I promised I'd post any information I received regarding the efficacy as a priority document in the EPO of a US provisional application. Here's the response from my European associate on the matter:
<BLOCKQUOTE>
In terms of your more general query regarding the use of US provisionals as priority documents, my understanding is as follows. The confusion stems from the original 1995 US legislation that created provisionals as things that automatically died after a year. It has been argued that these are not patent applications, since they could never mature into a granted patent. And if they are not patent applications, then under the Paris Convention there would be no right of priority.
The first point to note is that the problem (if any) has now been fixed, since the US 1998 patent legislation amended the situation for provisionals. These can now be converted into a full application if so desired, and so would appear to meet clearly the definition of a patent application.
Any dispute is therefore only relevant for provisionals filed prior to this change. The EPO has stated, as a matter of policy, that it does recognise priority from the older US provisionals. However, I'm not aware that this specific legal question has been tested, either by an EPO Appeal Board, or by a national court. Eventually it will in a case where priority is an issue. I suspect that the Courts would back the EPO line simply as a matter of convenience, but things do not always go this way ... (As a subtlety, the EPO handling of priority is governed by the European Patent Convention rather than the Paris Convention, but I don't think that this has much impact here).
In fact there are a couple of other reasons why priority from US provisionals may be problematic for some cases: (a) some people have tried to claim priority from a US regular filing, which in turn was filed 1 year after a US provisional (i.e. backdating up to 2 years), rather than realising that the 1 year priority clock starts from the provisional filing; (b) in some cases, the material filed as a provisional will be inadequate to maintain a claim to priority in Europe (e.g. too little detail, no delineation of the invention itself, etc)
Note that since Europe requires absolute novelty, losing priority via (a) or (b) might well invalidate the patent application (e.g. due to pubilc disclosures of the invention after the claimed priority date).
Regards,
Simon
(PS as a disclaimer, I should say that I'm fairly confident that the above is correct, but since yours is only a general query, I haven't checked it against actual texts or anything, which I would recommend doing before relying upon it).
Dr Simon Davies
European Patent Attorney
For and on behalf of:
D Young & Co,
</BLOCKQUOTE>
In short, the EPO will likely recognize a US provisional application as a priority document, but don't count on it.
I have or will pose similar questions to my Canadian and Japanese associates. Anybody concerned regarding other countries?
Regards.