WASHINGTON, May 28 (UPI) -- The Supreme Court tried to clarify U.S. patent law Tuesday in what many regard as a landmark intellectual property case.
A unanimous Supreme Court said patent owners have more flexible rights to defend their patents than a lower court had indicated.
At issue in the case out of Boston is how much protection an amended patent gives to a company's invention when a competitor manufactures a similar device with only small changes made to it.
The case also pivots around two basic elements of intellectual property law.
The "doctrine of equivalents" prevents a competitor from escaping liability under federal patent law "by changing only minor or insubstantial details of a claimed invention while retaining the invention's essential identity."
The doctrine first was embraced by the federal courts in 1853. Since then, the Supreme Court has based many of its intellectual property decisions on it.
However, the doctrine also can be abused. The courts have found that when they apply the doctrine too broadly, it conflicts with other facets of patent law, particular the requirement to give public notice of amendments in patents.
This gave rise to the second important element in the Boston case: "prosecution history estoppel."
Less complicated than it sounds, "prosecution history" simply means the record of the "prosecution" or pursuit of a patent. "Estoppel" is an expression that means someone is legally prevented from making a claim or asserting a right.
"Prosecution history estoppel" prevents a patent-seeker from using the doctrine of equivalents to protect the details of an invention when those details have been "relinquished" or given up during the pursuit or amendment of a patent.
The person or company seeking a patent has created a record that fairly notifies the public that the patent-seeker "has surrendered the right to claim particular matter as within the reach of the patent," according to an interpretation by a federal appeals court.
In the Boston case, the Festo Corp. owns two U.S. patents, called the Stoll and Carroll patents after their inventors. Both cover "magnetic rodless cylinders," devices used in a wide range of industrial applications to transport something from one point to another.
The devices have three basic components: a piston, a cylinder and a sleeve. The piston is driven by pressurized fluid. The magnetic linkage between the cylinder and the sleeve allows the sleeve to move back and forth along the cylinder without any mechanical linkage.
Both the Stoll and Caroll patents, however, were subject to amendments during the application process to satisfy the descriptive requirements of the U.S. Patent Act.
Festo sued SMC Peumatics Inc. in federal court for allegedly violating the patents -- saying SMC devices essentially duplicated the Festo patents "save in two insubstantial respects" -- and a federal judge ruled summarily for Festo under the doctrine of equivalents.
A federal appeals court panel in Washington upheld the judge, and SMC asked the Supreme Court for review. The high court justices took the case, threw out the appeals court ruling, and told the lower court to rehear the case in light of the Supreme Court's 1997 ruling in Warner-Jenkinson vs. Hilton Davis.
Warner-Jenkinson sharpened the requirements for using the doctrine of equivalents and prosecution history estoppel.
When the Festo case returned to the appeals court level, this time the full Federal Circuit Court of Appeals in Washington reversed the judge.
The full appeals court broadened the impact of prosecution history estoppel, saying virtually any patent amendment would trigger it, regardless of whether the amendment was made to avoid duplicating elements in someone else's earlier patent or whether to satisfy the requirements of the Patent Act.
Festo then asked the Supreme Court to take a second look at the case, saying the appeals court had accomplished a "virtual abolition" of the doctrine of equivalents. If allowed to stand, Festo argued, the appeals court decision "will seriously disrupt and damage the patent system."
"The Federal Circuit's decision abolishes most of the protection afforded by the United States patent laws," Festo's lawyers said in their petition to the Supreme Court. "No copyist need now fear the doctrine of equivalents and only a fool would fail to make an insubstantial change to avoid the literal terms of a patent claim."
Tuesday, the Supreme Court granted some of what Festo wanted.
The "estoppel" doctrine may apply across the board, the justices said, but the doctrine doesn't necessarily block lawsuits against other companies who duplicate an element of an amended claim.
However, the high court said, the burden is on the inventor to prove that amendments made during a patent application process did not surrender the rights to particular element of an invention.
The unanimous opinion was written by Justice Anthony Kennedy, but takes no firm stand on whether Festo won its case.
Instead, the Supreme Court sent the case back down to the lower court for a rehearing based on Tuesday's opinion.
(No. 00-1543, Festo Corp. vs. Shoketsu Kinzoku Kogyo Kabushiki Co. Ltd., a/k/a SMC Corp. and SMC Pneumatics Inc.)
