Please see the answer in this document.
Normalized patent numbers are imported from the European Patent Office (EPO) Espacenet database, these patent numbers appear in black. With the direct link to EPO’s database, it is possible to access directly all patent related information by clicking on the patent number.
Un-normalized patent numbers do not match with any number from the Espacenet database and are created manually. These numbers appear in purple so that users can easily distinguish the type of data that is displayed. These numbers might be correct, but they are not checked and they do not have link to Espacenet database.
The ETSI IPR database has a dynamic link with the European Patent Office (EPO) Espacenet database. In order to search patent numbers successfully or to disclose Standard Essential Patents (SEPs), the following information might be helpful:
a) Most of the application numbers are standardised to one format (including EP application numbers). For the majority of countries, application numbers in Espacenet are made up of the country code (2 letters - use the ISO country codes), the year of filing (4 digits), and a serial number (variable, maximum 7 digits). There is a fixed length of 13 characters in Espacenet. Where necessary, the fixed length is achieved by inserting leading zeros.
E.g. US application number 12/853861 can be normalized as US2010853861
CC = countrycode
YYYY = year
nnnnnn = number
b) PCT application numbers in Espacenet consist of the country code WO (2 characters) followed by the year of filing (4 digits), the country code of the country where the application was filed (2 characters) and a 5-digit serial number, adding up to a fixed length of 13 characters.
To find, for example, PCT application PCT/IB2007/51010, you have to type in WO2007IB51010. If you are searching for application number PCT/MX2007/000062, you should enter WO2007MX00062 (i.e. remove the leading zero).
c) There are twelve countries/organisations which use a different format. These are Australia, Germany, China, Brazil, Ukraine, Gulf Council, Hungary, India, Italy, Mexico, AIPO (African Intellectual Property Organization) and WIPO. They use application numbers made up of:
- a country code (2 letters)
- the year of filing (4 digits)
- "other" information (1 or 2 characters)
- a serial number (5 or 6 digits)
CCYYYYxxnnnnnn (between 12 to 14 characters)
Do not use dash, hyphen or underscore here, just fill in the characters in a string without any spaces. Kind codes shall not be entered (except if by following the recommendations under a), b) or c) you cannot find any patent document). Refer to Espacenet kind codes.
Further information on patent application numbering: