Logical Conclusion?: Claimed Open-Ended Ranges Lack Enablement

By Dennis Crouch

Magsil Corp. and MIT v. Hitachi (Fed. Cir. 2012)

In a unanimous opinion, the Federal Circuit has affirmed a district court summary judgment holding that the asserted claims of MIT's patent are invalid for a lack of enablement. The patent covers read-write sensors for computer hard disk drive storage systems and relies upon quantum tunneling in operation.

The courts have derived an enablement requirement from Section 112 of the patent statute. Under the doctrine, after studying the patent specification, a person of skill in the relevant art should be able to (theoretically) make and use the full scope of the claimed invention without undue experimentation. Patents ordinarily include many different claims that identify various legal rights given to the patentee. Enablement is judged independently on a claim-by-claim basis. Any claim that lacks enablement will be deemed invalid and thus unenforceable.

One of the murkiest areas of the doctrine is determining whether the "full scope" of the claim is enabled. The commonly used open ended "comprising" claim language allows for an infinite number of potential variants to be embodied within the scope of a single claim. In almost every case, it is possible to theoretically define an embodiment that falls within the claim scope but that is not fully enabled by the specification. Obviously, the fact that a particular theoretical covered embodiment is not enabled can't be sufficient to invalidate a claim. The difficult legal issue then is finding when a patent claim crosses the threshold from legitimately having a few non-enabled potential embodiments to illegitimately failing to enable the full scope of the claim.

Unbounded Range: Here, the patent claims that the device switch has a change in resistance of "at least 10%." Although it is desirable to have a device with a greater ΔR, the inventors best pre-filing device only reached 11.8%. The accused infringing devices had a greater ΔR and thus the patentee argued that the "at least 10%" claim scope could cover a ΔR of 100% or even 1,000%." The defendant (Hitachi) was able to prove that those ΔR levels could not have been achieved at the time of the patent filing without undue experimentation. The Federal Circuit found this sufficient to find the claim lacking enablement.

In sum, this field of art has advanced vastly after the filing of the claimed invention. The specification containing these broad claims, however, does not contain sufficient disclosure to present even a remote possibility that an ordinarily skilled artisan could have achieved the modern dimensions of this art. Thus, the specification enabled a marginal advance over the prior art, but did not enable at the time of filing a tunnel junction of resistive changes reaching even up to 20%, let alone the more recent achievements above 600%.

This case follows in re Fisher (CCPA 1970). In that case the court ruled that a claimed potency of "at least 1 International Unit of ACTH per milligram" was invalid as lacking enablement after the patentee attempted to enforce the patent against products with potentials of much greater than the 2.3 IUs disclosed in the specification.

The court particularly addressed the comprising issue discussed above. One key distinction is that the high ΔR range here is an explicit element of the claimed invention rather than being a mere latent vestige of the claim structure.

Not a Groundbreaking Invention: In both Fisher and here, the patentees' actual experiments were at ranges just above that already known in the art. That seeming small advance reflected in claiming a range that barely avoided the prior art at the lower bound but then attempted to claim an infinite range at the upper bound. In this case, the court identifies the advance as "marginal over the prior art." The suggestion from the court is that a marginal advance such as this is deserving of a much narrower scope than would be given a groundbreaking invention. The court is on the right track with this approach however, the language of the opinion can also be read to limit potentially broad scope of even groundbreaking inventions when the accused infringer (or others) have spent significant time and energy on developing a particular embodiment covered by the invention.

Whither Open-Ended Ranges and a Plurality of Members?: The opinion can also be read to eliminate the potential for open-ended ranges. The court writes that "the '922 patent specification only enables an ordinarily skilled artisan to achieve a small subset of the claimed range." Of course, a mathematician will explain that any claim with a range that potentially reaches to infinity (e.g., "a plurality of members") will suffer from this same defect – that only a small subset of the claimed range will be enabled (assuming that infinity is not enabled).

Transformative Research to Avoid Infringement: As mentioned above, the opinion relies somewhat heavily on the fact that extensive post-patent-filing research was conducted; and that the research eventually led to a new state-of-the-art that is much more advanced than that imagined by the inventors (even though still literally covered by the claims). This opens the door to manufacturing companies to offer testimony related to their extensive research and development programs and offer an argument akin to transformative copying in copyright law. If the research is sufficiently transformative (and took sufficient effort) then the patent will be deemed invalid for failing to enable that covered embodiment.

Enablement Doctrine Allows Follow-on Research: The court is straightforward in stating that a strong enablement requirement will help prevent over broad patent claims and thus allow room (and incentives) for "follow-on or improvement inventions."

Invalidity affirmed.

38 thoughts on “Logical Conclusion?: Claimed Open-Ended Ranges Lack Enablement

  1. 38

    Red Monkey,

    You have an error in your logic.

    It is not easy to enable the unknown, as, using Ned’s example, even though you have provided in gory detail how to build a car, you have not enabled the indefinite (or unknown) feature that you are attempting to claim (claiming functionally is a bit of a red herring – it is not the form of the claim that matters, but rather the substance). In your post of 10:05, you do not identify an indefinite feature. “Gets 40 mpg” is not logically the same as “Gets at least 40 mpg” – with an open-ended “gets all miles per gallon greater than 40 mpg.” It is this latter feature that is not enabled in all of your gory details of the car that can get the rather definite 40 mpg.

    You also mix legal logic in that claims themselves do not have to be fully self-enabled. That is why we have specifications. This is also why the efforts to denigrate functional claiming are misplaced.

  2. 37

    It’s easy. Going back to Ned’s example, if you have a functional claim like “A car that can get 40 MPG” you could have a specification that sets out in gory detail exactly how to build that car. So in answer to the question “does the specification disclose how to build a car that gets 40 mpg?” the answer must be yes. Therefore the specification fully enables “a car that can get 40 mpg.” Such a car is not unknown at all. One only has to read the specification to see it fully described.

    On the other hand, that claim does not recite any structural features of such a car, only its intended result.

    In reading 112, it looks like a lack of enablement is a defect in the specification, not of the claim, whereas a lack of definiteness is a defect in the claim, not of the specification.

  3. 36

    think an indefinite claim can be enabled though.

    How do you enable that which is basically unknown (indefinite means not known)?

  4. 35

    Yes, that’s probably a more serious issue. You can’t tell what is so special about the electrodes and the insulator that makes them yield more than a 10% change in R. Perhaps if they had referred to the lack of roughness that would have helped on the enablement problem. I think an indefinite claim can be enabled though.

  5. 34

    Red, range of what? Here, the claim had nothing to do with any novel features of the tunneling resistor disclosed in the specification. No new materials, no new fabrication techniques, nothing. It simply presented the result of increase performance and claimed it. The result was not the invention.

    This was almost like claim a car that can achieve greater than 40mpg without claiming any inventive technique to do so. The claim literally covers all cars that achieve that mpg whether it uses the disclosed techniques or whether it does not.

    Such claims are have to be invalid, and it shouldn’t take a case like this one to figure out why. They are as indefinite as all get out. They do not claim the invention at all.

    Moreover, they cannot possibly be enabled, can they?

  6. 32

    he did exactly that

    Actually, no, not at all. The court found that he did not enable what he claimed. Are you reading what I am typing?

    How would you have drafted the claim to avoid the Magsil result?

    Asked and answered: Enable what you claim. If you cannot enable it, don’t claim it.

    This is not a difficult concept – why are you struggling?

  7. 31

    But when you look at it literally, he did exactly that. His claim said “an electrical insulator between the first and second electrodes, wherein applying a small magnitude of electromagnetic energy to the junction reverses at least one of the magnetization directions and causes a change in the resistance by at least 10% at room temperature.” He did show that he could go past 10% and that in fact he could reach 11.8%. How would you have drafted the claim to avoid the Magsil result? Would you have said “between 10% and 11.8%”? If so, how would you deal with a defendant who manages to get to 11.9%, or to 13%? Just rely on DOE?

  8. 30


    Enable what you claim. If you cannot enable it, don’t claim it.

    Your idea of “to a value at which undue experimentation is required to achieve said value” is a non-starter.

  9. 28

    I should have said, “(for starters, obviousness).”

    If the art field already knows about the upper limit, chances are very high that your claim dies a quicker death than you think (and that risk is not minimal).

    You are saying “how high” is known, but you neglect the logic that to say that, what is really known is “how high for the claim is known.”

    If your claim is materially different, the person having ordinary skill in the art will not know “how high.” You have to know what you are talking about in the first instance in order to know “how high” for what you are talking about.

    In your baker’s world, “how high” for souffles and “how high” for biscuits are two very different things (in other words, your example is saying more than you think it is).

    You are not even likely to get to trial. You are not likely to get out of the office.

    As I said, you have jumped from the frying pan into the fire, from burnt, to burnt and irretrievable.

  10. 27

    There’s a risk of what you’re suggesting. But it might not be that high. For instance if I invent a new cookie recipe and the last step says “bake for a time between 10 minutes and an upper limit that any baker should be able to figure out” I am not admitting my recipe is known. I am merely saying that any baker of ordinary skill ought to know how high that upper limit is without undue experimentation. At trial, my plaintiff’s expert would say “At the time of invention, any baker would have been able to note charring around the edges that would have signaled that upper limit.”

  11. 26

    You are relying on a part of the statutory framework that says “I don’t need to disclose because what I disclose is known,” that part is a key part of your claim (consider it the defining point), and you don’t see the problem?

    Really? Stop and think about the big picture for a moment.

    To use a trite phrase, you have jumped from the frying pan directly into the fire.

  12. 25

    I guess I don’t see that problem. The claim and spec aren’t making any such admissions. The claim’s upper limit is defined by the point at which undue experimentation is required. Thus, the claim is no longer to an open ended range. It defines an upper limit. This avoids the holding in MagSil. The defense’s next step, with reliance on MagSil having been foreclosed, is to argue that the upper limit is indefinite. Not it is reduced to a battle of the experts. This is no slam dunk for plaintiff by any means, but it is much more promising to the plaintiff than being shot out of the water by MagSil.

  13. 24

    RM, consider what you typed – “what is well known” and consider the metes and bounds of the claim.

    Are you saying that your claim is well known?


    I think you are invting bigger problems with such an admission (for starters, novelty).

  14. 23

    Actually, according to MPEP on enablement “a patent need not teach, and preferably omits, what is well known in the art. In re Buchner, 929 F.2d 660, 661, 18 USPQ2d 1331, 1332 (Fed. Cir. 1991).” Therefore, the question to be resolved is this: Given the limitation “from X up to a value at which undue experimentation is required”, is that upper value something that is already well known in the art. If the answer is yes, the law does not require it to be disclosed. I think the fact that a fact-finder was able to make a determination of that value is probative in suggesting that the answer to the question is “yes.”

  15. 21

    Would there be something wrong with defining a range that says “from X up to a value at which undue experimentation is required to achieve said value”?

    Surely that would not be “indefinite” because as this case amply demonstrates, a fact-finder was easily able to make just such a determination.

  16. 20

    I mostly agree with both IANAE and Dennis. I don’t agree with 6. For most methods claims, a “wherein” clause that recites “at least” without an upper limit should raise a big flag. And such clauses should never be sufficient to overcome a prior art defect in a method or composition claim. In cases where the prior art is close and the alleged improvement is a result or property of the claimed composition, then the structure/step responsible for that result or property must be expressly recited in the claim.

    In practice, this is not how it works. Functional/result-based claiming is huge.

  17. 19

    RS, you might want to read the case. The inventors had developed a way of making a tunneling resistor that increased its responsiveness from around 3% in response to a change in current to around 12%. Rather than claiming any of the novel techniques, the simply claimed a tunneling resistor with a responsiveness above 10%.

    The claim was to a result. The claim itself included no part, feature, technique, step, composition or anything invented by the inventors in the claim. The claim simply claimed everything that worked.

    These kind of claims have been roughly and loudly condemned by the Supreme Court in any number of cases including O’Reilly v. Morse. See also Story’s opinion in the Weyth v. Stone case involving a claim to any mechanical way of carving and removing ice. That the PTO allows these kind of claims is an abomination.

    The disk drive industry in particular has been afflicted with these kind of claims for some time. The most notorious examples in recent time were the so-called form factor cases, where claims to particular sizes of a disc drive were claimed, such that the claims literally covered every future disk drive regardless of whether they employed any of the novel features invented.

    I applaud, wholeheartedly applaud, Hitachi Global for taking a stand, finally, on these cases on and the form factor issue. Finally!!!!

  18. 18

    I think the court was better off if it had based its ruling for the defendant on a semi-ensnarement doctrine as opposed to enablement. Enablement should not depend on later infringement claims by the patentee, but ensnarement can. A claim either is or is not enabled at the time of its drafting. But ensnarement could be triggered when the patentee tries to stretch its patent too far. Let’s assume that reaching the “at least %10” limitation was the claim’s novelty point and that prior art had reached just below 10%, as stated in this post. Under this semi-ensnarement doctrine the court could have argued that if the patentee interprets that limitation to cover the much larger percentages of 100% or above, then by the same token the claim’s “at least 10%” limitation would be within the obviousness reach of “just below 10%” in prior art. This argument is not exactly ensnarement , which renders a claim anticipated, but is a semi-ensnarement argument that renders a claim obvious. Such an approach will also respond correctly in a situation that the original patent is a real breakthrough and should be given stronger rights: If prior art could not change the resistance at all, then reaching a resistance change of 10% is a breakthrough. In this case, the “at least 10%” limitation may be allowed to cover later technologies with a 100% change, for example, without being deemed obvious, as there is no prior comparable art.

  19. 17

    IANAE, I must applaud your posts here. I have been arguing this position for a very long time. You have articulated it very well.

    It seems high time for the PTO to again begin enforcing the law and begin to reject functional claims or claims that are functional at the point of novelty under both 112, p.1 and p.2. The only possible way to functionally claim an invention (an I believe that 112, p.6 has been misinterpreted on this score) is to use means plus function claiming. That notifies the public, at least, that all one is claiming is the corresponding structure, materials and acts and their equivalents, and not all possible ways to achieve the claimed result as claims that are not limited by 112, p.6, literally claim.

  20. 16

    Why not simply ask the patent applicant in a request for information whether they have enabled the upper end of the range (infinity).

    Because it’s not an enablement issue, it’s a functional/indefinite claiming issue. Or, if you prefer, the enablement issue is enabling all the ways of achieving the claimed result, not enabling the entire range.

    If you “fix” the enablement issue by amending the claim to “between 10% and 11.8%”, the claim is still just as defective for all the same reasons. Morse the pity.

    If the applicant claims the structure he invented that enables the impressive 10%+ change, all his 112 problems will magically vanish.

  21. 15

    6 says “this kind of invalidity is practically impossible to catch at the PTO.”

    Why not simply ask the patent applicant in a request for information whether they have enabled the upper end of the range (infinity). This makes a nice record and will help (somewhat) to limit overreaching claims.


  22. 14

    Yes the only thing that is wrong with these kinds of cases is that this kind of invalidity is practically impossible to catch at the PTO save when the applicant digs himself into a hole of his own making arguing against other things or makes an admission in the spec.

  23. 13

    That may run afoul of Fed. Cir. case law [contrary to older case law] that claims will not be interpreted more narrowly for infringement suits just to save them from prior art. {I.e., absent some other reason to read them more narrowly, such as the specification, or prosecution disclaimers]. [One reason being that that would confuses infringement determinations with validity determinations, which have very differnt proof and evidence burdens.]

  24. 12

    John, I claim a genus and disclose only one species. Is that claim enabled?

    I claim all light bulbs that exhibit greater that X lumens when I disclose only one means for achieving X?

    I claim all semiconductors with line widths of X dimension or less and I disclose only one way of doing X and it will take tremendous effort of others to achieve smaller widths.

    There is an obviuos vice in these claims. What is it?

  25. 11

    The vice in the claim is that it covers every single tunneling resistor that is produced in the future regardles of whether or not it uses any of the techniques disclosed. That cannot be right.

    O’Reilly v. Morse.

    Indeed, O’Reilly v. Morse is the prime example of a functional claim that attempts to embrace all future embodiments regardless of whether they employ or do not employ the techniques disclosed.

  26. 10

    Mike, I think you are right. If the claim had been applied against a 20% increase in resistivity and expert opinion had been introduced to support the notion that the accused device had achieved the 20% inmprovement using the techinques disclosed, the court would have, I agree, not held the claim invalid.

    But this, really is nonsense, because the vice in the claim is that it covers every single tunneling resistor that is produced in the future regardles of whether it uses any of the techniques disclosed or not. That cannot be right.

    O’Reilly v. Morse.

  27. 9

    shouldn’t you have to show that your disclosure taught a PHOSITA how to make a device switch that has a 600% change in resistance

    Of course not. Someone who improves on your invention, even patentably, should still owe you royalties if he still infringes your claim.

    If he had claimed his invention structurally such that the 600% device infringed, what would you say then?

  28. 8

    Are you saying that the disclosure in the application as filed must be good enough on the filing date to enable the accused embodiment that is developed years later? I hope not.

  29. 7

    Here is the public policy argument: If you can assert this claim against a device switch that has a 600% change in resistance, shouldn’t you have to show that your disclosure taught a PHOSITA how to make a device switch that has a 600% change in resistance, without undue expermentation?

  30. 6

    Mike, “Invalid as applied”? What’s that then? What the claim means depends on what the infringing article is? Is this sane? Is it rational? I should add that English courts punctiliously construe an asserted claim “as if the infringer had never been born”. Doesn’t everybody?

  31. 5

    This same issue infects a lot of types of claiming language, famously “sub-micro” limitations that would encompass “nano” etc.

    Of course, these cases lead me more to the conclusion that the court is advocating an “invalid as applied” form of invalidity analysis. That is, the court would have been willing to uphold the validity if MIT had asserted against an infringer who fell within the disclosed range (e.g., 11%), but not against someone at 100-1000%.

  32. 4

    Although a “device” claim, the open upper end range re the subject 112 overclaiming issue here relates to an “electrical insulator.” I.e., a material. Thus, this seems more like a chemical claim, where the case law does much more commonly punishes overclaiming substantially beyond supporting specification examples.
    So I do not find this nearly as disturbing as the Fed. Cir. Lizardtech decision a few years ago and a few others where the panel majority treated electrical or mechanical claims as if they should be subject to the same kind of 112 claim narrowing to avoid invalidity as chemical [AKA “unpredictable arts”] claims.

  33. 3

    The opinion can also be read to eliminate the potential for open-ended ranges. The court writes that “the ‘922 patent specification only enables an ordinarily skilled artisan to achieve a small subset of the claimed range.”

    Yes, that’s how the opinion is written, but I don’t think that can be the correct result. The problem with this claim isn’t the open-ended range, but the fact that the plaintiff claimed “whatever works”. Had he claimed “from 10% to 11.8%” the claim wouldn’t have been any better, and still wouldn’t have enabled all of the later-discovered ways to achieve 600% change if they were used in a way that produced only 11%.

    If the change in resistance were a user-settable parameter rather than the desired result, I’d have had no problem with a claim to “greater than 10%” if it was shown that anything over 10% produced a patentably different result, even if the patentee had only achieved 11.8% in his lab.

    There’s nothing inherently wrong with open-ended ranges. Certainly nothing that can be fixed by requiring patentees to arbitrarily limit their claim to the range they’ve actually tested. The problem here is functional claiming at the point of novelty. Must be some kind of theme week at the Federal Circuit.

  34. 1

    One logical fallacy to watch for: comprising is not as open ended as is being portrayed as the non-identified additions do not include colorable differences.

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