Fourth in a series of articles aimed at scientists, engineers, business managers, non-patent lawyers, and other professionals that desire or need to understand basic principles of patent law and practice.  Check out parts III, and III.

The invention all admired, and each how he
To be the inventor missed; so easy it seemed,
Once found, which yet unfound most would have thought,
– John Milton, Paradise Lost, VI, 478-501

Milton’s insight into the clarity of hindsight rings true centuries later.  The solution to even a thorny problem seems easy once the solution is revealed.  Patent examiners have the difficult task of seeing the solution to a problem in the form of an inventor’s patent disclosure, and then needing to pretend they did not see it.  The examiner must accelerate Doc Brown’s DeLorean to 88 mph and travel back to a time just before the applicant’s initial filing to evaluate whether the now-claimed invention would have been obvious to a person of ordinary skill.  The examiner may not use insights gleaned from the inventor’s disclosure to form an opinion.

Obviousness is one of patent law’s basic requirements.  Section 103 of 35 U.S.C. provides that even if an invention is novel (as defined in Section 102), a patent may not be obtained if the “differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date to a person having ordinary skill in the art to which the invention pertains.”

Notice that the invention only needs to be unobvious to a person of “ordinary” skill.  Many scientists, engineers, and innovators that I know have extraordinary skill in their field of endeavor, so ideas that may seem “obvious” to them would not be obvious to a person of only ordinary skill.  As an inventor, you want to be careful not to dismiss your ideas as “obvious” too readily.

Patent examiners are supposed to use the “Graham factors” to decide whether or not an invention is obvious.  These factors, outlined by the U.S. Supreme Court in 1966, are factual inquiries.  First, the examiner determines the “scope and content of the prior art.”  Second, the “differences between the claimed invention and the prior art” are ascertained.  Third, the examiner resolves the “level of ordinary skill” in the pertinent field.  In addition to the Graham factors, examiners are supposed to consider any objective evidence of non-obviousness.  For example, was there a long-felt yet unresolved need for the invention?  Is there evidence of commercial success?  Did others try but fail to find a solution?  Are there unexpected beneficial results from the invention?

More recently, the Supreme Court weighed in on the law of obviousness in KSR International Co. v. Teleflex Inc., 550 U.S. 398 (2007).  The Court reaffirmed the Graham factors but criticized the “formalistic” manner in which the Federal Circuit applied its “teaching, suggestion, or motivation” (TSM) test for obviousness (see last bullet item below).  The Court ruled that inventions that might pass the TSM test could still be obvious to a person of ordinary skill.  It emphasized predictability as an indicator of obviousness.

After the KSR decision, the USPTO issued guidelines to its examiners.  The guidelines reiterated the Graham factors and reminded examiners of the need for a “clear articulation of the reason(s) why the claimed invention would have been obvious.”  According to the guidelines, rationales that may support a conclusion of obviousness after KSR include:

  • Combining prior art elements according to known methods to yield predictable results;
  • Simple substitution of one known element for another to obtain predictable results;
  • Use of known technique to improve similar devices (methods, or products) in the same way;
  • Applying a known technique to a known device (method, or product) ready for improvement to yield predictable results;
  • “Obvious to try” – choosing from a finite number of identified, predictable solutions, with a reasonable expectation of success;
  • Known work in one field of endeavor may prompt variations of it for use in either the same field or a different one based on design incentives or other market forces if the variations are predictable to one of ordinary skill in the art;
  • Some teaching, suggestion, or motivation in the prior art that would have led one of ordinary skill to modify the prior art reference or to combine prior art reference teachings to arrive at the claimed invention.

Many observers believe that the KSR decision “raised the bar,” making obviousness more of a problem for applicants.  However, notice that most of the bullets require predictability.  Consequently, the “TSM” test, which appears last on the list, remains an important tool, especially for analyzing the patentability of chemical inventions, and examiners will continue to rely on it.  So what is the cure for the KSR problem?  Experimental results, of course.  But we’ll get to that next time.

Stay tuned for Part V of our Basic Patent Law series!


–Jon Schuchardt
Check out Jon’s bio page


This article is for informational purposes, is not intended to constitute legal advice, and may be considered advertising under applicable state laws.  The opinions expressed in this article are those of the author only and are not necessarily shared by Dilworth IP, its other attorneys, agents, or staff, or its clients.