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The Spire Project: Searching Patents
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    Patent Classification
Search Strategy
A patent discloses certain facts about a commercially important invention in exchange for certain rights to exploit the invention. This is a little simplistic but explains why patents are factual, unique from other research resources, and a little vague in certain specifics.
(See a sample US patent, Australian patent, and this brief description.)

This article first addresses the most useful free databases, then describes national patent agency resources, commercial patent databases, then other commercial services. At the end of this article, we describe patent classification and patent search strategy.


to article list Free Patent Databases
These databases are freely available online:
database The US Patent and Trademark Office (USPTO) provides a US Patent Bibliographic database at with full use of fields, date and abstract text searching. Choose between their Boolean search, advanced (field) search or by US patent number. They also maintain a fulltext [US] Aids Patent Database and other resources.
database The IBM's Patent Server is a public service providing a different patent database of US Patent abstracts. The IBM service is similar but different from the USPTO service - certainly not less powerful.
database The Canadian Intellectual Property Office (CIPO) maintains the Canadian Patent Bibliographic Database that extends from '89 to the present. Abstracts are not provided. Descriptive info is here.
database The Japanese Patent Office ( has a searchable database of Japanese patent abstracts, which includes the patent number, title, inventor, company, and abstract of the patent.

There are more free patent databases - but each is limited and not as research-worthy. Consider also the Internet Patent Search System. Gregory Aharonian (remember currently delivers US Patent titles retrieved by class/subclass. He also delivers Patent abstract retrieval using patent numbers (but currently from 1981 to 1989). As you now know, also delivers abstract retrieval but I like the more minimal title lists here.


Patent libraries are an important and cost-effective patent resource.

to article list Australia
IP Australia ( (formerly the Australian Industrial Property Organisation (AIPO)) has a patent library in each state capital. Each library provides free access to the APAS database (Australian Patent Abstract Search) and includes a complete microfiche copy of all Australian patents and the Australian Official Journal of Patents, Trademarks & Designs (the official Australian patent gazette).

Staff will help you use the APAS database, arranged for free text searching by International Patent Classification.

webpage A particularly useful service by IP Australia is the delivery of copies of many foreign patents for AU$25. You will need the patent number, country and title for this.

to article list United States
The US Patent and Trade Mark Organization (USPTO) has the Patent and Trademark Depository Library Program (PTDL's) - which places the CASSIS database (The USPTO patent abstract database on CD-rom) and US patents around the US. Here is a list of sites.

US Full text Images are not visible on most web browsers. The images are in 300 dpi TIFF format. To view, get a free TIFF browser plug-in for your browser.
a) Try CPC light or AlternaTIFF
b) Consult this list at the USPTO.
Further, the USPTO provides US Patent Bibliographic & fulltext (with images) databases online with full use of fields, date and abstract text searching. Choose between their Boolean search, advanced (field) search or by US patent number. The IBM's Patent Server provides a different patent database of US Patent abstracts.

If you have the US patent #, retrieve the abstract with a USPTO patent search:
webpage US patent libraries also hold the Official Gazette of the US Patent and Trademark Office, The official US patent gazette. Importantly, the gazette is fully online, and searchable from 1995-98.

to article list United Kingdom
The [UK] Patent Office ( provides for the Patents Information Network (PIN) which hosts patent information in the UK. This page includes a clickable map. The British Library is one listed source of UK patents (further information online) and delivers some patent services.

to article list Canada
The Canadian Intellectual Property Office (CIPO) ( produces the Canadian Patent Index (CPI). They also publish The Patent Office Record, Canada's official patent gazette.
database CIPO maintains a free Canadian Patent Fulltext Database. This database is on par with the US Patent Database, with perhaps even better searching technology. Fielded & Boolean searches are possible and abstracts, claims & pdf files are retrieved. Read this database overview then use their advanced search.

to article list Other Countries
There are many more national & international patent organizations.
Intitut National de la Propriete Industrielle [France]
World Intellectual Property Organization (WIPO)
European Patent Office

If you need to find other sites, consider reviewing this list by IP Australia and the USPTO.

webpage CSIRO keeps a list of addresses for European Patent Libraries


One of the most invaluable resources in serious patent research is access to several of the very large commercial patent databases.

to article list Commercial Patent Databases
webpage Lexis-Nexis ( retails several patent databases. Thanks to Patscan (University of British Columbia), we also a guide to searching patents on Lexis-Nexis (dead link).
webpage The Dialog Corporation ( retails a collection of patent databases including:
Derwent World Patents Index [Files 351,352,280]
CLAIMS/US PATENTS [Files 340,341,942]
and others
webpage Cassis Database no details at this moment.

A little more information can be found with the Class Searching: Searching CASSIS by Classification, at the University of Washington.

Derwent Scientific and Patent Information ( is a prominent publisher of Patent and scientific information including commercial databases.

webpage Questel-Orbit ( also retails patent databases but we have not explored this venue yet.
webpage CAS/STN ( retails a collection of patent databases including:
Chemical Patents Plus for US Chemical patents

In addition to the database retailers and producers, there is a lively industry of patent services.

Patent Libraries : One source of patent assistance is, of course, the distributed patent libraries in each country. In addition to assistance with lodging patent documents, each library provides free access to bibliographical databases, and in the case of Australia, full text US and Australian patents on microfiche. IP Australia will also, for AU$15, retrieve most full patents from other countries (given a patent number, country & title).

PATSCAN ( within the University of British Columbia, provides patent search and retrieval services through databases like MicroPatent, the European Patent Office and others.

QPAT ( offers full text patent searching for paying subscribers and free front-page information of all US patents issued since 1974 for people who register.

MicroPatent ( offers limited recent patent searching and downloading of patent images for a fee. They have a registration system for the free service.


  5 Second Summary:
Free internet patent databases exist for US, Canada, Japan & Australia.      
A better search strategy makes use of patent classifications.
Patents are legalistic, with delays & delayed coverage in other countries.
Until recently, the legal profession has had a complete monopoly on patent work. As you can see, this need no longer be the case. Casual researchers will find the free patent databases easy to use, and more experienced researchers should not be dissuaded from searching the commercial databases or patent libraries themselves. The very large commercial databases, like Inpadoc, are particularly easy to use.

Article ListResearch CommentarySeminar datesUpdate Notices Of course, there are occasions when patent searches are critical, and experts should be sought. Certainly legal assistance is required if you are preparing to lodge your own patent but patent data as a source of information is another matter.


to article listPatent Classification
All patents are given a special number. Unfortunately, each country has a distinct numbering scheme: US patents are assigned a consecutive patent number (currently 5 million+). Australian patents have an alphanumeral that includes the year. Canadian patents are numbered.

Above these numbering systems, we have the International Patent Classification (IPC), by the World Intellectual Property Organization (WIPO). Most every country uses the IPC to classify patents, save the US. US Patent Classification is similar in many ways.

to article listInternational Patent Classification

Thanks to the World Intellectual Property Organization (WIPO), the International Patent Classification (IPC) works as a universal classification for patents. Started in 1975 and periodically updated, we currently use IPC 7th Edition.

Section, Class & Group. The International Patent Classification looks like this:

At the heart of the IPC is the unique coding of every invention by its specific form or function. The system is highly specific and logical, and includes numerous cross-references to other codes of similar form or function. Think of this as the Dewey Decimal System for patents.

The first letter is the section - one of eight broad categories labeled A through G. A represents Human Necessities. B covers Transport.

Each section is divided into Classes. Each class includes two numbers. In addition, each class is divided into subclasses, the letters which follow the first number.

Each subclass is then divided into groups and subgroups. The number before the slash is the group, the number after the slash is the subgroup. Subgroups only have two digits, with further numbers considered as resting behind a decimal point: 3/46 then 3/464, then 3/47.

Thus A 47 J 27/09 includes the safety device on your rice cooker and B 63 G 11/00 covers your various aircraft carriers.

The IPC system is fully described in these published directories:

The Official Catchword Index by World Intellectual Property Organization.
International Patent Classification : Guide, Survey of Classes & Summary of Main Groups
International Patent Classification : Section G - Physics
International Patent Classification : Guide

Thanks to the World Intellectual Property Organization (WIPO), these documents are online (see this page). We now have direct access to the International Patent Classification (7th Edition) through a bi-lingual search and directory site at The Official Catchword Index is inside.

Note: The International Patent Classification includes plenty of internal references - indicating this group is similar to another group; motorized boats take precedence over boat function. These internal references are important to effectively searching databases. There is more to the IPC, which you can see from the Introductory Manual to the IPC.

to article listUS Patent Classification

US Patents are classified with 400+ main classes and thousands of subclasses. Sound similar to the International Patent Classification? It is. US patents are numbered sequentially.

This means you can find US patents:

  1. by full text searching through the USPTO database CASSIS (found at US patent libraries),
  2. by bibliographic & abstract text searching online through the USPTO or IBM Patent Library,
  3. by US Patent number,
  4. by US Patent Classification class & subclass - to list similar patents,
  5. by an effective combination search (see patent research strategy),
  6. by the searching recent notices in the Official Gazette... available online.
The USPTO allows you to search or browse the US Manual of Classification online. The Internet Patent Search System lets you to browse US Patent titles by class/subclass.

to article listPatent Search Strategies
Here are the avenues open to you:

1_ Full text searching and retrieval through a commercial database.
2_ Free bibliographic & abstract searching online followed by selective patent perusal/ordering.
3_ Paging manually through the relevant official gazette (the US gazette is searchable).
4_ Retrieval of the titles & abstracts within appropriate class/subclass then selective review and patent perusal/ordering.

This last avenue is particularly resourceful and swift. Start by reaching for The Official Catchword Index [here], a book by World Intellectual Property Organization. This will tell you the possible class/subclasses that will interest you. You could word-search a patent database and note all the class/subclasses found. Lastly, you can always reach for the three separate printed guides that lead you from section to subclass.

The result should be a collection of class/subclasses that may interest you.

With this information, you can now browse all the patents in the class/subclass. This process will help you locate all the patents that may interest you since patent classification is more reliable than free text search. (Note, both British and American spelling appears in patent databases.) This also allows you to quickly review the patents in other countries.

If you are undertaking a novelty search - is a patent sufficiently unique from other existing patents - then you must review more than one country. There can be a significant delay before patent applications reach other countries without affecting the protection. Case in point: Australia only accounts for 7% of the world's patents.

Further Search Strategy
webpage Patent search strategy is further discussed in the Introductory Manual to the International Patent Classification (IPC) found on the WIPO website.
webpage You may also wish to reach Patents by Simon Fraser University Libraries.
to article listThe Spire Project - better ways to find information.
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