Strategy 1: Keyword Searching
A keyword search is a great place to start patent research. However, keyword searching in patent databases can be fairly complex. Patent language tends to be either technical or legal in nature, but is not standardized. Any form or synonym of a word can and probably is used. In addition, most inventions have several aspects and facets worth exploring. It is important to create a robust set of keywords before beginning your search. The following questions are useful in helping to generate keywords based on the different aspects of an invention:
Once you have answered these questions, get a thesaurus and write down synonyms for the answers to each question. Also try to think of equivalent technologies, and broader and narrower terms.
Strategy 2: Classification Searching
The patent classification system is used to organize patents into groups of similar technologies. When a patent is granted, the examiner assigns main and related U.S. class numbers to the patent. The patent examiner may also include an International Class number and the class numbers used to search for prior art. U.S. classification numbers take the form CCC/SSS where CCC is the three digit class number and SSS is the three digit subclass number.
Often a classification search begins by using a keyword search to find relevant patents, then looking up the classification numbers assigned to those patents in the Classification Schedule. If you have a general idea of the field of the invention you can look it up in the Index to the United States Patent Classification System.
You can also try using the search box available at the Classification Main Menu page.
Strategy 3: Citation Searching
Every patent includes a list of References Cited. This is usually a list of related patents and sometimes includes references to journal articles or other scholarly literature. When viewing the HTML version of a patent, the patent references usually appear as links so you can easily click through to read the references. If you know the patent number of a technology of interest and the patent is dated after 1976, a keyword search for the patent number will also return all the patents which cite your patent.
Citation searching is an excellent way to track trends in a particular field or technology.
Patents don't describe inventions as they appear in the market. Patents may cover broader concepts and they don't specify the final packaging, detailing, manufacturing processes, trademarked names, and other aspects of products.
Patents don't include product names. Searching patents by names of products, whether Formica or Blackberry mobile devices, rarely provides a direct path to the invention in question. Final product names are often determined long after patents are filed (trademarks rather than patents protect product names). In addition, the final product may be an amalgamation of several patents. So searching patents for, say, Apple's popular iPad requires knowing that the relevant patent was titled “Proximity detector in hand-held device" and never once uses the term iPad.
Patents aren't easy to read. Patents are legal documents and usually written by attorneys for analysis by patent examiners. They lack the directness of specifications, technical standards, or other types of descriptive documents. They often employ a specific legalistic vocabulary.
Patents aren't a true form of scientific literature. While patent applications are subject to examination by patent examiners, they are not subject to peer review and are not required to demonstrate proof of success through experiments and processes usually associated with scientific research.