Patent Claims as Elements rather than Boundaries

By Jason Rantanen

I teach Introduction to Intellectual Property Law every spring semester, an experience that often causes me to reflect on some of the fundamental premises of intellectual property law in a way that advanced courses don’t necessarily always invite.  When you’re deep in the nuances of the effective date provision for post-AIA § 102, it’s easy to lose sight of some of the big questions.  This post is one of a few half-baked ideas from that return-to-basics reflection.


I grew up steeped in the world of property law.  My father’s law office was in rural New York, and his core practice involved representing farmers, villages, and small businesses on land transactions, estate planning, and probate matters.  Some of my first memories are of photocopying property abstracts: voluminous documents that contained the transaction history for a property, often going back a hundred years or more.  We’d copy these abstracts and then affix the new deed or mortgage associated with the transaction.  Later, I learned to type up property descriptions for deeds, writing out the metes and bounds of the land being transferred.  These descriptions  used points and lines to articulate the land for which the property rights applied.

For me, the language of patent claims as boundaries resonated early and easily.  After all, patent cases routinely refer to claims in boundary-like terms.  One example is the likening of claims to “metes and bounds,” as Judge Rich did in footnote 5 of In re Vamco Machine and Tool, Inc., 752 F.2d 1564, 1577 (Fed. Cir. 1985).

The function of claims is (a) to point out what the invention is in such a way as to distinguish it from what was previously known, i.e., from the prior art; and (b) to define the scope of protection afforded by the patent. In both of those aspects, claims are not technical descriptions of the disclosed inventions but are legal documents like the descriptions of lands by metes and bounds in a deed which define the area conveyed but do not describe the land.

Another example is this passage from Judge Michel’s opinion  in Halliburton Energy Services, Inc. v. M-I LLC, 514 F.3d 1244, 1249 (Fed. Cir. 2008):

Because claims delineate the patentee’s right to exclude, the patent statute requires that the scope of the claims be sufficiently definite to inform the public of the bounds of the protected invention, i.e., what subject matter is covered by the exclusive rights of the patent. Otherwise, competitors cannot avoid infringement, defeating the public notice function of patent claims.

Patent law scholarship, too, treats patent claims as if they are boundary-setting.  Books and articles refer to modern claiming practice as “peripheral claiming”– language that implies an area that is within and that which is without.  Even those scholars who have critiqued the idea of peripheral claiming nonetheless visualize patent claims as defining an area: signposts instead of fenceposts.  The idea is still that there is a zone set by the patent claim.

And yet, the more I’ve litigated, studied, and taught about patents, the more I’ve realized that conceptualizing patent claims as defining an area is fundamentally wrong.  Patent claims are not boundaries, and it’s confusing to those who are trying to grasp patent law when we talk about them that way.  There is no area that is “encompassed” within patent claims.  Patent claims don’t define a “boundary.”  And they are quite unlike the metes and bounds of a deed description.  Even if one could plot the components of a patent claim in some n-dimensional space, it would still not define a closed form.  Conceptualizing patent claims as if they define some “area” of technology isn’t how they actually work. One cannot draw a line from one claim element to another, except in the sense that claim elements can interrelate with one another–but that, too, is really just another element, albeit one that is implicit from the semantic structure of the claim rather than explicit in its words.

So how should patent claims be conceptualized, if not as establishing a boundary?  My first answer goes back to how litigants and courts often actually approach them: as discrete legal elements akin to the elements of any other legal claim.  The limitations in patent claims aren’t like the boundaries defined in a deed; instead, they are like the elements of a tort.  Each of these elements must be met in order for the claim to be infringed, invalidated, or adequately supported by the disclosure.

Consider, for example, patent law’s novelty requirement.  In order for a prior art reference to anticipate a patent claim, each and every element of the claim must be present in the prior art reference.  Or the analysis for infringement: for there to be infringement, each and every element of the claim must be present in the accused product or process, either literally or as an equivalent.  In both cases, patent claims are treated as if they are a series of elements–not as boundary lines that are crossed or not.  They are, in the words of Nolo’s Plain-English Law Dictionary, “the component parts of a legal claim.”

In the end, despite my initial attraction to the language of real property to describe patent claims, I’ve come to realize that this rhetorical device–enshrined in patent law judicial opinions and used in briefs and legal scholarship–is both misleading and wrong.  Patent claims are not boundaries, and we should stop referring to them that way.  Instead, they are elements in their legal sense: sets of individual legal requirements that must each be proven to achieve a particular legal status.

Perhaps this is so obvious that it doesn’t need to be said.  And yet, for those who are learning patent law for the first time, it is hardly obvious – particularly when the opinions that we read talk about patent claims in boundary-like terms.


Thoughtful, non-repetitive comments welcome.  Comments that I think are crud or junk, in my subjective opinion, will be deleted without further notice or comment.


39 thoughts on “Patent Claims as Elements rather than Boundaries

  1. 22

    Thank you for all the thoughtful comments. Many are very insightful. Unfortunately, I have closed comments because one person started to spam responses to people that he or she disagreed with, and rather than spend my Saturday afternoon deleting comments, I instead decided to just close them.

  2. 21

    Look, the problem is simple to define. How to write in words the metes and bounds of the invention. Engineering textbooks speak about exactly this issue and describe how engineers do this. They use functional language to describe the known solutions that include the current solutions being described.

    This is trivial for a person educated in engineering to understand.

  3. 20

    Probably most of the conceptual confusion could be avoided by recognizing that with patent claims we are describing multiple embodiments in technology space using word-based concepts, whereas in real property we are (usually) describing single embodiments in physical space with word-based concepts. In both, there can be disagreement about the meaning and referents of the word-based concepts. E.g., “two-headed hammer” or “river’s edge”; and note the the doctrine of accretion also makes the physical space referents change over time, whereas we are not really changing the technology referent but the meaning of the terms used to describe technology (and thus what any “hammer”) actually encompasses (in technology space). With that clarification, the use of the “boundaries” metaphor makes much more sense. We just need to recognize that we don’t treat physical space and technology (conceptual) space similarly, and we are usually claiming multiple things with patent claims and single things with property metes and bounds descriptions. Since we’re on Plato, how about Aristotle (I think) – “tene rem et verba sequentur” (in Latin, for “grasp the thing and the words will follow”).

  4. 19

    In scanning through the comments, I have identified several concepts that are worth repeating.

    To understand claim language, it is a combination of “elements” and “boundaries” that make the most sense. I’ll add a third, “intersection” for which another term may have been substituted elsewhere, but I haven’t read all the comments to determine if it is or isn’t.

    A claim is comprised of multiple elements, and each element has their own boundary. As someone mentioned earlier, the term “boundary” is helpful when considering what is (or isn’t) indefinite. Speaking of indefiniteness, I couple of helpful considerations is that only reasonable definiteness is required — not perfect definiteness. Claims are not blueprints. They employ words, and words by their very nature have a bit of fuzziness associated with them. Another point I would like to mention about indefiniteness is that whether something is indefinite (or not) cannot be determined solely by looking at the words themselves. Oftentimes, what seems indefinite on its face becomes much clearer after reading the specification.

    I analogize an entire claim as a set of these circles (or blobs) (or spheres if you want to do 3-D) as a kind of Venn diagram. The intersection of all of the elements (or circles or blobs or spheres or whatever) are what constitutes the claimed subject matter.

    Consider a claim with the following elements:
    A method implemented with a computer (really broad but still eliminates a lot of things), comprising:
    displaying a graphical user interface (also really broad, but there are a lot of computers out there that don’t have GUIs),
    receiving a user input selecting an icon within the GUI (narrower than the previous element but begs the question whether the previous element is even necessary),
    receiving from a server connected to the computer a heartbeat (what the &^%% is a heartbeat — oh, after reading the specification I understand what that is — not entirely common but not uncommon either), and
    performing an operation on the selected icon using the heartbeat (this is an intersection of a couple elements that might be hard to find), wherein
    the operation is [X] (this is really unusual).

    To me, a good claim is one that has a bunch of individual elements (with their accompanying boundaries) that interrelate with one another such that the intersection of all of them accurately describe the claimed invention. To me good claims consider: the individual elements, the boundaries of those elements, and the intersection of the boundaries.

      1. 19.1.1

        WT, your Venn diagram analogy seems particularly appropriate for combination claims?
        I’m not sure what you mean by “combination claims.” All claims are combinations of elements. I’ve never met a single-element claim in my life and I’ve read tens of thousands of claims.

  5. 18

    The fact is that I write real claims for real inventions and work with real inventors. Most are highly educated many with Ph.D.s from places like MIT and Stanford.

    I don’t think the author can claim this.

    And the fact is that real inventors know exactly how to read the claims as functional representations of known solutions plus the specification.

    Many of my inventors can read claims and understand exactly what the invention is by using their engineering training to understand the claims.

    This is just another academic making up stuff from abstractions. Those of us that have written 100’s of applications and have done litigation including writing Markman briefs and worked with inventors for 20+ years know exactly how claims should be written and what they mean.

    The problem is the CAFC is invested with people that have no practical experience and no desire to strengthen and define patent laws but to weaken patents in any sneaky back-handed way they can.

    Reality my friends. Reality. Reality.

    1. 18.2

      It’s not so much the writing of claims that counts, in my opinion. Rather, it’s the plotting in (formerly) smoke-filled rooms for moths, half the time with petitioners for revocation of claims and the other half of the time defending the duly issued and asserted claims, that is needed by those who will serve as judges in patent litigation. You know, like how it happens in England.

      This experience leaves those who judge with a strong desire to construe claims sensibly, explain their claim constructions persuasively, see their claim constructions do justice and then survive inspection on appeal. Only about one third of cases in England that go to full trial get appealed. Mostly, it’s a complete waste of money, even to deliberate whether to do it.

    2. 18.3

      NW, yes, this blog is intended as an academic subject. But “reality” also includes lay jurors and D.C. judges with no technical or legal education. Also, is what scientist inventors may think their claim terms meant to them in their own patents important enough to even get a mention in patent decisions? How persuasive is the inventors interpretation of their own claims even in Markman decisions, given their inherent self-interest on one hand, and assignee estoppel on the other hand?

      1. 18.3.1

        Paul, “How persuasive is the inventors interpretation of their own claims even in Markman decisions”.

        The answer is that it should be dispositive. The reality is that there is no other meaning that is possible to the claims. The reality is that the reason there are so many problems with claim construction is that it does not reflect modern technology and how modern technological terms are used.

        But I am smelling the dinosaur again.

  6. 17

    Perhaps in your hurry ‘back to basics,’ you jumped too quickly to the mere analogy, and jumped past the point being presented….

    To wit (with different emphasis added): “In both of those aspects, claims are not technical descriptions of the disclosed inventions but are legal documents like…

    ALL too often on these boards (and I daresay even in the courts), we have people wanting to use their own colloquial viewpoints, and omitting that ‘back to basics’ understanding that these are legal documents.

    The terrain is a legal one — not a colloquial one.

  7. 16

    Jason, I still remember the first month or so of my “apprenticeship” in a patent law firm upon leaving university. I remember that initially I suffered confusion in between that which a claim “covers” and that which prejudices the novelty of a claim. The thing is, once it became clear in my mind, I could not bring back to mind whyever I could ever have been confused about it.

    It’s like learning to ride a bike, isn’t it? Once you have cracked it, you can’t for the life of you imagine how you could ever have had any difficulty with it.

    So, as between you and your brand new students, my advice to all concerned would be: 1) Accept that, initially, it will be confusing for most every student but 2) For most every one of those students, the early morning fog will soon evaporate, to reveal the full glory of the day. How many people 1) fail to master riding a bike and 2) How many of them assert that there is something wrong with putting in the effort to learn how to ride a bike?

  8. 15

    Dennis, I assume your Introduction to Intellectual Property Law course surveys all of IPL? I do not recall a discussion here of the interesting “Hot-News Doctrine,” a state court IP protection outside of present Federal copyright law, a different infringement test, and with a completely different time frame. With current battles between social media companies and the newspapers they take their news from, I wonder if it will become a hot IPL topic? In a very quick search, I noted, for example, articles such as this one from The Federalist Society:* “Hot News: The “Hot-News” Doctrine Is Hot Again! Or Is It?” Volume 12, Issue 3, November 2011.
    *[Considering who picked so many judges and justices in the past 4 years, should more attention should be paid to their articles?]

    1. 15.1

      As for patent claims analogized to boundary descriptions [like land deeds] versus element-additive-serial-limitations, does not the former suggest negative claim limitations, which U.S. patent practice can allow but seems to generally discourage? Also, no word will be as clear and immovable by argument as a boundary marker in the ground.
      But in any case, calling patent claims boundary descriptions like land deeds is useful for jury arguments, so unlikely to change.

  9. 14

    as a non-lawyer new to working with patents, both the article and the comments have been super helpful. this has helped me understand how to think about claims, and some of their problems and limitations. thank you all!

  10. 13

    Dennis: Excellent and profound question. The problem with claim definition is even more confusing under the current USPTO Design Patent system where the claimed design is much closer to your land plot examples above. In the claim structure of design patents, it is actually the visual structure of the object that defines the boundaries of the claims. While this seems like an easier model to teach and resolve the problem is actually far more complex when one considers the proffered DOJ 4 Factor test and the question of how to deal with features that may be dictated by a function that is present in the design patent claims. This issue of how to deal with modification of design patent claims by filtration and extraction of so-called functional features is the subject of major disagreements between leading design academics and design patent practitioners. The recent Berkeley Center for Law and Technology seminar illustrated the problems and conflicts. The issue of how boundaries are defined in design patent cases during litigation is confusing, to say the least, and is far from resolved. This undoubtedly makes teaching Design IP complex as well.


  11. 12

    Concur. The boundaries concept makes sense in terms of the coverage of the resultant patent, but not as much when looking at claim language. The elements/components framework is often more helpful – I’ve found that for people new to thinking about claims that a pizza analogy can work well, at least at first. A claim presents a set of toppings for a pizza. Nobody else can sell a pizza using that same collection of toppings, regardless of whether they do or do not add additional toppings to the pizza. Even though individual toppings may be well-known, the combination may not be – pepperoni, baked beans, horseradish, and breath mints. Also not perfect but often easier to grasp for those new to thinking about claims.

  12. 11

    I was introduced to the “metes and bounds” metaphor of patent claims at the earliest stage of my patent career in the late 1980s. I recall writing a law school paper discussing how the earliest utility patent statutes were substantially derived from the laws relating to land patents issued by the U.S. government in the 1800s, (e.g., the Maxwell Land Grant encompassing much of New Mexico and Colorado). (See Maxwell Land Grant Case, 121 U.S. 325 (1887)).

    Dennis, your reforming of this paradigm is intriguing and, I think, valuable.

  13. 10

    Prof. Rantanen’s conceptualization of patent claims as tort-like elements is powerful, but I think the real property metaphor can also be useful. Consider: accused products occupy a “space” in a “field” of technology. By the same token, one can view the patent claim as staking out a portion of this field, and the infringement question is whether the accused product falls within those staked-out boundaries. This metaphor may be imperfect, but I found it *very* useful in my scholarship to help explain the law-fact divide in infringement. See 27 Fed. Cir. B.J. 187, 200-201 (2018).

    1. 10.1

      Mr Sohn, there is more than one way to “stake out” a “field”. Consider a green on a golf course. Somewhere near the middle is a hole. That hole represents your “Best Mode”. The flag on the stick in the hole is your German-style “central” claim. When you bring infringement proceedings, the judge will decide whether the defendant’s “ball” is close enough to that flag to constitute an infringement of your duly issued patent.

      Otherwise, you can put a fence around the periphery of the green and call that your “claim” that “stakes out” the protected area.

      You might think that a “central claim” is a nonsense. But it is how it works (outside the USA) with design patents, isn’t it? It’s do-able also with utility patents. But it’s not ideal. Germany dropped it as a way of claiming in utility patents, all the way back, in 1973.

  14. 9

    Hello Jason,

    I think that this post is an insightful reflection on the “claims as boundaries” concept. And I appreciate you prodding it.

    Regarding teaching the “claims as boundaries” concept to students, I still think that this is good practice. I think that it is a good metaphor for them because it makes it easier to explain indefiniteness to patent newbies. Indefiniteness can be a weird concept for some students, and analogizing it to a physical concept or some previously known concept makes it easier to understand.

    And teaching it isn’t really harmful. I think that students get the hang of indefiniteness once they start applying rules to facts to get outcomes by reading cases. This new understanding is what they go forward with.

    Regarding the “claims as boundaries” concept used in judicial opinions, I think it is fine for courts to use it because it is a standard that they ought to strive for. Indefiniteness is decided on the “reasonable certainty” standard from Nautilus, but the “claims as boundaries” gets court thinking in the right direction.

    Regarding your analogy of patent claims as elements of a tort, I definitely agree. I think that we should teach it to students like this. I think we should teach both: patent claims are like boundaries and like elements of a tort.

    1. 9.1

      Brad, Jason, I support this point. Here in Europe, we call your “indefinite” out as “lack of clarity” and the jurisprudence emphasizes why clarity is essential, namely to define the “scope of protection” of the claim with the necessary precision. To promote orderly progress of the useful arts, under the Rule of Law, the public (including the competitor) definitely needs to know , with clarity, what product or process infringes the exclusive right given by issue, and what does not.

      Can it be, that some people are not able to see the logic or the sense in that?

      1. 9.1.1

        Remind me again MaxDrei, if clarity or lack thereof is challengeable after grant in your Sovereign.

        (Can you guess where I might go with your answer?)


          No, anon, I can’t guess. And you need no reminder, do you?

          Pre-issue, the EPO examines the clarity issue with ferocious severity, mindful that the claims it duly issues must be clear if they are to be fit for purpose.

          Post-issue, in inter Partes proceedings, woe betide any patent owner who needs to amend the claim to save the patent. Why? Because the clarity of the saving amendment seeking admittance is going to be examined even more ferociously than in the ex Parte pre-issue examination proceedings. Less than clear: no admittance.

  15. 8

    The boundary or real property analogy is helpful for understanding the relationship between infringement and anticipation: that which infringes, if later, anticipates, if earlier. It’s also helpful for understanding infringement and anticipation separately. Obviousness can be described as close (or within sight) of the boundary. For example, if the claim can be read to cover something that is within the prior art (or close), it’s anticipated/obvious. Yes, you have to allow for a piece of space being subject to multiple overlapping claims. Remember though that engineers/scientists often think visually and the real property (in n-space) analogy is a great visualization tool. Think of directions: do you want turn-by-turn or visual/map-like directions? My wife like turn-by-turn directions. I like to map where I’m going in my head. Both work, and different people will find different tools useful. The boundary analogy is not “wrong.”

  16. 6

    This is exactly the dilemma that confronted the drafters of the European Patent Convention back in 1973: how to mediate between UK peripheral claiming and German “central claiming”. The solution (see the Protocol on the interpretation of Art 69, EPC) has stood the test of time, only recently being unequivocably endorsed by the UK Supreme Court after 40 years of practice of the Protocol in the 38 Member States of the EPC.

    The thing is, to do justice, the court should construe the claim in such a way as to deliver BOTH reasonable legal certainty AND fair scope of protection for the inventor. One does this by NOT following the former over-lawyerly, over-literal UK approach NOR the excessively hand-waving approach taken prior to 1978 by the courts in Germany.

    Sounds impossible? Try it. It’s working well in Europe. It tends to cut out silly decisions over words like “half-liquid” or those based on unfortunate drafting slips like in Chef America. In fact, more than that. I mean ALL cases where any deemed addressee can see the reality of what the drafter was using the language of the claim to mean, even if it’s beyond the ability of some cloistered jurists.

  17. 5

    The description of a claim as a boundary is difficult to understand for engineers because it is counterintuitive with the existence of improvement patents. Using the analogy with land, an improvement patent would be piece of property inside another piece of property. Quite odd.
    The description of a claim as a check list of elements is also difficult to understand for engineers. As technology develops, it becomes apparent that not all the embodiments meeting the checklist are enabled. That becomes important when discussing infringement, because engineers feel that claims should only cover what was enabled at the time the invention was filed (or made for older US patents).

    I don’t think there is an intuitive analogy of patent claims that applies well to every question that can arise. I suppose it is because ensuring conceptual coherence is less of a concern than maintaining traditions, and traditions are created somewhat randomly by trials and errors.

    1. 5.1


      You alight upon a critical flaw in Random’s reasoning:

      As technology develops, it becomes apparent that not all the embodiments meeting the checklist are enabled.

      Quite in fact, outside of an excessive picture claim for which NO possible improvement patents of any kind are possible, Random’s world view necessarily collapses.

    2. 5.2

      “Using the analogy with land, an improvement patent would be piece of property inside another piece of property. Quite odd.”
      Great observation. Especially since real property owners usually get to keep improvements to their land even if they did not provide them. Indeed, it so confusing to some that I had to explain one time years ago to a prof working for the FTC on licensing guidelines that no patent provides a “right to use” what it claims, because most patents are improvements over and within someone else’s more basic or generic patent claims, which one can hope are all expired but may not be.

      1. 5.2.1

        Excellent reminder Paul: patents are a negative right – not a positive one.

        Improvement patents are one indicator of why this must be so.

  18. 4

    Claims are designed to capture and record the essence of an invention.

    Inventions are combinations of ideas and things that have use to human beings. As Plato realized, the perfection of an essence can only be approached- never precisely realized.

    Claims are made of words, and words are vehicles for the symbols that things or ideas are also made of. Sometimes the match between a symbol and its referent is nearly perfect and easily transmissible to people other than the inventor, other times, not so much.

    Claims are representations- abstractions- of inventions that must be taken as working systems intended to convey essences. They are illustrations- which include both boundaries and elements, depending on the views of the consumer and the drawer.

    1. 4.2

      Refreshing, Martin. refreshing. As I always maintain, no claim, directed to an inventive concept, can ever be 100% “definite” or “clear” precisely because it is composed of words, nothing more. I must now check out what Plato had to say on the subject, to see whether he agrees with me. Thanks for the tip.

      Me, I don’t think one can do better, when going about the business of construing a patent claim, than to follow the approach of the UK Supreme Court, and ask oneself: What was the writer of the claim using the language of the claim to mean?

      That at least would cut out silly outcomes, such as when the claim carelessly recites “half-liquid” or when the claim includes the word “to” when the word needed was “at” (as in the Chef America case).

  19. 3

    Regardless of how it is conceptualized, claiming the invention as required since the 1836 Act has failed. The invention is interpreted by words in a claim, then the words in the claim are interpreted by a Markman order, then the Markman order is interpreted by the in limine order, then the in limine order is interpreted by the expert witness, then the expert witness is interpreted by the trial counsel, then the trial counsel is interpreted by the jury.

    It gets even worse when inexperienced PTAB judges make up meanings for the words (where gasoline means crude oil, without arcing means with a little arcing, and single merchant means more than one merchant).

    This system has totally failed. It just spawns endless arguments over endless words.

    Know one cares what we invented. They only care that they can make money by arguing over the words.

    1. 3.1

      Bang-on accurate Josh. Yet again.

      Another example of ends-justifies-the-means word / language games:

      The CAFC and Patent Office incorrectly — and unconstitutionally — twisting SCOTUS’ “identify one abstract idea /concept” (is possible) in the claims at issue . . . to mean that it’s O.K. to identify more than one abstract idea / concept in the claims at issue.

      One is one is one is one. Simple, right?

      Just not to the CAFC and Patent Office . . . who believe that one can mean two . . . three . . . four or more . . .


  20. 2

    Jason bruh, they are plainly boundaries, in the sense you’ve discussed above, and elements, in the sense you’ve describe above, both. The end.

    Why is this distressing your mind? Because it is confusing to newbies? Let them spend some time in the field they’ll get the hang of it. Because it isn’t perfect analogistically? Just going to have to get over that bro.

    All those things mean are the the teachers need to up their teaching skill.

    What are you trying to accomplish with this post anyway?

  21. 1

    “Even if one could plot the components of a patent claim in some n-dimensional space, it would still not define a closed form.” I think you underestimate the flexibility of an n-dimensional space! Every element has “breadth” that might be viewed as a range of values within a dimension. The overlap of each range is the closed form. (It is possible that an element has a non-contiguous range, but one simply needs to reformulate the dimensional values to account for this, or just accept that two closed forms exist.)

    Look, no analogy is perfect. The question is–is it helpful? I think the boundary analogy is. As you describe, it is helpful for definiteness. Concepts of “breadth” are near ubiquitous and directly analogize to boundaries.

    Conversely, your analogy of elements is also helpful. That said, it has it’s drawbacks: one might assume, for example, that a claim is anticipated when every element is taught in the art. That is of course not true–it is a necessary but not sufficient condition.

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