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Electrical & Electronic Engineering / Applied Physics: Patents

What is a patent?

A patent describes a product or process that possesses or contains new functional or technical aspects. For example, it might describe

  • A method or process for manufacturing product X
  • A machine used in the manufacture of product X
  • Product X itself

It is a legal document granting exclusive rights to a person or organisation for a limited period of time, so prevents others from making, using or selling the invention without permission. In return for this monopoly, the inventor provides a full and sufficient disclosure for people to be able to carry out the invention, and (s)he also makes various payments. This makes patents the largest single body of technological information available anywhere and around 80% of this information cannot be obtained from any other source.

Finding patents

The following search tools will allow you to find patents.  There are sometimes many versions of similar patents, so if you have a patent number or other reference number, this is often the best way to search.

Understanding references for patents

The reference for a patent looks like this:

Inventor surname, initial. (year). Title of patent. Country of registration and patent number.

For example:
Hornung, A., Apfelbacher, A. (2009). Biomass Processing. UK patent GB 2460154 A.

The patent document

Each Patent has three sections:

  • front page
  • specification
  • claims

Front Page The front page includes: a title, abstract (summary), patent number, date, inventor and applicant (the company or individual applying for the patent). NB: The American term for an applicant is assignee. Each piece of information is identified by an INID Code (the Internationally agreed Numbers for Identification of Data Code). 

Some of the most important INID codes are:

  • 11 – Document number
  • 19 – Name of patent issuing authority
  • 20 – Local application number
  • 21 – Local application date
  • 26 – Language of document
  • 51 – International Patent Classification codes
  • 54 – Title
  • 57 – Abstract
  • 71 – Name of applicant
  • 72 – Name of inventor

Some two letter country codes which you may encounter are: 

  • (CH) Switzerland
  • (DE) Germany
  • (EP) European Patent Office
  • (FR) France
  • (GB) United Kingdom
  • (JP) Japan
  • (NL) Netherlands
  • (US) USA
  • (WO) Patent Co-operation Treaty

Specification The second section is the specification, which describes the invention and may include examples, drawings and an
account of the prior art (background technology).

Claims The third section has the claims which define the legal boundaries of the patent. Usually there is a series of claims, which start with broad claims and then become progressively narrower in scope.

The Status of the Patent The patent specification is often published twice, The first is the Application, the second is the granted patent after the claims have been substantiated. The two versions are differentiated in UK patents by the letters A or B after the patent number, with B being the granted patent.

You may have identified a patent that is relevant to you, perhaps by searching a bibliographic database, or browsing a list of references at the end of a journal paper. Patent references are easy to recognise because they each have a patent number.

Here are some examples of patent numbers:

  • British: GB2208189A
  • European: EP0050443A2
  • Patent Cooperation Treaty: WO 84/00080
  • United States: 4,718,426 (this may be preceded by US or PN)
  • German DE 3727042A1
  • Japanese JP 63-218215

To locate the full text of a patent, try searching one of the Patents Services listed below by patent number. 

Patents are legal documents and the information which they contain may be difficult to read because of its legal vocabulary. A patent may also be difficult to read if the inventor is deliberately cagey about the patent's main purpose. If refereed journal articles are available, you will probably find them much clearer than the equivalent patent. However, around 80 per cent of patents are never published as journal articles, and for those which are, the patent is usually published first.

Designing your patents search strategy

Due to the difficulties in interpreting patents and the technical language used therein, it is important to consider your search strategy carefully. There are two main ways to search for a patent:

1. International Patent Classification (IPC)

All patents are classified by an International Patent Classification (IPC) scheme, although many countries also have their own classification schemes. The IPC is a hierarchical classification system used for classifying and searching patent documents. There are eight sections in the IPC, for example; section C deals with Chemistry and Metallurgy whilst section F covers Mechanical Engineering. Sections are then subdivided into classes, then subclasses, then main groups, and finally subgroups. Finding the IPC code assigned to your subject and searching on it will reduce the number of irrelevant results. The IPC is available on the web at http://www.wipo.int/classifications/en
 
2. Keyword searching

Think broadly about the keywords that could be used to define your area of interest and go beyond the obvious. Consider searching word stems by using wild cards, and use Boolean operators.

The British Library offer useful guides on patent searching. See the British Library’s Patent Collection Page for more information. Once you have considered your search strategy, you will need to decide which database to search.