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Key Takeaways

• Supplemental examination lets a patent owner place close prior art before the USPTO and thereby potentially build a public record that strengthens later enforcement.  See 35 U.S.C. § 257.

 

• This process can be particularly beneficial to design patents, which often have little discussion of the claimed design’s key distinguishing features in their prosecution history.

 

• For example, across three proceedings involving 30 references, the USPTO repeatedly found no substantial new question as to the patentability of U.S. Design Patent No. D789,312.

 

• Section 257 also provides limited inequitable-conduct protection. Subject to statutory exceptions, a patent may not be held unenforceable based on conduct relating to previously unconsidered, inadequately considered, or incorrect information that is considered, reconsidered, or corrected during supplemental examination. See 35 U.S.C. § 257(c)(1).

 

• Timing is critical: § 257(c)(1) does not apply to allegations pled with particularity before the request and, in an infringement or ITC action, applies only if the supplemental examination and any resulting reexamination conclude before the action is filed. See 35 U.S.C. § 257(c)(2).

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What Is Supplemental Examination?

Supplemental examination is a post-grant procedure that allows a patent owner to place potentially relevant information before the USPTO for further review. When used proactively—particularly before an enforcement action is brought—supplemental examination can strengthen the patent’s prosecution record, address potential validity or enforceability concerns, and clarify the patent owner’s litigation position.​

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A Statutory Tool with Litigation Consequences

Under 35 U.S.C. § 257, a patent owner may request that the USPTO consider, reconsider, or correct information believed to be relevant to an issued patent. Within three months after receiving a compliant request, the USPTO issues a certificate determining whether the submitted information raises a substantial new question of patentability (SNQ). If an SNQ is identified, the USPTO orders ex parte reexamination; if no SNQ is found, the supplemental examination proceeding concludes.

Subject to statutory timing requirements and exceptions, supplemental examination may also protect a patent from being held unenforceable based on conduct relating to information addressed in the proceeding. To preserve that protection, the request must precede any related allegation pled with particularity, and the proceeding and any resulting reexamination must conclude before an infringement or ITC action is brought. See 35 U.S.C. § 257(c)(2).

Supplemental examination can be especially valuable for design patents because the claimed design is defined principally by the drawings, so the original prosecution history may contain little discussion of the visual features that distinguish the design from the prior art. By presenting close prior-art designs for review, the patent owner can develop a public record through supplemental examination showing that the USPTO considered those designs and explaining why the claimed overall appearance remains patentable.

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D789,312: Three Proceedings, Repeated No-SNQ Determinations

U.S. Design Patent No. D789,312, titled “Single Magnetic Brick,” was the subject of three separate supplemental examination proceedings involving a total of 30 patent and nonpatent references. In each proceeding, the USPTO concluded that the submitted information did not raise a substantial new question of patentability.

Across the three determinations, the examiner consistently characterized the claimed design as a transparent, relatively thin, square body with rounded corners, squared edges, slightly recessed central surfaces on the front and rear, and a raised rim extending around the perimeter. The examiner repeatedly identified the recessed-center and raised-rim configuration—which creates a distinctive framed appearance—as a significant feature distinguishing the claimed design from the prior art. The examiner also clarified that the interior features depicted in broken lines form no part of the claimed design.

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​Figure 1. The USPTO’s description of D789,312. Source: Control No. 96/050,079, Determination at 1.

How Supplemental Examination Can Strengthen Enforcement

• A more persuasive validity record. The patent owner can demonstrate that the USPTO considered close prior art—not merely remote or cumulative references—before determining that the submitted art raised no substantial new question of patentability. In the D789,312 proceedings, the examiner evaluated transparent square magnetic panels, commercial magnetic tiles, open-frame designs, and products with recessed centers, but consistently concluded that none disclosed the same overall recessed-center and raised-rim appearance.

 

• Reduced inequitable-conduct exposure. Subject to the requirements and timing limitations of 35 U.S.C. § 257, information considered, reconsidered, or corrected during supplemental examination may not serve as the basis for a later finding of unenforceability based on conduct relating to that information. This protection can eliminate an inequitable-conduct theory that might otherwise jeopardize enforcement of the patent.

 

• A clearer infringement narrative. The supplemental examination determinations create a contemporaneous USPTO record identifying the ornamental features considered significant to the claimed design. That record can help the patent owner explain why an accused product creates substantially the same overall visual impression, while properly excluding from the infringement analysis internal or other features depicted only in broken lines.

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Figure 2. Close art considered but distinguished: U.S. 2017/0065899 (left) and CN 303050982-S/Magna Tiles (right). The examiner found their primary surfaces flat rather than centrally recessed. Source: Control No. 96/050,079, Determination at 5 and 7.

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The Record Also Defines the Patent’s Boundaries

Supplemental examination can strengthen a patent’s prosecution history, but it does not immunize the patent from later validity challenges. A no-SNQ certificate means only that the submitted information did not warrant reexamination; it is neither a judicial validity determination nor estoppel against different prior art, combinations, or obviousness theories. Following LKQ Corp. v. GM Global Technology Operations LLC, 102 F.4th 1280, 1293–99 (Fed. Cir. 2024), design-patent obviousness is evaluated under the flexible Graham framework rather than the Rosen–Durling test formerly applied. That shift can make a carefully framed supplemental-examination request especially useful: because Graham permits a more flexible assessment of analogous art and combinations, the patent owner can present both the closest individual references and realistic combinations, creating a record responsive to likely litigation theories. The D789,312 determinations remain useful for the art they considered, but do not foreclose other challenges.
The resulting USPTO record may also define—and potentially narrow—the patent’s practical scope. For D789,312, the examiner’s repeated emphasis on the slightly recessed center and continuous raised rim may strengthen an infringement argument against a product that creates the same overall visual impression. At the same time, patent owners should assume that every distinction emphasized in the record may later be examined closely by both sides in litigation, and should characterize the claimed design with that audience in mind.
The practical lesson is to approach supplemental examination with disciplined timing and careful drafting. The patent owner should: (a) file the request before any related inequitable-conduct allegation is pled and early enough for the supplemental examination and any resulting reexamination to conclude before an enforcement action is brought, (b) submit the closest known prior art and realistic combinations, (c) characterize the claimed design consistently, and (d) expect that every asserted distinction will later be invoked in infringement, validity, or claim-scope arguments. Used strategically, supplemental examination does not make a design patent unassailable, but it can create a more credible enforcement record and a more coherent litigation position.

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