A Guide on How to Do a Patent Search

A Guide on How to Do a Patent Search
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A patent is the document that sets out certain exclusive rights to the inventor. The patent prohibits anyone else other than the inventor to buy, sell, use or import the invention in the country of issue, for a period of 20 years.

Patents provide exclusive rights, and as such, the primary condition for the issue of a patent is the unique and non-obvious nature of the invention. The first step in applying for patents is to conduct a patent search to determine whether an invention of a similar nature exists.

USPTO Database

The basic step in how to do a patent search is accessing the U.S. Patent and Trademark Office (USPTO) database. Investors and others interested in a patent search may access the USPTO’s patent database via their website. The USPTO maintains a full-text database of patents issued from 1976 to the present, and a TIFF image database from 1970 onward.

The USPTO website also provides a source to refer to international patent databases of countries such as Japan, Korea, and most European countries.

The USPTO databases constitute a good starting point for a patent search, but are by no means enough to conclude that the invention is unique. Not only does performing an accurate and thorough search require much research and knowledge, searching the USPTO database for newly developing fields such as biotechnology may remain inadequate owing to new inventions being filed almost every day.

Other Database

An alternative to the USPTO database is the Delphion database, which allows free searching of 54 million worldwide patents from 1974 to the present. The advantage of Delphion is its ability to perform multi-country searching by checking countries to include in the search from a list.

Another database, fast growing in popularity is Google Patents. Google allows for a much faster search, and the researcher simply needs to enter the keywords. The Google Advanced Search Page allows refining the search to generate more relevant results. Another advantage is that unlike the USPTO and Delphion that lists patents only from the 1970s, Google includes patents all the way back to 1836!

There are several other databases, but most other databases require payment in order to perform a search.

Another option is visiting any one of the 87 patent and trademark depository libraries, and conducting a search via paper / microfilm or a CD-ROM database

Search Methodology

Learnng how to do patent search requires knowledge of not just the resources, but also the search technique or methodology. The steps involved in a patent search are:

  1. Brainstorm the keywords and phrases relevant to the invention. Consider using common terms associated with the invention, its functioning, and the product. A good search bases itself on how the invention works rather than the intended use of the invention.
  2. List the classes and subclasses generated by the keywords search.
  3. Read the class definitions provided to establish relevance. The U.S. Patent Classification System provides definitions, and suggestions for other subclasses to consider.
  4. Search the entire class schedule of relevant classes for relevant patents.
  5. Search the complete text and drawing of closely related patents to determine the difference. The “references cited” at the end of the patent provides links to other patents closely related to the patented item.

Patent searching is an iterative task, requiring repetition of steps for each database. At times, search in the same database might require several revisions and re-starts as the complexity leads to the researcher getting lost in a maze.


Patent searches are a difficult and challenging task, made complex by the fact that much of the patent descriptions use legal, technical, and merely descriptive language, which adds to the difficulty. New original technologies do not have accepted keywords.

One good approach on how to do a patent search and obtain a patent is to employ the services of a patent attorney well versed and competent in the field.


  1. U.S. Patent and Trademark Office. “Search for Patents.” https://www.uspto.gov/patents/process/search/index.jsp. Retrieved March 31, 2011.
  2. McKinney Engineering Library. “Guide to Patent Searching. Patent Tutorials.” https://www.lib.utexas.edu/engin/patent-tutorial/index.htm. Retrieved March 31, 2011.
  3. Pressman, David. “Patent it yourself: your step-by-step guide to filing at the U.S. Patent Office.” ISBN 1413310583, 9781413310580.

Image Credit: flickr.com/dkpto