An Introduction to Patent Claims

owl-blackboardThe patent laws require that the applicant particularly point out and distinctly claim the subject matter which he or she regards as his or her invention. The portion of the application in which he or she does this is not surprisingly called the claims. Patent claims are in many respects the most important part of the application because it is the claims that define the invention for which protection is granted.  You can have the most thorough and complete description of an invention you can imagine in the issued patent and it won’t matter. Sure, such a thorough and complete description is an absolute prerequisite, but without adequate claim coverage no amount of description is enough to save you.

The exclusive right that the United States Patent and Trademark Office has granted to you is in the claims.  If you don’t have a claim that covers a particular thing then you don’t own the right, it is really that simple.  If your claims are too narrow, as is always the case when inventors represent themselves, it will be easy for others to get around your patent without infringement.  Patent claims isn’t the only reason you pay your patent attorney for assistance, but they are almost certainly the biggest single reason patent attorneys will always have work.

The statute that relates to patent claims most directly is 35 U.S.C. 112.  Congress did not label the parts of 112 with alpha-numeric references (i.e., (a), (b), (c), etc.), so each sub-part is referred to by paragraph, although some are just a single sentence.  Paragraph 1 relates to what must be disclosed in the specification, with paragraphs 2 through 6 relating specifically to the claims.

Relative to claims 35 U.S.C. 112 states:

The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.

A claim may be written in independent or, if the nature of the case admits, in dependent or multiple dependent form.

Subject to the following paragraph, a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers.

A claim in multiple dependent form shall contain a reference, in the alternative only, to more than one claim previously set forth and then specify a further limitation of the subject matter claimed. A multiple dependent claim shall not serve as a basis for any other multiple dependent claim. A multiple dependent claim shall be construed to incorporate by reference all the limitations of the particular claim in relation to which it is being considered.

An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.


It is necessary to include a full and complete description of the invention in the initial filing with the Patent Office.  Rearranging of a patent application is always allowed, but addition of new material is never allowed without the filing of a brand new patent application that will receive a new filing date.  It is typically of critical importance to keep and hold onto the earliest filing date possible, so refiling a patent application to add things left out is less than ideal.  That which you add is NOT entitled to the filing date associated with any previous filing, which means that additional prior art will be able to be used against those aspects of the invention.  There is simply no substitute for filing a complete application.

Why are we talking about this in a claims primer? There is a difference between adding what we call “new matter” and adding patent claims.  New matter, which is prohibited, is defined by first viewing whatever is present at the time of the original filing of the patent application.  In determining the breadth of what is covered by that initial patent filing you rely not only on the description contained in the specification and any drawings filed but also on the originally filed claims.  Thus, new matter is defined in the negative.  If it wasn’t there in the specification, drawings or originally filed claims then it is new matter.  If it was present somewhere in what you filed it is not new matter.

So let’s say that you file an exceptionally detailed specification with good drawings and a representative set of claims.  Let’s say that you fail to claim something that you later believe is of critical importance.  Can you add the claim?  The answer is MAYBE.  What is it that  you want to add?  New claims are added all the time in patent application after patent application.  The question is whether what you want to add is fairly described somewhere within the entirety of the patent application you filed originally.  If yes, you can add the claims.  If no, then you can’t.

This is why searching for bargain basement patent applications does you absolutely no good whatsoever.  The way that you obtain cheap patents is by spending less time and that means less disclosure.  The more time you spend the more complete and detailed the description of the invention is.  You describe the nuances of the invention, alternative versions of the invention and really anything that you can contemplate.  It is the act of contemplation — the mental activity — that makes you an inventor.


Sometimes when you file a patent application subject matter is not shown in any drawing, nor is it described in the description, but it is claimed in the application as originally filed.  While not ideal, as long as it is described somewhere you have the ability to rearrange the application.   The claim or claims originally filed fulfill the requirement that the initial application be complete.  The claim should not be attacked either by objection or rejection because this subject matter is lacking in the drawing and description. It is the drawing and description that are defective, not the claim.  Notice, however, that the drawings and description are not fatally defective because the original filing did contain a legally satisfactory description of the invention.  In other words, the modification of the drawings and/or description would not add new matter because the matter was already contained within the initial filing (i.e., in the claims).  In this situation, that which was contained only in the claims can then, through amendment, be rearranged within the application to provide the appropriate support in the specification for the claims as written.

The take away lesson here is that the specification, drawings and claims all play a role and work together to describe the totality of your invention in that critical first patent application filing.  Patent applications can be redundant, but that is actually required.  The claims are what will ultimately define your exclusive rights granted by the USPTO, and the specification needs to provide an understanding of the claims and the drawings are intended to illustrate things so that the reader can more easily follow along.  This redundancy between specification, drawings and claims also helps to provide a fail-safe mechanism to make sure that there is support somewhere in the application for each and every aspect of the invention, all of the alternatives, nuances, preferences and options.

To be sure, the originally filed claims need not be exhaustive.  As discussed, through prosecution claims can be amended and even added, provided of course the initial disclosure is broad enough to cover the added or amended matter.  Therefore, when drafting a patent application it is good practice to spend time drafting quality claims.  Do not simply rely upon your ability to add claims later.  Include enough claims with the initial filing to cover the invention in a meaningful way.  Your aim should be to have some patent claims you think are unique, but which are exceptionally broad.  You should, however, also have a series of more narrow claims leading up to something that is quite narrow, perhaps the “Cadillac version” of your invention.  By doing this you have achieved a nice representative set of claims for the patent examiner to consider.

It is absolutely critical to provide the patent examiner with a good set of representative claims that offer a variety of broad to narrow claims.  The examination you receive from the patent examiner is never going to be any better than the claims you provide.  If you provide preposterously broad claims and then add very few and perhaps common features to that preposterously broad claim in your dependent claims you are making it easy for the patent examiner to reject the preposterously broad claim and then also reject your barely narrowing dependent claims.  Worse, you are left with absolutely no useful information about what the patent examiner thinks might be patentable.  You are not in a meaningful position to know what prior art exists that the examiner will later throw at you, and you hardly have any useful basis to talk to the patent examiner.

In almost any case when you talk to a patent examiner about the claims and suggest modifications they will not tell you right then and there that your proposed modification is going to work.  They will say something like: “that would address my concern with this patent reference, but I’ll have to see if there is anything else…”  So even in the best case scenario you are going to be negotiating with the patent examiner.  That negotiation goes much more smooth (generally speaking) if you provide a good set of claims at the outset because with some narrow claims the examiner will already need to do some digging past the preposterously broad to get to the nuggets below the surface, which is really where your invention resides.


For more information on patent application drafting please see:



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Join the Discussion

7 comments so far.

  • [Avatar for step back]
    step back
    December 28, 2011 12:46 pm

    (I forgot to add:) … and still running in the wrong direction even though the kind hearted examiner is yelling at them, “No, go the other way, go the other way!”

  • [Avatar for step back]
    step back
    December 28, 2011 12:42 pm

    PTO Examiner,

    Thank you.
    Your post is a keeper.

    There are way too many weekend warriors out there who firmly believe that going to law school for 3 (or 4) years and apprenticing oneself to an experienced patent attorney for many more years is simply a waste of time because, “obviously” anyone with a decent IQ can pick up one of those Patent Law for DIY Dummies books and learn the whole thing in a weekend.

    When they get to the PTO, they are sure the name of the game is invention baseball.
    They have no clue that it is 4th down at the bottom of the 4th quarter in the claim footballing game and they are 99 yards shy of the goal posts.

  • [Avatar for jodi]
    December 27, 2011 05:32 pm

    Another item unclear is when you discuss whether new claims can be added:

    >>> “New claims are added all the time in patent application after patent application. The question is whether what you want to add is fairly described somewhere within the entirety of the patent application you filed originally. If yes, you can add the claims. If no, then you can’t.”

    From my experience, an Examiner does not look at the support – they look at the Claims and don’t really seem to care what support is present or not.

    So, when the support matters is later when the patent is needed (licensing, infringement suit).

  • [Avatar for jodi]
    December 27, 2011 04:57 pm

    Gene – good article but it’s not clear to me who the target audience is – inventors or perhaps new Attorneys/Agents?

    For example:

    >>> “The way that you obtain cheap patents is by spending less time and that means less disclosure.”

    It is obvious there would be a correlation between time spent + patent quality – but it’s not clear how this might be relevant for inventors, engineers, or bootstrapped startups writing their own patents since time is relatively abundant when compared to other resources (e.g. $money). Given some guidelines, the engineer should be able to write a decent support for “cheap”.

  • [Avatar for PTOExaminer]
    December 26, 2011 08:16 pm

    I deal with pro se applicants who insist on representing themselves 2 to 3 times per year. It is rare at least in my TC (electrical/computers). From my experience, pro se applicants do not understand the significance of claims. One inventor tried to convince me that the claims are just a brief summary and that he deserves a patent based on his lengthy specification and drawings; he eventually got a patent but only because he converted his entire specification into one massive independent claim. I advised him that he doesn’t need all that detail – that certain portions can be left out for more patent protection – but that’s something he did not seem to understand and did not want to discuss.

    Also, from my experience, I get the feeling that some pro se applicants view the patent office as some kind of registration-only office. I think they liken the PTO to the IRS where all that is required is filing of paper work. They expect to get a patent immediately because they filed all of the required documents. Perhaps they are under the impression that all patent attorneys do is file the paperwork for them.

  • [Avatar for Gene Quinn]
    Gene Quinn
    December 26, 2011 11:08 am


    Thanks for sharing this story.

    How often do you suppose this sort of thing happens? Is it your impression that the inventor doesn’t have the funds to hire an attorney/agent or something else? Maybe the inventor thinks they can do better than an attorney/agent or perhaps they just distrust attorneys/agents?



  • [Avatar for PTOExaminer]
    December 25, 2011 09:13 pm

    It seems like some inventors just want a patent to put on their CV / resume. I’m currently examining an application where the inventor is representing himself. His claims are full of 112, 2nd paragraph deficiencies. The inventor has requested that I help him write the claims. I have advised him that while I can do an examiner’s amendment with my version of the claims, it is in his best interest to find legal representation… but he refuses. He is going to get extremely narrow claims but he doesn’t seem to care.

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