The Australian courts have again rejected the notion that what the applicant says during prosecution can be held against the patentee during later litigation.

In Bradken Resources Pty Ltd v Lynx Engineering Consultants Pty Ltd, [2015] FCA 1100, the judge was asked to consider the meaning of the claim term “integrally formed” for the purposes of infringement. The defendant pressed upon the judge to utilise the applicant’s correspondence with the Patent Office, namely the “prosecution history”, as an estoppel against the patentee, and adopt a narrow interpretation.

The judge specifically noted that the weight of authority in Australia “eschewed recourse to extrinsic materials (such as correspondence between the patent applicant and the Commissioner of Patents) for the purpose of ascertaining the true scope of a claim”. The judge refused to consider the correspondence. However, the judge did adopt the narrow interpretation anyway.

The position in Australia represents a marked contrast to that in the United States, where prosecution history estoppel can play a significant part in restricting the breadth of patent claims.

This article by Shelston IP Principal, Peter Treloar, first appeared in Managing Intellectual Property magazine, December/January 2016.