Patent Searching

Legal Disclaimer
This guide is for instructional purposes only and is not intended to provide legal advice or to substitute for the legal advice of an attorney at law.

 Researching prior art: (to make sure no one has already patented your idea)

The America Invents Act, signed into Law in 2011 by President Barack Obama, switched the United States from a first-to-invent patent system to a first-inventor-to-file patent system, which was already the norm in the rest of the world. When researching prior art to determine the novelty of your invention, it is still a good idea to search in other databases than just U.S. and foreign patents. The USPTO provides for the filing of a provisional patent application which contains no details of the soon to be patented invention, but merely provides a place holder for a filing date. The non-provisional patent application must be filed within one year in order to be granted a patent. Products manufactured under provisional patent applications can legally be marked "Patent Pending." Provisional patent applications are not published, searchable, or made public in any way. Which means someone may file a non-provisional patent application to satisfy a provisional patent application on your invention after you have filed your non-provisional patent application, and you may lose the rights to your invention.

Places to search for prior art:

  1. U.S. Patents and published patent applications
  2. Foreign Patents and published patent applications
  3. Journal and magazine articles
  4. Books, manuals, and catalogs
  5. Websites
  6. Conference proceedings
  7. Scientific papers

 Cooperative Patent Classification System

Patent classification is a system of sorting inventions and their documents into technical fields covering all areas of technology. —Espacenet

A preliminary patent search is conducted to determine which class or classes one's ideas fall into, and then search that class(s) to find the patents in that class(s) to determine patentability of an invention. The classification system used by the United States and many other countries is called the Cooperative Patent Classification System – CPC for short. A classification search can be supplemented with a keyword search; however, there are dangers associated with relying exclusively on a keyword search.

The CPC sorts inventions into 9 broad categories:
A—Human Necessities
B—Performing Operations; Transporting
C—Chemistry; Metallurgy
D—Textiles; Paper
E—Fixed Constructions
F—Mechanical Engineering; Lighting; Heating; Weapons; Blasting
Y—General Tagging of new Technological Developments; General Tagging of Cross–Sectional Technologies Spanning over Several Sections of the IPC; Technical Subjects Covered by Former USPC Cross-Reference Art Collections [XRACs] and Digests

There are several tutorials concerning preliminary patent searching available in the column on the right. It is strongly recommended that you start with the 7–Step Strategy tutorial.

You do CPC classification searching for granted U.S. Patents and published patent applications (not all patent applications are published) in Patent Public Search. Patent applications have an A at the end of the number.

 Searching Utility Patents Using the CPC

About the Cooperative Patent Classification System
Browsing the CPC on the USPTO Website

 Searching Utility Patents Using Espacenet

Espacenet allows one to search for patent and patent applications of 90+ countries — or one can search just U.S. patent and patent applications.
About the CPC from Espacenet
Browsing the CPC in Espacenet with Links to Patents
Espacenet Classification Search Page
Espacenet Advanced Search Page
Espacenet Help Index

 Searching Design Patents

Design patents are not classified by the Cooperative Patent Classification system because the U.S. is the only country that issues what is actually called a design patent. One can use keyword and other field searching for design patents in the Patent Public Search database. Then in the list of hits, those patents with a "D" in front of the patent number will be design patents. However, that will only find design or any other patents issued since 1976.

A better way to search for U.S. design patents is to use the design classifications in the U.S. Patent Classification System. A tutorial is given below on how to do that. Many other countries offer similar protection to design patents called Industrial Designs. More information on Industrial Designs below.

Countries other than the U.S. do not offer design patents, but there is usually a registration system for industrial designs. Here’s background from WIPO:

In most countries, an industrial design must be registered in order to be protected under industrial design law. Depending on the particular national law and the kind of design, an industrial design may also be protected as an unregistered design or as a work of art under copyright law. In some countries, industrial design and copyright protection can exist concurrently. In other countries, they are mutually exclusive: meaning that once the owner chooses one kind of protection, he can no longer invoke the other.

Under certain circumstances an industrial design may also be eligible for protection under unfair competition law, although the conditions of protection and the rights and remedies ensured can be significantly different. —

International Industrial Designs are organized by the Locarno Classification System.

 How to Search Plant Patents

Patent numbers given for plant patents start with "PP." Use Patent Public Search to find plant patents from 1976 to the present. You'll need to do a keyword search. You can also search plant patents in Google Patents. Be aware that the images, which are so important to plant patents, are scanned in black and white both in Google Patents and in Patent Public Search. Physical copies of plant patents, which include color photographs of the plants patented, are required to be kept by Patent & Trademark Resource Centers, such as Malpass Library. When you find the number of the plant patent you wish to see, you can go to a PTRC and ask to see the patent.