By Eviatar Aron, US and Israel Patent Attorney

For an invention to be patentable in the United States, it has to be novel and non-obvious. While novelty is a relatively objective requirement, obviousness is quite subjective. A patent claim that is a combination of known technical features from multiple sources, including general knowledge in a particular art, can seem obvious to one person skilled in the art, while a second person might consider it to be nonobvious, and so patentable. One aspect of the obviousness question that is sometimes overlooked is whether a prior art reference is sufficiently enabled to support a rejection of a claim as obvious. Recently, the US Court of Appeals for the Federal Circuit issued a decision in an ongoing dispute between Raytheon and General Electric (GE) (Raytheon Technologies Corporation v. General Electric CompanyCAFC April 16, 2021) which addressed this question.

Raytheon is the owner of patent number US 9,695,751 (the ‘751 Patent) claiming a gas turbine engine, which was challenged by GE in an inter partes review (IPR) before the Patent Trial and Appeal Board (PTAB). In the ‘751 Patent, power density is defined as sea-level-takeoff (SLTO) thrust divided by the engine turbine volume; the key distinguishing inventive feature of the claims is the recitation of a power density range that the patent describes as being much higher than in the prior art. During the IPR, all claims except for claims 3 and 16 were subject to terminal disclaimer. Both claims 3 and 16 were found obvious in view of a single reference (Knip). Knip is a 1987 NASA technical memorandum that envisions “superior performance characteristics for an imagined advanced turbofan engine incorporating all composite materials.” (Raytheon v. GE, 6). During the IPR, it was undisputed that such an engine could not be built in 1987 and still cannot be built today.  However, as the court noted, the speculative nature of the memorandum allowed Knip “to assume aggressive performance parameters for an advanced engine, including then-unachievable pressure ratios and turbine temperatures.” (id., 6).  The PTAB found Knip rendered the claims obvious because it allowed a skilled artisan to “determine a power density as defined in claim 1, and within the range proscribed in claim 1.” (id., 9).  

On appeal, the court delineated the relatively low enablement bar for an obviousness reference used in combination with other sources, stating that: “a reference that does not provide an enabling disclosure for a particular claim limitation may nonetheless furnish the motivation to combine, and be combined with, another reference in which that limitation is enabled.” (Raytheon v. GE, 10).  Furthermore, “such a reference may be used to supply claim elements enabled by other prior art or evidence of record.” (id.). Therefore, the court noted that the issue in this case was whether “a standalone [obviousness] reference must enable the portions of its disclosure being relied upon” to reject a claim. (id., 11). The short answer is a resounding “Yes!”

The court found that the PTAB erred by focusing on whether Knip enabled determination of a power density. The court explained that the PTAB should have determined “whether Knip enabled a skilled artisan to make and use the claimed invention.” (id., 12). Furthermore, the PTAB’s conclusion of obviousness could have been supported “if GE had presented sufficient evidence to establish that a skilled artisan could have made the claimed turbofan engine with the recited power density.” (Raytheon v. GE, 13). However, GE did not present any evidence of this sort.  Therefore, without any supporting evidence or any other reference, the Court determined that “Knip’s self-enablement (or lack thereof) is not only relevant to the enablement analysis,” but it is the determining factor in whether Knip can be used to reject the claims. (id.).

Regarding the evidence necessary to demonstrate enablement of a reference, the Court found the expert testimony presented by GE to be lacking, because its expert constructed “a computer model simulation of Knip’s imagined engine” (id.). rather than the actual engine. In contrast, Raytheon’s expert presented unrebutted evidence of non-enablement, the “unavailability of the revolutionary composite material contemplated by Knip.” (id.). Put another way: a theoretical reference cannot be enabled by an in silico theoretical model. Finally, GE’s argument that a skilled artisan could achieve the claimed power density by optimizing Knip’s engine was rejected by the Court, which stated that “[i]f a skilled artisan cannot make Knip’s engine, a skilled artisan necessarily cannot optimize its power density.” (id.). Based on the above analysis, the Court reversed the PTAB’s obviousness finding regarding claim 3.

Although the issue decided in this case may seem at first glance to be narrow, there are several practical implications which should be noted by practitioners. 

First, an examiner relying on a single prior art reference for an obviousness rejection must meet a higher standard of enablement than if that reference is used in combination with another reference or the knowledge of the art. This may become particularly relevant even when a claim is rejected based on a combination of references, but one of the references is disqualified or becomes no longer relevant.

Second, the standard for enablement in an obviousness rejection requires consideration of the rejected claim as a whole and not just specific features recited in the claim. 

Finally, during an IPR, a third party is required to demonstrate that the prior art allows an actual recreation of the claimed invention; it is not sufficient to provide simulations or virtual reproduction of the claimed invention.  

In conclusion, the clarity provided by the court in the above case, serves to provide the patent practitioner and, by extension, patent applicants, with more than a glimmer of hope when it comes to the validity of obviousness rejections based on a single reference.

More Posts You May Find Interesting