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What do you need to do?Be aware of the impact of the description on the interpretation of the claims and do not assume that technical terms have a clear and unambiguous meaning.
Shyama Jayaswal
Senior Associate
Indra Bhattacharya
Solicitor
Wayne McMaster
Partner
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Sydney
Kim O'Connell
Melbourne
Robert Cooper
Brisbane
John Swinson
The recent Federal Court decision in Nufarm Ltd v Jurox Pty Ltd has again highlighted the importance of carefully considering the language used in the body of the specification when drafting patents.
The decision also serves as a timely reminder that even commonly used technical terms may be held to be ambiguous due to slight variations in definitions in different contexts.
The proceedings
This case involved the construction of Nufarm’s patent for a stable composition used primarily as an oral drench for the purpose of controlling intestinal parasites in sheep (Nufarm Patent).
Nufarm brought an action against Jurox alleging that a product sold by the company, Q-Drench, infringed each of the 5 claims of the Nufarm Patent. The key issue before the Court for determining infringement was whether Q-Drench was an “emulsion” consisting of separate “phases” as required by the Nufarm Patent.
Expert evidence on the meaning of technical terms
Both parties led substantive expert evidence on the meaning of the terms “phase” and “emulsion”. While there seemed to be agreement as to the basic definition of a “phase”, the parties disagreed as to whether in order to constitute a separate phase, there must be a minimum threshold number of molecules of the substance in question.
Further, given that an “emulsion” is a system in which there is separation of one liquid phase from another, the difference in opinion about the definition of a “phase” meant that the parties also disagreed as to the proper meaning to be given to the term “emulsion”.
Construction of the claims
Justice Middleton concluded that in view of the differing expert opinions, the terms “emulsion” and “phase” lacked clarity, and he therefore turned to the body of the specification to aid in the construction of the relevant claims. In particular, His Honour focused on a series of examples given in the specification.
Justice Middleton found that the examples were not included to illustrate what was covered by the claims, but rather to describe the process by which the invention had been developed, and to illustrate the inventive steps taken.
His Honour held that Nufarm had impliedly disclaimed the first four examples given. This finding was despite the fact that the Nufarm Patent did not expressly describe these examples as being comparative examples. Justice Middleton therefore concluded that the examples did not fall within the scope of the claims of the Nufarm Patent.
It was accepted by both Nufarm and Jurox that the composition of Q-Drench was very similar to those four examples. As a result, Middleton J held that Q-Drench was not within the scope of the claims, and so did not infringe the Nufarm Patent.
Conclusion
The decision in Nufarm provides an example of how the Courts are likely to approach the construction of technical terms which are capable of having more than one meaning. The decision demonstrates that in cases where there is ambiguity in the definition of such terms, the Courts will look carefully at the specification to determine the context in which the term is used instead of trying to resolve the issue in theoretical abstract. Further, even where a product copies an example given in the specification, the Courts will not necessarily find that that product infringes the patent.