A Standalone Reference Must “Enable” Claims to Render them Obvious

In Raytheon Tech. Corp. v. General Electric Co., the Federal Circuit recently overturned the USPTO Patent Trial and Appeal Board’s ruling that Raytheon’s claims to a gas turbine engine (in USPN 9,695,751) were unpatentable as obvious. The Board’s ruling came in an IPR proceeding initiated by GE.

The claims of the patent at issue are directed toward a gas turbine engine and posititively recite a power denity range achieved thereby. Raytheon argued that its recited power density range rendered its claims patentable over the standalone reference cited by GE.

The Board found the reference appliable, and the claims unpatentable, because the reference allowed a skilled artisan to “determine a power density as defined in [the relevant claims].” The Board acknowledged that whether the prior art is enabling is a threshold issue, and found it was met here as the standalone reference provides the basis for the power density limitation at issue.

In reversing the Board, the Federal Circuit held that the Board’s threshold inquiry was too narrow. The Federal Circuit explained that the proper inquiry is whether the prior art basis for an obviousness challenge enables a skilled artisan to practice the claimed invention — as opposed to just a feature of it. 

The analysis is founded on the doctrine that, “[t]o render a claim obvious, the prior art, taken as a whole, must enable a skilled artisan to make and use the claimed invention.” Where there are multiple references, each need not be individually enabling - they can be considered as a whole. But, in the case here, the whole of the prior art was a single reference. 

The single reference at issue did not enable a skilled artisan to practice a gas turbine engine. The reference was a non-patent NASA memorandum from 1987 about the potential performance capabilities of gas turbine engines with conceived, but non-existent, composite materials. In the IPR, Raytheon presented unrebutted evidence that such materials did not exist at the priority date at issue.

The Federal Circuit rejected the argument that the advanced engine design features, uncovered by the claims at issue, need not be enabled. As the reference stood alone, that unachievable advanced design was the only disclosure of any engine — and some engine needed to be enabled as a threshold to rendering claims to an engine obvious. The standalone reference didn’t meet this threshold as a skilled artisan could not rely on the disclosure of an unachievable design to actually build an engine. Thus, the obviousness challenge to Raytheon’s engine claims could not launch, and the Board’s decision was reversed.