Yangjiangshi Xicheng v. Shenzhen Lanhe: Phone Case Patent Suit Dismissed in 107 Days
Yangjiangshi Xicheng Trading Co. and Golbinbox Inc. sued Shenzhen Lanhe Technologies in the Northern District of Illinois, asserting US12040827B2 against phone cases sold under specific Amazon ASINs. The plaintiffs voluntarily dismissed the action without prejudice after just 107 days — leaving the door open for future proceedings.
Phone case patent dispute ends swiftly — but leaves litigation risk intact
On August 30, 2025, Yangjiangshi Xicheng Trading Co. LTD. and co-plaintiff Golbinbox Inc. filed a patent infringement action in the Northern District of Illinois against Shenzhen Lanhe Technologies Co., Ltd. The suit centred on US12040827B2, asserting that Shenzhen Lanhe’s phone cases — sold on Amazon under ASINs B0F38DVM9Q, B0F38GNPYL, B0CPPGX63N, and B0CPPDNH8C — infringed the asserted patent. The case was assigned to Judge John J. Tharp, Jr.
The case closed on December 15, 2025, when the plaintiffs filed a voluntary dismissal without prejudice pursuant to Federal Rule of Civil Procedure 41(a)(1). This procedural mechanism requires no court approval and takes effect immediately upon filing. Critically, a dismissal without prejudice does not resolve the underlying merits: the plaintiffs retain the right to refile the same claims against Shenzhen Lanhe in the future, subject to applicable statutes of limitations.
At 107 days, the case resolved before any substantive motion practice or claim construction activity appears on the public record. This timeline is consistent with early-stage resolution — whether through confidential settlement, a licensing arrangement, or a strategic decision to refile. The absence of defendant counsel on record suggests Shenzhen Lanhe may not have formally appeared, which can itself influence a plaintiff’s tactical calculus. The true drivers of the dismissal remain unknown from the public record.
Filing to Voluntary dismissal in 107 days
107 days — resolved before any substantive ruling, faster than the N.D. Illinois median for patent cases
Voluntarily dismissed: what Rule 41(a)(1) means for both parties
Rule 41(a)(1): plaintiff-controlled exit, no court approval needed
Fed. R. Civ. P. 41(a)(1) allows a plaintiff to dismiss an action without a court order before the defendant serves an answer or a motion for summary judgment. The dismissal is self-executing and takes effect on filing. It does not constitute an adjudication on the merits, meaning the court never ruled on whether infringement occurred or whether the patent is valid.
Procedural exit — no merits rulingWithout prejudice — but the record is silent on why
A dismissal ‘without prejudice’ preserves the plaintiff’s right to refile. A dismissal ‘with prejudice’ would permanently bar the same claims. The public record here confirms only ‘voluntary dismissal’ — it does not specify whether a settlement was reached, a licence was granted, or the plaintiffs simply chose to stand down. Observers should not assume a resolution was reached; equally, they should not assume the dispute is over.
Refiling rights preservedShenzhen Lanhe faces no injunction — but no patent clearance either
Because the case ended without a merits ruling, Shenzhen Lanhe received no judicial finding that its products are non-infringing or that US12040827B2 is invalid. The defendant cannot rely on this dismissal as a shield in future proceedings. If the plaintiffs refile — or a related party asserts the same patent — Shenzhen Lanhe would need to litigate the underlying infringement question from scratch.
No clearance obtainedAmazon ASIN-targeted enforcement: a recurring pattern in consumer electronics IP
Asserting patents directly against specific Amazon ASINs is a growing tactic among smaller IP holders targeting e-commerce competitors. A voluntary dismissal without prejudice in this context may reflect a takedown-and-settle dynamic rather than full abandonment of enforcement. Other sellers of similar phone cases under comparable ASINs should treat US12040827B2 as an active enforcement risk until a with-prejudice dismissal or a validity ruling is obtained.
ASIN-targeted enforcement risk remainsFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Yangjiangshi Xicheng Trading Co. LTD. | Company | Consumer electronics accessory trader — holder of US12040827B2 for phone case technologySearch in Eureka ↗ |
| Defendant | Shenzhen Lanhe Technologies Co., Ltd | Company | Shenzhen-based consumer electronics manufacturer accused of infringing phone case patent via Amazon listingsSearch in Eureka ↗ |
| Plaintiff counsel | Longhao Wang | Attorney | Counsel for Yangjiangshi Xicheng Trading Co. LTD.Search in Eureka ↗ |
| Plaintiff law firm | Longhao Wang | Law Firm | Representing Yangjiangshi Xicheng Trading Co. LTD.Search in Eureka ↗ |
| Presiding judge | Judge John J. Tharp, Jr. | Judge | Illinois Northern District CourtSearch in Eureka ↗ |
Official order — verbatim text
The dismissal notice invokes Rule 41(a)(1) verbatim, confirming this was a plaintiff-initiated exit requiring no judicial approval and carrying no merits adjudication. The explicit ‘without prejudice’ designation is legally significant: it preserves the plaintiffs’ full right to refile identical claims. The absence of any cross-claim, counterclaim, or court order means neither party obtained a binding legal determination on infringement or validity. The practical effect is that the dispute is suspended, not resolved.
US12040827B2 — Phone Case Design and Protection Technology
US12040827B2, filed under application number US18/098727, covers phone case technology in the consumer electronics accessories space. The patent was asserted specifically against products sold on Amazon, identified by ASINs targeting protective mobile device enclosures. As a recently granted US utility patent, it reflects a modern prosecution window and likely contains claims crafted with e-commerce enforcement in mind. The precise claim scope — whether directed at structural features, materials, or functional attributes — would determine the breadth of any infringement read.
In the highly competitive phone case market, design-adjacent utility patents have become enforcement tools for smaller IP holders seeking to protect market share against lower-cost manufacturers, particularly those based in China and selling through Amazon. US12040827B2 represents a live risk for any seller of structurally or functionally similar phone cases. Competitors in this space should monitor prosecution history and any continuation applications stemming from US18/098727, as claim scope may expand through related filings.
Should you run an FTO analysis against US12040827B2?
Any brand, distributor, or Amazon seller offering phone cases with features potentially covered by US12040827B2 should treat this patent as an active enforcement risk. The voluntary dismissal here provides no legal clearance. If your products are sold under ASINs in the same category as B0F38DVM9Q, B0F38GNPYL, B0CPPGX63N, or B0CPPDNH8C, an FTO analysis is strongly advisable before scaling inventory or expanding listings.
PatSnap Eureka’s FTO Search Agent can map the claim language of US12040827B2 against your specific product configurations, flag design-around opportunities from the prosecution history of US18/098727, and identify related continuation or divisional applications that could extend enforcement risk. Eureka surfaces prior art, claim amendments, and examiner rejections to give your legal team a complete picture before the next enforcement action lands.
Run a freedom-to-operate analysis on US12040827B2 to assess your product’s exposure
Run FTO in Eureka →Similar phone case patent infringement cases in N.D. Illinois
Browse comparable patent infringement actions asserting phone case and consumer electronics accessory patents in the Northern District of Illinois, including ASIN-targeted enforcement suits.
What this case signals for the consumer electronics accessories IP landscape
Short-cycle, ASIN-targeted patent suits in N.D. Illinois are reshaping enforcement strategy for phone case and accessories sellers.
Voluntary dismissal without prejudice is not a safe harbour for the defendant
Shenzhen Lanhe obtained no invalidity ruling, no non-infringement finding, and no covenant not to sue. US12040827B2 remains enforceable. Any seller of competing phone case products should conduct an independent FTO analysis rather than relying on this dismissal as proof of safety.
ASIN-level patent assertions are a low-cost, high-leverage enforcement model
Targeting specific Amazon ASINs lets plaintiffs frame infringement with product-level precision, potentially triggering ASIN suspensions alongside litigation. The 107-day resolution here is consistent with defendants settling quickly to restore marketplace listings rather than litigating on the merits.
Yangjiangshi v Shenzhen — key questions answered
The plaintiffs dismissed the case under Rule 41(a)(1) without prejudice, meaning no court ruled on infringement or validity. The plaintiffs retain the right to refile claims against Shenzhen Lanhe. The defendant received no legal clearance or finding in its favour.
Yes. A voluntary dismissal without prejudice does not affect the validity or enforceability of the underlying patent. US12040827B2 remains a live patent and can be asserted again by the patent holder against Shenzhen Lanhe or any other accused infringer.
The public record is silent on the specific reason. Possible explanations include a confidential settlement, a licensing arrangement, a decision to refile after improving service on the foreign defendant, or a strategic reassessment. The absence of defendant counsel on record may suggest Shenzhen Lanhe never formally appeared in the case.
The complaint targeted phone cases sold under ASINs B0F38DVM9Q, B0F38GNPYL, B0CPPGX63N, and B0CPPDNH8C. These product listings were alleged to infringe US12040827B2. The dismissal did not produce any finding about whether these specific products infringe the patent.
Yes. Because the dismissal was without prejudice, the plaintiffs or any successor patent holder can refile the same or substantially similar claims. Shenzhen Lanhe would need to litigate the merits in any future action. A second voluntary dismissal without prejudice, however, would typically operate as a dismissal with prejudice under Rule 41(a)(1)’s two-dismissal rule.
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