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Issues in Science and Technology Librarianship
Winter 2010
DOI: 10.5062/F4T151KT

URLs in this document have been updated. Links enclosed in {curly brackets} have been changed. If a replacement link was located, the new URL was added and the link is active; if a new site could not be identified, the broken link was removed.


Science and Technology Resources on the Internet

End-User Patent Searching Using Open Access Sources

Pat LaCourse
Engineering and Science Librarian
New York State College of Ceramics
Alfred University
Alfred, New York

Copyright 2010, Pat LaCourse. Used with permission.



Researchers can learn effective searching at their desktop and download files for immediate use. Students can learn about a particular field for program and career choices. Those seeking a job can do background checking on industry trends, individual company research, and watch a technology as it moves among companies, inventors, and locations. Because gathering information from patents is more important than ever, this paper focuses on free access points, and demonstrates comprehensive U.S. patent searching, using approaches not available via keyword terms. Other countries are developing quickly and many find that it is expedient to file international patents, so this type of searching is covered as well.


Patents are rich with cutting-edge research. Analyses of relevant patents indicate where, when, and by whom work is being done in a specific technology area. Data on properties, processes, manufactured products, compositions, machines, and applications may not be published until years later, if at all. In the Netherlands Tijssen (2004) found that the number of research articles from industry had declined steadily from 1996 to 2001. Patenting, on the other hand, has become a business strategy worthwhile for even small businesses and academic institutions. The number of patents added each year doubled during the nineties (Rivette & Kline 2000). Numbers continue to increase, the USPTO (United States Patent and Trademark Office) claimed a 21.3% increase in application filings from 2004-2008 (Performance and Accountability Report 2008). In fact, the American Association for the Advancement of Science (AAAS) surveyed its membership in 2005 and found negative effects on research due to the increase in patenting (Hansen et al. 2006).

Although patent searching should be part of a routine literature search, the process is not simple. Patent searching can be done through various electronic access portals: governments (issuing site), organizations, commercial databases, as well as priority art expert services. Licensed and fee-based databases (e.g., World Patent Index (WPI), Marpat, MicroPatent Patent Index (MPI), and QPAT) have value-added searching, but free access sites (Table 1) can serve most researchers' needs admirably. Analyses may be easier and more sophisticated with the commercial sites, but authors have outlined how they search free sites with field searching and parse data with software in order to sort by affiliation, etc. (Dou 2004; Meyer 2003).

Patent law offices are trained to determine the novelty, obviousness, and usefulness of a patent, a rigorous exercise. This paper is not intended as an aid for the inventor nor in determining prior art, but to describe methods of obtaining patent information for research. For those interested in the patenting process, the PTO site hosts guides for inventors [How to Get a Patent and Inventor Resources Web].

Although an extensive search for patents in all countries may be too difficult, most searches should include the three major patent authorities, U.S., Europe, and Japan (Hunt et al. 2007). A patent map is available to check which databases cover a particular country's patents.

Table 1. Selected Open Access U.S. and Foreign Patent and Patent Application Sites






AppFT (USPTO applications)


AusPat (Australian PO)




Canadian Patent Database



DEPATISnet (German PO)

{Depends on country}


-EP (applications)

Oldest is 24 months
Depends on country
Oldest is 24 months



SurfIP (Singapore)

Depends on country


x (US applications)




Depends on the country



Google Patent Search


-PAJ (Patent Abstracts of Japan)



Patent Lens

Depends on the country



PatentScope (WIPO)






MS -- Multiple Search -- coverage of several countries
P&A -- Searches both patents and applications
* -- classification search needed for earlier patents

U.S. Patents

The USPTO's PATFT searches and serves over 7,000,000 patents, all three types of U.S. patents (utility, design and plant). Utility patents, the most common, have stand-alone numbers, Design patents are preceded by "D", Plant by PP, and Reissued by RE. For effective searching one must know database content and capabilities. This is especially true in PATFT. Word searches only survey patents from 1976 to the present. Prior patents must be searched by issued date, patent number or classification number.

International Patents

The European Patent Office's (EPO) patent search engine, Esp@cenet, provides an interface to search for published patent applications in over 80 countries. The provision of full text vs. abstract/citation varies with the home country's database. Disadvantages include the fact that, in many cases, there is a year delay in patent access to countries outside Europe, and the broad search has a results display of 500.
According to the JPO (Japanese Patent Office) (Iwasaki 2007), JPO holds a large percentage of the world's patent documents in certain technical areas (e.g., 40-55% in vehicle and telephone related areas, respectively). That stat has to be evaluated with Adams' (2006) notation that for years Japanese patent applications "could only have one claim". Nonetheless, applications from East Asian countries are steadily increasing (Oda 2009).
WIPO (World Intellectual Property Organization), an agency of the United Nations, was developed to encourage innovation and creativity. Under its auspices a group of countries signed the PCT (Patent Cooperation Treaty), which allows the inventor/assignee to file a single application for protection in all member countries. It does not issue patents itself, but the cooperation it promotes has made PCT patenting increasingly popular.

Searching Patents

Keyword Searching

Government Sites

PATFT -- keywords search patents from 1976 to the present
All patents are in TIFF, the most "lossless" image format. Patents issued after 1975 also exist in HTML (full text). The "Images" link on the patent is to the TIFF format, which provides the figures and text in a printable format. TIFF pages can only be displayed with a TIFF-viewer (see more below). Unfortunately, TIFF-viewers freely downloaded are not compatible with all browsers and need periodic refreshing.

Most fields may be searched in HTML patents. Keywords work with truncation ($), and phrases in quotes ($ does not work in quotations), etc. Other search tips include:

  • 'Inventor' field uses a hyphen between surname and others. It's important to note that applications may be submitted with variations in the inventor name. For example, Stanley Donald Stookey may have one or both initials depending on the patent. Therefore, it's best to search last name with truncated first ("stookey-s$"). Searching "stookey-stanley$ missed patents issued as S. Donald Stookey.
  • Different formats work for searching 'Date' fields (20040103, 1-3-2004, or Jan /3/2004).
  • 'Assignee Country' or 'Assignee State' fields must have country or state two letter codes.
  • 'Assignee Name' may not return expected results unless exact or truncated. Use hyphens between words not quotes.
  • 'Other References' searches non-patented literature. This and the 'References Cited' field provide a rich background from the filer's thorough search of patent and published material. Future trends and patent impact help the researcher link forward to patents influenced by that work ('Referenced By' link).
  • Advanced searching works with field codes (listed on the search page). 'Claims' often have different keywords than 'Abstracts', and may be combined, e.g., an/corning AND (abst/(glass$ AND melting) OR aclm/(glass$ AND melting) [an=assignee, abst=abstract, aclm=claims].
  • Boolean "ANDNOT" is used.
  • Length of a search command is limited to 256 characters, and simultaneous searches to 300.
  • If site traffic is heavy, avoid EST business hours and Tuesdays, the weekly update.

If patent terms and jargon cause a headache even with government definitions, TMS (The Minerals, Metals & Materials Society) has a patent glossary for the layperson. Kaminecki (2002) outlines some peculiarities with patentese that aid in determining search terms. For instance, early 'Claims' generally started with verbs or nouns preceding descriptors, therefore a quoted phrase may not work (e.g., "ceramic filters" will bypass "filters with a ceramic substrate").

Industrial Property Digital Library
The JPO (Japanese Patent Office) serves patents from their Industrial Property Digital Library. The {PAJ} (Patent Abstracts of Japan) database has word searching back to 1976. Their classification system (F1/F-term) search goes back to 1885. They mention a three to six month delay in translations to English, and a disclaimer cautions the reader to take care when making decisions based on a translation.

SurfIP, the Singapore government's patent database, has a structured search that accesses any or all of the following countries' patent information: U.S., China, UK, Canada, Taipei, Korea, and Thailand. The choices also include EP patents. Interestingly, Japan is not listed. The number of stars in the results list indicates perceived relevance, and an active link leads to the home site for the full document.

The Canadian Intellectual Property Office (CIPO) database has full patents back to 1920 with text searching for patents back to 1978. Earlier patents are searched by patent number, title, inventor/assignee, or classification. The Office cautions that a patent obtained through the database may not be complete, and should not be used in any decision-making.

Patent Analysis
Countries like Australia and New Zealand have put patent information online in the last few years. Patent Analysis searches both along with the U.S. and European patents.

Non-government Sites

Google Patents
Google Patents searches only U.S. patents, although they have plans for a global reach. In typical Google fashion, it has digitized the U.S. TIFF-only patents into a searchable PDF format. Advanced Search provides most common field searching, including CCL and IPC. It would help, however, if there was a link to the government's classification manual to aid in code recall. Also, while nice to have word searching back to the earliest U.S. patents, machine reading of earlier text has flaws ("Plastics" read as "Flastics").

Freepatentsonline has search fields similar to PATFT. It searches U.S., EP, (European), JP (Japanese), and WO (PCT) patents. Alerts, portfolios, and PDF downloading are available with free registration, but only for the sites' word-searchable patents (i.e., U.S. from 1976). SumoBrain from the creators of, a new "patent search and workflow solution", is worth checking out. A free account has all of the Freepatentsonline perks, including collaboration, saved searches and alert services, and some may find it easier to use.

Patent Lens
Patent Lens, created by CAMBIA, an independent, international non-profit institute, has a structured search and range of coverage similar to SurfIP. Country coverage is different, however: full text of PCT (1978-present), USPTO (AppFT, and PATFT (1976-present), EPO (1980-present) and IP Australia (applications and patents 1998-present).

Classification Searches

Subject searching is the most powerful search for obtaining relevant results, as long as the correct subject terms are used. A classification number search works on the same principle, but has distinct advantages. Adams (2003) explains why a classification search is desirable, i.e., the problem with words. Using classification numbers facilitates finding documents in another language. Some inventors/assignees may not want their patents readily discovered, so uncommon terms may be used to obfuscate. Also, classification codes will catch term changes, variant spellings, and acronyms.

Classification codes, however, do not list chemical names directly. Chemical patents will be returned in full-text searches, and in classification categories (e.g., applications of the substance). SureChem Free is a gateway for chemical name and structure searches on USPTO, EPO, and WO full text collections.

There are two major patent classification systems: Current U.S. Classification (CCL) and International Patent Classification (IPC), sponsored by WIPO to better coordinate searches among countries across the world.

CCL Classification

Aids for CCL include the Index to the Patent Classifications, and the Manual of Classification, listings by subject and classification number, respectively. A CCL search is executed by Class/Subclass code, e.g., 501/13 [Class (Compositions: Ceramic)/Subclass (Radiation color change responsive)], or 501/$ for searching an entire class. The search term would be: CCL/501/13

To determine which class/subclass to search:

  1. use a narrow keyword search, identify relevant patents and check to see the primary class (usually listed first and bolded) designation, or
  2. search the Index by keyword. In the results list the active class/subclass link transfers to the Manual listing (as if you had done the classification number search).

On the manual list the active subclass number gives a full definition of the subclass. Sublevels, indicated by the number of dots in front of the caption, are confusing. A drop down menu at the top of the list allows you to hide sublevels. For instance, "Indent Level 1" will show the main subclass and the first level under it (those preceded by one dot). The active link preceding the subclass number leads to a list of patents (P) or applications (A) in that class/subclass.

If this appears confusing, call a USPTO patent examiner for help in determining a class. Hitchcock outlines patent searching for the neophyte (no dummies here, just early users). USPTO also has The 7-Step U. S. Patent Search Strategy for a Quick Start.

International Classification

WIPO Reformed IPC
The CCL is more specific, but most foreign patents use their own or IPC classification. IPC code uses a SectionClassSubclass (alphanumeric code) Group/Subgroups display. For example, C03C 4/04 is a code that comes from Section C (Chemistry; Metallurgy), Class 03 (Glass, Mineral or Slag Wool), Subclass C (Chemical Composition of Glasses, Glazes, or…), with Group 4/Subgroup 04 (for photosensitive glass).

U.S. to IPC Concordance
A Concordance on the USPTO site provides CCL equivalents to IPC and vice versa. To search by IPC (ICL field code) in PATFT, substitute a zero for the space. The search above would be: ICL/C03C004/04

EPO has its own classification system, ECLA, which also extends the IPC. JPO has two basic classification systems: FI (File Index), an extended IPC with technology areas having a further extension, the multi-dimensional F-Term indexing (Iwasaki 2007).

PatentScope, a database of PCT patents, has patent fields designated by INID (Internationally agreed Numbers for the Identification of Data) codes, another WIPO sponsorship, to enhance the ability to find field information in a foreign language patent. The bracketed code precedes the fields. (e.g., [11] is patent number, [54] is title, [45] date of publication).

Obtaining Patents

As mentioned above, many search sites offer PDF or TIFF downloads for the full document.



To protect the site from massive downloading (some patents are thousands of pages long), the patents on PATFT print one page at a time. InterneTIFF, one of the TIFF-viewer choices, can send all patent pages to the printer together. Downloading a patent may not be necessary if bookmarking will suffice. U.S. patents have persistent URLs. A hyperlinked listing of desired U.S. patents can be maintained as long as there is a clear indication that the link leads to the USPTO site.

U.S. patents are also available in print and microfilm at and from the Patent and Trademark Depository Libraries (PTDLs). The Scientific and Technical Information Center (STIC) collections include U.S. and foreign patents, and they are open to the public with trained staff to assist.

Other sites (e.g., Google and Freepatentsonline) provide a PDF of U.S. patents as well.


The government sites listed above host the full patent document for at least part of their collections. Obtaining non-electronic patents became more difficult once the British Library (BL) stopped its Patent Express delivery service in 2002. When patents became easy to obtain on government sites, Patent Express was accessed primarily to obtain difficult patents, which significantly reduced profitability (Lambert 2002). BL, however, still maintains and upgrades its extensive collection of patents. Some have had to resort to hiring a search firm in London to visit the Library to obtain a patent not readily available (Lambert 2002).

As for foreign language patents, machine translations are improving. SIPO provides machine translations for the Chinese patents with 85% correctness (Wang 2009). JPO has a new software search engine for Japanese patents, {JP-NETe}, that provides machine translation downloads for a fee (Oda 2009). It outperforms PAJ by providing more current searches. Paterra has machine translations for patents back to 1996 from Japanese, Korean, Chinese, Russian, German and French.

Patent Applications

AppFT ( (

Since it may take almost three years from application to issuance (USPTO Patent Average Total Pendency, Performance and Accountability Report 2008), searching for patent applications should be a part of the research process. Although many countries search their applications along with their patents, the U.S. and Canada store application info separately. AppFT and search U.S. applications. For those wishing to monitor the latest patent applications, there are RSS feeds and alert services available with some sites (e.g., and


Most will agree that patents are a necessary part of research literature. Not only is there specific information in the description of the patent work, there is extensive background and a link to its impact on future patents. The number of searchable fields allows for technological analyses. Although important decisions should be made only after expert searches, general trends of topic areas, competitors, inventors, and global movements can be noted. Patent searching services and commercial databases are convenient for the busy researcher, but free Internet sites are available for the confident searcher.

Unless only a cursory look is needed, it is imperative to know the content of the database chosen for a search. First, decide on coverage needed. If a thorough search of U.S. patents will suffice, Google Patents is an easy engine that can provide the most full-text search capabilities back to 1790 and offers the PDF of the full document. For an overall view of worldwide patents try PatentScope or esp@cenet.

If a search of more international patents is necessary as well, Google may be a strong contender as a major portal in the future. They don't hesitate to undertake huge digitization projects. For now, there is no one engine that stands above the others, so several should be used to gather as much coverage as possible.

Typical users can do a powerful search if willing to familiarize themselves with the idiosyncrasies of the patent systems. Open access searching has become more sophisticated and all signs indicate that it will continue to improve in breadth, depth and user-friendly interfaces. Librarians can provide the training to make patent searching an effective strategy for all.


Adams, S.R. 2006. Information Sources in Patents. 2nd ed. Munchen, Germany: K. G. Saur.

Adams, S. 2003. Patent Searching Without Words - Why Do It, How To Do It? FreePint Newsletter. 130 [Online]. Available: [Accessed: August 2009].

Dou, H.J.-M. 2004. Benchmarking R&D and companies through patent analysis using free databases and special software: a tool to improve innovative thinking. World Patent Information. 26 (4):297-309.

Hansen, S., Brewster, A., Asher, J., and Kisielewski, M. 2006. The Effects of Patenting in the AAAS Scientific Community. [Online] Available: [Accessed August 2009].

Hitchcock, D. 2007. Patent Searching Made Easy. How to Do Patent Searches on the Internet and in the Library. 4th ed:

How to Get a Patent. United States Patent and Trademark Office [Online]. Available: [Accessed: August 2009].

Hunt, David, Nguyen, Long, and Rodgers, Matthew. 2007. Patent Searching, Tools & Techniques. New York: Wiley.

Inventor Resources Web. United States Patent and Trademark Office [Online]. Available: [Accessed: August 2009].

Iwasaki, S. 2007. IPC and Other Classification Systems: Japanese Classification System (FI, F-terms) and Quality of Reclassification. [Online] Available: [Accessed August 2009].

Kaminecki, R. 2002. Searching Patents on Government Databases on the Web. FreePint [Online] Available: [Accessed August 2009].

Lambert, N. 2002. Patent Express: the end of an era. Information Today [Online] Available: [Accessed August 2009].

Meyer, M., Utecht, J.T., and Goloubeva, T. 2003. Free patent information as a resource for policy analysis. World Patent Information. 25 (3):223-231.

Oda, S. 2009. JP-NETe - An English-language search tool for Japanese unexamined patents. World Patent Information 31(2):131-134.

Performance and Accountability Report. 2008. USPTO [Online]. Available: [Accessed: August 2009].

Rivette, K.G. & Kline, K.G. 2000. Rembrandts in the Attic: Unlocking the Hidden Value of Patents. Boston, MA: Harvard Business School Press.

Tijssen, R.J.W. 2004. Is the commercialisation of scientific research affecting the production of public knowledge? Global trends in the output of corporate research articles. Research Policy 33 (5):709.

Wang, D. 2009. Chinese to English automatic patent machine translation at SIPO. World Patent Information 31(2):137-9.

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