For the Record
A patent is a publicly available document. That document has no shelf life. I can get copies of patents that were published 150 years ago. Why is this a big deal for patent attorneys?
These documents are not novels or even journalistic pieces. They are legal documents. For the first 20 years or so of their lives, they are supposed to provide patentees with a monopoly in the claimed invention. This means that they can be pored over by interested parties, like other patent attorneys. It's a source of anxiety for those of us who take pride in our work. Or perhaps it's a case of fragile egos. The point is that our work can undergo intense scrutiny at least for 20 years. If that were not enough, our correspondence with patent examiners is also available to the public. This correspondence is often a record of legal arguments that we make in support of our clients' patent applications.
The United States has an interesting legal doctrine called "Prosecution History Estoppel". You will be familiar with the line: "whatever you say may be held against you in a court of law." Well, replace "say" with "write" and you have Prosecution History Estoppel. It can be an interesting challenge for an Australian patent attorney to bear this doctrine in mind when communicating with an Australian patent examiner. To understand why this is relevant, one needs to understand what we mean by a patent family.
Simplistically, a patent family is a group of patents or patent applications in various jurisdictions that are generally directed to the same invention. There are a multitude of subtleties, but that will have to do. So, a we may be prosecuting patent applications from the same family in Australia and the United States. As I mentioned above, the official material generated during this parallel prosecution is publicly available and not subject to legal privilege. So there is nothing to stop a U.S. court from using material generated during patent prosecution in Australia to exercise Prosecution History Estoppel.
Patent prosecution is not only presenting the best argument to the patent examiner. It's rather traversing a sort of textual Scylla and Charybdis. On the one hand, our well-reasoned arguments convince the examiner and, on the other, they sink our client in subsequent U.S. patent litigation.