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Electronic Systems and Circuits: Sufficiency of Disclosure

By Matthew Howell, Partner

Article 83 of the European Patent Convention requires that a European patent application must disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. Failure to meet this requirement will result in an objection that the application lacks sufficient disclosure.

When we looked at the decisions of the EPO’s Technical Boards of Appeal for applications in the “Basic Electronic Circuitry” International Patent Classification H03, we found about 7% of them involved a question of sufficiency of disclosure. Sufficiency objections are therefore less prevalent than novelty or inventive step objections in applications in this field, but they do occur, and can be difficult to overcome by amendment, given the EPO’s strict prohibition on amendments that add subject matter that was not present in the application at the time of filing.

T793/07 is an example of a decision by a Technical Board of Appeal to refuse an application on the ground of lack of sufficiency of disclosure. In this case the application related to a synchronous delay circuit in which an essential feature was a “switching over unit” which performs a switching function to direct a selected one of three different clock signals (two internal clock signals and an external clock signal) to the input of a clock tree.

The Board found that the application provided “no teaching as to how this switching should be carried out, in particular what criteria should be used to decide which of the two internal clock signals should be selected”. The Board further held that “the implementation of this aspect of the switching over unit would not be straightforward”, and that “Since the various passages of the description which mention the functioning of the switching over unit only describe the general object to be achieved by the switching over unit, and not how it achieves that object, these cannot provide the skilled person with any information in that respect”. Whilst it may have seemed obvious to the inventor and draftsman how this switching over unit was implemented, the Board disagreed. The Board thus decided that the disclosure of the application was not sufficient to enable the skilled person to implement the switching over unit.

This case highlights the need to include enough technical information in the description to enable the invention to be put into effect. Features that may be considered obvious by the inventors may not be obvious to the skilled person, so it is important that when drafting the description care is taken to describe how each feature of the invention can be implemented.

Our Electronics Systems & Circuits team are always on hand to guide you through the pitfalls of patenting in this area. Feel free to reach out to us with any questions you might have.

This is for general information only and does not constitute legal advice. Should you require advice on this or any other topic then please contact or your usual Haseltine Lake Kempner advisor.

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