The following article appears in the journal JOM, 43 (1) (1991), p. 54. JOM is a publication of The Minerals, Metals & Materials Society

Interference Proceedings—
Winner Take All

When two or more parties claim identical or substantially identical invention, the U.S. Patent and Trademark Office may declare an interference proceeding to determine which party has priority of invention. The one ruled to have prior rights obtains the right to the patent claims at issue. The other party does not get the patent claims and may be precluded from practicing the invention because such conduct might infringe the patent claims of the one who prevailed in the interference proceeding.

While an interference proceeding may involve more than two parties, this review is confined to a two-party interference. Such a proceeding may be initiated between two pending applications or a pending application and an issued U.S. patent. If two patents are involved, the Patent and Trademark Office would not have jurisdiction over the controversy, and the matter would have to be resolved in the courts. The owner of one patent may, under certain circumstances, file a reissue application which has claims in common with the other party's patent and seek to have an interference declared in the Patent and Trademark Office.

In an interference proceeding, the act of invention consists of two distinct events—conception and reduction to practice. Conception is the creation of the idea. Reduction to practice involves verification, which generally involves physical testing to confirm the suitability of the invention for the purpose for which it was designed. If there has been no actual reduction to practice, one obtains the benefit of a constructive reduction to practice as of the date of filing a U.S. patent application that discloses and claims the invention. It is not essential that the invention be in commercially acceptable form for there to be a successful reduction to practice.

One who can prove that he or she both conceived and reduced to practice the claimed invention before reduction to practice by the other will win the interference. In some instances, the one who conceives the invention first reduces it to practice second. In such circumstances, there is no clearly defined "first inventor." The issue of diligence in reduction to practice then becomes critical. If the first to conceive reduces the invention to practice after the other party has both conceived and reduced the invention to practice, the central issue becomes whether the first to conceive exercised due diligence toward reduction to practice dating from a time before conception by the second. If so, the first to conceive is awarded priority even though reduction to practice occurred later. If not, the second to conceive is awarded priority.

Before an interference can be declared, it must be determined that the disclosure of each party's application permits the party to "make the claim" in controversy, which is designated the "count" in the interference. In the event that a party is claiming substantially the identical invention but cannot make all of the limitations of a claim of another party, the Patent and Trademark Office may create a "phantom count," which is generally broad in scope and supported by the disclosure of both applications.

An interference may involve a number of claims and a number of counts. There are times when only some of the claims in a patent or application will be involved in interference. In such cases, the ruling on the interference will involve only those claims which are part of the interference proceeding. The remaining claims are unaffected by the interference decision.

An interference can be a very complex proceeding. It is heard before and decided by the Patent and Trademark Office. Each party is put to its proof regarding dates of invention and has an opportunity to engage in discovery of the other party's evidence. Legal briefs are submitted that argue points of law as supported by the evidence, a final oral hearing is held, and judgment is rendered. A party dissatisfied with the judgment may appeal the case to the federal court system.

Keeping proper records of the invention frequently is the difference between success and failure in an interference. Records should be maintained in ink, preferably in a bound notebook, and be signed and dated by the inventor with the words "witnessed and understood" provided under the inventor's signature. Two or more individuals who are capable of understanding the notebook entry should review the same and sign and date it as witnesses. Such records can serve to confirm the date of conception of the invention. They also can serve to confirm reduction to practice. The essence of such proof in an interference involves the need for the inventor's evidence to be corroborated by a third party. Failure to keep proper records may result in the party who first actually created the claimed invention losing the interference and being subject to the patent rights of the party awarded priority.

Importantly, there must be a good correlation between the subject matter of the records (with respect to technical disclosure) and the patent application or patent claims or counts involved in the interference. Proof of early dates would be of lime consequence if it is not proof of the invention set forth in the claim or count. It is important, therefore, in keeping records that good judgment be exercised in determining the scope of general statements as well as specific preferred refinements. Failure to prove that records correspond directly in subject matter with the claim or count can result in loss of an interference.

Also, it is important that there be a direct correlation between the specification which describes the subject matter of the patent application and the patent claims themselves. Such correlation is normally part of sound patent practice. A further question can arise as to whether the patent disclosure of one party to the interference has an adequate basis to support the count in the interference. If it does not, the other party may move to have the interference proceeding dissolved as there would be no interference (i.e., the two parties do not have claims which are in direct conflict).

Diligence in filing a patent application can be important. There is an advantage in being the first to file as the one who files first is deemed the "senior party" in an interference with the second to file having the burden of proving priority over the first filed application. If one delays too long in filing an application after a reduction to practice of an invention, the second to create the invention may obtain priority as the first may be regarded as having "abandoned, suppressed or concealed" the invention.