by Dennis Crouch
I have been thinking about the potential rise in the use of means-plus-function (MPF) claims as a reaction to indefiniteness cases such as Williamson v. Citrix as well as pressure from other doctrines, including enablement, written description, and eligibility. But, my preliminary data show that the foretold rise has not yet come. As the chart above illustrates, MPF claims continue their descent into obscurity, with no sign from the preliminary data of rising from the grave any time soon.
The chart above shows a visualization of the percentage of issued patents that include means-plus-function (MPF) claims over time, with two separate estimates based on the wording used in the claims. MPF claims are a particular type of claim in patent law that allows an inventor to claim an invention based on the function that it performs, rather than the specific structure or materials used. 35 U.S.C. 112(f). Although MPF claims may seem broad on their face, the statute limits their scope to cover only the corresponding structures disclosed in the patent document (the specification) and their equivalents.
The chart shows a clear trend: a decline in the use of MPF claims from 1980 through to the mid-2020s. The high estimate in the chart indicates the broader inclusion of MPF claims that use the word “Means,” shows a more substantial presence and a steeper decline than the low estimate, which tracks claims specifically using the phrase “Means For” or “Means To.”
The decline in MPF claims can be linked to several legal decisions and changes in patent doctrine. Historically, MPF claims were indeed a powerful tool, as they allowed patent holders to claim a range of equivalent structures that performed the same function, without having to list them all out. However, this breadth of protection has been significantly curtailed by precedential decisions that have limited the scope of the claims (as required by the statute) and invalidated many MPF claims as indefinite (something that I believe is not required by the statute). These decisions from the 1980s and 1990s began the downward drive of MPF usage.
Functional claiming is a constant lure for patent drafters. The an invention’s function (what result it obtains) is typically tied more directly to the market and business goals than the particular structure or technological details used to reach that end. A functional claim limitation offers the tantalizing ideal of broad coverage and technological flexibility. By defining an invention by what it does rather than the nuts and bolts of how it is accomplished, functional claims can appear to encompass any means for achieving the stated function. This breadth can deter competitors by making it more difficult for them to design around the patent. Additionally, defining an invention functionally may allow the claim scope to adapt to future technological advances that arise after the patent filing date, as long as the new technologies perform the claimed function. The functional format also simplifies claim drafting for complex inventions and supports filing patents amidst technological uncertainty before landing on a final design.
As MPF claims were declining, patent applicants still felt the draw for functional limitations and began to use alternative claiming strategies. Rather than a “means for” performing an algorithm, applicants began claiming a “processor configured to” perform the algorithm, or other alternatives that avoided the magical words “means.” Under the (old) precedent, the use of alternative words such as “processor for” were ordinarily not treated as means-plus-function form and therefore did not have the narrow construction and invalidity risk mentioned above.
In its important 2015 decision in Williamson v. Citrix Online, LLC, 792 F.3d 1339 (Fed. Cir. 2015) (en banc), the Federal Circuit changed the law again — going after these non-means nonce words. Williamson established the absence of the term “means” no longer creates a strong presumption against applying MPF construction. Thus, words such as “mechanism for,” “module for,” “device for,” and “member for” are all likely to be treated as invoking 112(f) means-plus-function construction absent some indication that the limitation directly imparts a structural limitation.
Moreover, enablement and written description requirements have clamped down on non-MPF-style functional claims. For example, in Amgen v. Sanofi, the 2023 Supreme Court invalidated Amgen’s broad functional genus claim covering for monoclonal antibodies that bind to PCSK9 to lower cholesterol. The case suggests that some broad functional limitations might never be enabled even with extensive disclosure. Eligibility cases raise similar issues with functional limitations undergoing significant scrutiny. In Electric Power Group, for instance, the Federal Circuit explained that the “result-focused, functional character of claim language has been a frequent feature of claims held ineligible under § 101.”
One seeming solution to all of these arising issues is for patent applicants to more directly assert MPF claim limitations and include a number of embodiments. But, for now at least, the miracle resurgence of MPF remains elusive.
= = =
Just to confirm that there not a lagging rise in MPF usage, I did the parallel analysis on claims found in published applications and found similar results with continued decline of the use of “means” and “means for” language up through applications published in 2023.
Functional claiming is a constant lure for patent drafters. The an invention’s function (what result it obtains) is typically tied more directly to the market and business goals than the particular structure or technological details used to reach that end. A functional claim limitation offers the tantalizing ideal of broad coverage and technological flexibility. By defining an invention by what it does rather than the nuts and bolts of how it is accomplished, functional claims can appear to encompass any means for achieving the stated function. This breadth can deter competitors by making it more difficult for them to design around the patent. Additionally, defining an invention functionally may allow the claim scope to adapt to future technological advances that arise after the patent filing date, as long as the new technologies perform the claimed function. The functional format also simplifies claim drafting for complex inventions and supports filing patents amidst technological uncertainty before landing on a final design.
I think every word of this paragraph is true, and what an indictment of the system. Especially the notion that functional language is employed to deter market competitors that discover future advances that arise after the patent filing date. Imagine admitting that you haven’t enabled or even thought of all of the ways that you’re claiming you invented and still wanting the scope to be upheld.
Oh you “invented” the gun? No no, you see I invented the bow, but I described it by its function of firing a projectile rather than its structure. Therefore *I* invented the function, which includes inventing the embodiment of the gun, even though my disclosure is entirely string-tension based and I don’t know a lick about chemical explosion and I have no structure anything close to a gun.
Some advice – the only valid scope is the MPF scope anyway, so you’d be smart to have a MPF claim. A claim to a function is going to be found unenabled and unpossessed anyway unless you show possession of the entire scope, in which case the MPF would provide you coverage over all infringing embodiments anyway. The problem is that inventors with bad lawyers who invent the bow think they ought to be able to keep the gun from the market. There’s no amount of scrivening that gives the bow inventor a valid claim covering the gun. There’s some advantage to non-MPF claims in that you can apriori find a valid scope that falls within equivalent disclosed embodiments, but that valid scope is not “any structure that achieves the result, no matter how different from the disclosed structure”
“I don’t know a lick about chemical explosion and I have no structure anything close to a gun.”
But I do have this obnoxious attorney from Aspen! And some real pieces of work from Liberty University Law School as my associates. Together we will wipe the floor with you and any rogue judges who try to nullify our natural patent rights.
That is awfully specific, Malcolm.
Who exactly has ‘done you wrong’ to invoke such an emotional outpouring?
Sometimes, you have to claim something functionally. Take a memory controller. You cannot claim the actual circuitry, because it’s hundreds or thousands of devices.
You simply have to claim a memory controller that does Function A, Function B, etc. There’s no other way to claim it.
In a related manner (somewhat), this reminds me of my prior destruction of Malcolm’s canard of “must have objective structure in the claim” in regards to software.
I had posited that old style C W/R M could in fact be detailed out in objective physical terms (track X, radial position Y, physical denotation Z), but any such actual “objective physical claims” would BOTH be nigh impossible to examine, AND – through DOE – carry all the protection of using terms sounding in function.
By the by – it is most definitely NOT merely the computing arts that is DEEP in using terms sounding in function (as also has been shown year after year on this blog with the destruction of the anti’s position).
OT, but on point to Malcolm:
link to i0.wp.com
Prof. Crouch hit is out of the park with another great article confirming my suspicion. I started putting in an extra set of MPF claims with a standard set of primary structural claims in my provisional patent applications I used to write to 1. get a quick allowance from an examiner for the MPF claims, and 2. support in the spec if the primary claims were held indefinite MPF claims. The lead patent attorney loved to use vague claim language to be able to twist the patent claim to mean anything he wanted during litigation. I was worried that the main claim may get construed as MPF and always made sure there was support for such an eventuality in the spec. The lead attorney was cool with my “belt and suspender approach” so it stayed in the IFW if litigation had less than optimal results on the primary claims. I am glad my approach for deemed sound.
High quality comment here LOL Thsnks, Clippy!
Did you forget your /S sign?
I know the USPTO is tracking my phone and hacking. So the other side is my maternal family. It keeps showing me in ATLANTA where the law firm and Bupp are.
“ I started putting in an extra set of MPF claims with a standard set of primary structural claims in my provisional patent applications I used to write to get a quick allowance from an examiner for the MPF claims”
What?
Mpf claims also typically survive MTD at a much higher percentage , and it’s nuts that more practitioners don’t use at least one mpf claim.
Another driver in the “near death” of MPF claims is the corporate pressure to avoid “excess” claims fees.
Which is shortsighted, given that the great majority of patents would benefit — especially if and when litigation is ever needed to protect the invention (sorry not sorry Stroud) — from including at least a few (perhaps 3 – 5) such claims.
Note to my fellow independent inventors: Be sure your patent attorney / agent includes at least 3 – 5 MPF claims (and ideally 5 – 10) in your application(s) / patent(s).
They are well worth the relatively small additional cost.
For those old enough to remember, the huge drop-off in means-plus-function claiming you see in that chart, during the late 1990s, was largely the result of B. Braun Medical, Inc. v. Abbott Laboratories, 124 F.3d 1419 (Fed. Cir. 1997). That was the first case to hold that in interpreting means-plus-function limitations, a corresponding structure in the specification had to be “clearly linked” to the claimed function. The result was that, literally overnight, means-plus-function limitations went from being viewed as beneficial and broad, to overly narrow and restrictive.
The patent in suit, U.S. Patent No. 4,683,916 (the ‘916 patent), is generally directed to a reflux valve that attaches to an intravenous (IV) line and permits injection or aspiration of fluids by means of a needleless syringe.
Gasp – You mean that Malcolm was (shockers) making C R @ P up?
What was the standard before then? “Any credible linkage”?
Interesting that (1) usage was decreasing well before 1997 and (2) the drop in use was hardly “precipitous” and it took about a decade to bottom out. The best explanation for this is that there was no surprise about the correct answer once a semi-competent court got involved but there seems to have been a portion of the patent bar that was (ahem) slow on the uptake (or fantasizing about being given a “pass” because they are oh-so-special).
Old 112 last paragraph [new 112(f)]: “…such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.” I.e., narrower equivalents of only the spec example, not the broader DOE “equivalent.” That was clear at least since 1994 from In re Donaldson Co., 16 F.3d 1189, 1193 (Fed. Cir. 1994) (en banc), as well as latter Fed. Cir. decisions noted here. I remember the difficulty at the time in convincing some patent attorneys. This M-F claim scope problem should not be confused with the other, different, M-F problem where the spec does not even have a real “means” example or even a detailed algorithm.
Moreover, enablement and written description requirements have clamped down on MPF-style functional claims. For example, in Amgen v. Sanofi, the 2023 Supreme Court invalidated Amgen’s broad functional genus claim covering for monoclonal antibodies that bind to PCSK9 to lower cholesterol. The case suggests that some broad functional limitations might never be enabled even with extensive disclosure.
Wait a second, this makes no sense. MPF limitations are not “broad functional limitations.” MPF limitations are quite narrow in practice. Therefore, Amgen (et sequelæ) should drive people back to using MPF more frequently.
Thanks – Typo on my part.
Absolutely correct. Every patent application that I have filed since Amgen has a MPF claim. No one knows how a court will treat the claim, so the claim serves to encourage settlement.
+1
“ No one knows how a court will treat the claim”
LOL
Sure, run with that.
I do. MPF claims can only help post-Amgen.
Except when people do know how the court is going to treat the claim and, when they see that you don’t know, they realize that you aren’t serious and actually kind of a p r – c k who probably shouldn’t be trusted. Does that encourage settlement t?
Malcolm’s
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“Except when people do know… when they see that you don’t know, they realize that you aren’t serious and actually kind of a p r – c k who probably shouldn’t be trusted. ”
It’s uncanny.
MPFs were primarily the mainstay of the “do it on a computer” types who were “confused” about how to claim (or even describe) the range of novel logical operations that were obviously ineligible but were equally obviously the only creative subject matter in the claim and the only steps that imparted the functionality that was deemed valuable in the first place. After it became clear that the CAFC was okay with claiming imaginary “structures” and abstract “objects” as long as there was some fuzzed up effort to describe an “algorithm”, then MPF claiming ceased to be useful for anything beyond its trivial purpose (abbreviating claims).
I haven’t written a MPF claim in about 20 years and have ZERO intention of doing so in the future.
I cannot recall a Federal Circuit decision in which a MPF claim was treated favorably.
What is amazing about the decline in “means-function” or means plus function claims in patents is the amazingly number of years it took for so many patent preparation attorneys and agents to get any CLE or otherwise get clued in on the consequences. That is, years after the Fed. Cir. had made it very clear how narrow such claims are, and then latter, how dangerous such claims are if there is no actual spec support, i.e., no disclosed “means” for the “means.” Yet we still have no specific patent law MCLE requirements, or any MCLE at all for PTO agents. I am also not sure how well it is understood that M-F claims may still be desirable for further filings of equivalent applications in some foreign patent systems?
MPF claims are also still “desirable” for “hiding the ball”, if that’s your thing. The whole point, after all, was to provide a short cut so claims could be more easily abbreviated.
The idea that MPFs were created so that patentees could claim functionality at the point of novelty is an idea that could only survive unquestioned in the darkest corners of a comments section of the nation’s number 2 patent blog.
I know that I have asked this of you before (and I know that you have not provided a cogent answer), but let’s try again:
As to your “idea that MPFs were created so that patentees could claim functionality at the point of novelty” what is your legal source of such ‘reasoning’ as you would have it as to this notion of yours regarding functionality at the point of novelty?
Take your time to be cogent (that is, your typical mindless and misaimed ad hominem won’t move the legal point AT point at all, and I really want to try to understand what it is that you think is driving your legal position).
Once again, Billy: first you take the reading comprehension class, and then you take the ethics class, then you study up on patent law. THEN you practice writing a reply comment that merits a response.
I understand that this will interfere with your crucial efforts to protect academia from the Marxist-based scourge of “political correctness” but those are the breaks.
Please Pardon Potential re(P)eat
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November 22, 2023 at 5:47 pm
LOL – that sure is a lot of unrelated work that you want someone else to do before YOU provide legal reasoning for YOUR position.
I am going to call out B$ and point out that none of that is necessary for you to do as you are asked.
The only take away then is that you do not have any cogent reasoning for the legal position that you feel should be the law.
(rather unsurprising)
But please, you can either ‘be you’ or you can attempt to change my mind and actually share some (any) cogent reasoning behind YOUR assertions….
Your choice (as usual).
… Malcolm’s choice is noted.
Paul, I wonder, were you thinking of filing in Europe? Here a link to the EPO’s MPEP, the paragraph that addresses functional language in claims and explains where and why “objection arises”. What do you think: is the EPO one of those jurisdictions where it may “still” be desirable to include an M+F claim?
link to epo.org
Criminy (filter)
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November 24, 2023 at 10:21 am
Pretty darn sure that THAT is something that Night Writer would reply to with, “That is what I have been saying all along.”
Notwithstanding that your provision is NOT an item of US Sovereign law, and also tends to your usual EPO Uber Alles proclivity of “here, wear my spectacles.”….
In his comments, NW often alludes to his experience of prosecution at the EPO. So, what he has been “saying all along” will have been influenced to some extent by his experience at the EPO. So, yes, I daresay you are right, that what the EPO’s MPEP says is what NW has been writing here, all along
Good riddance! Destructive complexity at its finest. Said both as a former examiner, litigator, and now as one who sees awful MPF claims all the time.
… no bias here from Mr. Unified Patents…
“Good riddance! Destructive complexity at its finest.”
A “viewpoint” surprising . . . absolutely no one.
It strikes me that in view of Williamson v. Citrix Online, both of your lines are underestimates of the number of patents with MPF claims because these claims do not need to contain the words means (or step) to be a MPF claim.
Hi Walter – Yes. This just counted folks expressly using the word ‘means.’ I know that there are some folks still using other nonce words recognizing that it might be interpreted as MPF.
Better point – instead of, “One seeming solution to all of these arising issues is for patent applicants to more directly assert MPF claim limitations” — how about we simply eliminate Judge-made patent profanity and revert to the actual words (and intent) of Congress with the plain words — and only the plain words BY CHOICE OF THE APPLICANT – since this was always intended to be AN OPTION OF THE APPLICANT.
Hint: if an applicant did not choose those words, then the applicant fully intended to not choose those words.
(And yes, it is as simple as that)
So, overturn Williamson v. Citrix?
What is that phrase? “First, we turn to the statute.“
If you want to talk about “still waiting” for a type of usage chart, how about a usage chart of Jepson Claims (you know, that whole “Point of Novelty” thingie).
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