27.Festo Consideration

27. Festo Considerations You should have drafted a full spectrum of claims (from broad to specific) which cover every aspect of your invention and all possible permutations. The reason for this is the Supreme Court’s decision in Festo v. Shoketsu, which holds essentially that the Doctrine of Equivalents can be used to broaden any claim that was amended during prosecution provided (a) the equivalent was unforeseeable at the time the application was filed, or (b) the equivalent is not related to the way the claim is amended. However, if the court cannot determine the reason for the amendment, the DoE cannot be used. By submitting a full spectrum of claims, at least some of them will stand a good chance of being allowed in the prosecution stage without amendment, thereby preserving your full DoE rights for those claims. During the prosecution stage, you should try, if at all possible, not to amend any claims, or to amend as few as possible. If you have to amend any claims, state the reason for the amendment.