IP Law Daily, PATENT NEWS—Lynk Labs petitions High Court over Federal Circuit’s interpretation of ‘printed publication’ in IPR, (Sep 17, 2025)

By Saurabh Kashyap, B.A., M.A., LL.B., LL.M.

The Federal Circuit misapplied §311(b) of the America Invents Act by deeming a post-critical-date abandoned application a "printed publication," the petitioner contends.

Lynk Labs, Inc. has petitioned the U.S. Supreme Court to review a Federal Circuit decision that affirmed the Patent Trial and Appeal Board’s (PTAB) cancellation of its LED circuit patent claims. The Federal Circuit allowed Samsung Electronics Co., Ltd. to rely on an abandoned patent application published after the critical date of Lynk’s invention as prior art. Lynk contends that this ruling contradicts over a century of precedent and statutory text, including the Federal Circuit’s own holding in Constant v. Advanced Micro-Devices, Inc., 848 F.2d 1560 (Fed. Cir. 1988), and the foundational treatise of William C. Robinson, The Law of Patents for Useful Inventions (1890). According to Lynk, the decision undermines the predictability of the patent system, frustrates congressional intent, and invites opportunistic challenges that could destabilize patent rights (Lynk Labs, Inc. v. Samsung Electronics Co., Ltd., Dkt. No. 25-308 (U.S. filed Sept. 12, 2025)).

Background. Lynk Labs, headquartered in Illinois, is a pioneer in alternating-current (AC) powered light-emitting diode (LED) technology. Its circuits power applications ranging from ceiling lights to decorative string lights, helping reduce reliance on complex drivers and improving efficiency. The company has marketed its inventions to North American lighting manufacturers and consistently emphasized its leadership in AC-driven LEDs. Samsung Electronics Co., Ltd., a South Korean multinational electronics conglomerate and one of the world's largest producers of consumer devices, came into conflict with Lynk when accused of selling products that infringed Lynk's patented LED circuitry. The United States Patent and Trademark Office (USPTO), represented by Acting Director Coke Morgan Stewart, was also named as a respondent because of its central role in the inter partes review that invalidated Lynk's patent claims.

The case centers on U.S. Patent No. 10,687,400 (the '400 patent), issued on June 16, 2020. The patent discloses and claims circuit configurations that allow LED systems to be powered directly from AC mains. Claim 7, representative of the invention, recites an LED circuit array including a plurality of LEDs in series, a capacitor, and a bridge rectifier configured to receive AC voltage—all mounted on a single substrate. These features ensure that the LEDs' forward voltage matches the driver's rectified AC input. Lynk filed the provisional application leading to the '400 patent on February 25, 2004, establishing that date as the patent's critical date. Lynk's chief executive officer, Michael Miskin, is named as the first inventor, and the company has described the '400 patent as a cornerstone of its innovation portfolio.

Lynk sued Samsung in 2021 in federal district court, alleging that Samsung’s LED lighting products infringed the ’400 patent. Samsung responded by filing a petition for inter partes review before the PTAB, seeking to invalidate claims 7–13 and 17 of the patent. Samsung relied principally on a prior art reference known as “Martin” (U.S. Patent Application Publication No. 2004/0206970). The Martin application, however, was abandoned and never matured into a patent. Crucially, Martin was not publicly accessible until October 21, 2004—eight months after Lynk's February 25, 2004, critical date.

Lynk argued before the PTAB that Martin could not serve as prior art in an IPR because 35 U.S.C. § 311(b) expressly limits challenges to “patents or printed publications.” Citing Constant v. Advanced Micro-Devices, Inc., 848 F.2d 1560 (Fed. Cir. 1988), Lynk asserted that the statutory phrase “printed publication” refers only to documents that were publicly accessible before the critical date. Lynk also invoked William C. Robinson’s authoritative 1890 treatise, which defined printed publications as materials disseminated to the public prior to the relevant invention date. Because Martin was neither a patent nor a publication accessible before the critical date, Lynk contended, it fell outside the statutory scope of § 311(b).

The PTAB nonetheless ruled in Samsung’s favor, holding the challenged claims unpatentable. The Board reasoned that once Martin was published, it constituted a printed publication for IPR purposes, regardless of whether publication occurred after the critical date. On appeal, the Federal Circuit affirmed, rejecting Lynk’s arguments and allowing the use of Martin as prior art in the IPR. The panel concluded that § 311(b) did not bar reliance on patent applications that later became public, even if they were unavailable at the time of invention. Lynk sought rehearing, but the Federal Circuit denied its petition, leaving the PTAB’s invalidation intact.

Petitioner’s contentions. In its Supreme Court petition, Lynk frames the issue as one of statutory fidelity and historical continuity. Section 311(b), enacted through the America Invents Act, authorizes IPR challenges only based on "patents or printed publications." Congress, Lynk argues, deliberately excluded "applications for patent" as a separate category of prior art. Lynk highlights that for more than a century, courts and scholars have consistently understood "printed publication" to require public accessibility prior to the critical date.

To support this position, Lynk relies on Constant v. Advanced Micro-Devices, Inc., 848 F.2d 1560, 1568 (Fed. Cir. 1988), where the Federal Circuit held that "printed publication" under the Patent Act referred to documents that were published or publicly accessible before the critical date.” Lynk also cites Robinson’s treatise, which describes printed publications as materials that must be available to the public to qualify as prior art. According to Lynk, these authorities reflect a settled understanding that printed publications cannot retroactively become prior art after the fact of invention.

Lynk further warns that the Federal Circuit’s approach distorts the notice function of the patent system. By allowing later-published abandoned applications to serve as prior art, the ruling exposes patent owners to challenges based on materials that were not accessible when the invention was made. Lynk contends that this interpretation undermines inventors’ ability to assess the state of the art at the time of filing and threatens the predictability upon which the patent system depends.

The petition also points to the interaction with 35 U.S.C. § 315(e)(2), which estops litigants from raising in court any ground that they could have raised in an earlier IPR. Lynk argues that if post-critical-date applications are treated as printed publications, infringers could strategically withhold challenges and later use abandoned applications to attack patent validity, undermining estoppel protections and increasing litigation burdens.

Reliefs requested. Lynk requests that the Supreme Court grant certiorari, reverse the Federal Circuit’s judgment, and hold that applications published only after a patent’s critical date cannot qualify as “printed publications” within the meaning of § 311(b). It further asks that the Court reinstate the cancelled claims of the ’400 patent and clarify that the statutory term “printed publication” continues to mean what courts and commentators have long understood: materials that were publicly accessible before the invention’s critical date.

The Case is Dkt. No. 25-308.

Attorneys: Jeffrey A. Lamken (Mololamken LLP) for Lynk Labs, Inc.

Companies: Lynk Labs, Inc.; Samsung Electronics Co., Ltd.

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