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How to Conduct a U.S. Patent Search: A Step-by-Step Strategy (36 mins, from the U.S. Patent & Trademark Office)
You have an idea for an invention — or have gone so far as to create a prototype. Before marketing your invention, you will need to determine if your invention has already been patented. To do this, conduct a thorough patent search. This will usually involve searching a number of different patent sites, so it's useful to keep a log of all your search activity to avoid duplicate efforts.
See General Information Concerning Patents and Patent Process Overview for more information.
You can begin your search the following way:
1. Brainstorm keywords to describe your invention, such as synonyms.
2. Use your keywords to search for a similar match of your invention in Google Patents. The advanced search lets you enter phrases, exclude words, etc.
3. If you find a similar invention, write down its class and subclass.
4. Use the class and subclass to search patents and patent applications with the USPTO website classification search. The USPTO website is more current than Google Patents.
[Note: The default search is CPC (Cooperative Patent Classification), which harmonizes the former European Classification (ECLA) and United States Patent Classification (USPC) systems.]
5. Trace related patents through references.
If you need to look through a large number of patents it might be worthwhile to make an appointment to use the PubWEST database at a Patent & Trademark Resource Center (PTRC). This database is not accessible except through a PTRC workstation.
The primary purpose of a patent classification system is to provide effective and efficient means of organizing and retrieving patent documents by technological subject. Espacenet is particularly useful in drilling down on a classification number.
Searching by classification is more helpful than keyword searching because it is:
While it is possible to search patents using just keywords, the most effective way to conduct a comprehensive patent search is by classification. Classification helps bring together similar devices and concepts, even when different terms have been used to describe them. The following are more reasons why searching by classification is useful.
See a Detailed Seven Step Search Strategy from the USPTO.
In addition to the more frequently used (in the U.S.) CPC system for classification, there is also the International Patent Classification (IPC).
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