A patent gives inventors the right to exclude others from making and using their invention. This right is why patents are important assets. However, the United States Patent and Trademark Office, or PTO, will only grant patents if the invention is new. The conditions for patentability are set forth in a section of U.S. law called 35 U.S.C. 102.
Public Knowledge Defined
The PTO vigorously enforces 35 USC 102. For the purposes of this law, the term "public knowledge" needs to be more closely defined. Application of the law turns upon whether the invention has been described in print, whether it has been offered for sale in this country or abroad, or whether use was subject to a particular privilege.
35 U.S.C. 102 (a) states that an invention is not patentable if it “was known or used by others in this country.” For example, you could not patent an incandescent light bulb because such light bulbs have been known and used by others in the U.S. However, this prohibition usually is not applied if people in the same company know and use the invention, because such knowledge would be privileged.
One Year Rule
The second section of 35 USC 192 sets forth a “one year rule.” Under this rule, an invention is not patentable if it has been described in a publication anywhere in the world more than one year ago, or if it has been in public use or for sale for more than one year in this country. Under this exception, an invention could still be patented even if it had been offered for sale outside the U.S. as long as the inventor filed a patent application within one year.
Inventors can be their own worst enemy. For example, if a company describes an invention in a white paper that is presented in a trade show, that white paper counts as a publication, and triggers the one-year rule. If the inventor does not apply for a patent within one year of such an act, he or she will be forever barred from applying. Such a white paper would be considered "prior art," meaning any other invention that anticipates the invention described in a patent application.
Applying 35 USC 102 is fraught with pitfalls. Moreover, you have a legal duty to disclose information related to your invention, including prior applications, when you apply for a patent. If you feel your invention is public knowledge, you should consult a patent attorney or an on-line legal service so that you can clearly define your invention and determine whether this law will prevent it from being patented.