Supreme Court Overturns Federal Circuit, Adopts Rule of Reason in Applying Prosecution History Estoppel.
On Tuesday, May 28, 2002, the U. S. Supreme Court handed down its long awaited decision in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. case. The case has occupied the limelight in intellectual property circles since the Federal Circuit issued its en banc decision in 2000, because it goes to the heart of patent law: The balance between the patent owner's right to pursue those who have made minor changes to avoid infringement versus the public's right to certainty in determining what a patent covers and what it does not.
The Supreme Court's Festo opinion reinforces the reality that amending a patent claim during patent prosecution always risks a loss of legal rights for the client. Its rule of reason approach in determining the existence and the extent of the estoppel also reinforces time-honored practices of competent patent practitioners:
(1) Know and write claims to the potential commercial activity against which the patent rights will operate, not simply a verbal description of a piece of technology sitting on a table.
(2) Be aware of the state of the art against which patentability will be measured, rather than finding out first in a written rejection from the Patent Office.
(3) Establish a working relationship with the patent examiner to verify that he/she has the information needed and clearly understands your position.
(4) Advise your client at every step and get a meeting of minds before introducing amendments that could alter scope and enforcement of patent rights.
In Festo, the patent owner had amended claim language during the application process to add new limitations required by the Patent Office. The defendant commercialized a device which did not fall literally within the scope of the patent claims, but which the district court ruled constituted infringement by equivalents. The Federal Circuit ultimately reversed, finding among other things that when a patent applicant amends claims for a reason "substantially related to patentability," the doctrine of "prosecution history estoppel" precludes the patent owner from contending that any technology beyond the amended, limited claim is covered by the patent. The Federal Circuit recognized in doing so that it reversed a number of its earlier decisions and that this new, absolute rule of prosecution history estoppel would be counter to the expectations of...