EP 2 885 583 B1 relates to a cooktop with a device for fire mitigation and a corresponding method.
Brief outline of the case
In view of objections under Art 123(2) for the patent as granted and AR1, the OD decided maintenance according to AR2. The proprietor appealed.
The board confirmed the OD’s decision, as all other requests on file infringed Art 123(2).
The whole discussion on added matter centred on the interpretation of “continuously” in Feature F of the claim.
The proprietor’s point of view
The proprietor agreed that the expression “turning the heating element continuously on and off” in claim 1 as granted was not literally disclosed in the original application, but it did not extend beyond the content of the application as filed.
The expression first had to be interpreted with due consideration of the description and drawings.
There was no reason for interpreting “continuously” as in the other occurrences in claim 1, which referred to different features in different contexts. Nor was there any basis for interpreting the expression in a manner that was evidently not supported by the patent.
Rather, the term could be understood to relate either to the continuous control of the power level by turning the heating element on and off or to the control of the power level in accordance with a duty cycle, both of which were originally disclosed.
The proprietor argued according the “two-step approach” for the assessment of added matter as set out in the catchword of T 367/20.
The opponent’s point of view
The expression “turning the heating element continuously on and off” in claim 1 as granted extended beyond the content of the application as filed for the simple reason that it was not literally disclosed or explained in the original application.
Moreover, “continuously” should be interpreted as in the other occurrences in claim 1 where it meant “periodically“, with a fixed predetermined period.
The term “continuously” applied not to the control but to “turning the heating element on and off“. Even if power control in accordance with a duty cycle was covered by this term, this was not disclosed for an electric coil cooktop.
The board’s decision
Claim 1 as granted was amended with respect to claim 1 as originally filed inter alia by Feature F, specifying that, for an electric coil cooktop and an electric glass ceramic cooktop, the control device is configured to control the power level of the cooktop “by turning the heating element continuously on and off“.
It was common ground that there was no literal basis for “continuously” in the context of “turning the heating element on and off” in the application as filed.
The board noted that there were other occurrences of the term “continuously” in the description, both as filed and as granted, and in Feature F of claim 1 as granted in the context of monitoring/sensing the temperature and calculating a rate of change of the sensed temperature.
The parties agreed that, according to the patent, in these occurrences “continuously” meant “periodically”, albeit with different time periods for monitoring and calculating.
The board held that claims first have to be interpreted in line with G 1/24,in order to determine the subject-matter they contain after the amendment. The board considered that the interpretation applies not only for the question of “patentability of an invention under Art 52 to 57” but also for the issue of Art 123(2).
In a second step, it has to be assessed whether the subject-matter of the amended claim – determined by way of interpretation – contains subject-matter which extends beyond the content of the application as filed. In this regard, in accordance with G 2/10 the decisive factor is whether or not the skilled person is presented with new technical information after the amendment.
The term “continuously” in claim 1 applies to different features but is used in the same context. Hence, contrary to the proprietor’s opinion, there are good reasons for considering that “continuously” in Feature F also refers to “periodically” turning the heating element on and off
Moreover, periodic turning on and off is a well-established concept for controlling the power level of a heating element in accordance with a duty cycle.
Hence, taking “continuously” to mean “periodically” is a valid, technically meaningful interpretation of “continuously” in the context of Feature F, with the expression “turning the heating element continuously on and off” thus referring to a periodic sequence of the actions of turning the heating element on and turning the heating element off, as in pulse-width modulation of the power in accordance with a duty cycle.
For the board, changes at varying intervals are not understood to be covered by the term “continuously” in the sense of “periodically“. This understanding is also in line with the description of the patent.
Feature F does not specify controlling the power level “continuously” but controlling the power level “by turning the heating element continuously on and off“.
According to T 367/20, Reasons 1.3.2, a claim feature must not be interpreted in isolation but in the context of the whole document it forms part of. This is done, however, by taking due account of the primacy of the claims.
This is also in line with G 1/24 and UPC_CoA_335/2023, second headnote, according to which the claims are the “decisive basis“.
Interpreting “continuously” to mean “periodically” encompasses the heating element being operated in accordance with a duty cycle, which is disclosed in some embodiments of the patent. It thus does not represent an interpretation that is “obviously not in line with the disclosure in the patent”.
While it is undisputed that the application as filed does not disclose the expression “turning the heating element continuously on and off”, it does disclose embodiments where the heating element is controlled on the basis of a duty cycle and is thus “continuously” turned on and off.
According to the disclosure, the power level is in fact controlled by changing between two different duty cycles when certain threshold conditions in terms of the monitored temperature and rate of change are met. Moreover, the algorithm also contains phases where the heating element is kept “on” for a specific period of time without turning the heating element periodically on and off.
Accordingly, even in the algorithm using duty cycles, the heating element is not always “periodically” turned on and off, and the “continuity” of the duty cycle is interrupted under certain conditions.
As claim 1 as granted does not include these more specific aspects of the power control for the electric glass ceramic cooktop of the application as filed, and as the application as filed does not disclose a periodicity throughout the algorithm, the amendment in Feature F is at least an unallowable intermediate generalisation of the original disclosure.
Comments
When interpreting the claim in the light of the description different ways of continuously controlling the heating can be derived.
As according to the description, the “continuity” of the duty cycle is interrupted under certain conditions, there is indeed added matter.
The present board made also clear, that G 1/24 does not only apply when deciding patentability under Art 53-57, but also when assessing added matter. As it is the N citerion which applies, there is a direct link between Art 54 and Art 123(2).
T 367/20 was commented in the present blog
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