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  • 執筆者の写真York Faulkner

Federal Circuit Clarifies Permissible Scope of IPR Replies and Analogous Prior Art Tests


. . . Regarding Corephotonics’s second argument, the Federal Circuit found no abuse of discretion in the Board permitting Apple to introduce a new argument—based on the pertinent problem test—“to bolster” the analogous prior art assertions previously made in its petition. . . .


In Corephotonics, Ltd. v. Apple, Inc., No. 2022-1340, 2022-1341 (Fed. Cir. Oct. 16, 2023), the Court of Appeals for the Federal Circuit (“Federal Circuit”) remanded the inter partes review (“IPR”) determination by the U.S. Patent and Appeals Board (“the Board”) for further proceedings to determine if a prior art reference cited by Apple is “analogous” to Corephotonics’s patents (“the Challenged Patents”) under one or both of the court’s tests for determining “analogous prior art.” Notably, this is the second decision issued by the Federal Circuit within a span of just five weeks, pertaining to the court’s analogous prior art tests. The first of these decisions is Netflix, Inc. v. DIVX, LLC, No. 2022-1138 (Fed. Cir. Sep. 11, 2023).

Together, these decisions illustrate that an IPR petitioner’s articulation of how a particular prior art reference is “analogous” to a challenged patent is a contested issue in a growing number of cases. Demonstrating whether a reference is “analogous prior art” requires evidence satisfying at least one of two separate tests: “(1) whether the art is from the same field of endeavor, regardless of the problem addressed, and (2) if the reference is not within the field of the inventor’s endeavor, whether the reference is still reasonably pertinent to the particular problem the inventor is involved with.” In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004); see also Airbus S.A.S. v. Firepass Corp., 941 F.3d 1374, 1379 (Fed. Cir. 2019).

In addition to providing further clarity on the application and scope of the two tests for analogous prior art, the Federal Circuit’s decision in Corephotonics, Ltd. v. Apple, Inc. also offers useful guidance on the permissible scope and content of an IPR petitioner’s reply brief when introducing new argument and evidence. As discussed below, the petitioner’s expansion of argument and evidence in a reply is subject to two restrictions—the “newness” restriction and the “responsiveness” restriction.

The Challenged Patents

The Challenged Patents are directed to dual-aperture camera systems and methods for utilizing image streams from both lenses when zooming during video capture. Multi-lens systems often include a wide-lens camera, which captures a larger field of view, and a tele-lens camera, which provides greater magnification. While zooming in, the camera switches from the wide-lens to the tele-lens and vice versa when zooming out. As in Apple’s iPhones, the lenses are typically positioned adjacent to each other, which also results in slightly different image perspectives due to their relative locations.

A challenge faced by such a system is the presence of a “jump” or a sudden change in the image when transitioning between lenses due to differing fields of view used by wide and tele-lens cameras. The Challenged Patents aim to minimize this disruption through an image matching technique, which aligns certain image aspects such the position, scale, brightness, and color of the outputted images before and after the lens switching. This multi-faceted image alignment, which focuses on a designated “region of interest” of the images, smooths the transition between lenses.

The Prior Art

Among other references, Apple asserted two prior art references, “Golan” and “Martin,” in support of the obviousness challenges presented in its IPR petitions.

Golan addresses image alignment when switching between lenses. The reference discloses camera systems that employ multiple imaging sensors and lens assemblies to provide zoom functionality, eliminating the need for a lens with a mechanically adjustable focal length. Specifically, Golan teaches the method of digitally zooming in using the wide lens until a higher resolution image can be fully captured with the tele-lens. To avoid “jump” or discontinuity while switching images when zooming, Golan proposes a one-time calibration technique that adjusts for the differing points of view of the lenses.

Martin addresses image alignment based on regions of interest. The reference teaches methods for creating two-dimensional images that can be perceived three-dimensionally when displayed, without the need for special viewing aids. Martin’s approach involves capturing images of the same scene from diverse points of view, leading to parallax images, which when alternately displayed, give the illusion of a three-dimensional structure. Martin further outlines the importance of “critically aligning” the images to maintain a stable three-dimensional image. This critical alignment involves orienting the captured images around a common region of interest within each image frame.

Alleged Procedural Errors

Corephotonics asserted that the Board improperly permitted Apple to introduce new argument and evidence in its reply brief, implicating two procedural restrictions placed on the scope and content of a petitioner’s reply in an IPR proceeding—the so-called “newness” and “responsiveness” restrictions. The Federal Circuit’s analysis of Apple’s reply brief involved both restrictions. The court noted that it reviews the Board’s application of the two restrictions under different standards. The newness restriction is reviewed de novo, as it is a question of law. Opinion at 25 (citing In re Nuvasive, Inc., 841 F.3d 966, 970 (Fed. Cir. 2016)). The responsiveness restriction is reviewed for an abuse of discretion, as it is grounded in the Board’s regulations. Id. (citing Yita LLC v. MacNeil IP LLC, 69 F.4th 1356, 1366 (Fed. Cir. 2023)).

The newness restriction forbids introducing new substantive argument and evidence in a reply, such as new theories of unpatentability, that were not presented in the initial petition. Id. at 24 (citing Wasica Fin. GmbH v. Cont’l Auto. Sys., Inc., 853 F.3d 1272, 1286 (Fed. Cir. 2017)). In practice, “Determining whether a reply has improperly raised a new theory or argument requires a comparison between the petitioner’s petition and the petitioner’s reply.” Id.

The responsiveness restriction requires that argument and evidence presented in the reply “‘may only respond to arguments raised in the corresponding opposition, patent owner preliminary response, patent owner response, or decision on institution.’” Id. (quoting 37 C.F.R. § 42.23(b)); see also Anacor Pharms., Inc. v. Iancu, 889 F.3d 1372, 1380-82 (Fed. Cir. 2018) (petitioner “may introduce new evidence after the petition stage if the evidence is a legitimate reply to evidence introduced by the patent owner”). A reply therefore may be considered improper if it presents argument and evidence that are non-responsive to issues raised by the patent owner or the Board. Id.

Despite these restrictions, the Federal Circuit emphasized that there is “no blanket prohibition against the introduction of new argument during an IPR,” as long as the argument is an expansion on or a fair extension of a previously raised argument and has a nexus to an issue raised by the patent owner or the Board. Id. at 26 (quoting Rembrandt Diagnostics, LP v. Alere, Inc., 76 F.4th 1376, 1384-85 (Fed. Cir. 2023)). The court recognized that, in practice, the introduction of new evidence and argument consistent with the newness and responsiveness restrictions “is to be expected during inter partes review trial proceedings.” Id. (quoting Genzyme Therapeutic Prods. Ltd. v. Biomarin Pharm. Inc., 825 F.3d 1360, 1366 (Fed. Cir. 2016)).

In its appeal, Corephotonics asserted two procedural errors by the Board concerning the scope of Apple’s reply. First, Corephotonics contended that the Board improperly permitted Apple’s reply to fix an error in the petition—Apple initially showed that Golan and Martin were in the same field of endeavor with each other but failed to demonstrate that the two references were in the same field of endeavor as the Challenged Patents. Second, Corephotonics argued that the Board improperly allowed Apple’s reply to assert that Golan and Martin are analogous to the Challenged Patents based on both the field of endeavor test and the pertinent problem test where Apple’s petition had only invoked the field of endeavor test.

Regarding Corephotonics’s first assertion, the Federal Circuit explained that “‘[a] petitioner is not required to anticipate and raise all arguments in its petition.’” Id. at 27 (quoting Sanofi-Aventis Deutschland GmbH v. Mylan Pharms. Inc., 66 F.4th 1373, 1377 (Fed. Cir. 2023)). A petitioner can use its reply to respond to arguments subsequently raised by the patent owner. Id. Apple’s reply, therefore, was proper because it merely corrected an error in its petition concerning the analogous art requirement by showing that Golan and Martin are analogous not only to each other but also to the Challenged Patents. Id. at 26-27 (citing Sanofi Aventis, 66 F.4th at 1378-80 (similar facts)).

Regarding Corephotonics’s second argument, the Federal Circuit found no abuse of discretion in the Board permitting Apple to introduce a new argument—based on the pertinent problem test—“to bolster” the analogous prior art assertions previously made in its petition. Id. at 27. The Board, therefore, properly permitted Apple to respond to Corephotonics’s arguments by expanding, not the number of prior art references or theories of patent invalidity, but instead the asserted bases on which the previously identified prior art satisfies the analogous art requirement. Id. The Federal Circuit emphasized that although the field of endeavor test and pertinent problem test are separate inquiries to discern analogous prior art, the two tests do not provide independent grounds for challenging patent validity. Id. at 28. Adding arguments under the pertinent problem test, therefore, did not expand Apple’s bases for asserting the invalidity of the Challenged Patents. Id.

The Federal Circuit also addressed Corephotonics’s related argument that the Board erred in finding analogousness based on different reasons than those advocated by Apple. Id. at 29. The court explained that the Board may make independent factual findings based on the evidence of record, even if those findings differ from the positions argued by the parties. Id. at 30. If its findings are supported by substantial evidence, the Board can resolve a disputed issue by making its own findings. Id. Except as discussed below, the Federal Circuit was satisfied that the Board’s findings on the field of endeavor and pertinent problem tests were supported by substantial evidence and therefore perceived no procedural error in the Board’s approach to ruling on each issue. Id. at 31.

Substantive Rulings

Having satisfied itself that the Board committed no procedural error, the Federal Circuit turned its attention to the Board’s substantive rulings regarding whether Golan and Martin are analogous prior art to the Challenged Patents.

Regarding Golan, the Board determined that it is in the same field of endeavor as the challenged patents because both disclose digital zooming systems that uses a wide and tele-lens assembly in a manner that provides continuous zooming with uninterrupted imaging. Id. at 31. Corephotonics contested the board’s determination because the Challenged Patents teach a zoom-interrupt mechanism not disclosed in Golan. Id. at 32. The zoom-interrupt mechanism disclosed in the Challenged Patents is designed to stop lens transitioning where certain “no-switching” criteria are satisfied. Because of this difference, Corephotonics asserted that Golan cannot be in the same field of endeavor as the Challenged Patents. Id. The Federal Circuit, however, affirmed the Board’s conclusion that the field of endeavor broadly encompasses smooth multi-lens digital zooming without regard to specific features such as the zoom-interrupt mechanism disclosed in the Challenged Patents. Id.

Regarding Martin, Apple argued that the reference is analogous art because it satisfies both the field of endeavor test and the pertinent problem test. Id. The Board agreed with Apple as to the pertinent problem test but made no determination regarding the field of endeavor test. Id. In stating its conclusion regarding the pertinent problem test, however, the Board made an undisputed error in describing the technology. The Board said, “Martin is reasonably pertinent to the problem faced by the inventor: reducing an image jump effect seen in video output images when switching between cameras that have different fields of view. Both Golan and Martin have multiple cameras with differing fields of view.” Id. at 33 (emphasis in original).

Both Apple and Corephotonics agreed that the Board’s statement was wrong because Martin does not disclose switching between cameras with different “fields of view” based on their mechanical design but instead addresses cameras with different “points of view” based on their physical locations in relation to each other. Id. The parties nevertheless disputed the substantive impact of the error. Apple argued that the Board’s statement was merely a harmless typographical error, and Corephotonics argued that the Board’s determination was not supported by substantial evidence due to the obvious error. Id.

Ultimately, the Federal Circuit concluded that it could not determine if the Board’s error was a harmless typographical error or a potentially impactful error of substance. Id. The court noted that nowhere else in its determination did the Board treat the Challenged Patents as addressing a “point of view” problem but instead had emphasized that the dual-aperture cameras described in the Challenged Patents use lenses with different “fields of view.” Id. at 33-34.

The Federal Circuit acknowledged the possibility that the Board meant to say “field of view” instead of “point of view” when describing the problem addressed by Martin, because “field of view” is consistent with the Board’s description of the Challenged Patents. Id. at 34. The problem with that assumption, however, is that “Martin . . . makes no express reference to field of view, and the Board provides no explanation as to how Martin’s approach to point of view can have anything to do with the field of view problem faced by the inventors of the Challenged Patents.” Id. at 34.

The Federal Circuit, therefore, found no record basis to determine if the Board’s error was harmless or if it otherwise affected the substantive outcome. The court remanded the case to the Board for further explanation and, if needed, further fact-finding. The court left it to the Board to decide whether it should also consider Apple’s alternative contention that Martin is in the same field of endeavor as the challenged patents, regardless of whether it is pertinent to the problem faced by the inventors. Id.


The Federal Circuit's decision in this case provides useful guidance on the procedural limitations of introducing new argument and evidence in IPR proceedings. The court clarified the "newness" and "responsiveness" restrictions, emphasizing that while new evidence and arguments are generally prohibited in a reply, they may be permissible if they respond to issues raised by the Board or patent owner or otherwise expand upon matters previously raised by the petitioner. Therefore, despite Corephotonics’s assertion of procedural errors by the Board, the Federal Circuit ultimately found no abuse of discretion in permitting Apple to bolster its proof of analogous prior art by asserting an entirely new theory of analogousness in its reply. This decision further illustrates how the substantive issue of analogous prior art can turn on subtle distinctions in the relevant art such as differences between “field of view” and “point of view” which can be easily overlooked—here by the Patent Office itself.

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