To search U.S. Patents issued since January 1976, go to http://patft.uspto.gov/netahtml/PTO/search-adv.htm.
From that page, Select "All years." Type in a search
expression, and then select the Search button ([Search]).
Formulating an effective search expression may require substantial
thought and experimentation, because a patent document may verbalize
an idea using a variety of wordings and spellings. A search should
not be so overly restrictive such that it excludes relevant patents.
Conversely, a search must not be so expansive such that the search
results include too many irrelevant patents, making review of
the results too time consuming.
For example, suppose an inventor has conceived a better mousetrap
and wishes to review U.S. Patents for similar technology. First,
she may simply enter
The search above results in 112 patents. She may then surmise
that some patents may only refer to the plural, and, therefore,
, wherein $ is a wildcard that allows you to find words that
begin with certain letters. Mousetrap$ finds both mousetrap and
mousetraps. The search above results in 129 patents. She may
then surmise that some patents may use two words: mouse trap.
Thus, she enters
mousetrap$ OR "mouse trap" OR "mouse traps"
, wherein the operator OR finds documents containing either
the string in front of OR, or the string following OR. Group
of words enclosed in quotation marks are treated as a single
search term. The search above results in 258 patents. She then
surmises that requiring the words mouse and trap to be adjacent
may be too restrictive. Thus, she enters
mousetrap$ OR (mouse AND trap$) [Search]
, wherein the operator AND finds only those documents containing
both the string in front of AND, and the string following AND.
Parentheses clarify the search expression. In the absence of
parentheses, all operators associate from left to right. The
search above results in 3530 patents, most of which do not pertain
to rodent traps. At this point, she may wish to try a more restrictive
search expression, such as an expression that only finds documents
having the word mouse in the Title of the Invention. Conversely,
she may also surmise that some relevant documents may not have
the word mouse at all, and may instead use the plural or a synonym.
(See endnote 1 below). Thus, seaching may require substantial
thought and experimentation.
The search results include the text of patent. To completely
understand a patent, it is necessary to also see the drawings.
Drawings ("images") of the patents are available, if
you have the proper plug-in, which is available free of charge
The search tool described above has at least two important
limitations. First, the tool only covers U.S. patents issued since
January 1976. Thus, even assuming an appropriate search expression,
the tool may miss many relevant documents, especially for older
technologies. Second, as discussed in another article on this website, Prior Art is not limited to patents. Thus, a search
limited to patents may miss many relevant Prior Art references,
especially for newer technologies, such as software, in which
the U.S. Patent and Trademark Office (USPTO) has not yet accumulated
a comprehensive set of issued patents. Despite these limitations,
this search tool is a valuable resource provided free of charge
by the USPTO.
1. (TTL/mousetrap$ OR TTL/mouse OR TTL/mice OR TTL/rodent$)
AND trap$ results in 198 patents, wherein TTL only finds documents
having a certain word in the Title of the Invention. In addition
to TTL, there are 30 other field codes documented on www.uspto.gov/patft/help/helpflds.htm.
2. To search official publications of U.S. Patent Applications, go to http://appft.uspto.gov/netahtml/PTO/search-adv.html.
From that page, Select