How to search for patents
By subject
The most complete method of searching by subject for patents is to determine the class/subclass (there may be more than one) that apply to that subject.
There are three USPTO resources or tools that help in this undertaking. The online versions are available at http://www.uspto.gov/go/classification/index.htm.
The recommended procedure is to look in the 1) Index by an appropriate term that will identify the class/subclass for that term. Then further examine the class/subclass by looking in the 2) Class Schedule which provides a hierarchy of the relationships between the subclasses within a class and 3) Class Definitions which provides descriptions of the class/ subclass functions as well as references to other class/ subclass areas that are closely related.
By Keyword
Alternatively, you could look in the online patent database by keyword, and after identifying patents with similar subject areas to your interests, identify the primary class/ subclass for that patent (listed in the online full-text patent in bold). It is still recommended that you check the Manual and the Definitions to fully understand the class/ subclass description.
Why not just search by keyword?
Although keyword searching is quick and will identify some potential patents of interest, it will be an incomplete and haphazard search. Patents are notorious for variations in words used to describe a particular application. For example, the patent titles of “Frisbee” type applications have keywords including flying saucer, flying disc or disk, airfoil projectile, aerial disc, throwing disc, aerodynamic toy, disk for throwing, throwing toy, flying toy, flexible toss device, and flying object. Unless you can think of every possible wording for such an entity, your search will be incomplete. Keyword searching also brings in “false drops” or patents that include your words but are peripheral to your interest. For example, searching for flying saucer brings patents of the Frisbee variety, but also games that have flying saucers in their visual imagery. Class/ subclass searching is the only effective method for a complete topical search.
Can I search by a company name?
You can search the patent file “assignee name” field for a company and retrieve patents that have been assigned to that company. Please note: patents are granted to inventors, not companies. The inventor may then assign the patent to a company.
If the patent is assigned to a company after the patent is issued or the patent assignment changes after the patent is issued, search the Patent Assignment Database. A link is provided on the Patents Search opening page, the direct link is: http://assignments.uspto.gov/assignments/?db=pat
Other categories that may be useful…
Many products have the patent number inscribed on them. You can search by “patent number” to find the patent for that product. Some products have a “patent pending” notice; search both the granted patents, and the application file. Remember, however, that if the inventor has requested confidentiality until the patent is granted, that patent will not be found in the application file.
You can limit by “application date” or “issue date”. Limiting by a pre-defined date range is also available. In fact, the default search is for 1976-present.