For examples, see our list of Notable Inventors on the World Wide Web . As a part of the patent examination process , patent examiners search U.S. and foreign patents, as well as a wide range of other technological information to find prior art that will impact whether a patent is issued. Examiners spend about twelve hours reviewing each patent application. The PTO does not conduct searches apart from the patent examination process. No one is required to conduct a patent search.
Many inventors prefer to do a preliminary search before they apply for a patent.
They may find prior art that would affect the patenting potential of their invention. This can help them decide whether to pursue a patent, and whether to modify their efforts to improve the probability of getting a patent. Once an invention has been patented, it cannot be patented again, even if the original patent has expired. The PTO provides the PTDL with computerized databases , patent and trademark record s , and helpful brochures and other publications about patents and trademarks. The PTDL staff can help patent searchers get started and answer questions about how the databases work.