Support : Publications : Chronolog Archives : March 2001

Why Are US Patent Application Numbers So Hard to Find?

The application numbering system used by the United States Patent Office (USPTO) differs from systems used in other countries. When an inventor applies for a patent, the application is given a sequential application number that has a maximum of six digits. This number is used to identify the application throughout the application process and is also published on the cover of the patent. However, because the USPTO currently processes about 200,000 applications per year, it runs out of application numbers every few years and then must recycle them. Each time the application number reaches 999,999, or earlier if the number is approached near the end of a year, the USPTO starts over again at 1. One sequence of 1 through 999,999 is called a series. Currently, application numbers are in series nine. Thus, a typical number in the current series starts with a 09, as in 09/123456.

The problem with this system is that until very recently, the cover of the printed US patent did not display the series. Thus, the application date had to be used to identify the correct series. Quite often, however, a requester does not know the series or the date of application.

To ease this problem, Dialog has indexed the application numbers in the US Patents Fulltext files (652,653,654 or PATFULL) with the application year appended to the end of the application number. Thus, all you need to do is EXPAND the application number and Dialog shows you what years it was used, going back to about series 5.

The example here illustrates how to retrieve the correct application numbers. You will note that the application number 123461 was used in the years 1971, 1980, 1987, 1993, and 1998. By selecting E8 from the EXPAND list, you can retrieve the most recent entry. If you really don't know the year, you can also select E3 which includes all five entries. Then type out the result to verify the entry. Format 3 is the shortest format that gives the application number and date (see Figure 1).

Note that the searchable number does not need the comma or the series, as documented in the Bluesheet for this file (http://library.dialog.com/bluesheets/), to make searching easier. The record is formatted to include the series and the comma to make reading easier.

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