First interpretation of G 1/24 (the description must always be consulted) (T 1561/23)

T 1561/23 is the first decision from the Boards of Appeal to apply the recent EBA decision in G1/24. The EBA found in G1/24 that the description should always be referred to when interpreting the claims, and not just in cases of unclarity or ambiguity. Compared to some EBA decisions, G1/24 was fairly clear. The decision of the Board of Appeal in T 1561/23, however, highlights how G1/24 is also not that restrictive with regards to how Boards of Appeal may approach claim interpretation on a case-by-case basis. The Board of Appeal in this case particularly noted the requirement from G1/24 to "consult" the description does not even explicitly require that a definition from the description must be used for the interpretation of a claim (IPKat). 

Case Background: Tasks and additional functions

The appeal was filed by the applicant against the Examining Division's decision to refuse European patent application EP 17720035.9. The application related to methods for executing additional functions within real-time environments, specifically in programmable logic controllers (PLCs) used in production plants.

According to the application, control in programmable logic controllers (PLCs) occurs through "tasks" processed within specified task runtimes. In production plants, there are multiple different additional systems whose functions must be synchronised with the production process. These systems include, for example, complex vision systems, condition monitoring, AI, and numerical controls. These additional functions typically exist as independent software components separate from the PLC and have indefinite runtimes. The invention was aimed at enabling integration of these additional functions into the real-time environment of the PLC whilst maintaining predictable response times and avoiding temporal fluctuations.

Looking into G1/24

Claim 1 of the Main Request on appeal specified a method for executing at least one additional function (or auxiliary function, depending on how you interpret the phrase from the German) within a real-time environment where tasks are executed with predetermined runtimes. The key prior art disclosed an embedded real-time system where "co-operative tasks" were executed with specified task runtimes, alongside "pre-emptive tasks" that could exceed their allotted time. 

The primary issue on appeal was whether the "pre-emptive tasks" disclosed in the prior art constituted "additional functions" within the meaning of the claimed invention. The applicant argued that the prior art only disclosed tasks, not additional functions. 

Always consulting the description

The applicant argued that the feature of "additional functions" specified in the claims would be understand by a skilled person as being complex with indefinite runtimes, whereas pre-emptive tasks would be understood as having fixed runtimes. In their arguments, the applicant referred to the stipulation in G 1/24 that the description and drawings must always be consulted when interpreting claims. The applicant argued that the description of the application made a clear distinction between tasks and additional functions. The applicant particularly pointed to the passages in the description specifying that "tasks" control actuators and sensors, whilst, for example, "additional functions" included vision systems or condition monitoring represented.

The Board of Appeal had no issue with G1/24 requiring consultation of the description. However, importantly, the Board of Appeal noted that G 1/24 "does not define what it means to consider the description and drawings in a specific case [...], G 1/24 does not even explicitly require that the definition of a term from the description must be used for the interpretation of a claim" (machine translation from the German). For the Board of Appeal in this case, it followed from G1/24 merely that a definition provided in the description cannot be disregarded and must be considered as part of the description and drawings. 

However, in the case in question, the Board of Appeal was of the view that the description did not in fact provide a definition for the terms at issue. The Board of Appeal particularly noted: "the present application only provides examples of additional functions, but it cannot be deduced from this how 'tasks' and 'additional functions' would specifically and fundamentally differ" (r.2.10)

Unfortunately for the applicant, the Board of Appeal thus rejected the argument that the description clearly indicated that there was a distinction between pre-emptive tasks and additional functions. For the Board of Appeal, the claimed "additional function" was by its nature indistinguishable from a "task." To the Board of Appeal, both terms referred in the context to programs intended to have predictable runtime behaviour in a real-time environment. (r.2.3.2). Under its construction of the term of "additional function", the Board of Appeal found that the prior art disclosed all of the steps of the process according to claim 1 of the main request (r.2.8). The claims were therefore found to lack novelty. 

Final thoughts

G1/24 told us that the description should always be consulted when interpreting the claims (IPKat). We therefore know from G1/24 that we cannot simply read the claims without any consultation of the description. For this Kat, and as highlighted by the Board of Appeal in this case, the question remains how and if definitions in the description may override otherwise clear claim language. Such is the nature of patents that terminology used in the claims will always remain open to interpretation, even when the description is consulted. As the Board of Appeal pointed out in this case, it has been left to the Boards of Appeal to define what it means to consider the description and drawings in each specific case. 

Patkat's commentary on G1/24 has so far very much been through the lens of the field she is used to, namely biotech and the life sciences. In this field, most terms used in patent claims have well-understood definitions (IPKat). In other technical areas, however, such as the mechanical field, terms are generally more fluid and difficult to objectively define. The definitions of terms such as "widget" or "housing" (or gathered...?), for example, is likely to always need some context to be properly understood. The context needed comes first from how the term is used in the claims and then, now we have G1/24, from how it is used in the description of the invention provided in the specification as a whole. Failing sufficient guidance from the specification on how to interpret a term, it may then be necessary to consult the common general knowledge of the skilled person. T 1561/23 is a reminder that, whilst the overuse of unnecessary definitions of well-understood terms is to be generally avoided in patent applications (IPKat), definitions of unclear terms may be helpful, especially if there is the chance of confusion with a very similar feature that you wish to be distinguished from.  

Further reading

• EBA decides G1/24 on claim interpretation: The description should always be consulted
• Beware of boilerplate: Practical lessons for patent drafting from G1/24 (Claim interpretation)