Prior Art
Any evidence that an invention was already known or publicly available before a patent application was filed.
What It Means
Prior art is the body of existing knowledge that patent examiners use to determine whether an invention is truly novel and non-obvious. It includes previously granted patents, published patent applications, academic papers, conference presentations, products sold on the market, public demonstrations, and even oral disclosures, essentially anything that was publicly available before the patent application's filing date. When a patent examiner reviews an application, they search prior art databases to find references that describe the same or similar inventions. If prior art shows that the invention was already known, the claims will be rejected for lack of novelty. If prior art shows components that could be combined to arrive at the invention, the claims may be rejected as obvious. Prior art searches are also critical in patent litigation: defendants accused of infringement frequently argue that the patent should never have been granted because the examiner missed relevant prior art. This is the basis for invalidation defenses and inter partes review proceedings. Companies investing in R&D conduct their own prior art searches before filing to avoid wasting money on applications likely to be rejected. Patent attorneys use prior art strategically, both to strengthen their own applications by distinguishing from existing work, and to challenge competitors' patents by finding references the original examiner may have missed. The completeness of prior art searching directly affects the quality and defensibility of issued patents.
Frequently Asked Questions
What does Prior Art mean?
Any evidence that an invention was already known or publicly available before a patent application was filed.
Why is prior art important in patent law?
Prior art is the body of existing knowledge that patent examiners use to determine whether an invention is truly novel and non-obvious. It includes previously granted patents, published patent applications, academic papers, conference presentations, products sold on the market, public demonstrations...
Related Terms
Patent Application
The formal document filed with a patent office requesting the grant of a patent on an invention.
Patent Prosecution
The process of negotiating with a patent office to obtain a granted patent from a pending application.
Patent Examiner
A technical specialist at the patent office who reviews patent applications to determine whether they meet the legal requirements for grant.
Inter Partes Review (IPR)
A proceeding before the USPTO Patent Trial and Appeal Board to challenge the validity of an existing patent based on prior art.