DCT
1:25-cv-00859
Dongguan Hongyu Plastic Co Ltd v. Sun Pleasure Co Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Dongguan Hongyu Plastic Co., Ltd. (People's Republic of China)
- Defendant: Sun Pleasure Co. Ltd. (Hong Kong)
- Plaintiff’s Counsel: Prince Lobel Tye LLP
- Case Identification: 1:25-cv-00859, W.D. Tex., 09/18/2025
- Venue Allegations: Plaintiff alleges venue is proper because Defendant is a foreign corporation subject to suit in any U.S. judicial district.
- Core Dispute: Plaintiff seeks a declaratory judgment that its air mattress products do not infringe Defendant’s patent related to inflatable mattress structures and that the patent is invalid.
- Technical Context: The dispute concerns the structural design of consumer air mattresses, a mature and competitive market where incremental design variations can be significant.
- Key Procedural History: The complaint alleges this action follows a series of patent infringement takedown notices sent by Defendant to Amazon.com, resulting in the delisting of Plaintiff's products. Plaintiff also alleges that certain claim terms were added during patent prosecution to overcome prior art, potentially giving rise to prosecution history estoppel. Notably, an Inter Partes Review (IPR) proceeding on the patent-in-suit concluded in November 2024, with the Patent Trial and Appeal Board (PTAB) finding the challenged claims (1-9) patentable.
Case Timeline
| Date | Event |
|---|---|
| 2005-12-07 | ’555 Patent Priority Date |
| 2008-04-08 | ’555 Patent Issue Date |
| 2020-10-16 | IPR proceeding (IPR2021-00080) filed against ’555 Patent |
| 2022-01-26 | ’555 Patent assigned to Defendant Sun Pleasure Co. Ltd. |
| 2023-01-01 | Plaintiff begins selling accused products (stated as "Since at least 2023") |
| 2024-11-12 | Defendant allegedly submits first Amazon takedown notice |
| 2024-11-21 | IPR certificate issues, confirming patentability of claims 1-9 of the ’555 Patent |
| 2025-05-06 | Defendant allegedly submits second Amazon takedown notice |
| 2025-06-03 | Plaintiff files initial complaint |
| 2025-09-18 | Plaintiff files Amended Complaint |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 7,353,555 - "Inflatable Mattress Assembly"
- Patent Identification: U.S. Patent No. 7,353,555, "Inflatable Mattress Assembly," issued April 8, 2008.
The Invention Explained
- Problem Addressed: The patent background describes prior art inflatable mattresses that mimicked a "pillow-top" appearance but were often uncomfortable or unattractive due to deformation and creasing of the top frame when a user's weight was applied (’555 Patent, col. 1:16-24).
- The Patented Solution: The invention is an inflatable mattress structure featuring a "peripheral frame" around the upper edge. This frame is secured by two separate seams—one connecting an internal wall to the side panel and another connecting it to the top panel—which creates a stable, flat, and immovable border intended to provide better support and mimic the look of a traditional two-layered mattress (’555 Patent, col. 2:2-7; Fig. 3). The specific geometry of an "internal wall" (30) connecting the top panel (8) and side panel (16) at distinct seams (38, 40) is central to this structure (’555 Patent, col. 2:56-65).
- Technical Importance: This design aims to improve both the aesthetic and functional qualities of an inflatable mattress, providing a defined, supportive edge that resists deformation, a common issue in prior designs (’555 Patent, col. 2:50-55).
Key Claims at a Glance
- The complaint focuses on independent claim 1 as representative of the patent's limitations (Compl. ¶43).
- Essential elements of claim 1 include:
- An inflatable mattress with top, bottom, and peripheral side panels.
- A "peripheral frame" at the upper periphery, which has an "internal wall" connecting the top panel to the side panel.
- The internal wall connects to the side panel at a "first peripheral seam" below the top panel level and connects to the top panel at a "second peripheral seam" located inwardly from the first.
- An "external wall" connects the first and second seams.
- The internal wall includes a "fluid passage therethrough," is in "substantial pressure equilibrium" with the interior volume, and has a "substantially linear cross-section" between the seams.
- The complaint does not explicitly reserve the right to assert dependent claims but challenges the validity of all claims (Compl. ¶69).
III. The Accused Instrumentality
Product Identification
- Plaintiff’s VOSSER-brand air mattresses in Full, Queen, and Twin sizes, identified by ASINs including B0D53RCYFZ, B0D4Z6WLX7, and B0D53QF3VC (Compl. ¶¶36-38, 49).
Functionality and Market Context
- The complaint describes Plaintiff's products as falling within the "well-established commercial landscape" of air mattresses, featuring common elements like top and bottom panels, side walls, and internal support structures (Compl. ¶¶25, 28). The complaint alleges that the fundamental characteristics of such mattresses have been known since the late 1800s, referencing a historical advertisement for the "Perfection" Air Mattress (Compl. ¶24).
- Plaintiff alleges its mattresses have "structurally distinct internal configurations" from the ’555 Patent and embody its own patented innovations, covered by U.S. Patent No. 12,108,880 (Compl. ¶¶34, 53).
IV. Analysis of Infringement Allegations
The complaint seeks a declaratory judgment of non-infringement. The following table summarizes the key limitations of the ’555 Patent that Plaintiff alleges its products do not meet, based on Defendant’s assertions in takedown notices.
’555 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Non-Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| said internal wall has a substantially linear cross-section between said first and second seams | Plaintiff alleges its products do not include an internal wall with a "substantially linear cross-section" between the claimed seams. | ¶¶50, 79 | col. 8:54-56 |
| said internal wall of said peripheral frame includes a fluid passage therethrough | Plaintiff alleges its products do not include a "fluid passage therethrough" the internal wall. | ¶¶50, 79 | col. 8:50-51 |
| said internal wall is in substantial pressure equilibrium within said interior volume | Plaintiff alleges its products do not maintain "substantial pressure equilibrium" within the claimed internal volume. | ¶79 | col. 8:51-53 |
- Identified Points of Contention:
- Scope Questions: The primary dispute appears to center on the structural characteristics of the internal wall in the mattress's peripheral frame. The core question is whether the internal structure of Plaintiff's mattresses includes an "internal wall" that meets all three recited limitations: being "substantially linear," having a "fluid passage," and maintaining "substantial pressure equilibrium."
- Technical Questions: A factual question will be what the precise internal geometry of Plaintiff’s mattresses is. The complaint asserts that Plaintiff provided "side-by-side structural comparisons, internal images, and detailed technical explanations" to Amazon to demonstrate the structural differences (Compl. ¶52). The evidence supporting these alleged structural distinctions will be central to the non-infringement analysis.
V. Key Claim Terms for Construction
The Term: "substantially linear cross-section"
Context and Importance: This term is critical because Plaintiff alleges it was added during prosecution to distinguish the invention from prior art, creating a potential prosecution history estoppel that could limit its scope (Compl. ¶¶53, 72). Plaintiff’s primary non-infringement argument is that its products lack this specific feature (Compl. ¶79). Practitioners may focus on this term because its definition will likely determine the outcome of the infringement analysis.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification does not explicitly define "substantially linear," which could support an argument that it should be given its plain and ordinary meaning, potentially encompassing structures that are generally straight but not perfectly so.
- Evidence for a Narrower Interpretation: Figure 3 depicts the internal wall (30) as a straight line between the two seams (38, 40) (’555 Patent, Fig. 3). The specification states the internal wall is "disposed at a substantially upwardly and inwardly inclined angle," and the drawing supports a strictly linear interpretation (’555 Patent, col. 2:65-col. 3:1). The alleged prosecution history may further narrow the term's scope to exclude non-linear structures (Compl. ¶53).
The Term: "substantial pressure equilibrium"
Context and Importance: Plaintiff identifies this as a limitation its products do not meet and also argues the term is potentially indefinite (Compl. ¶¶73, 79). The dispute will concern what degree of pressure equalization is required to meet this limitation.
Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent links this equilibrium to the presence of a "fluid passage" (36), suggesting that any structure allowing air to pass between the main mattress body and the peripheral frame could arguably create "substantial" equilibrium (’555 Patent, col. 3:7-11).
- Evidence for a Narrower Interpretation: The term "substantial" is a term of degree. A defendant might argue it requires a specific technical threshold of pressure equalization that Plaintiff's products, with their allegedly different internal structures, do not achieve. Plaintiff's indefiniteness argument suggests the patent fails to provide an objective standard for measuring this equilibrium (Compl. ¶73).
VI. Other Allegations
- Indirect Infringement: The complaint states that Plaintiff does not indirectly infringe any claim because there is no underlying direct infringement (Compl. ¶81).
- Willful Infringement: The complaint does not allege willful infringement by Plaintiff. Instead, it alleges that Defendant Sun Pleasure engaged in willful and bad faith conduct by submitting "false and misleading" takedown requests to Amazon with knowledge of non-infringement and the patent's alleged invalidity, with the intent to harm Plaintiff's business (Compl. ¶¶84, 89, 91). These allegations form the basis for Plaintiff's state law claims of unfair competition, business disparagement, and tortious interference (Compl. ¶¶83-109).
VII. Analyst’s Conclusion: Key Questions for the Case
This declaratory judgment action appears poised to focus on the interplay between claim construction, prosecution history, and prior invalidity challenges. The central questions for the court are likely to be:
- A core issue will be one of claim scope and estoppel: Did the applicant’s amendments and arguments during prosecution—particularly the addition of the "substantially linear" limitation—surrender any claim to non-linear internal wall structures, and if so, do the accused products fall within that surrendered territory?
- A second key issue will be the preclusive effect of prior proceedings: How will the November 2024 IPR decision, which confirmed the patentability of the asserted claims over prior art challenges, impact the Plaintiff’s current invalidity arguments brought under the higher "clear and convincing" evidentiary standard required in district court?
- A final question will be one of improper enforcement: Independent of the infringement and validity outcomes, did the Defendant’s repeated takedown notices to Amazon, particularly after receiving detailed non-infringement explanations and after the second notice was sent, constitute an act of bad faith sufficient to support claims for unfair competition under state law?