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Searching for U.S. Patents on the Internet

Step 1:  Conduct a keyword search in the U.S. Patent databases: Issued Patents and Patent Applications.

Quick Search: The Quick Search provides 2 search boxes where you may type one word or a phrase. To input a phrase you must enclose your words in double quotation marks, ie: "digital signal processor"  To allow for varying endings for a word you can truncate only one word searches. The truncation symbol used is the dollar sign, $. For example a search of magnet$ would retrieve magnet, magnets, magnetic, magnetism, etc. You cannot truncate phases that are placed inside quotation marks. This is a major limitation when using the Quick Search. You cannot do a combination of 2 words in one search box, ie: polymer or plastic. You must do this more advanced search in the Advanced Search screen.

There are many Fields to Search by using the pull down boxes on the right. A field is a part of the patent that has been indexed and made searchable. The fields are: Title; Abstract (summary of the patent); Claims (statement of the scope of the invention); Description/Specification of the patent;  Issue or other Dates; Patent Number or Application Serial Number; Inventor Name, City, State or Country; Assignee (Company) Name, City, State or Country; U.S. or International Classification Systems; Patent Examiner; etc, It is very important to choose the correct field for your search. If you are starting a prior art search and do not want very large numbers of patents to look through, it may be practical to search the Abstract field. If you want more comprehensive results, searching a larger portion of the patent may be desired. You should then choose to search All Fields, Description/Specification, or Claims.

When using the Quick Search you also have the option to use And, Or, AndNot to link the two search boxes. Also choose the dates that are relevant for your search. Be sure to review the Help provided by the USPTO. Remember when searching by any field except the U.S. Classification numbers or the Patent Number you are only searching 1976 to the present. To search for older patents we will provide tricks throughout this tutorial. If you are searching for very recent information or want to be comprehensive in your search you also need to check for Patent Applications. Applications have been published since March 2001 and are searchable in a separate database. Note: an inventor may request that their application not be published, therefore this is not a comprehensive database of all pending applications.

Here is an example of a search using the Quick Search. U.S. PTO Full-Text and Image Database.

Quick Search Screen:  USPTO Patent Full-Text and Image Database:

Query [Help]

Term 1: in Field 1:
Term 2: in Field 2:
Select years [Help]

The result of a search provides a list of titles and patent numbers that match your search request. Review the titles and click on titles that you would like to see more information about. You also have the choice to modify your search.

Results list from the Quick Search, USPTO Patent Full-Text and Image Database:
PAT. NO. Title
1 6,489,256 Full-Text Fire escape blanket and other melamine resin containing compositions and products with fire blocking properties
2 6,383,623 Full-Text High performance insulations
3 5,167,876 Full-Text Flame resistant ballistic composite
4 4,780,359 Full-Text Fire retardent structural textile panel
5 4,743,495 Full-Text Seat cushion fire blocking fabric

When you click on an interesting title you will retrieve the full-text of the patent. Listed first will be the patent number and date granted and the inventor's name. Next will be the title and abstract. Next will be information concerning the company that has purchased the rights to the patent - Assignee.

Listed next will be the Current U.S. Class. This will be usually 3 - 15 classification numbers (class number/subclassnumber) that have been assigned to this patent. If this patent proves to be relevant than this is very helpful information because now you have starting points to look at when doing a classification search. It is recommended that you do this keyword searching first, locate classification numbers for relevant patents, and then proceed with a classification search.

Listed next will be References Cited [Referenced By] This hypertext link allows you to check whether there are more recent patents that cite this patent in their list of references. This allows you to bring your research more up-to-date and benefit from the patent research done by other inventors.

Following this is the list of U.S., Foreign and other cited literature used as background research for this patent. It is very valuable to check the full-text of these U.S. patents to further your research. Checking these references is one way to find patents published prior to 1976. Just click on the patent number to retrieve that patent. Use your Back button to come back to the patent you started with. 

Part of the list of cited U.S. Patents. from patent 6,383,623.

5529826 Jun., 1996 Tailor et al.
5578368 Nov., 1996 Forsten et al.
5607531 Mar., 1997 Needham et al.

Suggested Record Keeping:

  • While looking at patents you should note the patent numbers on a chart with two columns, those that are relevant and those that are not useful. By keeping track of patents that you have reviewed you will not duplicate this work later when they keep coming up in later lists of patents.
  • Also when reviewing patents make a list of the Current U.S. Class numbers that are assigned to the most relevant patents.
  • Also while reviewing the title and abstract note other keywords that should be tried. Look for synonyms and varying spellings that you want to include in your search.
  • Print out full patents for later reading and for ideas in devising your own application.

This Quick Search shown above retrieved only 5 patents. We now want to utilize more keywords, synonyms, and spellings to make the search more comprehensive. We need to go to the Advanced Search.

When performing an advanced search remember the following points:

  • Think of synonyms for each concept in your search. Link synonyms with the OR operand and put each group of synonyms inside a set of parentheses. The parentheses tell the computer system how to perform the logic of your search and which terms stay together as a group.
  • Put two and three term phrases inside double quotation marks. You cannot use the truncation symbol $ when searching a phrase. You need to type out the various spellings and OR them together.  See example below.
  • Truncate one word terms with the $ to allow for varient endings on the word. It is often dangerous to truncate on less than 4 or 5 characters because words that you did not want will be retrieved.
  • Include abbreviations or acronyms  
  • Remember to think about which fields you want to search. A chart is provided on the Advanced Search screen with all of the fields that can be searched. You can click on the field name and retrieve information on how to input a search in this field. Possibly start with searching the abstract (abst/) to retrieve more focused results. The field name abbreviation and a slash are typed before the search term. Searching all fields or the entire text can often retrieve too many patents which are not relevant. For example the search below when searched on all fields retrieved over 6,000 patents. When searching using the same keywords and logic but restricting to abstract, the result is 242 patents.
  • Link your concepts with the AND operator.  

Advanced Search screen from the USPTO Patent Full-Text and Image Database:

Query [Help]

ttl/(tennis and (racquet or racket))
isd/1/8/2002 and motorcycle

Select Years [Help]


Patents from 1790 through 1975 are searchable only by Patent Number and Current US Classification!

The result of a search provides a list of titles and patent numbers that match your search request. The most recent patent are listed first - reverse chronological order. Review the titles and click on titles that you would like to see more information about. You also have the choice to modify your search. This is the point when the list of patents that you have already reviewed will be valuable. You can skip over patents that you have already reviewed. Now you will be able to refine your list of search terms further and determine the best classification numbers to consult. You may also create a list of important or recurring inventors and companies that should be checked. You can do a new search on inventor or assignee name and review all of their patents.

While reviewing patents in the full-text HTML format, you will want to print out relevant patents in the Image format. You need a TIFF viewer loaded on your computer to load these patent image files. See the following information page on where to find and download a free TIFF viewer for your computer.

The keyword search has been successful, but in order to feel confident of a through review of U.S. patent literature you need to re-run these searches in the Application database and also go on to   Step 2 which describes the process of a classification search.  See also the 7-Step Strategy recommended by the U.S. Patent Office. 

Go to Step 2.

Return to the Fogler Library Patent and Trademark Resource Center homepage. 

For more information, contact:
Martin Wallace
Science and Engineering Center
Patent and Trademark Depository
Raymond H. Fogler Library
Orono, Maine 04469-5729 
Phone: 207-581-1678

Created by: Martin Wallace | Revised: 12/23/2014

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