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No “Magic Words” for Field of Endeavor for Analogous Art

Posted by James Juo | Sep 14, 2023 | 0 Comments

For determining the obviousness of a claimed invention, qualified prior art is that which a person of ordinary skill in the art would look to if it is “analogous to the claimed invention.” In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004); Airbus S.A.S. v. Firepass Corp., 941 F.3d 1374, 1379 (Fed. Cir. 2019) (considering the teachings of “all the prior art in the field of his endeavor” at the time the invention was made); see also Manual of Patent Examining Procedure (“MPEP”) § 2141.01(a).

Two Tests for Analogous Art 

There are two separate tests to define the scope of analogous art:

  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 still is reasonably pertinent to the particular problem with which the inventor is involved.

Airbus S.A.S. v. Firepass Corp., 941 F.3d 1374, 1379 (Fed. Cir. 2019); In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004).

Whether prior art is analogous is determined with “the foresight of a person of ordinary skill, not with the hindsight of the inventor's successful achievement.” See Sci. Plastic Prod., Inc. v. Biotage AB, 766 F.3d 1355, 1359 (Fed. Cir. 2014); see also KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) (“A factfinder should be aware, of course, of the distortion caused by hindsight bias . . . .”); In re Kahn, 441 F.3d 977, 987 (Fed. Cir. 2006) (defending obviousness inquiry “against hindsight”); In re Oetiker, 977 F.2d 1443, 1447 (Fed. Cir. 1992) (“The combination of elements from non-analogous sources, in a manner that reconstructs the applicant's invention only with the benefit of hindsight, is insufficient to present a prima facie case of obviousness.”).

Determining the Field of Endeavor

The field of endeavor is determined “by reference to explanations of the invention's subject matter in the patent application, including the embodiments, function, and structure of the claimed invention.” Bigio, 381 F.3d at 1325; see In re Deminski, 796 F.2d 436, 442 (Fed. Cir. 1986) (affirming that the references were within the field of endeavor of the invention where the references shared the same “function and structure”); MPEP § 2141.01(a) (considering “similarities and differences in structure and function” when assessing analogous art).

The field of endeavor is “not limited to the specific point of novelty, the narrowest possible conception of the field, or the particular focus within a given field.” Unwired Planet, LLC v. Google Inc., 841 F.3d 995, 1001 (Fed. Cir. 2016). Importantly, “the scope of any field of endeavor will vary with the factual description of each invention.” Bigio, 381 F.3d at 1326. Unlike the reasonable-pertinence test, the field-of-endeavor test does not look to the problem that the patent purports to address. In re Clay, 966 F.2d 656, 658–59 (Fed. Cir. 1992). It is enough that the prior art reference falls within the relevant field of endeavor of the patent-in-suit.

Analogous art may be established where the references shared a general field of endeavor. See Unwired Planet, 841 F.3d at 1001–02 (affirming Board's finding of analogous art where the patent-in-dispute and prior art were both “in the field of interface design, with [the prior art] focusing on graphical user interfaces and the [patent-in-dispute] focusing on interfaces for location-based services,” because “[t]hese two areas of focus overlap within the broader field of interface design because the teachings in graphical user interface design . . . have relevance in interfaces for location-based applications”); In re Mettke, 570 F.3d 1356, 1359 (Fed. Cir. 2009) (affirming Board's identification of the field of endeavor as “pay-for-use publication communication terminations” where the specification described various communication media, not just “providing access to the Internet” as directed by the claim-in-dispute).

Field of Endeavor Need Not be Explicitly Identified with Magic Words

Even where a party arguing obviousness does not explicitly define or identify a field of endeavor for analogous art in its briefing, more general language in that briefing may nonetheless present an argument on that issue when taken as a whole. Netflix v. DivX, No. 22-1138, — F.4th — (Fed. Cir. Sept. 11, 2023).

In Netflix, U.S. Patent No. 8472792 for encoding, transmitting, and decoding multimedia files to enable “trick play” functionality like fast forwarding, was challenged as obvious over a primary reference (Zetts) in view of a secondary reference (Kaku). The Kaku reference disclosed using AVI files and index chunks to reproduce motion images in digital cameras. The PTAB, however, held that Kaku did not qualify as analogous art.

On appeal, the Federal Circuit held that the Patent Trial and Appeal Board (“PTAB”) had an “unduly rigid view of the analogous art framework” and that the exact words “field of endeavor” need not be used to meet the burden of responding to a patent owner's argument concerning analogous art.

Thus, the PTAB abused its discretion by requiring explicit identification of a field of endeavor using specific “field of endeavor” language within the briefs.

Netflix identified two alternative theories for what it viewed as Kaku's and the patent-in-suit's overlapping fields of endeavor— (1) AVI files; or (2) encoding and decoding multimedia files. Although Netflix's reply brief before the Board did not formulaically articulate a field of endeavor using those exact words, our precedent does not require the use of magic words.

The Federal Circuit, however, that the PTAB's conclusion that Kaku was not analogous art under the reasonably pertinent test was not unreasonable. The court found substantial evidence supported the Board's determination that Kaku addressed a different problem related to image compression and camera memory limitations, and was not reasonably pertinent to the ‘792 patent's problem of facilitating trick play in streaming multimedia. Thus, the case was remanded for the PTAB to reconsider only the field of endeavor issue for analogous art.

Professor Crouch noted that “[a]n oddity of the analogous art test is that it generally takes a binary approach—either a reference qualifies as analogous art and is considered as valid prior art, or it is deemed non-analogous and categorically excluded.” He further posited that an explicit statement of the particular problem the invention seeks to solve “may limit the applicable scope of prior art during litigation” but, on the other hand, “may make the claims more vulnerable to workarounds.”

The patent attorneys at Thomas P. Howard, LLC enforce patents and defend against infringement in litigation nationwide including in Colorado.

About the Author

James Juo

James Juo is an experienced intellectual property attorney. He has successfully litigated various intellectual property disputes involving patents, trademarks, copyrights, and trade secrets. He also has counseled clients on the scope and validity of patent and trademark rights.


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