I'm drafting the specification of a patent for my invention. The invention is in the field of computer vision and augmented reality. I'm quite sure that the main subject mater is novel enough and useful enough to be patentable. However, in order to implement my system I'm using some technologies that are quite cutting edge but I know there is a lot of other people working on the same thing and probably there is some patent filed for these already -- although I haven't been able to find any published patents on these. I'm implementing the mentioned technologies myself by putting together parts that independently don't seem that novel to me. So I think that if I wanted to patent these underlying technologies too it would be more difficult.

My main intention is to patent the final invention, not the underlying technologies. However, I want to make sure my description meets the sufficient disclosure criteria. Describing what my invention does is not too difficult, but describing the underlying technologies is more difficult, in part because: (a) I haven't finished the prototype and some of the unfinished parts use the mention technologies, which I'm still implementing; (b) I'm not so sure I could patent these underlying technologies anyway.

So would it be safe to write a patent specification describing an invention and give references to the closest prior art for the invention and for the underlying technologies I use? Or would it be necessary to describe these underlying technologies in detail too?

2 Answers 2


Perhaps it's best to back up and consider the "social contract" a patent is intended to fulfill. You get protection for your patented invention until the patent expires. You, however, are expected to give something in return for that protection. Specifically, you're required to document your invention, revealing all its secrets, so that after the patent expires it's reasonable and practical for others to implement your invention.

To fulfill that purpose, you're required to document your invention in sufficient detail that a "person of ordinary skill in the art" [emphasis added] (POSITA) can implement that invention. The "ordinary" there is probably the most important word in the phrase -- this is supposed to signify not just some other person, but essentially any other person who's received a normal level of training in that field. It also requires that s/he should be able to do so relatively directly -- it should be primarily a matter of just building the thing, not doing things like experimenting with different techniques until something is found that works.

Just for example, let's assume your invention relates to electronics, so "the art" would be electrical engineering. In that case, you don't have to include things in your patent specification if you can expect them to be known to any/all electrical engineers -- for example, if you'd expect it to be included in a normal college electrical engineering text book, and probably included on some test before somebody could get a degree, it's fair to call that something known to a POSITA.

On the other hand, if the technology involved is something that probably would not be known to an average college graduate in that field, you really want to include at least some pointer to the background necessary to understand it. This can include things that are new enough that they're simply not included in typical text books yet, as well as anything obscure enough that it wouldn't necessarily be included in the curriculum at all (or nearly all) schools, even though it's actually been known for a long time.

The same would apply to an even greater degree if (for one example) you're combining knowledge from two (or more) fields that are typically taught separately, so you can't pick out one specific field to point to where you can expect people of ordinary skill to have been taught all the background to understand your patent. If something should go to court, you don't want to have to tell the judge that a POSITA is a person with doctorates in geology, music, and underwater basket weaving.

  • Ok. Thanks you for your answer. I see now that it'll be better to describe in detail these technologies. Which makes me wonder if I should perhaps make a separate application of the technologies and another for the main invention.
    – martinako
    Jan 27, 2013 at 0:15
  • I thought the underlying technologies were already known. If that is the case, then they wouldn't be the sole subject of a separate patent filing by you.
    – George White
    Jan 28, 2013 at 8:40

One of the primary purposes of the written description is to provide support for the claims. It is the claims that define your invention and serve notice to others what is protected. It is difficult to draft the written description without first thinking about the claims which in turn depend on prior art and other patentability considerations.

The written description is required to be in such full, clear, concise, and exact terms as to enable a person skilled in the field of the invention to practice the claimed invention.

The written description and claims must describe the invention to distinguish it from other inventions and from what is old. The written description must describe completely a specific embodiment of the invention.

In the case of an improvement, the written description must point out the part of the invention to which the improvement relates, and the description should be confined to the specific improvement and related features that interact with it necessary for a complete understanding of the invention.
37 C.F.R. 1.71

If the underlying techniologies are disclosed in other patents or publications, you usually do not need to repeat the disclosures, but may instead cite them as related art. It is often assumed that someone skilled in the relevant field will be familiar with related patents and publications.

More here: http://www.uspto.gov/web/offices/pac/mpep/s608.html#d0e42440

  • Thanks for your answer. I understand what you mean about writing the specification without having the claims being difficult. Although I see this happening more for the underlying technologies I'm talking about that for the main invention. Although there isn't anything exactly the same as the technologies I refer, there are many similar ones. But the main invention it's a new concept, very different to what I've seen so far.
    – martinako
    Jan 26, 2013 at 14:48
  • Perhaps I could describe these technologies in detail and refer to the similar ones that are appearing as allowing alternative embodiments?
    – martinako
    Jan 26, 2013 at 14:49
  • My situation is that I can't afford a patent attorney at the moment. So my plan is to file a specification for the main invention myself, no claims yet. Then advance my prototype a bit more and find investors. Once I have money for the project, and no later than 12months after my initial filing, I can get a patent attorney to write a full patent. Then my assumption is that as long as my first specification includes enough support for my main invention writing a full patent for it should be possible.
    – martinako
    Jan 26, 2013 at 14:51
  • 1
    This might be a good question to ask in a separate thread; a lot of people might benefit from from the question and answers.
    – Yorick
    Jan 26, 2013 at 16:47
  • 1
    I would err on the side of more detail and more support directly in the specification. You might also describe more than one implementation. For purposes of judging obviousness the person of ordinary skill in the art is assumed to be all-knowing of what has been done previously. I do not believe that same prsumption applies when enablement is being judged.
    – George White
    Jan 26, 2013 at 19:05

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