Patent Prosecution Tips: Drafting Preambles

In a recent posting on Patently-O, I asked for advice on whether it is a better practice to use a generic preamble (e.g., "A method comprising") versus a more detailed preamble (e.g., "A method for content selection of digital media stored in a memory…., the method comprising"). Ron Slusky has provided his suggestions in this guest post. Ron's two-day seminar based on his book Invention Analysis and Claiming: A Patent Lawyer's Guide is being offered in Philadelphia on November 16-17.

By Ron Slusky

Any extra word in a claim "can and will be used against you in a court of law." Thus on the one hand, recitations in a detailed preamble may unduly limit the claim in unintended ways. By contrast, a generic preamble can never get you in trouble in that regard.

On the other hand, detailed-preamble claims can serve any number of useful purposes. The trick is to draft detailed preambles with our eyes open.

The pivotal issue is not the length of the preamble, per se, but coming to grips with what legitimate function (if any!!) is served by any particular preamble detail—be it a single word, a phrase or a whole paragraph.

It is important to note that a claim's preamble limitation can be deemed limiting when one goes to enforce the claim, even though the preamble limitation was given no patentable weight during prosecution, and thus did not help to secure the claim's allowance. Such a preamble limitation will have given up claim breadth without having received anything of benefit in return.

Consider the following claim to an automobile floor mat.

An automobile floor mat comprising

a semi-rigid monolayer having a gradually sloping edge portion extending outward from a central section, said edge portion terminating in a lip disposed at an elevation above the central portion, the lip having a plurality of indentations disposed a regular intervals around its periphery.

There is nothing in the body of this claim that requires the claimed structure to be an automobile floor mat. Thus an examiner may well regard "automobile" as being a mere statement of intended use and may reject the claim based on prior art disclosing the claimed "semi-rigid monolayer" whether or not the prior art structure was designed for use in an automobile. Or intended to be placed on a floor. Or perhaps even whether it was intended to be used as a mat.

Suppose, on the other hand, that there is no such prior art, so that the claim is allowable as presented above. Although the descriptive label "automobile" was of no help in securing allowance of this claim, it may come back to bite the patent owner when asserting the claim against suppliers of locomotive cab mats that cannot be used in automobiles (because, for example, they are too big). The patent owner will argue that the term "automobile" should be given no limiting effect because it is not necessary to give "life, meaning, and vitality" to the claim. Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1305, 51 USPQ2d 1161, 1165-66 (Fed. Cir. 1999). That argument may or may not carry the day, depending on how the Markman judge understands what the gives-life-meaning-and-vitality test actually means and how that test applies to the invention at hand.

In any event, the Opposing Team will have a field day with this claim, hammering on the notice function that a patent's claims are supposed to serve and arguing that "if the applicant didn't intend to be limited to automobile floor mats, why did he put it in the claim?" The prosecuting attorney makes the job of the licensing/litigating attorney all the more difficult by opening the door for such an argument to even be raised.

Drafting this claim with a generic preamble, viz.,

A manufactured article comprising,

a semi-rigid monolayer…

may thus save everyone a lot of grief. Indeed, it may save the day.

Descriptive labels and modifiers, such as "automobile" and "floor" in the above example, should always be suspected as creating an infringement loophole without providing any countervailing patentability benefit. Other "usual suspects" are advantages and/or intended uses of the invention. Indeed, the reader should have little trouble in conjuring up reasonable technological embodiments in which claims having the italicized preamble language could be argued to be non-infringing even if the limitations of the body of the claim are met:

An optical system in which at least two out of phase light beams of different frequencies are combined with improved output efficiency, the system comprising…              

An on-chip debug system for a programmable VLSI [very-large-scale-integration] processor, the debug system comprising…

A high speed rotor of a type applicable for use with a flywheel, the rotor comprising [no flywheel mentioned in the rest of the claim]

This is not to say that a detailed preamble is necessarily a bad thing. For example, certain intended-to-be-limiting recitations sometimes fit better in the preamble than in the body. In that situation, recitations that call out to be placed in the preamble during the course of the drafting the overall claim invariably tie into other limitations in the claim body and/or replicate them explicitly. Such preamble recitations will thus certainly give life, meaning and vitality to a claim and thus can be effectively relied upon in arguing the claim’s patentability.  

Below is a claim that uses Dennis’s exemplary detailed preamble. Note how every limitation in the preamble ties into the body of the claim.

A method for content selection of digital media stored in a memory…, the method comprising,

assigning an individual portion of the digital media to a particular portion of the memory based on whether or not the content of that portion includes video data,

selecting one of the individual portions by …..

It is helpful to start out with a generic limitation, and not packing a limitation into the preamble until the structure of the evolving claim makes it clear that it is needed there. This helps protect the preamble from details that can only hurt and not help.

38 thoughts on “Patent Prosecution Tips: Drafting Preambles

  1. Every time I hear this discussion on the so-called best ways to keep from over-limiting a claim in a patent application, I can’t help but wonder how often over-limiting language in a patent has actually helped defend against invalidity. My view is that it is impossible to know until the issues in litigation are fully vetted.

    I think the best bet is to determine what the client wants the patent for, and write the patent for that purpose. Figuring out how to draft the patent for litigation down the line is likely an impossible task.

  2. > There is nothing in the body of this claim that requires the claimed structure to be an automobile floor mat. Thus an examiner may well regard “automobile” as being a mere statement of intended use and may reject the claim based on prior art disclosing the claimed “semi-rigid monolayer” whether or not the prior art structure was designed for use in an automobile. Or intended to be placed on a floor. Or perhaps even whether it was intended to be used as a mat.

    I know it’s an example and all, but with examples like these, you have to understand why people are suspicious of the claims of “novelty” made by patent lawyers and the inventors they represent. I mean, you’re saying “someone else might have invented this hi-tech dimpled, sloped monolayer thingy, but WE were the only ones smart enough to use it as a floor mat!”

    I wouldn’t hold a mere example against you all so much if I hadn’t seen issued patents like the one where the *only* “novel” element was the fact that it used 4 knowledge bases (not 3, nor 5, nor…) and that fact was buried deep in the prosecution history…

    Maybe I should go patent using it as a floor mat?

  3. Federal Circuit rationalizing aside, “comprised of” is, simply, wrong.

    The only reason the Federal Circuit legitimized the otherwise improper usage is because so many otherwise smart people get this wrong all the time.

    There are many websites of prominent law firms that use phrases like “…our IP practice group is comprised of attorneys having…”

    How embarrassing if they were actually called on it (even though some marketing type probably wrote the copy).

  4. ” my general rule of thumb now is to avoid preambles. ”

    As I said above, these kinds of “rules of thumb” are overly pedantic and based on the illusion that “rules of thumb” can absolve you of the hard work involved in analyzing each application, or each claim set within an application, on the individual merits.

    If you have to write claims for, for example, complicated communications inventions in crowded arts, then, IMHO, you need a detailed preamble to “set the stage.”

  5. Having reviewed the Federal Circuit case law relating to when preambles will be given “weight” for the purposes of patentability or infringement, my general rule of thumb now is to avoid preambles. What I’ve seen tells me that the Federal Circuit is, at best, inconsistent on when preambles matter, and at worst for patentees, either gives the preamble no weight in determining patentability (thus rendering the patent invalid), or gives it weight in determining there is no infringement. Put differently, my philosophy on claim drafting is “less is more” (i.e., broader coverage).

    If the “element” or “feature” (I also avoid characterizing the language in the claim as a “limitation” because of the baggage that word carries in infringement analyses) is needed for patentability, be decisive and put it in the body of the claim (i.e., after the transitional word “comprising,” etc.). For example, if you want (or more importantly need) to claim an automobile floor mat, write the claim as follows: “An article comprising an automobile floor mat comprising [then defined the needed elements/features of the automobile floor mat].” Otherwise, use one word to describe generically what statutory class the invention belongs to in the preamble and leave it at that.

  6. This is news to anyone? As with any part of a claim, don’t use a term unless you’re ok with it being a limitation.

  7. Bryan said:

    “The worry that a preamble is a claim limitation only afflicts those who did not properly claim their invention, or who are trying to stretch the claims beyond what they thought they had invented at the time they wrote their claims.”

    Bingo! #1 rule in claim drafting: Claim your invention, because an overly-broad claim will get shot down either by the examiner or the defendant.

  8. Grass is green. The sky is blue. Words in a patent claim (anywhere in the claim) limit the claimed invention.

    This is not exactly groundbreaking news.

    I’m curious. Are there patent attorneys out there who don’t already know this?

  9. If you intend to use your preamble to limit, then make sure you use a term that is used in the body of the claim.

    If you don’t have a specific reason to use the preamble to have some limiting effect, then don’t put excess words in the preamble.

    The notion that preambles should always be simple is pedandtic and one of the things that irks me about some patent lawyers, they forgot how to think…

  10. “…in the same field or a different one.”

    vs.

    “reasonably pertinent to a known problem in the field of the endeavor.”

    hmm, seems like two different things being said.

  11. Re: non-analogous art

    From KSR:
    “When a work is available in one field of endeavor, design incentives and other market forces can prompt variations of it, either in the same field or a different one.”

    Also from KSR:
    “Under the correct analysis, any need or problem known in the field and addressed by the patent can provide a reason for combining the elements in the manner claimed”

    The old analogous art test was (1) was it in the same field of endeavor, and if not (2) was it reasonably pertinent to the problem being solved. KSR spoke many times to the “field of endeavor,” so that has not been abandoned. Instead, KSR has modified “reasonably pertinent to the problem being solved” to “reasonably pertinent to a known problem in the field of the endeavor.”

    Thus, you cannot take a piece of prior art from a different field of endeavor and use it to solve a problem that was not known in the field of endeavor.

    Although people seem to forget this, obviousness is based upon what would have been obvious to one skilled in the art. If one skilled in the art does not know about the teachings (because of a different field of endeavor) and does not know of a problem that can be solved by by the reference, then one skilled in the art would not have looked outside the field of endeavor to find this reference.

  12. RE: non-analogous art. There’s a 2008 CAFC decision that has a phrase along the lines that one of ordinary skill in the art is attributed with all relevant knowledge.

  13. I created the example using Dennis’s exemplary preamble, “A method for content selection of digital media…” simply to show a case in which a “wordy” preamble might be harmless enough—at least in theory–because the preamble doesn’t introduce anything that isn’t in the body of the claim anyway. But Billy James is 100% correct in saying that that particular claim is equally patentable without the preamble and so better to leave it out.

    That being said, there are any number of reasons why a “wordy” preamble can be useful:

    1. Sometimes trying to put everything into the body of the claim can make the overall claim more wordy than if particular limitations are put in the preamble. This isn’t so much of an issue for physical structure types of inventions—which are typically amenable to an “Apparatus comprising” type of preamble— but can often come up when writing a claim directed to, for example, a component or module designed for use in a system environment and you are writing a claim limited to the component itself. Been there many times.

    2. To establish an intended-to-be-limiting structural environment for a method claim.

    3. To enhance the diversity of the overall claim suite by having claims with both minimal and “wordy” preambles. (See my book on the general topic of claim diversity.)

    4. To recite characteristics of, say, an input signal that claimed apparatus is going to do something to. Putting such limitations in the preamble emphasizes to the claim interpreter that apparatus for (or the step of) generating such a signal is outside of the claimed subject matter.

    5. Etc.

    Ron Slusky

  14. I’ll leave to others the pleasure of answering the Breadcrumbs question (assuming that it isn’t merely rhetorical). I was only thinking that more and more Americans contemplate filing also outside the home jurisdiction. Suppose that choosing a particular preamble has +ve consequences within the US but -ve ones everywhere outside the US, how’s a poor drafter (wherever in the world she is) supposed to do the right thing?

    I continue doggedly to adhere to the idea that, while caselaw changes, what constitutes “good” drafting is universal, and endures in perpetuity.

    Cue for Paul Cole.

  15. Maybe Mr Slusky would agree that thinking about the preamble is no substitute for thinking through just what the invention is, and then ensuring that every word of the specification and claims is consistent with the inventive concept. Otherwise, whatever preamble you choose will hurt you.

    If the invention is a new sheet, don’t claim a mat. If it’s a mat for a vehicle driver, don’t claim an automobile mat, and so on.

    But setting the preamble too broad can also have consequences, as others have noted. The more so outside the USA. If it can be shown that at least one sort of “sheet” with your features is obvious, then amending down to mat, or floor mat, or vehicle floor mat, or automobile mat, might feel like successive attempts to get the tip of your ice pick to bite, as you slide towards the precipice of invalidity. After all, you yourself said at the outset that your “automobile mat” is just a fancy name for a sheet.

  16. regarding the preamble:

    1) non-analogous art is ONLY an issue in 103 rejections, if you have a 102 meeting all of the claimed structure, and it can perform the intended use/functional limitation (if there is one claimed), then you reject

    2) the preamble only will impact the examiners search in method claims (at least in my mechanical art)

    3) i’ve seen plenty of claims that begin with: “An article of manufacture, comprising:” – that’s the easiest way (that i’ve seen) to get around this preamble junk

  17. regarding the preamble:

    1) non-analogous art is ONLY an issue in 103 rejections, if you have a 102 meeting all of the claimed structure, and it can perform the intended use/functional limitation (if there is one claimed), then you reject

    2) the preamble only will impact the examiners search in method claims (at least in my mechanical art)

    3) i’ve seen plenty of claims that begin with: “An article of manufacture, comprising:” – that’s the easiest way (that i’ve seen) to get around this preamble junk

  18. I am not and have never been an examiner, nor do I even play one on this website.

    But my guess is that a narrower preamble would effect the scope of the examiner’s’ prior art searches and what they consider to be analogous art.

  19. Preambles are easy. Assume that the Examiner will not give anything in the preamble patentable weight and assume that an infringer will require that everything in the preamble be found in the infringing device.

    Preambles can be useful to introduce a couple of terms that you want to later on discuss in the body of the claim without messing up the flow.

    For those experienced claim drafters there are “claim limitations” that aren’t exactly limiting. Since claims are not required to enable the invention, there are a whole lot of things you can leave out. As such, whether these items actually get put into the claim (e.g., in the preamble) is a matter of taste — just remember the two rules I gave you.

  20. Another issue with premables is as soon as the premable is something that is not generic, the claim is potentially open to a attack/rejection for missing a critical element. Specifically, one way of invalidating the claims is for a clever litigator to figure out a how to contrue the claim so that an element is missing that is crtical to the functioning of the device/method decribed in the premable.

    It seems to me that writing a preamble potentially introduces ambiguities (sometimes ones that are not foreseen in advance), and I not sure why or when one you would want ambiguities in a claim. Maybe sometimes such ambiguities are beneficial or give the patent owner something that is beneficial in litigation, but I just don’t see when that might be the case.

  21. Dear Former American,

    Firstly, please be an American again — it is all we can be since other choices suck worse. And, there is no way in hell Obama will ever be elected to any office again, God willing.

    Secondly, yes, I remember the thread.
    It was Judge Newman’s worse decision in her career!
    She got suckered-in.
    “Comprised of” was the only thing she got right.

    I understand that “comprise” (and all its derivations) is “open ended,” and that “consist” (and all its derivations) is not, in patentese, but what about “compose”?

    Is your comment to say that “comprise” and “compose” and there derivations are both open ended?

  22. Non-generic preambles can help make a claim easier to understand, and thus help readers identify the invention. The bias that the preamble is not a limitation encourages patentees to use non-generic preambles to help the readers of their claims.

    The worry that a preamble is a claim limitation only afflicts those who did not properly claim their invention, or who are trying to stretch the claims beyond what they thought they had invented at the time they wrote their claims. An inventor of a general purpose mat is making a mistake claiming (only) an automobile floor mat; some claims of broader scope should be presented. On the other hand, the inventor of an automobile floor mat may not be making a mistake claiming an automobile floor mat. The mistake may be trying to stretch claims on an automobile floor mat to cover other kinds of mats never contemplated by the inventor.

    In claim drafting, there is no substitute for correctly identifying the inventive concept at the outset.

  23. (Excuse my typos, etc; re-posted now)
    Just an ordinary:
    Interestingly enough, Dennis had a blog topic that addresed the use of the phrase “comprised of” (which should be comprising or composed of, btw, and it got the drafter (inventor/applicant) into a bit of trouble that required an appeal to reverse.

  24. Just an ordinary. Interesting enough, Dennis had a blog topic that addresed the use of the phrase “comprised of” (which should be comprising or composed of. bte, and it got the drafter (inventor) into a bit of trouble that required an appeal to reverse.

  25. Considering the example, there are four choices I would consider:
    “An automobile floor mat”
    “A floor mat”
    “An automobile mat”
    “A mat”

    I’m not sure the word “floor” hurts, because I can’t think of anywhere else that you put a mat in an automobile, except maybe the trunk, and I think I could still argue that’s a floor.

    I agree the word “automobile” hurts.

    I don’t know if the word “mat” itself hurts.

  26. How ’bout

    Something comprised of, …

    or

    Anything comprised of, …

    or

    Any old thing comprised of, …

    or

    One or more embodiments of the present invention comprised of, …

    or

    A method comprised of , …

    or

    A system comprised of, …

    or

    Software configured in an apparatus comprised of, …

    or

    Programming adapted to a device comprised of, …

    - – - – followed by

    … etc.

  27. Can’t a preamble sometimes save you from having a court construe your claim to cover prior art during litigation? That seems like an advantage.

    Billy James:
    I’m told you need one just to specify what statutory class you’re in, and also to include an open-ended word like “comprising.” Your proposed claim might not cover ABCD even if it covers ABC.

    Having said that, it might be fun to see how far you can get with “A thing comprising…”

  28. smart venture capital would realize that wordy preambles are self defeating. use other marketing tools to appeal to the venture capitalists and keep integrity of claims intact.

  29. I’m told that wordy preambles are more useful in soliciting venture capital. If so, then it’s probably best to include only terms that are already recited in the body of the claims.

  30. Ironically, I was just thinking today about when a preamble might ever be helpful, and sadly this article didn’t convince me that a preamble is *ever* useful. I’m still willing, even hoping, to be convinced since it seems to be accepted practice.

    If every limitation in the preamble is also in claim, why have you said it twice? Is “A method comprising: assigning an individual portion of digital media to a particular portion of a memory based on whether or not content of that portion includes video data; selecting one of the individual portions by…” less patentable somehow?

    Similarly, if your structure inherently performs a function, why should you say what it is in the claim? Anticipating structure will also inherently perform the function. What is gained?

    In the extreme, is a preamble even required? Could a claim just not have one? “I CLAIM: 1) Structure A; Structure B; and Structure C coupling Structure A to Structure B.”

  31. “creating an infringement loophole without providing any countervailing patentability benefit”

    A great insight into claim drafting.

    Also, good advice about advantages. The advantages should be implicit.

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