PCT Applications - How to determine the corresponding National Phase Entry

Patent Cooperation Treaty (as in force from April 1, 2002) allows an inventor to file a single "International Application" (commonly known as the PCT OR WIPO application) and thereafter file subsequent "National Phase Application" in each of the contracting states that are part of the PCT treaty. By default, each of the contracting states are designated when an International Application is filed.

The PCT application in itself does not result in the grant of the patent. The inventor/applicant has to subsequently enter a national or regional phase by filing a subsequent application in the contracting states/country. In order to enter into the national phase, the applicant has a time period of 30 or 31 months depending on the country where entry into the National Phase is desired.

The PCT application is usually published after 18 months from the filing date of the PCT application. Further, an International Search Report is usually provided by an International Search Authority that is used by National Patent Offices as well as the applicant to assess the patentability of the invention covered in the International Patent Application.

Patent applications are considered to be in the same family if they have at least priority claim identical. Examples of family member are Continuation application, continuation in part, divisional application, patent of addition. In order to determine the family information, one can look up the family information in patent databases such as Delphion, Micropatent, Total Patent, and QPAT. There are a few free patent databases also that provide information about the family members.

In order to determine the family information when a PCT number is available, one can search the WIPO site and check the national phase information corresponding to the PCT application. One of the problems that patent professionals will face while searching for corresponding national phase patent application numbers for a PCT application is that information will be available for certain patent offices and will be missing for certain other patent offices.

The primary reason for this is that regional patent offices fail to inform the WIPO office about the status of the National Phase Application. Other reasons include lack of timely updates on the WIPO site about national phase status and unpublished application in the national phase.

If you are aware that a certain PCT application has entered the National Phase and the corresponding number is not available on sites such as Delphion, Espacenet.com, and WIPO, then how do you determine the correct number.

The first and the foremost thing to do is mark certain information such as Assignee, Inventor, Title and Priorty date. Thereafter, using one of  Assignee, Inventor, Title or Priorty date, perform a search on the regional patent office site. In case of India, you can search on sites such as bigpatents and IPO.

You may get more than one results for your query. In order to finalize and determine the correct national phase application, compare the priority date of each patent application that was returned based on the query to the priority date of the PCT application.

The application for which the priority date matches with the PCT is your national phase application corresponding to the PCT application.