As a community service, an educational series by the

IP and Business Law Offices of Howard L. Hoffenberg, Esq.

HOLDING: (1) The doctrine of equivalence is viable. (2) Central to the determination of equivalence is an objective inquiry made on an element-by-element basis of the claim to the accused product. (3) There is no rigid formula. Both the triple identity and insubstantial differences tests are viable frameworks. (4) An analysis of the role of each element in the context of the patent claim informs whether a substitute element matches the function, way, and result of the claimed element. (Consideration is given to purpose, qualities when combined and function.) (5) Interchangeability is an important factor. With regard to the objective nature of the doctrine, a skilled practitioner's knowledge of the interchangeability between claimed and accused elements is not relevant for its own sake, but rather for what it tells the fact finder about the similarities or differences between those elements. The perspective of a skilled practitioner provides content to, and limits on, the concept of "equivalence." (6) The proper time for evaluating equivalency--and thus knowledge of interchangeability between elements-- is at the time of infringement, not at the time the patent was issued. The Court rejected that equivalents must not only be known, but must also be actually disclosed in the patent in order for such equivalents to infringe upon the patent. (7) Intent of the infringer plays (e.g., copying, designing around a patent, or independent experimentation) and there is no equitable threshold. (8) The determination of prosecution history estoppel requires a court to consider the purpose of a claim amendment. Where the patentee has no explanation, estoppel is presumed. (9) While not an issue before the Court, the Court commented that Federal Circuit decisions that equivalents was a jury question was in accord with the precedent of the Court. (10) On remand from the Supreme Court is FESTO CORPORATION v. SHOKETSU which will be reheard en banc. The following issues were heard and the case returned to the Sumpreme Court:

 

1. For the purposes of determining whether an amendment to a claim creates prosecution history estoppel, is a substantial reason related to patentability,Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 33 (1997), limited to those amendments made to overcome prior art under Sections 102 and 103, or does patentability mean any reason affecting the issuance of a patent?

 

2. Under Warner-Jenkinson, should a voluntary claim amendment - one not required by the examiner or made in response to a rejection by an examiner for a stated reason - create prosecution history estoppel?

 

3. If a claim amendment creates prosecution history estoppel, under Warner-Jenkinson what range of equivalents, if any, is available under the doctrine of equivalents for the claim element so amended?

 

4. When no explanation [for a claim amendment] is established, Warner-Jenkinson, 520 U.S. at 33, thus invoking the presumption of prosecution history estoppel under Warner-Jenkinson, what range of equivalents, if any, is available under the doctrine of equivalents for the claim element so amended?

 

5. Would a judgment of infringement in this case violate Warner-Jenkinson's requirement that the application of the doctrine of equivalents is not allowed such broad play as to eliminate [an] element in its entirety, 520 U.S. at 29. In other words, would such a judgment of infringement, post Warner-Jenkinson, violate the all elements rule?

WARNER JENKINSON COMPANY, INC. v. HILTON DAVIS CHEMICAL CO. (March 3, 1997)

 

FACTS: The patent-in-suit claimed a dye purification process. During prosecution, the patentee added a limitation, without explanation, of pH above 6.The process by Defendant operated at pH 5 and it challenged infringement under the doctrine of equivalents.

Tour of US Supreme Court Patent Cases from 1961 to 1999

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A Fast and Easy Way to Learn the High Points of Patent Law and Related Anti-trust Law

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Community Service and

Pro Bono

In addition to this education series, Mr. Hoffenberg gives of his time to benefit the community and contribute to the quality justice in the State of California. For many years, he served as a volunteer pro tem in the Municipal Court in traffic, landlord-tenant, small claims and short cause matters. Currently, Mr. Hoffenberg serves as a volunteer arbitrator for the Dispute Resolution Service in attorney-client fee disputes and as a quasi-volunteer mediator in the Court of Appeals.