Patent documents are given a range of extensive numbers. From the mere numbers, quite some information can be deduced.
Application number EP
The application number of European patent applications comprises 8 digits and a check digit. The first two numbers reflect the filing year, the remaining digits reflect the filing instance. For every filing instance slots of numbers are reserved.
The slots are for applications filed in Munich: 000001–075000, in The Hague 075001–090000, in Berlin 90001–95000 and finally applications filed via the online filing system: 100001–2500002
The sizes of the slots give an indication of the workflow of the various instances of the European patent office:
Within the slots, the numbers are given out time based consecutively. So if an certain application cant be retrieved, the number itself still does reflect its date of filing. Sometimes, the exact date of filing can be deduced, from a one number up one number down analysis.
Application number US
In the USA, the application number comprises a serial code and a consecutive number, reflecting the filing date. Here the serial code is ticked up every time the following consecutive filing number is about to surpass 5 digits in size.
Applications with serial codes 7 are filed between 1987 and 1992, 8 between 1993 and 1997, 9 between 1998 and 2001, 10 between 2002 and 2004, 11 between 2005 and 2007, 12 between 2008 and 2011, 13 between 2012 and 2014, and finally the serial code 14 is still in use for applications being filed in 2015. Likely in 2016 the serial number will be 15.
The patent publications numbers are consecutively numbered, either based on the filing date, e.g. the European system or the date of the grant of a patent, like in the USA. So from the number alone a neat estimation of the effect of the relevant patent can be guessed. Most likely, USA patent numbers below US5500000 have expired and European patents numbers below EP079900 have expired and are no longer in force.
In Europe, the publication number is regularly followed by a two character code A1, A2 or B1. These codes are reflecting the status of the document at the time of publication.
The codes starting with an A all relate to publications of applications for patents. A1 represents a publication, with an accompanying search report. A2 represents a publication of the application without an accompanying search report, A3 represents the publication of the search report following an A2 publication, A4 represents a supplementary search report.
Rarely used: A8 a publication of a corrected page of an A1 or A2 application, A9 a full reprint of an A1, A2 or A3 publication.
The codes starting with a B all relate to a granted patent. So the scope defined in the claims in these documents do reflect the scope of protection as being granted to the holder of the patent in question.
B1 reflects the patent as granted, B2 a reissue after amendments after e.g. an opposition procedure, B3 a reissue after amendments following an limitation procedure.
Rarely used: B8 a publication, a corrected title page of a B1 or B2 publication, B9 a full reprint of a B1 or B2 publication.
Which number is which?
If you do not know which number is an application number and which is the publication number, look at the so called INID codes, small numbers placed in brackets or circles before most data entries on a publication cover sheet. Typical the application number bears the INID code 21, the publication number bears the INID code 11.
So the numbers do tell you something!
I wish you happy inventing,
Hendrik de Lange
Dutch and European patent attorney
+31 (0)6 481 74 686
Sources:Wipo standard 13: http://www.wipo.int/export/sites/www/standards/en/pdf/03-13-01.pdf
USPTO application numbering system: http://www.uspto.gov/web/offices/ac/ido/oeip/taf/filingyr.htm
EP publication coding: https://www.epo.org/searching/essentials/definitions.html
INID codes: http://ip-science.thomsonreuters.com/m/pdfs/dwpicovkinds/inid_codes.pdf