The Patent Trial and Appeal Board (“PTAB”) and the Federal Circuit have each recently addressed the standard for determining whether a reference qualifies as “analogous art” in connection with an assertion of obviousness. According to the Federal Circuit, a reference is analogous art if it is either in the field of an applicant’s endeavor or reasonably pertinent to the particular problem with which the inventor was concerned.1 While both the PTAB and the Federal Circuit began their analyses with the same standard, they arrived at opposite outcomes based on the particular facts of each case. As outlined below, understanding how the two prongs of the analogous art standard have been interpreted and the types of facts the PTAB and the Federal Circuit are likely to consider relevant may make the difference in establishing, or surviving, an obviousness attack.


On July 10, 2015, the PTAB issued a final written decision on Petition for Inter Partes Review by SkyHawke Technologies, LLC of U.S. Patent No. 5,779,566 (“the ‘566 patent”).2 In the decision, the PTAB discussed whether two cited references, Palmer3and Vanden Heuvel,4 qualify as analogous art and therefore could be combined to render certain of the claims-at-issue obvious. In particular, the PTAB focused on whether the two references fall in the same field of endeavor.

The ‘566 patent is generally directed to a “handheld computerized golf data recording, reporting and advising unit, and a method for its operation.”5 The specific claims-at-issue, with respect to the combination of Palmer and Vanden Heuvel, relate to “a computer with a display for user interaction before, during, and after a game.”6 According to the Petitioner, Palmer describes a handheld computing device cited to illustrate a keypad connection with a processing means for the input of data related to play and actuations of given functions.7 The Petitioner argued that Vanden Heuvel, directed to a pager-type device, receives, stores, and displays messages utilizing a plurality of screens.8 According to the Petitioner, a person of ordinary skill in the art would recognize both references and the ‘566 patent as all being in the same field -- “human-computer interaction.”9 Accordingly, the Petitioner asserted that the combination of references was both proper and sufficient to render the claims-at-issue obvious.

The Patent Owner disagreed, arguing that Vanden Heuvel is not in the same field of endeavor as the ‘566 patent and thus does not qualify as analogous art. The Patent Owner asserted that the “Field of the Invention” of the ‘566 patent is “related to an apparatus and method for reporting and recording golf information and for providing golf advice.”10 As such, the Patent Owner asserted that the field of the invention is strictly the recording and reporting of sports information.

In rendering its decision, the PTAB noted that “[i]n order to rely properly on a prior art reference to support a rejection, 'the reference must either be in the field of the applicant’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned.’”11 Ultimately, the PTAB rejected both parties’ interpretations as either too broad or too restrictive. Instead, the PTAB turned to the disclosure of the ‘566 patent as “representative of a more objective form of evidence” concluding that the field was “portable computing devices for the entry, organization, and analysis of data, including, but not limited to, sports data.”12 In doing so, the PTAB determined that both Palmer and Vanden Heuvel qualified as analogous art in the same field of endeavor as the ‘566 patent. With both references qualified as prior art, the PTAB held the claims-at-issue of the ‘566 patent to be obvious.


On July 28, 2015, the Federal Circuit issued an opinion in Circuit Check Inc. v. QXQ Incthat addressed the issue of analogous prior art.13 In contrast to SkyHawke Technologies, the Federal Circuit quickly acknowledged the cited art was not in the same field of endeavor as the applicant, and thus analyzed the cited art under the second prong of the standard -- whether the art was “reasonably pertinent to the particular problem with which the inventor was concerned.”

Circuit Check owns three patents directed to interface plates, which are commonly used in testing circuit boards before their integration into finished products.14According to the patents, the interface plate is one color, and the surface of the interface plate is covered with paint of a different color. Paint is then removed from select holes of the interface plate to signal where probes should be inserted.15 Circuit Check believed that QXQ had infringed these patents and sued it in the District Court for the Eastern District of Wisconsin.

During the District Court trial, QXQ argued that three prior art references constitute “analogous art” and when combined render certain of the claims-at-issue obvious. The first reference was directed to rock carvings, the second reference was directed to engraved signage, and the third reference was directed to a machining technique whereby dye is applied to a workpiece and then removed by a drill. With respect to the first reference, QXQ analogized the patented technology to primitive pictures (petroglyphs) made by ancestors using rudimentary chisels to remove the dark “desert varnish” that coated large stones, revealing a lighter color underneath. QXQ argued that the lighter chiseled area thus stood out against the darker surface to delineate the picture. In addition, QXQ pointed out the machining technique of the third reference is commonly used in metalworking to stain a metal object, after which the surface coating can be scratched off with a sharp instrument to reveal markings that contrast with the blue stain. QXQ made similar arguments with respect to the engraved signage of the second reference, in which a top layer is removed to expose a bottom layer.

Circuit Check argued that these references were not analogous, noting that none of the disputed art – ancient rock carvings, machining techniques, and engraved signage – fall within the field of circuit board testers, and that one skilled in the art would not have contemplated these fields when designing an alignment plate.16Since the cited art was not, according to Circuit Check, analogous to the asserted claims, the art was allegedly insufficient to render the claims obvious.

The jury agreed with Circuit Check, awarding a $1.86 million patent jury verdict. However, QXQ filed a motion for judgment as a matter of law, and the court overturned the jury’s verdict, finding the claims-at-issue obvious in view of the prior art. The court analogized the prior art with an example that “any vandal who has ‘keyed’ a car knows that stripping the paint with a key will result in the underlying metal color showing through” as it “is a way of marking something by removing a surface coating having a different color from the underlying thing.”17Accordingly, the Judge determined that any layman would have understood that interface plates could be marked using the techniques described in the prior art.

The Federal Circuit disagreed. It held that an inventor would not look to disparate fields such as rock carving, engraved signage or removable machining techniques when analyzing an interface plate, as recited in the patent claims. The Federal Circuit acknowledged that the prior art was not from the same field of endeavor, but turned to the second prong to determine whether the cited art “is reasonably pertinent to the particular problem the inventor is trying to solve.”18 The Federal Circuit explained that “a reference is only reasonably pertinent when it ‘logically would have commended itself to an inventor’s attention in considering his problem.’”19

In response to the lower court’s analogy, the Federal Circuit explained “[j]ust because keying a car…is within the common knowledge of humankind does not mean that keying a car is analogous art.”20 The Federal Circuit emphasized that the proper analysis is “not whether simple concepts such as rock carvings…are within the knowledge of lay people or even within the knowledge of a person of ordinary skill in the art,” but “whether an inventor would look to this particular art to solve the particular problem at hand.”21 The Federal Circuit found, inter alia, that the plaintiff had submitted evidence that an inventor would not have considered the prior art as analogous.22 As such, the Federal Circuit reinstated the jury verdict and reversed the District Court’s judgment.


It is evident from these decisions that the analogous art analysis is indeed highly fact-specific. This not only relates to assigning the specific fields associated with the individual pieces of cited art, but also in determining what “field of endeavor” is applicable against a patent claim, a process that may take into consideration statements within the patent specification itself. From a drafting perspective, this latter consideration may be an important tool for delineating what prior art may be precluded during subsequent litigation. Additionally, both plaintiffs and defendants should take great care in establishing facts as to what would or would not be reasonably pertinent to an inventor working on a particular problems addressed by the patent claims. Ultimately, the interplay of all of these facts could mean the difference between a valid claim and a finding of obviousness.