Extending Liebel-Flarsheim: “distinctly different” embodiment of claim elements must be enabled

ScreenShot049Automotive Technologies International v. BMW, et al. (Fed. Cir. 2007).

ATI’s patent claims are directed to an automotive side impact crash sensor used to trigger an airbag and include the following means-plus-function limitation:

“means responsive to the motion of said mass upon acceleration of said housing in excess of a predetermined threshold value, for initiating an occupant protection apparatus”

Following ATI’s suggestion, the district court construed the means limitation to include both mechanical and electronic sensor structures. Then, based on this interpretation, the district court ruled the patent invalid for lack of enablement. (summary judgment).  

On appeal, the CAFC affirmed the ruling — finding that the specification did not enable the full scope of the claimed invention.

The specification describes the mechanical sensor in detail with multiple figures. The electronic sensor, however, is only shown in a sparse “conceptual” Figure 11 (see image at right) and described in broad terms as potentially operating “through variety of technologies using, for example, optics, resistance change, capacitance change or magnetic reluctance change.”

Enabling One Embodiment Is Insufficient: Following on the heels of Liebel-Flarsheim v. Medrad, this case reaffirms the principle that the full scope of a claim must be enabled. Enablement of a single embodiment is not sufficient. Thus, the patent’s enablement of one mode of practicing the invention (the mechanical sensor) was not sufficient to satisfy the enablement requirement.

Looking back, Liebel-Flarsheim discussed “full scope” enablement as being “at least reasonable enablement of the scope of the [claim] range.” Here, the CAFC further defines that principle by noting that electronic sensors must be particularly enabled because they are “distinctly different” from the enabled mechanical sensor.

Novel Aspects Must Be Enabled: ATI also argued that Figure 11 and its accompanying text were enabling — especially when coupled with the knowledge of one having ordinary skill in the art. This argument was rejected based on the CAFC’s combined measure of law and fact. As a matter of law, enablement of the novel aspects of an invention must be enabled by the specification even if implementation would have been within the PHOSITA’s skill level. As a matter of fact, the CAFC concluded that sensor mechanism must be a novel aspect based on statements in the specification that side impact sensing is a “new field” and that the only available side-impact switch was a crush sensor.


  • Its unclear how the enablement doctrine will work in conjunction with the doctrine of equivalents.
  • The summary judgment was reviewed de novo for clear and convincing evidence of non-enablement sufficient to overcome the patent’s presumption of validity.
  • Disclaimer: My former firm, McDonnell Boehnen Hulbert & Berghoff LLP, handled this appeal on behalf of the plaintiff. Although I have not worked on the case, MBHB took-over the case while I was of counsel last year.

The New Law of Enablement

Liebel-Flarsheim v. Medrad (Fed. Cir. 2007).

This case raises an interesting enablement issue. The issue involves how we should interpret patent claims that extend coverege over material that is not enabled.  This is an important question because most patent claims are written to literally cover embodiments that are not fully enabled. 

Facts: Liebel-Flarsheim’s patent describes a preferred embodiment of a needle holder that includes an associated pressure jacket but do not enable a jacket-free embodiment.  The patent claims did not claim (or even mention) the pressure jacket and thus, based on comprising language, were construed to cover injectors regardless of whether they have an associated pressure jacket.  Medrad’s accused products do not have the pressure jacket.

Lower Court: The lower court found the patent invalid as not enabled — holding that it would have taken undue experimentation to practice the claimed invention without the pressure jacket.

Argument on Appeal: Liebel argues that "the asserted claims do not recite or require the absence of a pressure jacket and the court improperly focused on such an embodiment."  In particular, the question of creating an embodiment without a pressure jacket is not one of "experimentation" but rather additional follow-on innovation.

Appellate Decision: On appeal, CAFC panel found the patent invalid as not enabled.

We have previously construed the claims … such that they are not limited to an injector with a pressure jacket, and therefore the full scope of the claimed inventions includes injectors with and without a pressure jacket. That full scope must be enabled, and the district court was correct that it was not enabled.

There must be “reasonable enablement of the scope of the range” which, in this case, includes both injector systems with and without a pressure jacket.

The irony of this situation is that Liebel successfully pressed to have its claims include a jacketless system, but, having won that battle, it then had to show that such a claim was fully enabled, a challenge it could not meet. The motto, “beware of what one asks for,” might be applicable here.

Invalidity affirmed.


  • "During the prosecution of the front-loading patents, Liebel removed all references in the claims to a pressure jacket."