Let's suppose that a patent claim consists of 3 elements, A, B, and C.

It is only infringement if someone creates a product that contains at least 3 of those elements.

Hence, would it not beehive the original inventor to only include 2 of those elements in his or her claim? Or maybe even one?

4 Answers 4


In general you always want the broadest claim coverage possible. So yes, if you can get a claim allowed for elements A and B instead of A, B and C you would do so. However, the invention must be patentable over prior art. Thus there needs to be some aspect that is novel and non-obvious.

The patent examiner is likely to reject claims that are overly broad so you may be required to narrow them until an acceptable specificity exists. It is rare for patents to have just one claim so you can always add additional claims with more specificity.

  • If a claim is not patentable over prior art with just elements A and B, then automatically it would not be patentable over prior art with elements A, B, and C? Commented Jan 19, 2022 at 16:42
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    @freelionsntigersfromcages It is the other way around, if not patentable with A+B+C then it is not patentable with just A+B. Commented Jan 19, 2022 at 17:53
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    @freelionsntigersfromcages Europeist has it exactly right.
    – Eric S
    Commented Jan 19, 2022 at 18:06

Is the goal of a patent claim to have as few elements as possible?

Actually what is important is a claim set. In a set of claims each claim is doing a different job. Certainly there should be a claim as broad as your search of the prior art would allow. If it is a thing (not a method) then just A would not fly since if there is thing known as A, it already exists. Maybe an A'.

Then there would be dependent claims that narrow in various dimensions. Possibly based on different embodiments described in the specification.

In the U.S. many independent claims are allowed so you might have a picture claim also called a "teaching" claim that quickly gives the reader (examiner, judge, jury, competitor) a clear picture of an embodiment of the invention.

If the required elements are A, B and C there is usually more than one way to express each element and their interconnection. Two differently worded claims can have the element A, B and C.

If someone is already making a product (assuming you filed before they disclosed or sold) you might tailor a claim to their embodiment to make an infringement claim as black and white as possible.

You might want one claim written in a "means plus function" form.

It is not as relevant in practice as it was a few years ago but there was a series of cases collectively called "Festo" in the U.S. The SCOTUS held that claims that were amended in the course of patent prosecution lost some of the presumptions around the Doctrine-of-Equivalents. If the only independent claim initially presented is too broad for the prior art, it will be amended to be narrower and therefore have a weakened DOE application. So it was recommend to have an independent claim initially presented that was narrower than the go for the max claim. Now DOE seldom flies anyway.

And remember the claim will be interpreted in the light of the case law that accumulates between now and when it is enforced possibly ten years in the future.

Method claims

If a thing is being patented, one issue is about patenting methods of making it or using it. If so, do you put method claims in the same application as device claims or in a separate application.

In summary, there is no single criteria for an isolated claim.

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    Thank you for an authoritative answer.
    – Eric S
    Commented Jan 20, 2022 at 2:02

I don't want to sound negative, but it's usually unhelpful to treat the goal of patent-claim design by analogies that look like a mathematical exercise in something like set theory.

The business goal is to have the claims directly cover

(a) whatever is planned to be the subject of trade in the invention, e.g. whatever forms of invented product/process/'embodiment' are going to be sold or otherwise traded, and

(b) any other product (&c) that would effectively use enough of the patented invention to compete with (a).

(A mention in passing: if other envisaged products would compete just as well even where they use nothing of the invention, it's time for a re-think. Maybe the invention isn't worth patenting after all: but on the other hand, perhaps the envisaged alternatives, if new, could even represent a further invention that should be patented as well!)

At the same time, as is well known, the claims must not cover anything that is part of the prior art or is in any way citable against the claimed invention.

It can occasionally be helpful to think of the problem of claim design as not unlike like the encircling game of 'go' -- with areas of categories that need to be covered, and other areas that must not be covered.

But in addition, there is a further legal goal, that the claims actually define an invention (and not just some random collection of features). The claims should point out, at least in general terms, a useful thing effected by the claimed collection of features. This is also why an invention consisting of some A, B and C can't in general be effectively claimed just by A and B, or even by A alone -- except in special cases where the missing essential element can be understood as implied by the claim. Outside those special cases, subcombinations are likely to cover inoperative things, thus, not patentable invention. (If on the other hand, some A+B's that can be envisaged are actually operative and useful for the invention's purpose without any C, then this demands another urgent re-think about what the invention really is: and a serious re-draft that should take place before filing the application!)

Not only that, but one wants to have a graded set of claims: the broadest of them as described above, and others carefully delimited to include subgenerically useful features. The aim here is to build in advance a second line of defense against the possibility -- far from unlikely -- that some further prior art should turn up in the future, something that turns out to be fatal for the broadest claims initially made. Then, the subgenerically useful claims may (hopefully) turn out to be of a kind that has the best chance of being still patentable against the sum of the previously-known and newly discovered prior art, at the same time retaining a useful scope so that the remaining claims still cover the core product and as far as possible its similars.

If you think that this is an impossible demand for clairvoyance, well perhaps it is: but it shows the nature of the problem that calls for solution when drafting patent descriptions and claims -- and sometimes for the luck that can favor a prepared drafting mind.

Much of the reason why all of this is necessary is an artificial reason: that the law in general allows amendments of the scope of the claims in one direction only -- to give up part of the scope of protection originally described and claimed. (The US law, but few if any others, allows -- within a time limit -- to add or broaden claims to include initially unclaimed subject-matter, provided that the resulting claimed subject-matter was originally present in the application and sufficiently described.) There is in general no legal opportunity, after submitting the application, to get nearer the truth of the invention (so to speak) by redefining the claims later to embrace anything inadvertently left absent from the whole application i.e. description and claims as first submitted.

(This legal one-way path can be seen as in some ways unfair. But irrespective of that, the result of it is a strong tendency in practice towards broad-as-possible claiming at the outset. In turn, the results of that can lead to complaints of overclaiming and abuse of the system -- complaints sometimes also reasonable in their turn.)

In any event, the scenario painted in the question, of a hypothetical set of elements A, B and C, is almost always going to be seriously inadequate to the description of any invention. Any three elements are susceptible of alternative decriptions, A', B' C'; A", B", C", &c, practically ad infinitum. How each element is described, and how well its essential features, forms, functions and attributes are captured in language, is always going to be crucial to the effectiveness (or otherwise) of any patent rights obtained.

That's why I suggested at the outset that this is not a problem in set theory. It involves suiting the language of description to the new thing at hand, in several ways -- generically; as economically as feasible; and well enough to capture and make explicit the forms, functions and results.

I hope this may be somewhat helpful, even though the problems can be difficult!

  • If course a claim can’t be amended to the existent that it is not supported by the specification as-filed. But there is no one-way rule that claims can’t be broadened at any point in prosecution In fact, in the US claims can be broadened after grant by a reexamination within a two-year window. Also a claim can have only the limitations A and B even if it takes more than A an B to make an operative device. Otherwise a good answer.
    – George White
    Commented Jan 25, 2022 at 6:59
  • @George White: I appreciate what you correctly said about the US practice to add or broaden claims where there is original description and enabling support, up to 2 years after issue. But you may have missed the general context; my post was (a) not limited to US (unusual here among patent laws and practices), and (b) about trying to amend to add what was not "originally described and claimed". A claim mentioning only A & B where C is also needed for function may be ok in special cases where the rest is implied. But in general, omitting C risks claiming the inoperative and undescribed.
    – terry-s
    Commented Jan 25, 2022 at 15:10
  • @George White : I've amended the answer with the intent to clarify it in view of your points -- thanks for raising them.
    – terry-s
    Commented Jan 25, 2022 at 15:40
  • Welcome to Ask Patents I upvoted your insightful answer. However I don’t understand your worry about inoperative claims. I do not see that as an issue. Unclaimed features can be brought in by inference as you say. Or in a two-part format. And while your point that claims can’t go beyond the initial disclosure is fundamental and critical that does not create any one-way ratchet on claim amendments during prosecution that I’m familiar with.
    – George White
    Commented Jan 25, 2022 at 17:18
  • @George White : thanks. The concern comes (in US, with ~ parallel concerns elsewhere under other legal language) from 35 USC 101 (must be new and useful for patentability) and from the enablement part of 35 USC 112(a) and cases arising, e.g. In re Wright, 27 USPQ2d 1510, 1513 (Fed. Cir. 1993) (would the patent description "have taught one skilled in the art how to make and/or use the full scope of the claimed invention without undue experimentation?"). On the last point, the full scope of a claim without C covers embodiments without C -- unless there's provable implication otherwise.
    – terry-s
    Commented Jan 26, 2022 at 16:22

In general, every feature is limiting the scope of the patent. So the fewer feature you include in your claims the more items are protected by your claims. For example, there are much fewer "soccer balls" than just "balls", the feature "soccer" limited the number of protected products.

But inventors may have different goals with his/her claims/patent.

If the inventor intends to manufacture the product, an important goal would be, that the claims cover the produced product. It requires probably at least one very specific claim.

If the inventor intends to license the product, a goal would be, that the claims cover as many products as possible. Thus, broader claims might be better.

But there may be other goals as well. As an example, if the inventor gets his yearly bonus based on the number of patents he filed, he will probably maximize the number of patents and choose the scope of the claims of his patents accordingly.

  • Can you explain why the goals are different if the inventor intends to manufacture vs licensing his/her invention? Commented Jan 19, 2022 at 14:43
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    I don't see how wanting claims to be less broad is helpful. Since there are multiple claims, why wouldn't one try for the most broad claim possible and then add more specific claims too?
    – Eric S
    Commented Jan 19, 2022 at 16:19
  • An example of a useful narrow claim is a so-called “picture claim”. Rather than attempt to define the scope with more general terms like “coupling member” a picture claim would say “hinge” if the planned product has a hinge. If someone does make a close copy of your planned product you would like to be able to point to something that makes it very clear they copied you. Much less arguing in court about what a hinge is. You would want other claims that did say “a coupling member” or left off that element altogether to protect against someone trying to design around your claims.
    – George White
    Commented Jan 19, 2022 at 16:53
  • @GeorgeWhite I wasn’t questioning why you would want a narrow claim in addition to a broad claim, I was questioning why you would want a narrow claim instead of a broad claim.
    – Eric S
    Commented Jan 19, 2022 at 20:37
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    @picibucor If "ball" is patented, then how can someone patent "soccer ball"? Commented Jan 19, 2022 at 21:52

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