Home > Insights > When does a public disclosure yesterday not prejudice a patent application filed today?
8 June, 2017

The above question does not relate to grace periods, breach of confidence or international exhibitions, the details of which vary from jurisdiction to jurisdiction and can be very complicated. Instead the question in the title relates to a more fundamental concept of patent law. Specifically, what is meant by the “filing date”, by which we mean, what is a date?

At first glance this question appears trivial: a date is the 24 hour period from midnight yesterday to 23:59 today. However, the question becomes more complicated when you consider the whole world and its multiple time zones.

In theory, if you start at the international date line (in the middle of the Pacific Ocean) at midnight on 31 December and set off westward, keeping pace with the Sun, you could celebrate new year 24 times; once for each time zone. If you were to stop once you reached the final time zone you could experience the full 24 hours of New Year’s Day. In total, you would experience 48 hours of New Year. That is, the date for you would be 1 January for a period of 48 hours.

So which is it? Is the first of January the 24 hour period experienced by a person in a specific location, or the 48 hour period where experienced by the Earth as a whole, or something else entirely?

This question arose as part of the ongoing Unwired Planet litigation regarding their patent relating to the LTE (4G) standard. The original applicant Ericsson uploaded a standards proposal known as “the Ericsson TDoc” and then filed a patent application relating to the same matter. It is well accepted that the Ericsson TDoc would destroy the novelty of the application if it were considered as a prior art disclosure.

On 12 April 2017 the England and Wales Court of Appeal handed down its decision relating to this matter. The appeal court decision relates to EP (UK) 2 229 744. Accordingly the relevant law is the EPC, and in particular Article 54, paragraphs 1 and 2:


(1) An invention shall be considered to be new if it does not form part of the state of the art.

(2) The state of the art shall be held to comprise everything made available to the public by means of a written or oral description, by use, or in any other way, before the date of filing of the European patent application.

And Article 89:

Effect of priority right

The right of priority shall have the effect that the date of priority shall count as the date of filing of the European patent application for the purposes of Article 54, paragraphs 2 and 3, and Article 60, paragraph 2.

Accordingly, the critical question is whether the Ericsson TDoc had been made available to the public before the date of filing.

The facts of the case are summarised in the following table reproduced from the Court of Appeal decision:


The priority application was filed at the USPTO on 8 January, but the TDoc was available in some places, including California and Hawaii, on 7 January.

At first instance Birss J asked 2 questions:

(i) what is the priority date?
(ii) was the putative prior art made available to the public before that date?

Birss J ruled that the relevant time zone for both questions was that of the patent office of filing. Accordingly, both the disclosure of the TDoc and the filing of the patent occurred on 8 January.

The court of appeal confirmed Birss J’s ruling, and Lord Justice Floyd elegantly summarised the key point:

The priority date is the 24 hour period of the day on which filing took place, in the time zone of the patent office where it was filed. The publication must occur before that day, on a time basis, by reference to the time zone of the patent office of filing.

Accordingly, when it really comes down to it, determining what constitutes prior art requires consideration of not just the date of filing but also the place of filing.

In the present case, the filing of the application happened after the disclosure. However, it is well established that the TIME of filing of an application is irrelevant, provided only that the DATE of filing was the same or earlier than the date of disclosure. It is worth noting that had the present decision gone differently it would have been possible for filings made in the early hours of a New Zealand morning to be anticipated by a disclosure nearly 22 hours later by a publication in the evening of the previous day in Hawaii.

While this issue may be niche, and the issue could have been avoided by following the standard advice of disclosing nothing until you have filed, or better yet until the application has published, it is an interesting point of law. Additionally, the demands of global business and the ubiquity of internet disclosures means this will almost certainly not be the last time this issue arises.

For further information on this, please contact Michelle Pratt or your usual Boult Wade Tennant adviser.