Patentability Overview: Obviousness and Adequate Description

There are essentially five patentability requirements. In order for a claimed invention to be patented each of these requirements must be satisfied. The claimed invention must be (1) comprised of patent eligible subject matter; (2) useful; (3) novel; (4) non-obvious; and (5) adequately described. The first three of these requirements were discussed generally in Patentability Overview: When can an Invention be Patented? published last week. This article picks up with an overview of the law of obviousness and what constitutes an adequate description.

The Nonobviousness Requirement – 35 U.S.C. 103

Obviousness is a critical element to patentability. In essence, even if the applicant can demonstrate patentable subject matter, utility and novelty, the patent will not issue if the invention is trivial. In order to determine if an invention is trivial it is necessary to see if there was motivation in the prior art to do what the inventor has done. If the prior art does not explicitly, and with identity of elements, teach the invention, the patent applicant may still be thwarted if there are a number of references that, when combined, would produce the claimed invention.

A patent may not be obtained if it contains only obvious differences from prior art. An invention is obvious if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. The obviousness inquiry is highly fact specific and not susceptible to per se rules. Defendant cannot simply present evidence of anticipation and then say “ditto” to establish obviousness. Nevertheless, for a patent to be nonobvious it must display “ingenuity beyond the compass” of a person of ordinary skill in the art.

In a nutshell, an invention would be obvious when someone knowledgable about the area would look at your invention and consider it to be already known; not exactly but rather known if one were to combine several references.  In other words, the predictable and non-unique combination of what multiple references teach would yield your invention. The prototypical example is when you have invented A+B. A is known in the prior art, and B is known in the prior art. Upon looking at A and then looking at B, would someone of skill in the art consider A+B to be already known? If the answer is yes, then A+B is obvious. If the answer is no, then A+B is not obvious.


Sometimes combining things is not readily apparent, sometimes it is. That is what makes obviousness a tricky inquiry. Obviousness is a fact based and subjective inquiry, and in my experience many inventors are simply not capable of making an honest determination.  Frequently inventors are blinded by the fact that no single reference describes the invention in total.  That is the first step, but that exact identity relates to novelty.  Obviousness is the next step in the road to patentability, and a significant hurdle.

While the obviousness inquiry asks about whether something is a trivial, non-inventive combination of prior art references, the inquiry is not boundless.  For example, hindsight is not permissible.  Therefore, in order to demonstrate obviousness the patent examiner would need to establish that there existed some reason to anticipate that one could successfully combine A and B to result in A+B.

The obviousness determination is based on four factual inquiries: (1) the differences between the prior art and challenged claims; (2) the level of ordinary skill in the field of the pertinent art at the time of plaintiff’s invention; (3) what one possessing that level of skill would have deemed to be obvious from the prior art reference; and (4) objective evidence of obviousness or nonobviousness. Notwithstanding these factual inquiries, objective evidence of obviousness or nonobviousness MUST also be considered before reaching a conclusion on obviousness. Objective evidence includes: (1) the commercial success of the invention; (2) whether the invention satisfied a long felt need in the industry; (3) failure of others to find a solution to the problem at hand; and (4) unexpected results.

In determining what would have been obvious to a person of ordinary skill in the art, the decision maker may examine the following factors: (1) type of problems encountered in the art; (2) prior art solutions to those problems; (3) rapidity with which innovations are made; (4) sophistication of the technology; (5) educational level of the inventor; and (6) educational level of active workers in the field.

Adequate Description Requirement – 35 U.S.C. 112

The crux of this so-called adequate description requirement is that once the first four patentability requirements are satisfied the applicant still must describe the invention with enough particularity such that those skilled in the art will be able to make, use and understand the invention that was made by the inventor. For the most part this requirement can be explained as consisting of three major parts. First is the enablement requirement, next is the best mode requirement and finally is the written description requirement.

The enablement requirement requires the inventor to describe his or her invention in a manner that would allow others in the industry to make and use the invention. Enablement looks to placing the subject matter of the claims generally in the possession of the public.

The best mode requirement requires the inventor to disclose his or her preferred way of carrying out the invention at the time the patent application is filed. There is no requirement that the inventors preferred embodiment be updated as the patent application works its way through the PTO. Best mode looks to whether specific instrumentalities and techniques have been developed by the inventor and known to him at the time of filing as the best way of carrying out the invention.

The enablement requirement, thus, looks to the objective knowledge of one of ordinary skill in the art, while the best mode inquiry is a subjective, factual one, looking to the state of the mind of the inventor.

The best mode requirement has now been eliminated from U.S. patent law for the most part.  The America Invents Act (AIA), which was signed into law on September 16, 2011, prohibits a claim from being found to be invalid as a result of failure to present the best mode.  In other words, during litigation (for example) a defendant cannot challenge a patent claim saying that the inventor failed to disclose the best mode.  The best mode requirement, however, continues to live.  35 USC 112, 1st paragraph continues to require patent applications to contain the best mode of the invention, if in fact one exists.  This best mode requirement is now viewed as a paper tiger.  Yes, it is required, but there is no penalty for the inventor or patent owner for failure to disclose the best mode. There are some in the patent bar community, however, who fear that the Patent Office may be able to discipline patent attorneys and patent agents for willful hiding of the best mode.  I think this is an unlikely scenario.  In time Congress will likely remove the best mode requirement.

The third description requirement is the written description requirement, which is also found in the first paragraph of 35 U.S.C. §112. The written description requirement is separate and distinct from the enablement requirement, although related in important ways. The written description requirement serves a teaching function, as a “quid pro quo” in which the public is given meaningful disclosure in exchange for being excluded from practicing the invention for a limited period of time.

Still confused as to what this means? If you are confused you are understanding well. To be sure, the definition of the written description requirement is quite elusive. For generations the written description requirement had been confined to making sure that what was originally filed in the patent application adequately defined the full parameters of the invention being claimed. Today, the written description requirement means much more, but the Federal Circuit has yet to be able to articulate the requirements in a coherent way. Commentators have called the new written description requirement a super-enablement requirement. The Federal Circuit has dismissed this, but has yet to really offer a meaningful test of their own. Given this uncertainty and lack of judicial clarity the best thing to do to meet this requirement is to define your invention with as much specificity as possible. Perhaps the key to understanding the difference between enablement and the written description requirement is that you can bootstrap knowledge of one of skill in the art into your application for enablement purposes, but no such bootstrapping is allowable under the written description requirement.  If you leave something out it is not a part of your written description even if someone of skill in the art would understand that you left something out.

The remaining elements of the adequate description requirement relate to claims. It is the claims that define the invention, so particular attention must be given to writing good, broad claims. Discussion of claims, however, goes well beyond the scope of this primer.  For discussion of claims see:


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Join the Discussion

11 comments so far.

  • [Avatar for PS DIP]
    PS DIP
    June 11, 2012 04:43 pm

    Re: Obviousness – Best advice I ever received (from an in-house patent searcher at a tiny little company called P&G) was to try and cite a teaching away reference. Especially a reference that says A+B doesn’t work to solve C. These are the type of reference that are often not cited in patentability searches because they do not help us crush dreams, but they are gold for a prosecutor who might need some anti-obviousness ammo.

  • [Avatar for MaxDrei]
    June 11, 2012 10:45 am

    Thanks Cowboy. Yes, EPO prosecution is painful but, as Blind helpfully pointed out, it gets much more painful in litigation if the PTO Examiner was too lenient during the earlier prosecution. To be kind to an Applicant, they have to be cruel to him.

    BTW, I take it you are referring to the EPC prohibition on adding subject matter after the filing date. EPO Examiner strictness on this count is hard to explain to American clients. I have found the best way to be to say “Rose by any other name would smell as sweet. It’s a bit like your written description requirement, that is to say, more of a novelty than an obviousness test of admissibility of the amendment. Actually, attorneys have been teaching EPO Examiners for 30 years how even the most seemingly non-existent difference confers novelty. So, when it is a novelty test that decides the admissibility of a prosecution amendment, EPO Examiners are by now adept at seeing novelty where, in fact, none exists. we EPO attorneys have made a rod for our own back”.

  • [Avatar for American Cowboy]
    American Cowboy
    June 11, 2012 10:10 am

    Max and B-D, the problem with your discussion is that you come from two quite different patent cultures. As a result, the things one of you says is very easily misinterpreted by the other, so give each other a break.

    Max, I agree with your observation that “As a practical matter, the requirement for a written description is most painfully felt in prosecution, when you can’t amend to what you want to amend to, because of the lack of it.”
    I have found that PAINFULLY in European prosecution where even if the drawings show a widget, if the word widget was not in the original specification you can’t add it to the claims. In this regard, I think US practice is much more forgiving.

  • [Avatar for Blind Dogma]
    Blind Dogma
    June 11, 2012 09:56 am


    Your concern that I might be wasting my time is touching, but misplaced.

    Compose your posts with a little more thought so that you avoid wasting everyone’s time. There is an added benefit that if you actually put forth that minimal level of effort, that when you actually do have something worthwhile to say, people will not immediately retch at your name and give you credit for what you write.

    As far as educating you, I have seen your drivel at Patently-O. You overestimate my time and patience.

  • [Avatar for MaxDrei]
    June 11, 2012 02:28 am

    One would have thought tht blind would have something better to do with his time then, rather than waste it here, typing replies to somebody who has nothing to say. I’m happy to read his efforts to educate me though, and the reminder that what is really painful is litigation.

  • [Avatar for Stan E. Delo]
    Stan E. Delo
    June 10, 2012 10:42 pm

    Sounds like New England, as just a wild guess.

    Stan E. Delo
    Port Townsend, WA
    [email protected]

  • [Avatar for Blind Dogma]
    Blind Dogma
    June 10, 2012 09:18 pm

    What am I trying to say?

    1) What does “useful arts” include (or not include)? What does “old” mean? What does “obvious” mean?

    So you are saying nothing, then, as these questions are basic to patent law. You are saying nothing and adding nothing.


    2) As a practical matter, the requirement for a written description is most painfully felt in prosecution, when you can’t amend to what you want to amend to, because of the lack of it.

    Actualy there is a worse, more painful case: your patent is invalidated when you go to enforce it for a written description problem. At least in prosecution you a) have not spent all you can obtaining a worthless patent and b) still possibly have a chance to amend for some patent coverage.

    In sum, you have nothing worthwhile to say, and what you do say, you get wrong.

    Really nice.

  • [Avatar for Stan E. Delo]
    Stan E. Delo
    June 10, 2012 07:12 pm


    I tend to agree, as it seems to be an apples and oranges type of question. What is *obvious* seems to have been mucked up pretty badly by the Supreme Court lately, leaving us trying to guess what they really mean, when they contradict well settled patent law of several decades.

    The FedCirc seems to have gotten it mostly right in the near past, and then the Supremes come along and seriously upset the proverbial apple cart. It is not fair, and especially since they don’t seem to understand basic US patent law as Gene has suggested in other posts.

    All well and good or not for patent attorneys who are trying to make some sense out of things, but potentially very corrosive to the patent rights of US or other inventors filing in the US. Common sense? I learned in about the 6th grade that *common sense* is an extremely subjective sort of thing. Perhaps it is just a dare for the circuit courts, just because they Can, even if they don’t understand what they are talking about.

    The latest batch of Fatalistic Fennel is coming along nicely, but I have been considering adding a few proprietary ingredients to try to smooth things over just a bit.


  • [Avatar for MaxDrei]
    June 10, 2012 12:57 pm

    What am I trying to say?

    1) What does “useful arts” include (or not include)? What does “old” mean? What does “obvious” mean?

    2) As a practical matter, the requirement for a written description is most painfully felt in prosecution, when you can’t amend to what you want to amend to, because of the lack of it.

  • [Avatar for Blind Dogma]
    Blind Dogma
    June 10, 2012 12:06 pm

    Sudoku is a lousy example, as each puzzle has only one unique solution. Further, the puzzle is not even of the useful arts, so the question is dead before it is fully formed or put forth. Further, your comment is a trueism, and whether or not you find yourself needing to limit your application based on rpiro art found but unknown at the time of writing impacts written description regardless of any state of “legal requirement being – or becoming – problematic.

    In other words, your post makes no sense. What are you trying to say?

  • [Avatar for MaxDrei]
    June 9, 2012 04:18 pm

    A comment and a question:

    Written description: This legal requirement becomes problematic, I suppose, when the USPTO search brings to light prior art so relevant that the claim has to be narrowed. In other words, the definition of your invention has to be made tighter. Suppose that the text you need for your claim amendment is just not there in the app as filed. That, I suppose, is when you find out that………” If you leave something out it is not a part of your written description”.

    Assume that a hard Sudoku problem is published, but not its solution. Is its solution old and obvious, old but not obvious, obvious but not old, or none of those? If “it depends”, on what does it depend?