Patent law in the United States bestows legal rights upon a person who invents a new or useful process or device. Parties who challenge a patent may do so by denying the device is, in fact, new. They support their argument with writings, blueprints or other documents, with known dates that can establish the process or device was already publicly known before the filing.
The All-Elements Rule
Courts in the U.S. interpret the novelty requirement so that a claim will fail if a single document can be produced that has already described the invention within its "four corners." This means that somebody before the patent applicant previously put all the critical pieces together. For example, an applicant for a patent proposes an invention with elements A, B and C. The challenging party asserts that three years previously, Jane Doe discussed elements A and B of this invention, and at about the same time, in a separate writing, author Joe Smith discussed element C. This argument does not undermine the novelty requirement because, in this example, neither Doe nor Smith have all three elements together within the same "four corners."
Prior Art and Similarity
The body of publicly available discussion of an invention and possible modifications prior to the filing of a patent application are known as the "prior art" of that device or process. According to Walter Blenko Jr., an attorney who practices patent law with the firm Eckert Seamans Cherin & Mellott, "Finding a single piece of prior art, which discloses the same invention as that claimed in a patent, is not the most likely scenario." Often, though, the parties who are challenging a patent do find that there was something similar available publicly. This leads to some closely contested disputes.
But what if the inventor has created the "prior art" herself? For example, Jane Doe has been working on an improved product for many years. Thirteen months ago, she negligently allowed others to copy her preliminary designs. Now, she has applied for a patent. Her application could be rejected because it is not novel, on the basis of the prior art created by the applicant herself. The inventor has already put her invention, as embodied in that prior art, into the public domain. But if the leak occurred less than one year before the application was filed, it is within the statutory grace period.
European Patent Convention
Patent law in other countries also grapples with the issue of the novelty of an invention. The European Patent Convention, for example, also demands that devices be original in order to be protected.