Shenzhen Zhimei Lianchuang Technology Co Ltd v. Partnerships Unincorp Associations

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Shenzhen Zhimei Lianchuang Technology Co., LTD (People's Republic of China)
  • Defendant: The Partnerships and Unincorporated Associations Identified on Schedule A (Foreign entities)
  • Plaintiff's Counsel: VERITAS LIGHT LAW GROUP, P.C.
• Case Identification: 4:26-cv-00593, E.D. Tex., 06/03/2026
• Venue Allegations: Venue is asserted under 28 U.S.C. § 1391(c)(3), which allows suits against foreign, non-resident defendants in any judicial district.
• Core Dispute: Plaintiff alleges that Defendants' rechargeable, self-heating electric lunch box products infringe a patent related to a multifunctional rechargeable heat preservation lunch box.
• Technical Context: The technology concerns portable food containers with integrated, battery-powered heating systems, aiming to improve upon traditional insulated lunch boxes and early electric models.
• Key Procedural History: The complaint is brought against numerous, allegedly foreign-based entities selling products through online storefronts on Amazon.com. The plaintiff alleges these defendants conceal their identities and that joinder is proper because the infringement arises from the same series of transactions-the sale of substantially identical products on the same online marketplace.

Case Timeline

Date	Event
2025-01-15	Patent Priority Date ('781 Patent)
2025-09-09	'781 Patent Issue Date
2026-06-03	Complaint Filing Date

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

• Patent Identification: U.S. Patent No. 12,408,781, Multifunctional Rechargeable Heat Preservation Lunch Box, issued September 9, 2025.

The Invention Explained

• Problem Addressed: The patent's background section describes the limitations of traditional insulated lunch boxes, which have limited heat retention and no ability to reheat food, and early electric models, which suffer from weak battery life, poor waterproofing, and a lack of intelligent controls '781 Patent, col. 1:11-38
• The Patented Solution: The invention is a multi-component lunch box designed to solve these problems. It consists of an outer box housing a rechargeable battery and control electronics (PCBA), and an inner box, which holds a removable "rice basin" and contains a heating plate at its base '781 Patent, abstract '781 Patent, col. 1:52-64 A waterproof display screen allows for user control, and the entire assembly is designed with seals to prevent water damage, thereby improving safety and durability '781 Patent, col. 2:44-50 '781 Patent, Fig. 6
• Technical Importance: The claimed configuration seeks to integrate long-term heat preservation, active reheating, intelligent temperature monitoring, and improved safety into a single, portable device suitable for a variety of users, from office workers to outdoor enthusiasts '781 Patent, col. 2:51-59

Key Claims at a Glance

• The complaint asserts infringement of at least independent Claim 1 '781 Patent, col. 5:36-50 Compl. ¶23
• The essential elements of Claim 1 are:
  • An inner box, an outer box, a rice basin, and an upper cover.
  • The inner box is "fixed on" the outer box, the rice basin is placed in the inner box, and the upper cover is "detachably mounted" to the inner box.
  • A battery arranged at the bottom of the outer box.
  • A "waterproof display screen," a PCBA, and a "waterproof sealing cover" mounted on a side edge of the outer box.
  • A heating plate and a heat insulation sheet mounted at the bottom of the inner box.
  • The PCBA is electrically connected to the display screen, the heating plate, and the battery.
• The complaint does not explicitly reserve the right to assert dependent claims, though it accuses products of having features recited in dependent claims Compl. ¶7

III. The Accused Instrumentality

Product Identification

• The "Accused Products" are identified as "rechargeable, self-heating electric lunch box products" offered for sale by the various defendants on Amazon.com Compl. ¶1 Compl. ¶9

Functionality and Market Context

• The complaint alleges that the Accused Products share "substantially identical structural features and functional configuration" Compl. ¶7
• These alleged features include a multi-compartment structure with an inner box, outer box, and rice basin; an internal battery; a side-mounted waterproof display and PCBA; and a heating plate at the bottom of the inner box Compl. ¶7
• The complaint alleges that the defendants are numerous, nominally independent storefronts operating from foreign jurisdictions and that the Accused Products are likely sourced from a small number of original-equipment manufacturers Compl. ¶7 Compl. ¶13 No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint references claim charts in a sealed Exhibit C, which was not provided for analysis Doc 1-4 However, the complaint itself provides a narrative mapping of the accused features to the patent claims Compl. ¶7, which is summarized below.

'781 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
a multifunctional rechargeable heat preservation lunch box, comprising an inner box (1), an outer box (2), a rice basin (5), and an upper cover (3)	A rechargeable, multi-compartment electric lunch box with an inner box, outer box, rice basin, and upper cover.	¶7	col. 5:36-38
wherein the inner box (1) is fixed on the outer box (2), the rice basin (5) is placed in the inner box (1), and the upper cover (3) and the inner box (1) are detachably mounted	The lunch box components are assembled such that the upper cover is detachably mounted.	¶7	col. 5:38-41
a battery (22) is arranged at the bottom of the outer box (2)	An internal battery is housed at the bottom of the outer box.	¶7	col. 5:41-43
a waterproof display screen (21), a PCBA (23), and a waterproof sealing cover (24) are mounted on a side edge of the outer box (2)	A waterproof display screen, PCBA, and waterproof sealing cover are mounted on a side edge of the outer box.	¶7	col. 5:43-45
a heating plate (4) and a heat insulation sheet (41) are mounted at the bottom of the inner box (1)	A heating plate and heat insulation sheet are located at the bottom of the inner box.	¶7	col. 5:45-47
and the PCBA (23) is electrically connected to the display screen (21), the heating plate (4), and the battery (22)	Temperature sensors are arranged on the inner box and electrically connected to the PCBA.	¶7	col. 5:47-50

• Identified Points of Contention:
  • Scope Questions: A potential issue for claim construction may be the term "fixed on" as it relates to the inner and outer boxes, particularly in contrast to the "detachably mounted" upper cover. The litigation may explore whether "fixed on" permits any form of separation (e.g., for cleaning) or requires a more permanent connection.
  • Technical Questions: The complaint alleges the Accused Products contain "temperature sensors" connected to the PCBA Compl. ¶7 While this feature is described in the patent's dependent Claim 2 '781 Patent, col. 6:5-8, it is not a required element of the asserted independent Claim 1. This raises the question of whether the infringement allegations in the complaint's narrative section Compl. ¶7 are precisely aligned with the formal count of infringement, which is based on Claim 1 Compl. ¶¶22-24

V. Key Claim Terms for Construction

• The Term: "fixed on"

• Context and Importance: This term defines the structural relationship between the inner and outer boxes. Its meaning is critical because the patent explicitly distinguishes it from the "detachably mounted" upper cover. If an accused product's inner and outer boxes are easily separable, a defendant may argue they are not "fixed on" as required by the claim.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The patent specification does not appear to define "fixed on" or describe the specific mechanism for joining the inner and outer boxes. A party could argue this supports applying the term's plain and ordinary meaning, which might encompass a connection that is stable in normal use but not necessarily permanent.
  • Evidence for a Narrower Interpretation: The explicit use of "detachably mounted" for the cover '781 Patent, col. 5:41 in the same claim creates a potential contrast. A party could argue that, by choosing a different term, the patentee intended "fixed on" to mean a non-detachable or semi-permanent connection, reinforcing the structural integrity of the main body.

• The Term: "waterproof display screen"

• Context and Importance: The patent identifies poor waterproofing as a key safety flaw in prior art devices '781 Patent, col. 1:35-38 The definition of "waterproof" is therefore central to a key feature of the claimed invention.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The term could be construed to mean any screen designed to resist water ingress to a degree that prevents the "circuit damage or even safety accidents" mentioned in the background '781 Patent, col. 1:36-37, without requiring a specific industry rating (e.g., IPX7).
  • Evidence for a Narrower Interpretation: A party might argue that in the context of the invention, which touts improved safety and durability, "waterproof" implies a higher, more robust standard. The explicit inclusion of a "waterproof sealing cover" (24) for the electronics port in the same claim limitation '781 Patent, col. 5:43-45 may suggest a design where specific, targeted waterproofing measures are contemplated.

VI. Other Allegations

• Indirect Infringement: The complaint's prayer for relief seeks to enjoin aiding and abetting or contributory infringement Compl. Prayer A(b) However, the factual allegations in the body of the complaint focus on direct infringement by offering for sale, selling, and importing the Accused Products under 35 U.S.C. § 271(a) Compl. ¶¶1, 15, 23 The complaint does not plead specific facts to support knowledge or intent for indirect infringement.
• Willful Infringement: The complaint alleges that the infringement has been willful Compl. ¶20 The allegation appears to be based on the defendants' alleged knowledge of their infringing acts rather than pre-suit knowledge of the patent itself Compl. ¶19

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

• A central procedural question will be one of joinder: is it proper to join dozens of allegedly separate, non-resident entities in a single lawsuit based on allegations that they sell "substantially identical" products on the same e-commerce platform Compl. ¶¶6-9? The court's decision on this issue will significantly shape the structure and complexity of the litigation.
• A core substantive issue will be one of definitional scope: can claim terms such as "fixed on" and "waterproof display screen" be construed to cover the range of features present in the accused products sold by the numerous defendants? The outcome will depend on how the court interprets these terms in light of the patent's specification and the distinctions drawn within the claims themselves.
• A key evidentiary question will be one of product-by-product proof: assuming the case proceeds against multiple defendants, the plaintiff will bear the burden of proving that each defendant's specific product practices every limitation of Claim 1. This may present a logistical challenge in a case involving many "substantially identical" but potentially distinct products.