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
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.
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)
The ULTIMATE authority is the freely available USPTO database http://patft.uspto.gov/ - 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.
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
Google Patents https://patents.google.com/ 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:
Do not use Google Patents for serious patent searching.
The following free search engines perform better compared to Google patents:
Based on: http://patentlibrarian.blogspot.com/2008/09/comparison-of-free-patent-databases.html
For utility patents:
Check here for more information Current fee schedule
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
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.
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.