Assignment of “inventions and discoveries” assigns more than just the single listed patent application

A new Federal Circuit opinion highlights the benefits of having a broadly worded assignment when acquiring a patent application from inventors.  In particular, the case confirms that an assignment of “inventions and discoveries” described in a patent application can cover claims that issue in unrelated patents if the claims are supported by the assigned application.

In MHL Tek, LLC v. Nissan Motor Co. (Fed. Cir. Aug. 10, 2011), the Court considered whether MHL Tek had standing to bring an infringement lawsuit for U.S. Patent 5,731,516, which related to a tire pressure sensor.  MHL Tek asserted that it acquired the ‘516 patent from the inventors pursuant to a 1997 assignment agreement.

The inventors were also named in several prior patent applications that were assigned to a different entity (Animatronics, Inc.)  in 1993.  The 1993 assignment document stated that the inventors

do hereby assign, sell and set over to ANIMATRONICS, INC. . . . the entire right, title and interest, domestic and foreign, in and to the inventions and discoveries in [patent application serial number 08/101,379]

In addition to being owned by different companies, the court noted that the ‘379 application and the ‘579 patent were not related by any claim of priority.  The ‘379 application also related to tire pressure sensors, and when the court compared the ‘579 patent’s claims with the ‘379 application’s specification it found that the older document’s specification supported the patent’s claims.  The court noted that:

so long as the written description of [the ‘379 application] ‘reasonably conveys to those skilled in the art’ . . . the invention claimed in the ‘516 patent, the ‘516 patent was assigned to Animatronics.  [citation omitted]

Thus, the court held that the inventors could not have assigned the ‘579 patent to MHL Tek in 1997 because they had already assigned it to Animatronics in the 1993 assignment document.

In addition to illustrating why comprehensive assignment documents can be important, this case also provides a tip for comprehensive patent due diligence.  When acquiring a patent or patent application, the buyer should consider searching for the inventor’s previous patents and patent applications.  If the prior patent documents are in a similar technical field but assigned to a different entity, the buyer should consider comparing the new patent to the old patents and (if available) check the old assignment document to see if it may sweep the new patent into its scope.

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