Patent opposition refers to the act of raising objections against a patent grant. Issues with a patent can be raised against the accepted standard patent as well as a certified innovation patent. Essentially, patent opposition allows a third party to challenge the validity of a granted patent.
If any member of the public wants to raise opposition to a European patent granted under the European Patent Convention, he or she must file an opposition within nine months of the publication that highlights the patent grant.
In the US, an applicant can oppose a patent within nine months of the patent grant. It is important to note that the nine-month window to raise patent opposition cannot be extended.
Generally, the patent office notifies the patent applicant when a post-grant opposition is raised. This leaves the applicant with an option to file a response in support of his or her patent application.
The two main types of patent oppositions are pre-grant oppositions and post-grant oppositions. Notably, a pre-grant opposition allows third parties to oppose a patent grant right after publication of the patent application. While a post-grant opposition can be filed within 12 months from the publication date of a patent grant by giving a notice of opposition.