Prior Art Research

• The best-known type of patent research in patent prosecution is a prior art search. Before drafting a patent specification, the patent agent or attorney researches other approaches to the problem solved by the invention at hand. For example, the prior art on a fluorescent light bulb might be an incandescent light bulb. Prior art research is very important because it allows the person drafting the application for a patent to distinguish the invention from the prior art.
  
  

Prior Art Research Tools

• A prior art search begins by interviewing the inventor and asking general questions about the context of the invention. Web sites from competitors provide further information about how other people are approaching similar problems. The PTO provides fantastic ways of searching every U.S. patent issued. The researcher might also use search tools provided by the European Patent Office and the Japanese Patent Office.
  
  

File Wrapper Research

• Litigation research often begins with a file wrapper review. The file wrapper includes every document between the patent office and the inventor (or his attorney or patent agent) regarding a patent application. It is valuable because it provides insight into possible flaws in a patent. Occasionally (but rarely), the research will find stray notes, left on a page by a patent examiner, that provide a way into the patent examiner's mind.
  
  Traditional paper file wrappers have been replaced with electronic file wrappers. They are available from the PTO or through a search company.
  
  

Case Law

• Patent researchers also review case law pertaining to other patent suits. These cases are tried in federal courts (instead of state or municipal courts). Although most patent researchers have a good command of leading patent law cases, they must be able to find and apply all patent cases that have not been overturned. An imaginative application of the facts and findings in earlier cases is important, because those cases might be binding in the present case.
  
  

Other considerations

• Related to case law research is research involving motions or court orders in prior cases. This history is critical because it can have the effect of estopping (preventing) a party from making a particular claim.
  
  Likewise, research into how patent claims have been construed by the courts is also very powerful. Claim language is often ambiguous, and it is helpful to know how courts have interpreted a particular word or phrase in the past. Powerful software products, such as those from LexisNexis and Docket Navigator, are very helpful.