Priority date

The priority date is the filing date of the very first patent application for a specific invention. Within 12 months of that first filing, a subsequent patent application for the same invention can be filed claiming this "priority right". In Espacenet you can find the priority date in the Bibliographic data section right after the Priority number(s) in the format yyyymmdd.

There is no dedicated search field for the priority date.

You can, however, search for patent documents with a specific priority date by using the priority number field of the Advanced search mask. Simply enter the date in the format yyyymmdd and click on Search.

Note: If a patent application has multiple priorities, only the first one is displayed in the result list, and the date you searched might not be visible. You should therefore always check the results in the Bibliographic data view. The priority date you searched will be highlighted.

For more information on Espacenet, see the following pages: