Chen Li v. Partnership Unincorp Associations

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Chen Li (People's Republic of China)
  • Defendant: The Partnerships and Unincorporated Associations Identified on Schedule "A" (Jurisdiction Unknown, alleged to operate from the People's Republic of China or other foreign jurisdictions)
  • Plaintiff’s Counsel: D&A|RM DeWitty, U.S. Pat. Atty., LLC
• Case Identification: 1:25-cv-10772, N.D. Ill., 12/11/2025
• Venue Allegations: Venue is based on allegations that the Defendants target business activities toward consumers in the United States, including Illinois, through interactive e-commerce stores, offer shipping to Illinois, and have sold accused products to Illinois residents.
• Core Dispute: Plaintiff alleges that Defendants' e-commerce stores sell slippers that infringe a U.S. design patent covering the ornamental appearance of a slipper.
• Technical Context: The dispute is in the consumer footwear market, specifically focusing on the ornamental design of casual slippers sold through online retail platforms.
• Key Procedural History: The complaint is an action against a group of unidentified online sellers, designated as "Partnerships and Unincorporated Associations" operating under various seller aliases. This procedural posture suggests a strategy common in actions against diffuse online infringers, where identifying and serving individual defendants can be a primary challenge.

Case Timeline

Date	Event
2021-09-22	’901 Patent Priority Date (Application Filing)
2023-05-16	U.S. Patent No. D985,901 Issued
2025-12-11	Amended Complaint Filed

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

U.S. Design Patent No. D985,901 - SLIPPER

• Patent Identification: U.S. Design Patent No. D985,901, titled "SLIPPER", issued May 16, 2023.

The Invention Explained

• Problem Addressed: Design patents protect the novel, non-functional, ornamental appearance of an article of manufacture rather than a technical problem. The ’901 Patent seeks to protect a particular aesthetic design for a slipper (D985,901 Patent, Claim).
• The Patented Solution: The patent claims the specific visual characteristics of the slipper as depicted in its figures. The design features a slide-style slipper with a thick, platform-like sole and a single wide strap over the instep (D985,901 Patent, FIG. 1). Key ornamental elements include a consistent, woven-like texture applied to the outer surface of the sole and the top of the instep strap (D985,901 Patent, FIG. 9), a contoured footbed, and a distinct tread pattern on the bottom of the sole composed of wavy ridges and circular indentations (D985,901 Patent, FIG. 2, FIG. 4). The overall impression is one of a minimalist but texturally detailed piece of footwear.
• Technical Importance: The complaint alleges Plaintiff's products embodying the design have been widely promoted and have become a "symbol of excellence" recognized by the consuming public (Compl. ¶7).

Key Claims at a Glance

• Design patents have a single claim. The asserted claim is: "The ornamental design for a slipper, as shown and described." (D985,901 Patent, Claim).
• The scope of the claim is defined by the solid lines in the nine patent figures (D985,901 Patent, FIGS. 1-9).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are "slippers products" (the "Infringing Products") that are advertised, offered for sale, and sold by Defendants through various e-commerce stores operating under the "Seller Aliases" identified in Schedule A of the complaint (Compl. ¶3, ¶4).

Functionality and Market Context

The complaint alleges that Defendants operate e-commerce stores designed to appear as authorized retailers to "unknowing consumers" (Compl. ¶4, ¶11). These stores allegedly target U.S. consumers, including those in Illinois, accept payment in U.S. dollars, and ship products into the United States (Compl. ¶3). The complaint asserts that these products embody the design protected by the ’901 Patent (Compl. ¶4, ¶18). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not contain a claim chart or provide specific visual evidence of the accused products. It alleges infringement based on the assertion that Defendants are making, using, offering for sale, and selling "Infringing Products that infringe directly and/or indirectly the Design claimed in Plaintiff's '901 Patent" (Compl. ¶18). The infringement theory relies on the "ordinary observer" test, which is the standard for design patent infringement. This test asks whether an ordinary observer, in the context of the prior art, would be deceived into believing the accused design is the same as the patented design. The complaint alleges direct infringement, literal infringement, and infringement under the doctrine of equivalents (Compl. ¶19).

• Identified Points of Contention:
  • Visual Similarity: The central question will be whether the accused slippers sold by Defendants are substantially the same in overall visual appearance as the design claimed in the ’901 Patent. The analysis will depend on a side-by-side comparison of the accused products with the patent figures.
  • Scope Questions: A potential issue may arise regarding which specific features of the slipper are ornamental and contribute to the overall design, versus which, if any, are purely functional. Functional aspects of an article of manufacture are not protected by a design patent.

V. Key Claim Terms for Construction

In design patent litigation, claim construction does not involve interpreting written terms as it does in utility patent cases. Instead, the court construes the single claim by reference to the patent's drawings.

• The Term: "The ornamental design for a slipper, as shown and described."
• Context and Importance: The entire infringement analysis hinges on the visual scope of the design depicted in Figures 1-9 of the ’901 Patent. The dispute will not center on the definition of words but on the overall visual impression created by the patented design as a whole. Practitioners may focus on identifying the key ornamental features—such as the specific sole and strap texture, the sole's thickness and profile, and the bottom tread pattern—that create this overall impression.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim is for the design as a whole, not any single feature in isolation. Parties arguing for broader scope may contend that minor variations in the accused product do not change the overall visual impression that is substantially the same as the patented design.
  • Evidence for a Narrower Interpretation: The specific, detailed renderings of the surface texture (D985,901 Patent, FIG. 9), tread pattern (D985,901 Patent, FIG. 4), and proportions (D985,901 Patent, FIGS. 5-6) provide a basis for a narrower interpretation. A defendant could argue that any deviation from these precise details is sufficient to create a different overall visual appearance for the ordinary observer.

VI. Other Allegations

• Indirect Infringement: The complaint makes a passing reference to indirect infringement (Compl. ¶18), and the prayer for relief seeks to enjoin "aiding, abetting, contributing to, or otherwise assisting" infringement (Compl. ¶22.D). However, the factual allegations primarily focus on direct infringement by the named Defendants through their own sales and offers for sale (Compl. ¶14, ¶19).
• Willful Infringement: Willfulness is alleged based on the assertion that Defendants had "full knowledge of Plaintiff's ownership of the '901 Patent" (Compl. ¶7) and that their infringement is "obvious and notorious" and lacks a "good faith basis" (Compl. ¶20). The complaint further alleges Defendants act "knowingly and willfully" to manufacture and sell the infringing products (Compl. ¶14).

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

• Procedural Viability: A primary issue will be procedural: the feasibility and legal sufficiency of pursuing an infringement action against a large, shifting, and unidentified group of foreign e-commerce entities. The case's progression may depend on the court's willingness to allow proceedings against "John Doe" style defendants and the effectiveness of enforcement mechanisms against third-party platforms.
• The "Ordinary Observer" Test: A core substantive issue will be one of visual identity: once evidence is presented, will an ordinary observer, familiar with other slipper designs, find the accused products to be substantially the same as the specific ornamental design shown in the ’901 Patent's figures, or will any differences be sufficient to avoid infringement?
• Damages and Enforcement: A key practical question will be one of remedy: if infringement is found, can Plaintiff effectively identify infringers' assets, calculate damages or profits from diffuse online sales, and enforce a judgment against foreign entities alleged to use offshore accounts and multiple aliases to avoid liability (Compl. ¶14)?