Category Archives: Patenting

Problems behind sufficient disclosure

The scope of the exclusive right pertaining to a patent is delimited by the (granted) patent claim(s). The exclusive right extends to all technical devices which possess the features specified in the claim. It is irrelevant what other features the devices or methods may or may not possess. The owner of a granted patent has the right to bar others from using devices with the claimed features, but no right to bar anyone from using devices with some, but not all, of the claimed features.

Patent claims have a problematic dual role in the advancement of the public and private benefits of patenting. The applicant’s private benefit requires that the claimed scope be as broad as possible. Breadth is determined partly by the generality of the terminology in the claim (e.g. “a vehicle” is a more general term than “a car”) and partly by the number of claimed features. Each added feature F shrinks the scope because it excludes all devices which do not possess F. The applicant would therefore preferably claim a patent by specifying as few features as possible using the most general terminology possible.

However, the public benefits of the patent system require that the scope of each granted patent should not be too broad.  Scopes are limited by granting patents only to patent claims which meet the criterion of inventive step. A typical patent application proceeds from an initial version with very broad claims to a restricted version where the definitions given in the claims have either been increased in number or amended with a more detailed terminology based on the cited objections.

The public benefits of the patent system also require that the scope of each granted patent should be clear and that every patent application should be informative. Clarity reduces legal disputes and costs. Clear and informative patent publications are potentially useful source material for further technological development, whereas unclear publications are not.

It is evident from my previous post that the inventive step criterion can be quite complicated when it is explored in detail. Clarity is often considered a simpler concept than inventive step because the difference between a clear and an unclear technical feature is not assumed to be problematic. Another reason why lack of clarity is not always judged very strictly is that it raises the bar for inventive step, at least in principle. If some of the claimed features are ambiguous or unclear, patent examiners are advised to consider them as broadly as possible. In the absence of better objections, a distant objection D to inventive step can therefore sometimes be raised when a claimed feature F is so unclear or ambiguous that it can be interpreted to correspond with the device disclosed in D. This is sometimes possible even though D on the whole may be quite different from the claimed device and could not have been considered an objection had feature F been clear.

However, even though lack of clarity in a patent claim slightly increases the likelihood of rejection due to lack of inventive step, this is not a sufficient discouragement against deliberate obfuscation. After all, lack of clarity isn’t just a result of an inappropriately general terminology in feature F. The examiner usually has to be both imaginative and lucky to discover distant objections D which happen to correspond to the claimed feature simply because the feature is ambiguous. Furthermore, if no other objections are available, the search for D may take an inordinate amount of time and the objection may be easily circumvented in the next round of the examination.

In view of the above, patent criteria which concern clarity and sufficient disclosure (which are very closely linked, so I will simply label them the “sufficiency criterion” below) are required to protect the public benefits of the patent system. However, unlike the inventive step criterion, a sufficiency criterion has not been formalized in European patent practice. Examiners, boards of appeal and courts only apply vague general guidelines concerning how sufficiency should be judged. In brief, these guidelines refer merely advise the examiner / board member / judge to consider whether or not the content of the claims would be clear to a person skilled in the art, and that’s it.

Objective technical problems revisited

I propose that the sufficiency criterion should be formalized in the same manner as the inventive step criterion. It can be done in a very similar way. In the following presentation I will draw on the problem-solution approach which I discussed in my previous post.

The important insight of the problem-solution approach as it applies to inventive step is that the claimed invention may actually solve a different prior art problem than the applicant assumed. In other words, the applicant’s view of the prior art may be, and often is, incomplete. The risk of granting patents to deliberately obfuscated claims would be greatly reduced if this same insight were to be applied also to the sufficiency criterion. Sufficiency should not depend on the applicant’s own view of the invention and its relation to prior disclosures, but on the true state of the prior art.

The reason why some applicants deliberately obfuscate their patent claims is that even a weak argument for inventive step can be made to appear if the subject matter is unclear across the broad. Ambiguous technical terms which are not elaborated in the description are useful for obfuscation because it is never certain how such terms are delimited, that is, which real-world component fall into under this term and which do not. The applicant may nevertheless argue that the meaning is certain. Patentability examinations and infringement proceedings then become an uncertain game of equivocation, where the meaning of the term can be shifted based on the required arguments.

Of course every examiner recognizes that there is a limit to the degree of ambiguity that a claimed term can have if the claim is to be granted. Obfuscating applicants try to push the proceedings as close to that limit as possible. Obfuscating applicants typically possess large numbers of obscure applications. Most of them may be rejected in patentability examination, but some of them will not. The ones that are granted can be very valuable to the applicant if a reasonable case for infringement can be built. Lack of clarity again facilitates infringement attacks.

The public benefits of the patent system are clearly harmed by deliberate obfuscation. The limit between clear and unclear terms, supported or unsupported features, cannot be marked with any consistency from case to case if the sufficiency criterion is internal. If the sufficiency criterion is internal, patent applicants can use the ambiguous vocabulary which surrounds an ambiguous technical term to describe a putative technical effect which solves a putative technical problem. It can be hard for an examiner to maintain that the claimed feature is too ambiguous if it is supported by a description which has the outwardly appearance of a proper technical problem and solution.

Clarity and sufficient disclosure must therefore be judged against some other yardstick than the application itself. Instead of having examiners assess whether or not the person skilled in the art would be able to carry out the invention as described by the applicant based on the information given in the description, the sufficiency criterion should be that a person skilled in the art is able to carry out the invention as it is manifested over the closest prior art, based on the description given by the applicant.

This means that applicants would no longer be allowed to support the scope of their claims merely through their subjective understanding of the invention. Let’s assume that a patent application A1 specifies a patent claim which includes features F1, F2, F3 and F4. F1 and F2 form the preamble of the claim, while F3 and F4 form the characterizing part. The first component of the sufficiency criterion should be that the applicant must identify in the description a prior art document upon which this division of features is based. In other words, the applicant must disclose a document D1 which discloses features F1 and F2. Citations requirements for prior art documents known to the applicant should be enforced much more rigorously than most patent offices do today.

Lets assume that no closer prior art document than D1 is discovered in the patentability search. The corresponding sufficiency analysis would also ask what the combined technical effect of features F3 and F4 is. In other words, what beneficial or different result, not achieved in D1, is obtained with features F3 and F4? The analysis continues by asking  what corresponding technical problem the person skilled in the art would have had to solve, starting from an apparatus which contained only features F1 and F2 (when reading the application text on its earliest priority date), to achieve the technical effect over D1.

This may seem like a minor technical problem. After all, the person skilled in the art is thought to be reading the application text itself, where the solution should be directly disclosed. However, the gist of the sufficiency analysis is that the technical effect must be conceived in its detailed form A, that is, as a detailed description of the changes which take place in the apparatus/method itself, and/or in the surroundings on which it operates, due to F3 and F4 (see the earlier essay). This differs from inventive step analysis, where only the general description of the technical effect may be included in the technical problem. The information given in the application must be so detailed that the skilled person can  in a straightforward manner see where the technical effect in its detailed form (a form which may not itself be disclosed in the application) originates.

Just like in inventive step analysis, the subjective technical problem presumably corresponds to the objective problem when no better prior art document than D1 is discovered. And just like in inventive step analysis, the sufficiency analysis will be more or less of the standard kind when this is the case. In other words, the analysis could be carried out just about equally well even without invoking formal problem-solution analysis.

However, the situation is markedly different if the applicant included both features F3 and F4 in the characterizing parts of the patent claim but, as it turns out, feature F4 was in fact known from another prior art document D2, which was unknown to the applicant. This means that only F3 contributes to the technical effect. The requirement of a sufficient disclosure now becomes that F3 and its consequences be described in such detail that the objective technical problem relating to this (detailed) technical effect over the prior art should be solvable for a skilled person from the application text A1.

The utility of this problem-solution approach to sufficiency, again in direct parallel to how the problem-solution analysis tests inventive step, comes from the fact that the number of claimed features not disclosed by the prior art determines how broad the objective technical problem will be. If, in the above example, none of features F2, F3 and F4 would be disclosed by the closest prior art document, then the corresponding technical effect would usually (even in its detailed form) be a lot more general than if just feature F3 distinguishes the claimed invention from the prior art.

It is, and should be, harder for the application to meet the sufficiency criterion if only F3 separates the claim from the prior art. The technical effect of just one feature is necessarily more particular than the technical effect of two or three features. In order for the description to provide sufficient support for a lone distinguishing feature F3, the technical content of this feature must be described in such detail, in the terminology must be shared with document D2 to such an extent, that the person skilled in the art would see where the technical effect comes from.

This does not mean that the applicant would have been required to foresee this technical effect when writing the application. On the contrary. Just as a new argument for inventive step can be introduced in problem solution analysis once the closest prior art has been reliably established, new arguments for sufficiency can also be introduced when the closest prior art is known. What is required from the description of a patent application is that every claimed technical feature must be described in such detail, and linked to such an established vocabulary, that the skilled person can recognize the technical consequences of the feature even in situations which may not have been described in the application.

What does all this have to do with obfuscation? A typical obfuscating patent application is self-contained in the sense that it seeks to link ambiguous technical terms and explanations to each other in a pseudo-consistent manner without linking them to any established scientific or technical vocabulary.

A certain degree of self-containment is to some degree unavoidable in most applications due to the generality of the protection sought with a patent claim. The description therefore has to be a kind of dictionary for all technical terms used in the claims because their meaning in a particular application may differ from their regular meaning. In other words, the dictionary of a patent claim does not necessary have to conform either with general-purpose dictionaries or with the lexicon of other patent applications in the same field.

However, insofar as new meanings are introduced for a technical term T, the description should be an unambiguous dictionary to that meaning. It should contain examples and links which establish a connection between the term T and established technical, scientific and regular vocabularies. This facilitates a clear yes-or-no categorization between objects that correspond to term T and objects which do not correspond to it.

The problem-solution method described in this essay puts the description to the test. Depending on how many of the claimed features are disclosed in the closest prior art document, the bar for sufficient disclosure is either raised, lowered or kept unchanged compared to the amount of detail that the applicant deemed sufficient when writing the application. The question is: has the applicant nevertheless presented enough details about the feature(s), and linked it so clearly to established vocabularies, that the person skilled in the art would recognize the technical effect?







Problems behind inventive step

The inventive step criterion is usually the center point of most contestable patentability examinations (there are of course many inventions which are incontestably not patentable, and some which are incontestably patentable). When the applicant writes an application, the true extent and content of previously published inventions in the same technological field is more or less unknown. The examination process is normally a comprehensive search for prior art documents which have hitherto been unknown to the applicant. Once the closest prior art documents have been found, the patent examiner gives an opinion on whether or not the claimed invention meets the requirement of inventive step in view of the prior art.

The public benefits of the patent system require that patent monopolies be restricted. In particular, patents should not be granted to claimed inventions whose differences with regard to the prior are nonexistent or technically insignificant. It makes no difference whether or not the applicant was actually aware of any particular prior art document when the application was filed. The applicant cannot, for example, argue that a Japanese prior art document which matches her invention claimed should be disregarded, because she does not understand Japanese. Her defense may be truthful, but she loses the patent due to the unfortunate coincidence that a Japanese person made the same invention before her. In order to prevent copycats from receiving patent monopolies, patents must be granted only to inventions which could not have be reached through minor modifications from any previously published document – no matter how unlikely it may be that the applicant would in reality have read and copied this precise document.

Although the inventive step criterion is clear in abstract form (“grant only those applications which exhibit a significant difference over the prior art”), it is difficult to apply in practice. It is difficult for a patent examiner to decide, on any quasi-objective scale, where the line between significant and insignificant differences should be drawn. For a long time, patent examiners based these decisions primarily on their personal judgment and past experience, comparing each new case to decisions they had made earlier. This method was not as arbitrary as it may sound. Experienced examiners could most probably apply their personal experience fairly to new applications when they set their mind to it. However, it was very hard to ensure that this informal way of applying the inventive step criterion remained constant, or even comparable, between different examiners. Another problem with personal judgment was that it usually involved fairly little explicit reasoning which could be put in writing. Decisions which were based purely on personal judgment tended to be opaque to an outside audience, including the applicant who received the decision.

In the past 25-30 years, especially at the European Patent Office, the influence of examiner’s personal judgments has been reduced, and been made more explicit, by consistently judging the inventive step criterion through a theoretical framework. With the help this framework examiners can split their decision process into logical parts and exercise critical reflection on each part. This so-called problem-solution framework is the only attempt to formulate a general theory of inventive step. The benefits of a more theoretical approach is that it promotes clear and legible argumentation and helps examiners avoid hindsight fallacies.

Problems and their solutions

The problem-solution approach can be studied best through the case law of the European Patent Office. Very briefly, it involves a comparison between one patent claim and one document (usually the document which has been deemed the closest prior art). The claim comprises a list of technical features. One by one, the examiner checks which features are directly disclosed in the document (either explicitly or implicitly). The examiner then focuses on the remaining features (the ones not disclosed in the document) and asks what their combined technical effect (over the prior art disclosed in the document) is. In other words, what technical  benefit, which is not achieved in the same in the closest prior art document, is achieved through these features. A clear benefit is not a necessary requirement under all circumstances, but it is easier to understand the problem-solution method in these terms.

If no beneficial technical effect can be discerned, the claim clearly lacks an inventive step over the prior art document and the decision is clear. But if there is a beneficial technical effect, the examiner then seeks to formulate the technical problem which a person skilled in the art would have had to solve, when reading the prior art document on the day when the application was filed, to achieve the benefit which the invention achieves.

Instead of asking whether or not it would have been obvious to a person skilled in the art that the undisclosed features produce the beneficial technical effect (a question which involves a hindsight fallacy), the examiner instead thinks about the general improvement which the person skilled in the art may have sought to make to the prior art document, and asks whether or not the person could have solved the problem pertaining to that improvement by adding the undisclosed features to the apparatus known from the document.

The applicant has usually presented some technical problem pertaining to the invention in the application. A basic consequence of problem-solution analysis is that this so-called subjective problem may not be relevant. The examiner may, for example, discover a closest prior art document where those features which the applicant presumed to be unknown in the prior art are in fact disclosed. Features which the applicant assumed to be known in the prior art, may on the other hand not be known from this document. This means that the so-called objective technical problem, which the examiner (or anyone else) formulates after a closest prior art document has been discovered, may differ significantly from the subjective problem which the applicant assumed to be most relevant for the invention.

The objective technical problem

Although the problem-solution approach provides a theoretical framework for assessing inventive step, the examiner (or any other person who might make use of it) is still left with a lot of discretion in applying it. There are no comprehensive guidelines concerning how the objective technical problem should be formulated. The guidelines published by the EPO state merely that the general form of the problem should be “how to modify or adapt the closest prior art to achieve the technical effect(s) which the invention provides over the closest prior art”.

An very important addition to this guideline is provided in section I.D.4.3.1 of the Case Law of the EPO Boards of Appeal: “the problem should be as specific as possible without containing elements or pointers to the solution”. In the following sections I will examine what this means.

Two important questions arise from the general for of the problem (cited above) and from the above guideline: (1) how should the closest prior art be conceived if the problem is to be as specific as possible without containing pointers to the solution, and (2) how should the technical effect(s) be conceived if the problem is to be as specific as possible without containing pointers to the solution?

The closest prior art

Question (1) may at first seem nonsensical. A prior art document is what it is, fixed and unchangeable. There may seem to be very little room for free interpretation when a person skilled in the art reads the closest prior art document in full and sets out to make improvements by solving problems pertaining to the document.

However, the definitions in a patent claim are usually made in general terms. This means that the apparatus or method described in the prior art document may in fact differ from the claimed apparatus or method, even though it possesses the claimed features.

For example, let’s imagine mirrors with two kinds of shapes: convex-shaped mirrors and convax-shaped mirrors (the latter concept is my own invention). Convex and convax shapes have some similarities, but also certain differences. Let’s also imagine that the terms “convex” and “convax” are well-established for conceptualizing their differences. In other words, most practitioners in this field of technology know what the difference between a convex shape and a convax shape is.

Furthermore, let’s assume that the additional term “convux” (also my own invention) has conventionally been used to conceptualize the similarities between convax and convex shapes. In other words, “convux-shaped” is used as a general term to cover both convex-shaped and convax-shaped mirrors, and possibly other shapes as well. This means that all convex mirrors are convux mirros and all convax mirrors are also convux mirrors.

Now, let’s imagine that inventive step is assessed on a patent claim which contains a feature F1 which defines a convux mirror, and that the closest prior art document discloses convax mirror. The patent claim we are imagining may be included in a patent application which discusses convex mirrors, or one which which discusses only convux mirrors – this makes no difference for the argument which follows.

Our imaginary patent claim specifies only the general term “convux”, but the prior art relates to a more specifically defined “convax” mirror. The prior art mirror certainly falls into the scope of the claim, even though the category “convax” does not exhaust the category “convux”.

In this case, conceiving the closest prior art “as specifically as possible” means that the convax mirror in the prior art document must be conceived as a convux mirror, not as a convax mirror.

Let’s imagine that the patent claim mentioned above also specifies features F2 and F3, and that F2 is disclosed in the prior art document, while F3 is not.

Feature F3 produces a technical effect which solves a general problem P, which is common to all convux mirrors. This problem may be more difficult than the corresponding subproblem P’ which pertains specifically to convax mirrors. For example, some properties of convax mirrors may make the problem P’ fairly small and easy to solve, while other properties of convex mirrors may make the corresponding subproblem P” for these types of mirrors much more difficult.

In this case “the closest prior art” must therefore specifically be conceived as a convux mirror, not a convax mirror. The scope of the problem P may not be the same as the scope of either subproblem P’ or P”. A correct formulation of the objective technical problem must take this into consideration.

To summarize, we might say that in the objective technical problem the prior art should be designated with the most specific term which fits both the claim and the prior art. In this case, that term is “convux”.

The technical effect

Question (2), how should the technical effect(s) be conceived if the objective technical problem is to be as specific as possible without containing pointers to the solution, is simpler. The technical effect of a claimed feature F (which is not disclosed in the closest prior art document) can generally be described in two different ways:

(A) a detailed description of the changes which take place in the apparatus/method itself, and/or in the surroundings on which it operates, due to F.

(B) a general description which specifies the property (in the apparatus/method, or in its surroundings) which is changed due to F.

A detailed description (A) may specify various parts of the apparatus and how they interact both with each other and with their surroundings. A general description (B) instead specifies a property such as quality, performance, efficiency, cost, durability, yield, storage requirements, versatility, user-friendliness, etc.

A clear way to state the technical effect of a claimed feature F is that this property changes because this happens in the method/apparatus or their surroundings. Or, in the shorthand notation introduced above: B because A.

With these distinctions in mind, the answer to question 2 is this: in the objective technical problem, the technical effect must always be conceived only as a general description B. Any attempt to include the detailed description A in the technical problem would be a pointer to the solution. The problems that a person skilled in the art may identify in the closest prior art document have to do with general properties which could be improved. After noticing a property which could be improved, the person skilled in the art may get down to the details. But the crucially important line between as specific as possible and no pointers to the solution lies precisely after the moment when a problem has been noticed on a general level.

In other words, a problem should be general and should not contain any details which pertain to its solution. Including in the objective technical problem any detailed descriptions (A) would lower the bar too much in the inventive step criterion, because a pointer to the solution would then be included in the problem itself. That is why the objective technical problem must always state the technical effect of a feature F as a general description (B).


This essay demonstrates that the objective technical problem, usually formulated as “how to modify or adapt the closest prior art to achieve the technical effect(s) which the invention provides over the closest prior art” must be formulated and interpreted very carefully if it is to be “as specific as possible without containing elements or pointers to the solution”.

The objective technical problem is the fulcrum around which the inventive step criterion revolves in European patent practice. Fair decisions on inventive require careful considerations of the objective technical problem by practitioners who apply the problem-solution approach.







A first introduction to patent criteria

Patent law rests on two fundamental assumptions:

  1. Technical progress is a good thing and should be promoted.
  2. Most inventors will keep their inventions to themselves unless given a strong monetary incentive to make them public.

Neither of these assumptions is unchallengeable. Progress in weapons and gene technology, for instance, can be morally questionable, while some inventors, such as university researchers and freelance software developers, would disseminate their inventions even without any additional incentive. Nevertheless, assumption 1 holds true in most areas of technology and assumption 2 holds true for most inventions made in commercial industry. The assumptions are thereby presumably true enough to at least justify the existence of a patent system.

This justification can be stated as follows: a patent is an exchange between a private inventor and the general public, beneficial to both parties. The inventor agrees to publish his invention in such detail that the patent publication (where the invention is described) allows other inventors to learn from it and improve upon it. This accelerates technical development because publication reduces overlapping and duplicate inventive work. In return the inventor may be granted the right (for a limited time, in a limited geographical area and for gradually increasing fees) to prohibit others from selling, manufacturing or using the invention.

The inventor faces many uncertainties with respect to his private monetary benefits. Quite often the invention becomes public but the inventor receives only a rejection letter in return. If patent applications were to become irrevocably public immediately upon filing, this fundamental uncertainty would probably be a very strong deterrent against filing anything in the first place. To encourage active filing, patent applications do not become public until 18 months after their filing date. The application is examined at least once in this period, and the inventor is allowed to withdraw his application before it becomes public. The inventor may consider withdrawal especially if the first examination turns up strong objections against patentability. The possibility of withdrawal reduces uncertainty a lot, but not to zero. Sometimes the inventor is given an initial green light in the first examination, but damning objections are discovered after the publication date. By then it is too late to retract the application.

The benefits accruing to the inventor in the publication-for-exclusive-right exchange are therefore not automatic or certain. The patent may not be granted at all, it may be granted only for a very restricted part of the invention, or a green light before the invention becomes public may turn into red light after it has been irrevocably published. However, the public benefits of the patent exchange are not automatic, either. In fact the reason why the private benefits are so uncertain is precisely that complicated criteria have been put in place to protect the public benefits. Applications must meet these criteria if a patent is to be granted and a lot of examination and argument is therefore often required before a final decision can be made. There are three substantive patent criteria that are centrally important: inventive stepclarity and sufficient disclosure.

Inventive step:

Like any other exclusive right, every granted patent prevents competition (albeit only in the very limited subfield of technology defined by the patent claims). It is therefore clear that not every application can be granted. Inventive and industrial activity would grind to a halt if every field of technology would be laden with monopolies. It would also place a great burden on the courts where patent disputes are resolved. This is why applications have to be examined by patent offices, and some of them have to be rejected.

On the other hand, it should not be overly difficult to obtain a patent because there must be a sufficient incentive for inventors to disclose their inventions to the public. Patent offices have to separate useful and unique inventions from ones which merely repeat technical solutions which have been discovered before. To do this in a rational and informed manner, they judge every claimed invention by so-called inventive step criteria.

In very simplified form, the criterion for inventive step is that the same invention (or a very similar one) should not have been published before anywhere in the world. A direct copy of someone else’s invention can therefore not be patented (at least in principle – it is of course in practice very difficult to compare prior publications comprehensively with a global scope). But more importantly, inventive step criteria separate inventions which present only small, trivial or obvious improvements from the ones whose inventive contribution is large, significant, or surprising. The expression “very similar” in the parenthesis above is therefore at the heart of the discussion whenever inventive step is disputed.

Clarity and sufficient disclosure:

The public benefits of the patent system also suffer because some people abuse the patent system.The forms of abuse are multifarious, but one is particularly important. Applicants may present a so-called invention in deliberately obfuscated form. An invention defined in slippery terminology is problematic from a public-benefit perspective because it can be interpreted in many ways. The application process becomes muddled because comparisons to previous publications can be difficult to make. If the application happens to be granted with an ambiguous scope, the door is opened to creatively argued infringement lawsuits. In order to prevent such abuses of the patent system, applications have to meet the two remaining criteria: clarity and sufficient disclosure.

The patent claims are the centerpiece of a patent publication and they are always the primary focus of the clarity assessments performed by patent offices. The criterion of sufficient disclosure is more concerned with other parts of the patent application, especially the description and the figures. Patent publications will not be useful to the public (and will probably not even be read) unless they reveal a sufficient number of useful details about the invention. The quality control exercised by patent offices on sufficient disclosure is sometimes only cursory, because the primary reasons for rejection or acceptance nearly always relate to the patent claims, to inventive step and clarity. But in subsequent essays I will argue that all three of these criteria are in fact closely intertwined and cannot be separated from each other.The sufficient disclosure criterion is fundamentally important for realizing and balancing the private and public benefits of the patent system.


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