The Supreme Court affirmed that inventors have the rights to versions of their inventions that use ‘equivalent’ elements.
On 05/28/02, the Supreme Court published its decision in the case of Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. (aka SMC). The case affirmed that inventors have the rights to not only the literal versions of the inventions claimed in their patents but also to inventions that use “equivalent” elements, unless the equivalent element was abandoned by the patentee during the patent process in order to secure a patent. Consider the following hypothetical. A patentee’s invention includes elements A, B, and C. A competitor’s product includes elements A, B, and D. Element D is the functional equivalent of element C. The competitor’s product is within the scope of the patentee’s rights. If, however, the patentee claimed element D during the patent process but abandoned it in favor of the narrower element C, then the competitor’s product would not be within the scope of the patentee’s rights.
What does Festo mean for inventors? The so-called “Doctrine of Equivalents” (DOE) that the Festo decision upholds is, in some respects, a line of last defense (or offense, as the case may be) in a patent dispute. It would be better not to have to rely on the DOE at all. Instead, when you are drafting your patent applications, you should review them from the point of view of your competitor. You should imagine every possible way to get around your future patent, and then you (or your trusty patent attorney) should rework the patent application to fully protect your invention. On the other hand, if you have really deep pockets and a lot of time to spare, you could try litigation. For those scoring at home, Festo has over 10,000 employees and SMC has over 5,000. Since the Supreme Court ruled on the law and not on the merits of the case, the lower courts are still chugging along on the case, which has been going on for 14 years!