Patent Drawings and Written Description

Posted Monday, March 5, 2012.

I wrote a guest blog post for my colleague Jim Ruttler recently regarding a February, 2012 appeal heard at the USPTO’s Board of Patent Appeals and Interferences (BPAI). In this appeal, Ex Parte Waide, a dependent claim had been rejected under 35 U.S.C. 112, first paragraph. The subject matter of the claim was a “controller” which could keep a rotor of a rotorcraft running even after a failure.

The patent examiner had rejected the claim because the inventor’s patent application did not discuss the “controller” in any depth, other than to say that one could be present. By pointing out that the controller was not described in detail, the examiner was saying that the patent application had an insufficient written description for the invention to be patentable.

You can read more about the appeal and the written description requirement here. A purpose of the written description requirement is to show the patent office that the inventor has actually invented something, and not just described a problem along with a wish for a solution. The term of art used is that the written description demonstrates that the inventor “had possession of the invention” at the time the application for a patent was filed. “Written description” also ensures that a third party who wants to be sure not to infringe can ascertain the scope of the boundaries of the invention by reading the patent document. The patent serves notice to the public of those boundaries, but can only do so when the invention is adequately described.

Written description issues often arise in two contexts. The first is during prosecution of a patent application, where a patent claim has been amended with new terms that the examiner believes is not supported by the application as it was originally filed. Claims can be amended during prosecution, but new matter is not allowed. Any claim amendments have to be consistent with the contents of the application as it was filed originally. Patent practitioners say that the amended claim has to be supported by the specification. In fact, the USPTO requires applicants when amending claims to directly point out where the support is in the specification for the amendment.

The second context is when a continuation application is filed which claims priority to a prior application. To have the same priority date as the original application, the patent claims in the continuation must be supported by the specification of the original.

What constitutes adequate support is a very simple question in theory but very challenging in fact. The theory is that the support for a claim term is adequate when one with skill in the art would recognize that the specification must necessarily disclose the subject matter claimed. (The blog post I referenced earlier discusses this in much more detail.)

An interesting wrinkle, however, is that patent drawings may actually provide support for a claim. It may be that the textual portion of the specification does not expressly recite structure corresponding to an element of a claim. However, drawings alone may provide that support. Vas-Cath, Inc. v. Mahurkar, 935 F.2d 1555, 1565 (Fed. Cir. 1991).
In that case, the inventor (Mahurkar) had first disclosed his invention in a design patent to save money. A design patent does not contain a textual description of the invention, but contains only drawings. Mahurkar later followed the design patent with an application for a utility patent which claimed priority to the design patent (in other words, the second context I mentioned earlier where a written description issue can arise). The patent was allowed, leveraging the priority date from the design patent.

In a subsequent infringement suit, the alleged infringer challenged the validity of the patent on the basis that it wasn’t entitled to the priority date of the design patent because the design patent did not adequately describe the invention ultimately claimed in the utility patent. The district court disagreed, finding a drawing alone could provide a sufficient written description. The Federal Circuit affirmed that holding. Id.

Consequently, Vas-Cath v. Mahurkar is best known among patent attorneys and patent agents for its holding that a drawing may provide adequate support for a patent claim, which may overcome a written description rejection.

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