adjacent outlets are key market features.
- 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 scope of asserted Claim 1 was amended to narrow a dimensional limitation for the housing length from "equal to or less than 2.0 inches" to "less than 2.0 inches," and to add a width limitation of "less than 1.75 inches." This amendment may focus the court's infringement analysis on these specific physical dimensions.
Case Timeline
| Date | Event |
|---|---|
| 2008-05-21 | Earliest Priority Date for RE48,794 Patent |
| 2015-05-05 | Original U.S. Patent No. 9,024,581 Issued |
| 2021-10-26 | Reissue Patent No. RE48,794 E Issued |
| 2025-08-19 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Reissue Patent No. RE48,794 E - "Charger Plug With Improved Package"
The Invention Explained
- Problem Addressed: The patent describes issues with prior art power adapter plugs, noting that designs with reduced vertical and lateral dimensions often require an increased length, which can prevent use in outlets behind furniture and make the plug susceptible to being struck or dislodged (RE48,794 E Patent, col. 1:42-58). Additionally, conventional manufacturing methods like insert molding for the electrical blades were described as costly, time-consuming, and prone to error (RE48,794 E Patent, col. 2:1-12).
- The Patented Solution: The invention claims a charger plug with a housing of specific, limited dimensions designed to solve the physical interference problem. The detailed description explains that the plug is sized so as not to "impede access to or use of an adjacent outlet" (RE48,794 E Patent, col. 4:66-67). The design also focuses on a simplified construction where separate blade members are slidably mounted into the housing and connected to internal circuitry via spring contacts, obviating the need for insert molding and soldering (RE48,794 E Patent, col. 3:14-23; Fig. 2A-2C).
- Technical Importance: This approach aimed to produce a smaller, more user-friendly charger that was also less expensive to manufacture by simplifying the assembly process (RE48,794 E Patent, col. 1:16-19).
Key Claims at a Glance
- The complaint asserts infringement of at least Claim 1 (Compl. ¶29).
- Independent Claim 1 requires:
- A charger plug for connecting to a power source to convert AC input power to DC output power.
- First and second separate blade members with prong portions to be received in a power source.
- A DC connector to transmit power to a rechargeable device.
- A housing with a specific physical configuration, including a front face, an outer profile, and a rear end.
- The housing being sized so its "longitudinal length is less than 2.0 inches" and its "width...is less than 1.75 inches."
- The housing's outer profile having "no interference with an adjacent receptacle of the power source."
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- "6Pack USB Wall Charger, iGENJUN 2.4A Dual USB Port Cube Power Plug Adapter" (ASIN B0B1ZX3D5Q) and "5Pack USB Wall Charger, iGENJUN 2.4A Dual USB Port Cube Power Plug Adapter" (ASIN B0CSYPGDDR), sold under the brand name "Sxsllslso" (Compl. ¶21).
Functionality and Market Context
- The accused products are described as chargers that connect between an AC power source, like a wall outlet, and a device like a mobile phone to provide DC power for recharging a battery (Compl. ¶22).
- The complaint alleges the chargers "employ a reduced plug-size" which allows them to be plugged into a wall outlet without blocking or interfering with the use of adjacent outlets (Compl. ¶23). It is also alleged that the size and shape allow a power cord to be easily inserted and removed (Compl. ¶24).
- No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
The complaint references a claim chart attached as Exhibit 3, which was not provided with the filing; the following summary is based on the narrative allegations (Compl. ¶¶ 22-24, 29).
RE48,794 E Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A charger plug capable of connecting with a two or three receptacle power source to convert 120V input power received from the power source to DC output power... | The accused products are advertised and sold as chargers "to be connected between a source of AC power, such as a wall outlet, and a device such as a mobile phone that includes a battery with the battery being rechargeable through the use of DC power." | ¶22 | col. 13:18-24 |
| being sized so that the charger plug housing comprises a longitudinal length extending between the front wall and the rear end and the longitudinal length is less than 2.0 inches, a width of the housing outer profile being less than 1.75 inches... | The accused chargers are alleged to "employ a reduced plug-size charger plug." | ¶23 | col. 13:47-col. 14:1 |
| the outer profile having no interference with an adjacent receptacle of the power source located on all sides of the first receptacle when a like charger plug is mounted in all available orientations... | Upon plugging the accused chargers into an AC power source, "the chargers do not block or interfere with the use of adjacent outlets." | ¶23 | col. 14:2-10 |
- Identified Points of Contention:
- Scope Questions: A central question will be whether the accused products, described as having a "reduced plug-size," actually meet the specific numerical limitations of "less than 2.0 inches" in length and "less than 1.75 inches" in width, which were added during reissue to narrow the claim.
- Technical Questions: The functional limitation of "no interference with an adjacent receptacle" raises an evidentiary question: what is the factual basis for this allegation, and does it hold true across all standard outlet configurations as the claim requires? The complaint does not provide dimensional measurements, test results, or photographic evidence to substantiate this allegation.
V. Key Claim Terms for Construction
The Term: "no interference with an adjacent receptacle"
Context and Importance: This functional language is a cornerstone of the infringement allegation (Compl. ¶23). The definition of "interference"—whether it means any physical overlap, a practical inability to plug in a standard cord, or something else—will be critical. Practitioners may focus on this term because its breadth will determine whether a wide range of compact charger designs fall within the claim scope.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states the goal is for "the plug itself provides little or no interference with use of an adjacent receptacle" (RE48,794 E Patent, col. 1:46-48), suggesting the term's plain and ordinary meaning should apply broadly.
- Evidence for a Narrower Interpretation: The claim requires this non-interference "when a like charger plug is mounted in all available orientations in any of the other receptacles" (RE48,794 E Patent, col. 14:7-10). This language could be interpreted to narrow the term, requiring proof of non-interference in a specific, and potentially demanding, multi-plug test configuration.
The Term: "longitudinal length is less than 2.0 inches, a width of the housing outer profile being less than 1.75 inches"
Context and Importance: These limitations were added during reissue, replacing a broader "equal to or less than 2.0 inches" limitation (Compl. ¶12 & fn. 1). Their precision makes them a likely dispositive issue. The defendant will likely argue for strict construction, and the case could turn on precise physical measurements of the accused products.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent provides exemplary, not mandatory, dimensions, stating the width is "preferably approximately 1.35 inches" and length is "preferably approximately 1.75 inches" (RE48,794 E Patent, col. 14:5-8). Plaintiff may argue these are merely preferred embodiments and the claim language itself sets the boundary.
- Evidence for a Narrower Interpretation: The patent prosecution history, specifically the act of adding these limitations during reissue to overcome prior art or for another reason, will be highly relevant. A defendant would argue this history demonstrates a clear and deliberate surrender of any subject matter at or exceeding these dimensional thresholds.
VI. Other Allegations
- Indirect Infringement: The complaint does not contain allegations of indirect infringement.
- Willful Infringement: The complaint alleges that the defendant had "actual or constructive knowledge" of Plaintiff's intellectual property rights (Compl. ¶20) and requests a determination that infringement has been "willful, wanton, and deliberate" in its prayer for relief (Compl. p. 13, ¶C). The complaint does not specify facts to support pre-suit knowledge.
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of evidentiary proof: can Plaintiff demonstrate through measurement and testing that the accused chargers meet the precise dimensional limitations ("less than 2.0 inches" length, "less than 1.75 inches" width) that were added during the patent's reissue?
- A second key question will be one of functional scope: what is the proper construction of "no interference with an adjacent receptacle," and does the accused product's design satisfy this limitation under all conditions specified by the claim?
- Finally, a threshold question regarding personal jurisdiction may arise, as the complaint asserts jurisdiction over a foreign defendant based on sales into the United States through an online marketplace, a common but sometimes contested basis for jurisdiction in patent cases.