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Patents and Trademarks: Patents

Information on how to search for patents and trademarks

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This page is maintained by Khue Duong and Hema Ramachandran

What is a patent?

A patent is a legal document giving the patent owner certain exclusive rights to his/her invention for a limited time.
A patent granted by the US Patents and Trademarks Office (USPTO) is valid for 20 years from date of application (as long as periodic maintenance fees are paid).

Patents are an excellent (free) information resource: on new technology, trends in technological development, competitor tracking, technical information not found elsewhere. Like other information resources patents include bibliographic citations and more recently cited references. The introduction and background sections provide a statement of the problem and a concise review of the literature and how the inventor addressed and solved the problem.

New law went into effect in March 2013 - US became a "First to File" nation (in line with other countries)

A more simpler version of the law First to File in Plain Englsih

US Patents: different types

Utility patents may be granted to anyone who invents or discovers any new and useful process, machine, article of manufacture, or compositions of matters, or any new useful improvement thereof.

Design patents may be granted to anyone who invents a new, original, and ornamental design for an article of manufacture.

Plant patents may be granted to anyone who invents or discovers and asexually reproduces any distinct and new variety of plant.

A Provisional Patent is a way to establish early “claim” without the formality of filing a patent and inventor can use the term  “Patent pending” but  must file a “non-provisional” patent within 12 months.

 From How to get a patent

KIND codes categorize the type of patent (usually denoted by a letter after the patent number)


Searching for US Patents

The ULTIMATE authority is the freely available USPTO database - see below on tips to search the USPTO database

Also there is "dirty data" - for example a company name (even such a well known company as Kodak) may be entered in different ways.

Other companies (free and for fee)  have developed search engines and databases.  Dialog, Derwent  and STN are the main commercial vendors.

Derwent, in particular corrects data such as names of companies.

Searching the US Patents dtabase

The U.S. Patent & Trademark Office (USPTO) Patent Database includes full text of patents from 1790 - present and also provides TIFF images of most of them.

By Patent Number

  1. Go to USPTO Database.
  2. Select Patent Number Search or Publication Number Search.

By Subject

  1. Go to USPTO Database and select Quick Search. Enter keywords in the search box.
  2. Find a patent that is close to what you're looking for.
  3. Note the U.S. Classification number/Subclass for that patent, e.g. 711/111 .
  4. Do a search of that Class/Subclass in USPTO Database to find more patents on that subject.

OR ...

  1. Go to Index to the U.S. Patent Classification System and search for common terms or keywords.
  2. Use the Class/Subclass numbers you found to check the Manual of U.S. Patent Classification to see if they are on target.
  3. Search by Class/Subclass numbers in USPTO Database.


Free Patent Search Engines

Google Patents  while having a user-friendly interface does not perform well in terms of comprehensiveness or currency.  Use the "Advanced Search" to search for patent number, inventor name, assignee, patent type etc. However, the USPTO database offers more options for searching (e.g. inventor city, assignee city).  For the beginner and for educational purposes, Google patents is sufficient and easy to use:                                                                               

  • ·    An easy to use search interface for beginners. 
  • ·    Convenient access to patent images in PDF format
  •  ·   See important keywords directly in the PDF patent document. 
  • ·    Fast search engine and fast downloads of PDF patent documents


 Do not use Google Patents for serious patent searching.

 The following free search engines perform better compared to Google patents:

Based on:                                                                                                                                  


For utility patents:

  • Non-refundable filing fee whether or not a patent is granted is: $280.00
  • Issue fee (you pay this only if your application is granted): $1780
  • Maintenance fees (paid at 3.5, 7.5, and 11.5 years after your patent is granted:: $1600, $3600 and $7400
  • Provisional application fee is $260.00

Check here for more information  Current fee schedule


International Patents

The European Patent Office maintains a free database of worldwide patents (including U.S. patents) called esp@cenet. Images of patents are provided in PDF format, but can only be printed one page at a time.

By Patent Number

  1. Go to esp@cenet and select Number Search.
  2. Select the Worldwide Patent Database
  3. Enter the patent number in the search box in the format given.

By Subject

  1. Go to Espacenet and select Quick Search.
  2. Enter your keywords in the Search Terms box.
  3. Find a patent that's close to what you're looking for.
  4. Note the International Classification number/Subclass for that patent, e.g. H04B1/59.
  5. Do a search of that Class/Subclass in the esp@cenet database to find more patents on that subject.


esp@cenet Tutorial - How to search esp@cenet, the European Patent Office's online patent database

PatentLens A free public resource for patent system navigation worldwide.

Local Patent Resources and Assistance

The Los Angeles Public Library is a United States Patent & Trademark Office Depository Library. The Science, Technology & Patents department at the Central Library has a collection of U.S. patents dating from 1790. It is the largest patent collection on the West Coast.

The Central Library’s Science, Technology, and Patents Department offers computerized searching of patents, trademarks, and copyrights.Their Intellectual Property Resources  page is useful.

The Small Business Development Center (SBDC)  at Long Beach City College offers assistance on patent and other intellectual property issues for inventors and entrepreneurs.