Federal Circuit Provides Insights on Arguments Against Obviousness

June 26, 2012

Michael J. Attisha PhD

What This Means To You

  • To make a “change in operating principle” argument against obviousness, argue the reference exclusively relied on a principle that would be lost in the proposed combination.
  • To make a ‘teaching away’ argument against obviousness, argue the claimed combination would have been unworkable, not just undesirable, based on the prior art.


In In re Mouttet, the US Court of Appeals for the Federal Circuit (Federal Circuit) found a change in operating principle argument to be unsuccessful against an obviousness rejection because the broad concept embodied in the references was combinable even if the technology strictly was not. In addition, a mere preference voiced in the primary reference suggesting the undesirability of the technology used in the secondary reference does not preclude the combination from being made.

Case Background

The sole inventor in this case, Blaise Mouttet, filed a patent application for an arithmetic processing system in April 2006. The system uses very small scale electrical circuits to store values and perform arithmetic calculations.

The US Patent and Trademark Office rejected Mouttet’s independent claims as being obvious based on references by Falk, Das, and Terepin. Mouttet appealed after the first final rejection, and the rejection was affirmed in the appeal. Mouttet then filed a further appeal in the Federal Circuit, representing himself.

Decision Analysis

The Federal Circuit ruled that a change in operating principle argument against obviousness will be unsuccessful if the broad concept embodied in one reference can nonetheless be combined with a second reference. While a direct substitution of Falk’s optical pipe technology into Das’ system of electrical circuitry would not result in a functioning system, the Federal Circuit ruled there is no prerequisite that the features of the primary reference must be equivalent to those in the secondary reference. It is sufficient that the broad concept embodied by Falk – that of using a network to store values for the purposes of performing calculations – may be substituted into Das.

In addition, the Federal Circuit ruled that a statement in Falk indicating the superiority of optical pipe technology over electrical circuitry is insufficient for a successful ‘teaching away’ argument against obviousness. Without evidence that the claimed combination would have been unworkable based on the prior art, the Court ruled that such an argument would be unsuccessful.


This case suggests it may be more difficult to argue against obviousness without clear affirmative evidence that the combination would be unworkable. At some level, every obviousness combination results in some kind of ‘operating principle,’ no matter how small. It may be possible to draw a distinction between these kinds of changes and genuine differences by arguing a reference indicates only its approach will work, but this is a high bar.

One alternative is to argue that substitution of known elements requires those elements to be performing their known functions and, in making the combination, the elements would be performing a different function.