CAFC's Sigray v. Zeiss Could Open the §102-Inherency Door Wider for PTAB, Examiners

Important considerations when dealing with ranges and claims

In a significant precedential decision for patent practitioners, the Federal Circuit, in Sigray, Inc. v. Carl Zeiss X-Ray Microscopy, Inc., (Case: 23-2211) reversed a finding by the Patent Trial and Appeal Board (PTAB), holding that patent claims for X-ray imaging systems were inherently anticipated by prior art. This ruling scrutinizes the PTAB's implicit claim construction of numerical ranges, particularly "between 1 and 10 times" for projection magnification, and emphasizes that even infinitesimally small, physically inherent characteristics in prior art can lead to anticipation. This decision signals a potentially more aggressive approach to inherent disclosure arguments in IPRs, potentially urging PTAB panels, courts, and examiners to consider broader interpretations of prior art references and their inherent physical realities.

For years, the PTAB has been a formidable arena for patent challengers—a body often perceived as a "patent death squad" due to its historically high invalidation rates. Statistics consistently show that when the PTAB institutes an inter partes review (IPR) and proceeds to a final written decision, a significant percentage of challenged claims are ultimately found unpatentable. This perceived propensity for invalidation has made the PTAB a preferred forum for accused infringers and a source of considerable anxiety for patent owners. The Federal Circuit's role, in this landscape, has largely been to affirm PTAB decisions, with reversals being less common, especially on factual findings like anticipation. However, Sigray v. Carl Zeiss upends this narrative and reverses a PTAB finding of no anticipation.

The IPR (No. IPR2022-00218) revolved around U.S. Patent No. 7,400,704, owned by Carl Zeiss, directed to X-ray imaging systems. At issue was a critical claim limitation: "projection X-ray stage magnification between 1 and 10 times." Sigray, as the IPR petitioner, argued anticipation based on a prior art reference, "Jorgensen," which described an X-ray system using a collimated X-ray beam. The PTAB, in its final written decision, declined to find the claims unpatentable, implicitly construing "between 1 and 10" to exclude infinitesimally small, unspecified divergences, thereby allowing Zeiss's claims to survive.

The Federal Circuit, with its characteristic meticulousness, disagreed with the PTAB's approach. Authored by Chief District Judge Goldberg, sitting by designation, and joined by Circuit Judges Dyk and Prost, the court's reasoning hinged on the plain meaning of "between 1 and 10." It asserted that this numerical range includes any magnification value greater than 1, no matter how small or seemingly insignificant to a person of ordinary skill in the art at the time.

The opinion highlighted that Jorgensen's use of a collimator was to reduce beam divergence, not eliminate it. The fundamental physical reality is that perfect collimation, resulting in absolutely no projection magnification, is practically impossible. Therefore, the Jorgensen system, by its very nature, would inherently produce some magnification greater than 1, necessarily falling within the claimed range of "between 1 and 10 times."

The Federal Circuit’s decision underscores a critical principle of inherent disclosure: a prior art reference anticipates if the missing characteristic is necessarily present in the disclosed elements, regardless of whether a person of ordinary skill would have recognized that presence at the time the reference was created. The PTAB seemingly stumbled by focusing on the "meaningfulness" or "detectability" of the magnification in Jorgensen, rather than its undeniable, inherent existence. The court's message is clear: when a claim recites a numerical range, and prior art inherently falls within that range, even if at an extreme or practically imperceptible end, anticipation can be found.

What does this mean for patent attorneys and IPRs moving forward?

First, it could encourage IPR panels to adopt a broader reading of prior art references, particularly when those references describe systems or processes that inherently possess characteristics falling within claimed ranges. The PTAB, under the weight of this reversal, may become more willing to infer inherent disclosure, even for seemingly subtle or implicit features, if physical principles dictate their necessary presence. This shifts the burden to patent owners to demonstrate why such inherent characteristics are not present or are not necessarily within the claimed range, rather than relying on a lack of explicit disclosure or perceived lack of "meaningfulness" in the prior art.

Second, for patentees, this case serves as a warning about drafting claims with broad numerical ranges. While tempting to claim a wide range to maximize coverage, Sigray v. Carl Zeiss illustrates how such breadth can become a vulnerability. If any value within that range is inherently present in the prior art, even a practically insignificant one, the claim can be anticipated. This could lead to a more conservative approach to numerical ranges in claim drafting, favoring narrower, more precisely defined parameters where a clear distinction from prior art can be established. Attorneys might need to meticulously consider the inherent properties of prior art systems when drafting claims, anticipating arguments of "inherent presence" even at the fringes of their claimed ranges. Also, even though the dependent claims are still TBD here on remand to the PTAB, varying the breadth of scope using dependent claims could help overcome some references.

Third, for petitioners, Sigray v. Zeiss provides a powerful tool in arguing anticipation, particularly through inherent disclosure. It reinforces that expert testimony on what a person of ordinary skill would have "recognized" is less important than the objective physical reality of the prior art. If the prior art, by its very nature, must include a certain characteristic within a claimed range, then anticipation can be established, even if that characteristic was not explicitly discussed or deemed significant at the time of the prior art's publication. This case offers a clear roadmap for leveraging inherent disclosure arguments to challenge claims with seemingly generic numerical ranges.

Sigray, Inc. v. Carl Zeiss X-Ray Microscopy, Inc. might be viewed as more than just another patent case, representing a pivotal moment in how anticipation arguments are assessed, particularly at the PTAB. By affirming that inherent disclosure can indeed anticipate claims, even when the features are minute or unstated within broad numerical ranges, the Federal Circuit has offered a valuable perspective for those analyzing prior art.

This decision could gently encourage courts, panels, petitioners, and examiners to consider a broader lens when evaluating anticipation, potentially recalibrating approaches to these arguments. Patent attorneys must consider the implications of this ruling when evaluating references, especially concerning the inherent properties of prior art and the strategic drafting and defense of claims that encompass numerical ranges.

Disclaimer: This is provided for informational purposes only and does not constitute legal or financial advice. To the extent there are any opinions in this article, they are the author’s alone and do not represent the beliefs of his firm or clients. The strategies expressed are purely speculation based on publicly available information. The information expressed is subject to change at any time and should be checked for completeness, accuracy and current applicability. For advice, consult a suitably licensed attorney and/or patent professional.