Patent Classification refers to categorizing patent documents into different classes. Patent Classification is primarily carried out by patent examiners or other people maintaining patent documents at the patent office. Each patent office has a classification system. A granted or a published application is classified by the classification system based on its technical content. The Patent Classification enables a search technique called “class based search” for finding prior arts and arriving at improved search results pertaining to an invention. The class based search will identify all patents in the same class as that of the invention.
There are different patent classification schemes used across the world. Some of the prominent ones are the International Patent Classification (IPC) agreed internationally, the European Classification (ECLA) adjudicated by the European Patent Office (EPO), the United States Patent Classification (USPC) adjudicated by the United States Patent and Trademark Office (USPTO). Patent offices across the world use the IPC code for classification of patent documents. Additionally, a new classification system known as Cooperative Patent Classification (CPC) is a mutually agreed classification system between the USPTO and the ECLA to have a centralized classification system. The CPC will be effective from the beginning of 2013.
The classification under USPC has a main class and subclass. For example a main class “101” under USPC belongs to content related to “Printing”. A subclass “5” under the main class belongs to content related to “rolling contact” under the main class “Printing”.