The purpose of United States patent law is to promote the advancement of science and technology by providing a mechanism by which the knowledge and ideas embodied in inventions become available to the public. To provide an incentive to inventors to make their inventions public, patent law grants to inventors a temporary right to exclude others from making, using or selling their inventions. The most basic requirements for obtaining a patent are that an invention or process be useful and new and that it be non-obvious to those skilled in the field in which the invention is classified. To further the objective of disclosure of inventions, however, there are additional provisions of the Patent Act that will disqualify an invention from patent eligibility called "statutory bars."
A patent for an invention will be denied if that invention "was patented or described in a printed publication in this or a foreign country or in public use or on sale in this country, more than one year prior to the date of the application for patent in the United States." In essence, the public disclosure of an invention begins the running of a one-year period within which a patent must be applied for in order to receive patent protection, and the statute delineates the different ways in which the disclosure can be effected. In addition, even if one inventor has taken pains to prevent the disclosure of an invention, the subsequent disclosure of the same invention by a second inventor will start the clock against the original inventor.
The one-year period within which a patent must be applied for following its public disclosure serves several functions. It ensures that inventions that have been in the public domain long enough for people to have relied on their availability will not suddenly be subject to patent protections, ensures that inventions will be promptly and widely disclosed by way of the patenting process, allows the inventor a reasonable period to test the commercial potential of the invention, and prevents inventors from the exclusive exploitation of the invention beyond the period granted by the Patent Act by delaying patent applications.
Patents are generally published, so the "patented or described in a printed publication" provide the same sort of public disclosure. If a patent does not fully cover all aspects of the invention for which a patent is sought, those aspects of the invention that are included in the existing patent will be ineligible for patent. "Printed publication" has been broadly construed to include any type of media that provides a form of viewable communication, such as microfilm, computer storage media, and the like; however, documents that are subject to nondisclosure agreements are not considered to be published because such documents are not accessible by the public.
Public use of an invention is an extremely low threshold, and a widely cited case held that the use of an improved undergarment worn by the inventor's wife for more than one year constituted public use that disqualified the invention from patent protection. However, an inventor's private, personal use of an invention does cause the one-year time period to begin to run. In addition, because an inventor may need to use an invention to ensure that it works properly, experimental use of an invention to test its functionality does not cause the application time period to begin. On the other hand, experimental use to test the commercial viability of an invention, as opposed to its proper functioning, does trigger the one-year period.
For an invention to be on sale, it must be offered for sale and must also be ready for patenting. Offering to sell the invention itself and selling rights to the patent for the invention are distinct, and an offer to sell patent rights in the invention does not start the one-year application window. To be ready for patenting, an invention must have been built and function as intended or must have been sufficiently described in words and drawings such that a person with necessary skills could build the invention.
An invention may lose its eligibility for patent without regard to the one-year
period if the inventor abandons his rights to apply for a patent. For example,
an inventor may wish to relinquish all rights to an invention and dedicate
the invention to the public. This is called express abandonment. Implicit
abandonment occurs when the inventor acts in some way that indicates that
he or she does not wish to seek a patent, for example, failing to apply for
a patent for an invention for several years. In addition, an invention is
not eligible for a United States patent if the invention was already patented
in a foreign country pursuant to a foreign patent application that was filed
more than one year before the U.S. patent application was filed.