CASELAW-EPO - reviews of EPO Boards of Appeal decisions

T 149/21 – Describing one way to carry out an invention might not be enough when it comes to sufficiency

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The patent relates to a method for reducing the energy consumption of a rolling mill installation.

During the operation of such a system, rolling pauses of different lengths occur, e.g. for a roll change or in case of disorders. During unscheduled rolling pauses, there is normally no shutdown of certain system components that are not directly affected by the rolling pause.

The unaffected plant components therefore also absorb quantities of energy during the “unproductive” rolling pauses, resulting in corresponding additional costs.

These plant components are usually switched off manually by the rolling operators at their own discretion only during long rolling pauses. Due to the complexity of the shutdown, the interventions are usually only carried out on individual, easily manageable plant components.

Accordingly, the task underlying the invention is formulated in the patent in suit as “to maximally exploit the energy saving potential of a rolling mill installation during a rolling break“. According to the patent in suit, this task is to be solved by a targeted start-up and shut-down of carefully selected plant components.

Brief outline of the case

The opposition was rejected and the opponent appealed the rejection of the opposition.

For the board, the ground of opposition under Art 100(b) prejudiced maintenance of the patent as granted

AR 1-3 suffered a lack of sufficiency under Art 83 and could not allow maintenance in amended form.  

The board thus decided the revocation of the patent for lack of sufficiency.

The board had interesting considerations about the respective purpose of R 41(1,e) and Art 83.  

The understanding of the patent by the board

In paragraphs [0008] and [0025] of the patent in suit, an example of an embodiment is shown in which a “rolling operator” identifies the type of disorder. Based on this identification, a control device then determines the expected duration of the rolling break by means of a database, e.g. on the basis of a “disorder matrix“. The corresponding system components, whose time for shutdown and start-up is shorter than the rolling pause, are then automatically shut down into an energy-saving mode

In the board’s view, the skilled reader would readily understand that this feature covers not only manual identification (i.e. carried out by the “rolling operator”) covered by paragraphs [0008] and [0025] of the patent in suit, but also automatic identification of the nature of the disorder.

For the board, the subject-matter of claim 1 is not limited to only such disturbances. The specific features could also refer to previously unknown disorders. Nor is the disorder mentioned in claim 1 in any way limited to a “frequent” or “typical” disorder.

The proprietor’s position

During the OP before the board, the proprietor argued that, according to the case law of the boards of appeal, it was sufficient that at least one way of carrying out the invention was shown in the original application in order to fulfil the requirement of Art 83. Whether other “exotic” scenarios or “unknown disorders” were also covered by the subject-matter was irrelevant in this context.

The proprietor argued also that applying the criteria of sufficiency over the whole breadth of the claim to “unknown disorders” would lead to an “excessive requirement” for sufficiency under Art 83.

The board’s position

The board agreed that the patent in suit discloses at least one way of carrying out the claimed invention in detail and thus fulfils at least R 42(1,e).

However, according to the established case law of the Boards of Appeal, the sufficiency of the claimed invention must be present in the entire claimed field. the board referred to e.g., T 409/91, grounds 2; T 435/91, grounds 2.2.3; T 862/11, grounds 5.2 (b); T 941/16, grounds 9; all from the field of chemistry. Accordingly, the indication of at least one way of carrying out the claimed invention is necessary but not sufficient to fulfil the requirement of Art 83. Nor is this case law generally limited in any way to the respective field of technology.

In addition to the field of chemistry the same criterion has been applied in the field of

A qualification of this case law according to different technical fields would also be difficult to convey, if only because of the requirement of a harmonised application of the EPC with regard to the requirement of sufficiency.

However, in recent decisions from the field of mechanics, see T 2773/18, grounds 3.2; T 500/20, grounds 3.6 and T 1983/19, grounds 2.1.3, it was suggested that the criterion “over the entire claimed field“, which originated in the field of chemistry, was not necessarily applicable to other technical fields such as mechanics.

In particular, it was emphasised in this context, e.g. in T 1983/19, grounds 2.1.3, that the case law developed above all in the context of chemistry, according to which the invention must be practicable “over the entire claimed field”, was not transferable without qualification to mechanics, since for almost every claim of mechanics any number of embodiments could be devised which would not be practicable.

However, this did not mean that the “invention as such” could not be carried out. Rather, it was sufficient that the patent merely showed the skilled person a way of carrying out the invention.

The board considered that, while indicating a way of carrying out the claimed invention may be sufficient to satisfy the description requirement under R 42(1,e), it was not necessarily sufficient to satisfy Art 83.

Rather, according to the case law, the skilled person referred to in that Article should be enabled, across all technical fields, by the patent in suit and his general knowledge of the subject-matter, to carry out the claimed invention over the entire field, i.e. according to all technically possible variants of interpretation which the skilled reader would draw upon according to objective criteria based on his general knowledge of the subject-matter. In other words, according to the board, all “technically reasonable” claim interpretations should be taken into account in the examination under Art 83, and only those claim interpretations for which the requirements of the EPC are deemed to be fulfilled can be considered “technically reasonable”, see T 2210/16, grounds 3.12.

The requirement that the disclosure must enable the claimed invention to be carried out “in its entirety” is also consistent with the fundamental legal policy concern that, in principle, the right of exclusion conferred by a patent with respect to its scope of protection should be justified by the actual contribution of the patent to the state of the art, cf. T 435/91, grounds 2.2.1, fourth paragraph.

The present case is no exception in this context. With regard to the arguments put forward by the parties, the difference between an interpretation variant that is objective for the expert reader and one that is only theoretically possible must be particularly emphasised.

Thus, the example of a “disorder” mentioned by the proprietor, according to which an aircraft crashes onto the rolling mill, clearly falls into the latter category of interpretation. The same applies to the example given by the opponent that the rolling mill could be destroyed by a nuclear bomb. Those two examples fall under “technically unreasonable” interpretations and have nothing to do with sufficiency.

On the other hand, the interpretation variants belong, in the board’s view, to the “objective for the expert reader” interpretation category, because the expert reader would be absolutely familiar with the mere possibility of an automatic identification of the “type of disorder” in the context of a rolling mill installation through his general expert knowledge.

Furthermore, unknown disorders can also occur in a rolling mill installation, e.g. after a new or a conventional component has been installed in a different way or the control software for individual modules of the rolling mill installation has been updated.

With regard to the automatic identification of the “type of disorder”, paragraphs [0008] and [0025] of the patent in suit do include the terms “example” and “in particular” respectively, but this does not mean, as correctly argued by the opponent, that the person skilled in the art would be able to provide an automatic embodiment for the identification according to one of the specific features merely on the basis of his general knowledge of the art.

The proprietor’s submission that a “typical” disorder would also cause “typical” signals, the combination and corresponding automation of which would not exceed the skill of the skilled person, is not convincing in its generality. This is because the subject-matter of claim 1 is not limited to “typical” disorders. In this respect, the board emphasises that even if a rolling operator, could identify the nature of a previously unknown disorder on the basis of “typical” signals, it is not guaranteed that any previously unknown disorder can also be accommodated in the “disorder matrix” mentioned in the description.

Indeed, the patent in suit does not indicate how the expected “duration of the rolling pause” could actually be determined in such a case. Rather, in the case of an unknown disorder, it is typically not possible to estimate with certainty the extent of the “rolling pause” that would have to be expected.

In Ground 4.3 of the contested decision it was considered that “it is part of the skilled person’s expertise how to identify the type of disorder in a rolling mill by technical means, such as sensors“.

However, the board was of the opinion that not only a sensor but also appropriate programming is needed for automatic identification of the type of disorder, e.g. in the form of a “classification” referred to by the opponent. How such an automatic identification is actually to be programmed cannot be inferred from the patent in suit and is left entirely to the imagination of the skilled person.

In summary, the patent does not disclose how the skilled person can actually perform an “automatic identification” for the method claimed in claim 1 and determine the expected “duration of the rolling pause” even for unknown disorders.


The board considered that the criterion of sufficiency cannot be judged differently depending on the technical domain of an invention. The mechanical field is no exception to this requirement contrary to some recent case law.

Independently of the technical domain, sufficiency has to be given over the whole breadth of the claim. Only “technically unreasonable” claim interpretations do not fall under this requirement. There is a long list of case law illustrating this position. See for instance T 2166/17, T 1599/16 or T 875/11.

The board can be followed when it considers that in order to satisfy the description requirement under R 42(1,e), it is not necessarily sufficient to satisfy the requirement of Art 83.

Any “technically reasonableinterpretation of the claim should be sufficiently disclosed, so as to cover the whole breadth of a claim.

Another example

I was once confronted with a bidirectional line transmitting an alarm signal. In case of an alarm the bidirectional line was pulled to ground, which makes it impossible to transmit any signal.

In one embodiment pulling the line to ground, triggered the discharge of a capacitor and set an alarm circuit on. Once limited to this embodiment, the patent could be maintained. During OP the opponent even made the comment that he now realised why the claimed invention did not work in all circumstances.

One embodiment was disclosed under R 42(1,e), but the claim was not enabled in its whole breadth. This case is comparable to the present one.


Art 83 / R 41(1e)

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