Analogous Art under 35 U.S.C. § 103

In Netflix, Inc. v. DivX, LLC ¹⁾, the Federal Circuit vacated the Board’s nonobviousness determination because the Board applied the field-of-endeavor branch of the analogous-art test too rigidly. Although the IPR petitioner did not use the precise phrase “field of endeavor,” its briefing sufficiently identified overlapping fields: AVI files and/or encoding and decoding multimedia files. The court emphasized that analogous-art arguments need not be framed with “magic words,” and that the Board should consider the substance of the party’s arguments taken as a whole. The field-of-endeavor inquiry may be broad and is not limited to the claimed point of novelty or the narrowest problem solved by the invention.

Stated the court:

• “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.”
• “Even where a petitioner does not explicitly define a field of endeavor, its briefing may nonetheless present an argument on that issue when taken as a whole.”

The court separately affirmed the Board’s reasonable-pertinence determination. Unlike the field-of-endeavor test, reasonable pertinence focuses on the particular problem the inventor was trying to solve. Substantial evidence supported the Board’s finding that the challenged patent addressed facilitating trick-play functionality in streaming multimedia, while the prior-art reference addressed a different problem involving image compression and memory limitations in digital cameras. Thus, even though the Board had to reconsider field of endeavor on remand, it did not need to reconsider reasonable pertinence.

Stated the court:

• “Prior art that is outside an inventor’s field of endeavor is reasonably pertinent only if its subject matter logically would have commended itself to an inventor’s attention in considering his problem.”
• “A prior art reference is reasonably pertinent only if a person of ordinary skill would reasonably have consulted those references and applied their teachings in seeking a solution to the problem that the inventor was attempting to solve.”
• “In light of the evidence supporting the Board’s finding, as well as the Board’s thorough consideration of the record, we cannot say that the Board’s finding is unreasonable.”

In In re Klein, ²⁾, the Federal Circuit reversed the Board’s obviousness rejection because the cited references were not analogous art. The court emphasized that a reference may be used in an obviousness rejection only if it is either from the same field of endeavor or, if outside that field, reasonably pertinent to the particular problem faced by the inventor. Because the Board relied only on the “reasonably pertinent” test, the key question was whether an inventor trying to solve Klein’s particular nectar-mixing problem would logically have looked to the cited divider/container references. The court held that substantial evidence did not support the Board’s finding that he would have done so.

Stated the court:

• “A reference qualifies as prior art for an obviousness determination under § 103 only when it is analogous to the claimed invention.”
• “Two separate tests define the scope of analogous prior 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.”
• “A reference is reasonably pertinent if, even though it may be in a different field from that of the inventor’s endeavor, it is one which, because of the matter with which it deals, logically would have commended itself to an inventor’s attention in considering his problem.”

The most important reasoning is that superficial structural similarity is not enough. Three of the references had movable dividers, but they were directed to separating solid objects, not mixing sugar and water in selectable ratios. The other two references involved mixing separated substances, but did not have movable dividers or the ability to prepare different ratios. The court therefore rejected the Board’s attempt to generalize the problem at too high a level; the proper inquiry was tied to the actual problem identified by the Board—making a nectar feeder with a movable divider to prepare different ratios for different animals.

Stated the court:

• “The purpose of each of Roberts, O’Connor, or Kirkman is to separate solid objects.”
• “An inventor considering the problem of ‘making a nectar feeder with a movable divider to prepare different ratios of sugar and water for different animals,’ would not have been motivated to consider any of these references when making his invention.”
• “While Greenspan and De Santo are each directed to containers that facilitate the mixing of two separated substances together, an inventor considering the problem of ‘making a nectar feeder with a movable divider to prepare different ratios of sugar and water for different animals,’ would not have been motivated to consider either of these references since neither of the references shows a movable divider or the ability to prepare different ratios.”

The opinion is also useful for pushing back against post hoc reformulations of the problem on appeal. The PTO attempted to recast Klein’s problem more broadly as a “compartment separation problem,” but the Federal Circuit refused to sustain the agency’s decision on that new ground. That aspect of the case reinforces that the analogous-art inquiry depends on the problem actually found and applied by the Board, not a broader problem newly articulated during appellate review.

Stated the court:

• “We agree with Mr. Klein that, to the extent the government attempts to do so, it cannot redefine the problem Mr. Klein was addressing as a ‘compartment separation problem’ on appeal.”
• “In the Decision, the Board did not set forth any reasoning in support of its finding that Greenspan and De Santo are analogous, and thus, this finding is also not supported by substantial evidence.”