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Patent Searching

A patent is a legal right granted by the government to an inventor that prevents others from making, using, or selling the invention.
  • Patents are granted for new and useful inventions, or for improvements made to existing inventions.
  • Patentable inventions include manufactured articles, machines, chemical compositions, or processes.
  • Patents are valid for a limited period of time and only for the country that issued the patent. In Canada, patent protection is for 20 years from the date the patent application is filed. Inventors must apply for a foreign patent to obtain patent protection in another country.
  • Patents not only protect the rights of inventors: they are a valuable source of information. 

A patent search can help a business keep informed of trends and developments in a specific field and can show what the competition is doing. The information found in patents may offer solutions to technical problems or uncover new products available to be licensed or used freely if the patent has expired.

Scholarly Research

Patents are a primary source of technical information. They contain detailed information and drawings about new technologies that are not normally published in other sources such as books or journal articles. Patents can provide ideas for further research in a field, as well as prevent duplication of research. Note: Patents may contain useful information, however, they are not considered authoritative or scholarly sources. Unlike articles in scientific journals, patents are not peer reviewed. Just because a patent is granted, does not mean that the processes or technologies described in the patent are viable.


If you want to patent an invention, a preliminary search of existing patents will help you to determine if your invention is novel or unique, or if it has already been patented. Information found in patents may help to inform or refine your ideas surrounding your invention; alternatively, it may save you from investing further time and money if you discover that your invention has already been patented.

The Library does not collect patents, but there are many online sources of patent information. The following key databases are free to search via the Internet:

You may also search for patents through Google Scholar. Some Library databases also contain patent information. For example, you can search for patents in the LexisNexis database (note: LexisNexis is only available in the Library).

Most patent databases allow you to search using both basic and advanced search options. Here are some general tips to keep in mind when searching a patent database.

1. One of the fastest ways of locating a patent is to search by patent number. If you have access to the product, check to see if it is stamped with the patent number. Patent numbers may also be found on packaging, user manuals, or product information. Company websites may also be a source of patent numbers.

2. You can search using the name of the inventor or assignee/owner. Inventors may sell or transfer a patent to someone else who then controls the patent. Inventors, for example, may assign ownership of a patent to the company or organization that they work for. Many patent databases enable you to search by assignee or owner name. When searching for names, consider nicknames, abbreviations, name variations (e.g., Shawn, Shaun, Sean, etc.), and possible misspellings. The same applies when searching the name of a company or organization. Additionally, company names sometimes change, so it’s advisable to search both current and former company names.

3. Most inventions are patented before they are given a brand name or trademark, which means most patent documents will not contain the product name of the invention. Searching by product name, however, can sometimes lead you to other similar or related products. For example, if you searched for the brand name Swiffer Sweeper in a patents database, you would not find the patent for the Swiffer Sweeper, the popular cleaning product manufactured by Procter & Gamble, because the patent makes no mention of the brand name. However, you may find other patents that mention or refer to the Swiffer by brand name, such as patents for products that are designed to be used with the Swiffer.

4. Titles of patents can be ambiguous and difficult to guess. For example, the title of the Swiffer Sweeper patent is “Cleaning Implements Having Structures for Retaining a Sheet.” When searching for patents, think about what the invention does, what it’s made of, and what it’s used for. Then, make a list of words that describe the invention, words that you think might be in the description of the patent you are looking for. For example, if you were searching for the Swiffer Sweeper patent, you might try searching for words such as: cleaning, floor, dust, and mop. Include as many synonyms as possible to broaden your search.

5. If you don’t find the exact patent you are looking for, review patents that are similar and note the classification number. A patent classification number is an alphanumeric number that represents the subject of the invention. Most patent databases allow for searching or browsing by classification number.

6. Patents contain cited references to other patents for similar inventions. Search the citations to find related patents. 

For more information about patents and how to search for them: