To be patentable, an invention must satisfy two key requirements, as determined by the U.S. Patent and Trademark Office (PTO). First, the invention must be novel. This means that the same invention cannot have been disclosed in a single prior art reference. The prior art is all of the publicly available information that existed before the date the patent application was filed. Second, the invention must not have been obvious to a (hypothetical) person skilled in the art (the field of the invention) based on the prior art.
When a patent application is filed, it is assigned the technical area in the PTO that is closest to the technology of the invention as set forth in the claims. A patent examiner in that technical conducts a search of the prior art, and examines the claims to determine whether the requirements for patent ability (novelty, nonobviousness, and others) are met. If requirements are met, the examiner allows the claims. If the requirements are not met, the examiner rejects the claims. The patent applicant may then amend the claims and/or argue with the examiner about the merits of the rejections.
To determine whether an invention is obvious, the examiner must analyze and make factual findings on four questions: (1) what is the scope and content of the prior art? (2) what are the differences between the prior art and the claims? (3) what is the level of ordinary skill in the art? and (4) what, if any, is the evidence of secondary considerations? In other words, the examiner must decide what the prior is and whether a person skilled in the art would have achieved the claimed invention based on the prior art.
There are several different rationales that the examiner may rely on in making an obviousness rejection. One of the rationales is that a person skilled in the art would have modified the prior art, based on some motivation or teaching in the reference, to achieve the claimed invention. When this is the rationale relied upon by the examiner, the examiner must make two additional factual findings: (1) that a person skilled in the art would have had a motivation to combine the prior art references to achieve the claimed invention; and (2) that a person skilled in the art would have had a reasonable expectation of success in doing so.
There are several additional rules established by the PTO or the courts that govern the examiner’s process in determining obviousness based on modifying the prior art.
The examiner cannot use hindsight in determining obviousness. This means that the examiner cannot use the applicant’s own patent application as a roadmap or template to work backwards to find each element of the claims somewhere in the prior art.
The examiner cannot choose parts of a prior art reference and ignore other parts in the same reference that teach away from the invention (i.e., that suggest the modification would not work). A prior art reference must be considered as a whole, in its entirety including the parts of the references that teach away from the modification as well as the parts that suggest the modification.
All of the prior art must be considered. The hypothetical person skilled in the art is deemed to have knowledge of all the references that became public before the date the patent application was filed. The examiner cannot ignore the references that teach away from modifying the prior as the examiner proposes or teach away from the invention itself.
If the examiner’s rejection is based on a modification that changes the principle of operation of the primary prior art reference, the rejection is improper. Similarly, if the examiner’s proposed modification would result in the primary reference being unsatisfactory or inoperable for its intended purpose, the rejection is improper.
These are just some of the arguments that a patent applicant can make to overcome an obviousness rejection. If the arguments don’t work, the applicant can amend the claims to try to overcome the rejection. Ultimately, the applicant can appeal to the Patent Trial and Appeal Board, and then to the Federal Circuit Court of Appeals, for a court to decide the issue.