WARNING: Although the information which follows was correct at the time of original publication in the PCT Newsletter, some information may no longer be applicable; for example, amendments may have been made to the PCT Regulations and Administrative Instructions, as well as to PCT Forms, since the PCT Newsletter concerned was published; changes to certain fees and references to certain publications may no longer be valid. Wherever there is a reference to a PCT Rule, please check carefully whether the Rule in force at the date of publication of the advice has since been amended.
Q: I am going to file an international application claiming priority from two earlier applications, one filed in the
A: There are basically three ways of meeting the priority document requirements:
1. Send a conventional certified copy of the earlier application to either the RO or the IB. This option is always available. (PCT Rule 17.1(a))
2. Request the RO to prepare and transmit a certified copy of the earlier application to the IB. This option is available if the Office where the earlier application was filed is also acting as RO. (PCT Rule 17.1(b))
3. Request the IB to retrieve a copy of the earlier application from a digital library. This option is available when the earlier application was filed in an Office participating in the WIPO Digital Access Service for Priority Documents (“DAS”, also known as “PDAS”) 1, irrespective of the RO chosen (PCT Rule 17.1(b-bis))
Note that the paper request form (PCT/RO/101) also mentions the possibility of the RO obtaining a priority document from a digital library, but at present no RO offers that service (even Offices which have priority document exchange for national applications) so this should be disregarded. In the PCT‑SAFE interface, this option is grayed out and you cannot select it.
If you choose to file your international application with CIPO as RO (RO/CA), the most practical option would be to request the RO to furnish a copy of the earlier Canadian application, and then either obtain a conventional certified copy of the earlier
If you choose to file your application with the USPTO as RO (RO/US), you may request the USPTO to furnish a copy of the earlier
If you choose to file your application with the IB as RO (RO/IB), you will need to obtain a certified copy of the Canadian application from CIPO, but then have the choice of either obtaining a conventional certified copy of the
You should only check a single box (if any) relating to transmission or retrieval of a particular priority document and ensure that the option which you select is actually available for that document. If you check more than one box, or your selected option is not available, you are likely to have to deal with additional correspondence from either the RO or the IB to clarify what was intended.
Choosing between DAS and a conventional certified copy
If you have used the priority document exchange (“PDX”) system between the USPTO, the European Patent Office, the Japan Patent Office and the Korean Intellectual Property Office, the prospect of using DAS to meet your priority document requirements probably looks quite appealing. The service is free and you do not have to worry about requesting, receiving and forwarding a conventional certified copy. However, it is essential to understand DAS procedures because the process is not the same as PDX and the provision under PCT Rule 17.1(a) deeming the time limit to have been met as long as the IB receives the certified copy before the international publication date does not apply to requests under PCT Rule 17.1(b-bis).
The PDX system operates based on bilateral arrangements between Offices, largely on the basis of trust. Although DAS can be used for PCT applications, it was designed primarily for
If you decide to request the IB to obtain the priority document from a digital library, you need to take all of the following steps in order to satisfy the requirement under PCT Rule 17.1(b-bis) that the request be made within the time limit of 16 months from the (earliest) priority date:
(a) Request the Office with which the earlier application was filed to make the application available to DAS. The particular arrangements for this vary amongst the participating Offices – applicants should check on the Office’s website for details, but since in this case the first filing was with the USPTO, you should file Form PTO/SB/39 (or check the relevant box of Form PTO/SB/01) with the USPTO. Further information about the written authorization to permit access to US priority documents via DAS is available at:
(b) [This step is specific to USPTO as Office of first filing – for most other Offices, the equivalent processes are done automatically as part of step (a) without any further user interaction.] Go to the WIPO DAS web portal at:
and enter the relevant information to register the application with the WIPO Digital Access Service. The “access code” is the confirmation number for the
(c) Go to the web portal again 2 and use the “Update Access Control List” tab to give the IB access to that earlier application.
(d) Request the IB to retrieve the document, either by checking the box in Box No. VI of the paper request form or the corresponding box in PCT-SAFE, or by requesting the IB to do so separately (for an example of the wording which may be used for this purpose, see PCT Newsletter No. 01/2010, pages 4 and 5).
Steps (a) to (c) depend on one another and can only be taken in that order. It is also strongly recommended that steps (a) to (c) be completed before step (d) in order to avoid having to enter into additional correspondence with the IB because they are not able to access the document when they first try. To avoid all risk of problems, you should perform steps (a) to (c) before filing the international application, or at least before the record copy is likely to be received by the IB from the receiving Office. Compliance with PCT Rule 17.1(b‑bis) requires a timely request to obtain the priority document, including steps (a) to (d).
It is expected that DAS will become an increasingly popular method of priority document retrieval in the future as more Offices participate in the service, especially for Paris route applications where applicants need to deal with multiple priority documents, rather than the PCT system where only a single certified copy is required, which can often be provided by the RO simply by checking the relevant box on the request form. The IB is seeking to simplify the process of using DAS and also intends to propose a change to Rule 17.1(b‑bis) to provide the same flexibility on the 16-month time limit as applies under Rule 17.1(a), whereby the time limit is deemed to have been met as long as the IB actually receives the priority document before the date of international publication, but for the moment it is essential for applicants to be fully aware of the DAS procedures which apply in relation to the Office where the earlier application was filed and to strictly observe the time limits.
1 At the time of writing, the DAS-participating Offices are: the Australian Patent Office, the Japan Patent Office, the Korean Intellectual Property Office, the Spanish Patent and Trademark Office, the United Kingdom Intellectual Property Office (an operating name of the Patent Office), the United States Patent and Trademark Office and the International Bureau (for PCT applications filed with RO/IB). Some of these Offices only allow certain types of applications (for example, electronically‑filed applications) to be transmitted using DAS.
2 For priority applications filed with other DAS participating Offices, this will be the first visit to the web portal. The access code will have been supplied to you by either the Office of first filing or the IB, depending on the way that the system has been implemented by the Office of first filing.
Date retrieved: 30 December 2018