Skip to Main Content

Patents: Locating Patents

Resources for finding, obtaining and understanding patents.

Why search the patent literature?

For inventors:

remember that one of the requirements for patentability is novelty. If your  invention has been previously reported or publicly manufactured or sold anywhere in the world, at any time, the patent office should refuse to grat the patent.  Since patent applications are expensive, you should thoroughly search the patent literature (and non-patent literature as well) to ensure that ther is no prior art that would disquality your invention for patenting.

For other researchers, students, entrepreneurs, etc.

Ptents can be a valuable source of three types of information:

  • Legal - Who, if anyone, holds a patent on a given invention? Is the patent still in effect, or has it expired? From whom might you want to license technology?
  • Business - What areas of invention are currently "hot"? What areas are your competitors currently developing? Are there inventors out there whom you might want to recruit? Are their companies or institutions where you might want toapply for a job or grduate study?
  • Technical - Since a patent must describe in detail the nature of the invention, patents can contain useful data to assist in your research, or inspire new research.

Tips for Locating Patents

Tips to Remember in Searching Patents:

  • Patents are a combination of a technical document and a legal document.  While they must describe an invention in sufficient detail for someone else "skilled in the art" to recreate it, the language used may not be the same language that you would expect in a journal article on the topic.  So, a simple keyword search is unlikely to be comprehensive.
  • While there are several free databases which index the patent literature, in general they do not offer advanced searching or analysis techniques.  Our subscription databases (see below) include sophisticated fatures such as patent citation searching, ehanced titles and abstracts, , sophisticated chemical structure earching, and bioswequence searching.There are  other commercial, value-added databases which do have such advanced features, but they are expensive to use, and, with a few key exceptions, UCSB does not subscribe to them.
  • If you need to do a thorough search of the patent literature, consult with a librarian.  For technical or business information, we can help you find what you need.
  • If you need a comprehensive search of the patent literature, as for a "prior art" search to determine if you have a patentable invention,  you will ultimately need to consult a professional patent searcher.
  • If you are interested in an in-depth look at patent searching, or are considering a career in patent information, see:

What are Patent Classification codes?

Searching patents by keywords alone is tricky. First, since patents are issued in dozens of different languages, searching terms in any single language, even English, runs the tisk of missing important patents. Second, even within a given language, the terminology of patents can vary widely. The descriptions used are often writen by lawyers, not by scientists or engineers.

So, to get around these problems, systems of patent classification codes have been devised to provide standard descriptors of patent subjects.  The most important classifcation codes are:

International Patent Classification (IPC)

The IPC is used by virtually all patent issuing organizations. It divides technology fields into eight sections (A-H) with approximately 75,000 subdivisions, each represented by a language independent symbol consisting of Latin alphabet characters and Arabic numerals. The IPC consists of several hierarchical levels. Subgroup level is indicated by a number of dots: a higher number of dots represents a lower subgroup level. The eight broad IPC classes are:

  • A- Human Necessities
  • B - Performing Operations; Transporting
  • C - Chemistry; Metallurgy
  • D - Textiles; Paper
  • E - Fixed Constructions
  • F - Mechanical Engineering; Lighting; Heating; Weapons; Blasting
  • G - Physics
  • H - Electricity

Each is then subdivided. For example:

  • C12 - Biochemistry; Beer, Spirits, Wine; Microbiology; Enzymology; Mutation or Genetic Engineering
    • ​​​​​​​C12M - Apparatus for Enzymology or Microbiology
      • ​​​​​​​C12M 3/00 - Tissue, human, animal or plant cell, or virus culture apparatus
        • C12M 3/04 - ...with means providing thin layers.

​​​​​​​You can find a genreal description of the IPC at the WIPO International Patent Classification site and the browsable and searchable guide to IPCs ..​​​​​​​​​​​​​​​​​​​​​

Cooperative Patent Classification (CPC)

The U.S. Patent and Trademark Office, (USPTO) in collaboration withe the European Patent Officd (EPO), developed a new patent classification system.  In 2013, the USPTO replaced its earlier United States Patent Classification (USPC) with the CPC.  While the USPTO has updated their own records with the new codes, you may still find some source of older patents which only have the USPC. 

The CPC codes frequently closely resemble the IPC codes.  You can find the USPTOs tools for locating both CPC and USPC codes at their Classification Resources site.

Using Classification Codes

The classification codes are designed for use by patent information professionals, who wish to do comprehensive prior art searches of the patent literture. For scientists, engineers and others who may wish to dive deepr into the patent leterature than just keyword searching, they best way to find and use classification codes is to do an initial search using keywords. If you find one or more patents that match your interests, look at the IPCs (and/or cpCs or USPCs)   on the front page of the patent. Check to see what those codes mean at the WIPO or USPTO sites above. You can then use the codes that seem to fit your needs as alternative search terms to potentially find more patents like those in your starting set.