''Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Co.'', 520 U.S. 17 (1997), was a United States Supreme Court decision in the area of patent law, affirming the continued vitality of the doctrine of equivalents while making some important refinements to the doctrine..

Facts

The plaintiff Hilton Davis Chemical Co., a dyemaker, had developed an " ultrafiltration" process to purify

dyes A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution and ...

. An amendment to the patent had specified that a solution used in the process must have a pH level between 6.0 and 9.0. The amendment was filed in order to clarify that this patent did not overlap with a previously patented process that used a solution with a pH level above 9.0 - however, the plaintiff was unable to explain why the amendment stated a ''lower'' level of 6.0. The

defendant In court proceedings, a defendant is a person or object who is the party either accused of committing a crime in criminal prosecution or against whom some type of civil relief is being sought in a civil case. Terminology varies from one jurisdic ...

had developed a process using a solution with a pH level of 5.0, which was outside the range of the plaintiff's patent. The plaintiff sued for infringement, conceding that the defendant's process did not ''literally'' infringe, but relying on the doctrine of equivalents to support the claim of infringement. The defendant argued that the doctrine of equivalents was no longer appropriate for courts to use because Congress had made some changes to the patent statute after the Supreme Court's 1950 decision establishing the propriety of using the doctrine.

Issue

Is the doctrine of equivalents still in force? How is the plaintiff's amendment to figure into the problem?

Result

The Court, in an opinion by Justice Clarence Thomas, held that the doctrine of equivalents had not been eliminated by changes to the patent statute. Instead, the Court determined that the United States Congress would have explicitly stated that they were eliminating the doctrine if that was their intent. The Court enunciated a test for amendments, finding that if the plaintiff can prove the reason for the amendment was not to limit the patent, then infringement was still possible. The case was remanded to the trial court to determine if the plaintiff could explain his lower pH limit.

Concurrence

Justice Ruth Bader Ginsburg wrote a concurring opinion, in which Justice Anthony Kennedy joined, expressing some concern about whether patentees would have sufficient notice that they must explain the reasons for their amendments. Nevertheless, they agreed with the remand to the lower court to establish the plaintiff's reason for setting a lower limit.

References

External links

* {{caselaw source , case = ''Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Co.'', {{ussc, 520, 17, 1997, el=no , cornell =https://www.law.cornell.edu/supct/html/95-728.ZS.html , courtlistener =https://www.courtlistener.com/opinion/118092/warner-jenkinson-co-v-hilton-davis-chemical-co/ , googlescholar = https://scholar.google.com/scholar_case?case=1167640840017617484 , justia =https://supreme.justia.com/us/520/17/case.html , loc =http://cdn.loc.gov/service/ll/usrep/usrep520/usrep520017/usrep520017.pdf , oyez =https://www.oyez.org/cases/1996/95-728 1997 in United States case law United States patent case law United States Supreme Court cases United States Supreme Court cases of the Rehnquist Court

Facts

Issue

Result

Concurrence

See also

References

External links