In a recent appeal of a United States Patent Office (“USPTO”) final rejection of a claim, the Court of Appeals for the Federal Circuit enunciated a rule that would limit the ability of patent Examiners to rely on disparate prior art references as the basis for an obviousness rejection when they could not be shown to be pertinent to the problem the inventor sought to solve. In re Klein, No. 10-1411, 2011 WL 2178134 (Fed. Cir. June 6, 2011).

Specifically, the Federal Circuit sided with the patent applicant and rejected the USPTO Board of Patent Appeals and Interference’s obviousness conclusions. The court held that none of the five cited prior art references could be considered “analogous art” because they were relevant to only a portion of the problem to be solved by inventor Klein’s invention, and were therefore excluded from the court’s obviousness analysis. Although arguably contrary to conventional patent prosecution practices, the holding in Klein may provide incentive for prosecutors to include, in limited conditions, a statement of purpose in the independent claims.

Standard For Analogous Art

A reference qualifies as prior art for the purposes of 35 U.S.C. Section 103 only when it is analogous to the claimed invention.1 A prior art references is considered analogous if it is either (1) in the same field of endeavor as the invention or (2) “reasonably pertinent” to the problem with which the inventor is involved.2 In turn, a reference is reasonably pertinent if it logically would have commended itself to an inventor's attention in considering his problem.3

MPEP Section 2141.01(a) states that “[a]ny need or problem known in the field of endeavor at the time of the invention and addressed by the patent [or application at issue] can provide a reason for combining the elements in the manner claimed.”4 Particularly in the mechanical5 and electrical/computer arts,6 Examiners are given broad discretion to locate and apply prior art addressing a similar problem.

The Claimed Klein Invention

While the rule articulated by the Federal Circuit has broad implications on obviousness analysis, the impact of the rule should be tempered by the fact that the patent at issue dealt with an extremely simple mechanical invention. Klein’s patent application is directed to a cup with movable dividers so that users may fill one side with water, one side with sugar, and remove the divider to mix the water and sugar in various predetermined ratios for use in a bird feeder.

Of particular importance to this case, Klein's broadest independent claim is both narrow in scope and recites a purpose of the invention. Claim 21 recites:

21. A convenience nectar mixing device for use in preparation of sugar-water nectar for feeding hummingbirds, orioles or butterflies, said device comprising:

a container that is adapted to receive water,

receiving means fixed to said container, and

a divider movably held by said receiving means for forming a compartment within said container, wherein said compartment has a volume that is proportionately less than a volume of said container, by a ratio established for the formulation of sugar-water nectar for hummingbirds, orioles or butterflies, wherein said compartment is adapted to receive sugar, and wherein removal of said divider from said receiving means allows mixing of said sugar and water to occur to provide said sugar-water nectar.

Klein admitted in the application that the predetermined ratios were well-known in the prior art. The USPTO, based on the admission, issued five separate obviousness rejections of Claim 21, each utilizing a different prior art reference in combination with the admitted ratios.

The Prior Art

Because the USPTO had based its rejection only on the “reasonably pertinent” prong of the analogous art test, the Federal Circuit similarly limited its analysis, and did not address whether any of the references were in the same field of endeavor.

Three of the references (Roberts, O’Connor and Kirkman) were directed toward containers with movable dividers used to separate solid items. The CAFC first considered the problem being solved by Klein and arrived upon a narrowly-defined single problem of: “making a nectar feeder with a movable divider to prepare different ratios of sugar and water for different animals.” Based on this narrow statement of the problem Klein sought to solve, the court concluded that the three solid item separators were not pertinent to Klein's problem “since none of these three references shows a partitioned container that is adapted to receive water or contain it long enough to be able to prepare different ratios in the different compartments.”

The two other references (Greenspan and De Santo) were directed to inventions dividing liquids that would be later mixed. The court found neither of these pertinent to Klein's invention because they did not address the multiple ratio problem and lacked movable dividers.

Incentives For An Explicit Statement Of Purpose

The holding of Klein may create an incentive for patent prosecutors to include a narrowly-tailored statement of the purpose of their claimed invention in the patent claims. Klein's success on appeal may be attributed to, at least in part, the singular narrow purpose of his invention, which allowed him to argue that the cited references were outside of that purpose. On appeal, the USPTO Solicitor characterized the problem being solved as a “compartment separation problem.” However, this argument was rejected by the Federal Circuit as untimely, because it had not been raised before the Board of Patent Appeals.7 The BPAI may broadly define the problem being solved in future appeals to avoid this issue going forward.

Additionally, a narrow statement of purpose may exclude entire swaths of prior art references that are not pertinent to the problem as a whole. Although the court did not explicitly articulate a rule that prior art references in a separate field of endeavor will not be analogous unless they are pertinent to the entire problem being solved, all of the references were pertinent to some aspect of the stated problem, but they failed the test because none was related to the problem as a whole.

However, because the court failed to reconcile this holding with the holding of KSR, which has previously been interpreted as expanding the scope of analogous art, it is difficult to predict the practical effect of the Klein decision. Furthermore, the Federal Circuit failed to reconcile the result of Klein with a large body of arguably-inconsistent case law in both the mechanical and electrical arts. See, e.g., Pentec, Inc. v. Graphic Controls Corp., 776 F.2d 309, (Fed. Cir. 1985) (addressing claims at issue that were directed to an instrument marker pen body, the improvement comprising a pen arm holding means having an integrally molded hinged member for folding over against the pen body. Although the patent owners argued the hinge and fastener art was nonanalogous, the court held that the problem confronting the inventor was the need for a simple holding means to enable frequent, secure attachment and easy removal of a marker pen to and from a pen arm, and one skilled in the pen art trying to solve that problem would have looked to the fastener and hinge art.); and Ex parte Goodyear Tire & Rubber Co., 230 USPQ 357 (Bd. Pat. App. & Inter. 1985) (holding that a reference in the clutch art was reasonably pertinent to the friction problem faced by applicant, whose claims were directed to a braking material, because brakes and clutches utilize interfacing materials to accomplish their respective purposes.). Therefore, excessive reliance on the implicit rule of Klein is likely ill-advised until further case law takes up the issue of synthesizing and harmonizing the Klein holding with those in previous precedent.

Practical Advice For Patent Prosecutors

Klein's statement of a narrow purpose of the invention runs contrary to much common patent attorney practice because the recited narrow purpose might lead courts to narrow the claim scope during claim construction and in their analysis of infringement under the doctrine of equivalents. Thus, patent prosecutors should consider including a narrow statement of purpose in a small set of conditions: first, when the patent claims are already narrow in scope, second, when the prior art references are from a different field of endeavor and third, when the references are pertinent only to part of the entire problem to be solved. Close consultation with prosecution counsel as to the nature of the prior art landscape, the intended targets the patent aims to cover, and the pros and cons of a recitation of a specific purpose for claims that might otherwise have more generic scope, will likely be advisable in cases in which a statement of purpose for the invention is under consideration.