In a precedential and significant ruling that clarifies when a published patent application can serve as prior art in an inter partes review (IPR), the Federal Circuit has affirmed the Patent Trial and Appeal Board’s (PTAB) decision in Lynk Labs, Inc. v. Samsung Electronics Co., Ltd. The case hinged on the determination of whether a published patent application is considered prior art as of its filing date or its publication date.

Lynk Labs, Inc. held U.S. Patent No. 10,687,400 (the ’400 patent), which pertains to LED-based lighting systems, specifically alternating current (AC)-driven LEDs and LED circuits. In November 2021, Samsung filed an IPR petition challenging claims 7–20 of the ’400 patent for obviousness under 35 U.S.C. § 103. In response, Lynk Labs disclaimed claims 14 and 18–20, leaving claims 7–13 and 15–17 under review.

A key issue in the case was whether a specific prior art reference, Martin, which was filed before the ’400 patent’s priority date but published afterward, qualified as prior art in the IPR proceeding. Samsung relied on Martin in combination with other references to argue that the challenged claims were obvious.

The PTAB determined that claims 7–13 and 17 of the ’400 patent were unpatentable for obviousness based on the combination of Martin and another prior art reference. The Board rejected Lynk Labs’ argument that Martin could not serve as prior art in the IPR, concluding that under the relevant statutory provisions, a published patent application can be considered prior art as of its filing date rather than its publication date.

On appeal, the Federal Circuit upheld the PTAB’s decision, affirming that under the applicable laws, a published patent application is deemed prior art as of its filing date in an IPR proceeding. The court found no error in the Board’s unpatentability determinations and concluded that the challenged claims were properly found to be obvious.

This ruling provides important clarification for both patent holders and challengers in IPR proceedings. It underscores the significance of early filing dates for patent applications and their potential impact as prior art in future disputes. Patent owners should be mindful of earlier-filed applications that could be cited against their claims, even if those applications were published later. Meanwhile, petitioners can leverage earlier-filed applications as prior art in IPR challenges, reinforcing their ability to establish unpatentability based on prior disclosures.

As the Federal Circuit continues to refine its interpretation of patent law in IPR contexts, this case highlights the evolving landscape of prior art considerations and reinforces the importance of strategic patent prosecution and litigation planning.

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