Under U.S. patent law, an invention is unpatentable if it would have been obvious to a person having ordinary skill in the art to which the invention pertains on the date of its invention by the applicant for patent. [35 U.S.C. 103]. The "non-obviousness" requirement is one of the most difficult for all those involved in the patenting process to understand, but it is a critical hurdle for inventions to clear.
This rule is applied when "dead ringer" prior art references do not exist, i.e., when the individual references that are available under 35 U.S.C. 102 do not teach each and every element of a product claim or each and every step of a process claim as those elements or steps are set forth in the claim. In this situation, the Examiner will attempt to put together the subject matter as a whole of claimed invention from the pieces of teachings he/she can find in the prior art and will also attempt to find motivation in the prior art for having done so. Under this rule, one or more prior art references (including public knowledge, public uses and offers for sale) must have existed on the applicant(s)'s date of invention, each of which would have taught "how to make" and "how to use" at least a part of the subject matter of the claimed invention to a person having ordinary skill in the art to which the invention pertains. Moreover, there must have been some explicit or implicit suggestion or motivation in the prior art to combine, substitute or otherwise modify the prior art in a way that would produce the claimed invention. The "differences between the subject matter to be patented (the claimed invention) and the (available) prior art" must be such as to have rendered the "subject matter as a whole" obvious. Exceptions to this rule are explained in other elements of this evaluation.
Under this rule, the prior art includes all 35 U.S.C. 102 references (including knowledge and actions) that have effective dates before the date of invention. How the effective dates of such references, knowledge and actions are determined is explained in the previous elements of this module. Admissions by the applicant about what existed before an applicant(s)'s date of invention (or, in other situations, before his/her/their U.S. filing date) in the patent application or in other papers filed with the USPTO can make a reference or action "prior art," even if the admission is an error (MPEP 2129). For this reason, great care must be taken in characterizing references, and, in fact, the phrase "prior art" should not ever be used by applicants. Similarly, whenever an Examiner uses "personal knowledge" to reject a claim, the Examiner should be required to supply the facts upon which the knowledge is based in a sworn affidavit or declaration.
Prior art references used in obviousness determinations must be either in the field of the inventor's(s') endeavor or reasonably pertinent to the problem that the invention solves. The courts have called such prior art "analogous" prior art and have not allowed obviousness rejections to stand that are based on nonanalogous arts. Neither the inventor(s) nor the hypothetical "person having ordinary skill in the art" to which the invention's subject pertains is expected to be aware of every teaching in every art, just every teaching in the art or arts "to which said subject matter pertains." The level of skill that the person in the rule is supposed to have is "ordinary skill in the art" not extraordinary skill, expertise or genius.
The combined teachings of the prior art must render the claimed invention obvious at the time the invention was made. The claimed invention as a whole, not just its individual elements or steps, must be considered. Moreover, it is inappropriate to use hindsight guided by the applicant(s)'s disclosure - one must place one's self at the time the invention was made and use only the prior art that existed then in an obviousness determination.
Because, in situations in which this rule is applied, no one reference taught each and every element or step of the invention, some combination, substitution or modification of the reference(s) is necessary. The rule requires that a reason, suggestion or motivation to combine or modify the reference(s) must have existed in the prior art (i.e., prior to the applicant(s)'s date of invention). A person skilled in the art must have already had an incentive or reason to combine or modify the reference(s) in the way that the inventor(s) did. References that "teach away" from the claimed combination, i.e., those that would have discouraged a person of ordinary skill from combining or modifying the references, must also be considered.
Objective evidence can and should be considered in making an obviousness determination. Although such evidence is known as "secondary considerations," these objective factors are just as important as the more subjective factors set out above. That is, it is not secondary in significance and may be the most probative and cogent evidence to be considered. During prosecution of a patent, this type of evidence is typically presented in the form of a sworn affidavit or declaration with the hard evidence attached as exhibits. Evidence of non-obviousness includes commercial success (in the U.S. or elsewhere), fulfillment of a long-felt need, failure (unsuccessful attempts) of others, copying by others, unexpected results, and synergism (which is not required). A cause-and-effect connection or "nexus" must be established between the claimed invention (the cause) and each effect (e.g., commercial success).
It is also helpful to understand what obviousness is not. The courts have pointed out that a great variety of improper standards have been proposed for determining obviousness. One improper standard is that a non-obvious invention must produce a "synergistic" result, i.e., the claimed invention must produce a result that is greater than the sum of its parts. Another improper standard is that a claimed combination or modification is deemed "obvious to try" by the Examiner. Another is forgetting to examine the claimed invention "as a whole," but rather focusing on each of the individual features of the invention. These improper standards continue to confuse today - watch out for them!