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Prosecution History Estoppel in Europe at the Unified Patent Court

Jan 31, 2024

Table of contents
    Sebastian Greding

    As a Patent Attorney, I help clients to choose the best IP strategy based on the actual invention as well as based on the business case and the overall business strategy of the clients. Only with a thorough understanding of the respective technology on the one hand and the business behind the invention on the other hand, a solid protection of the IP assets can be reached. Consequently, I work closely together with clients to provide the optimal IP protection for them.

    At the end of 2023 the UPC Munich Local Division (MUC LD) handed down its decision in UPC_CFI_292/2023 as an early holiday gift for IP enthusiasts. The decision addressed substantive patent matters by providing useful guidance on how issues like claim interpretation will be assessed by the new European court system.

    While the various pieces of legislation underpinning the UPC are well known, many aspects of the new court’s practice, including the way that it approaches claim interpretation, will develop over time. Early decisions on substantive matters, such as this one, provide much-needed guidance on the manner in which the UPC interprets claims and thus will have significant implications for patent litigation, drafting and prosecution.


    In the case under consideration, the local division of the UPC had to consider the effect of a feature of the claims as originally filed, that was removed during prosecution, to interpret the claims as granted. It is already challenging to make amendments to a patent application’s scope after filing, based on the European Patent Office’s strict rules on amendments. The decision, as discussed in more detail below, highlights how important it is to draft claims properly from the start.

    The UPC Decision in SES-imagotag v. Hanshow

    The UPC Munich Local Division (MUC LD) handed down its decision UPC_CFI_292/2023 on 20 December 2023.

    SES-imagotag sought a preliminary injunction (PI) against Hanshow Technologies and its German, Italian and Dutch affiliates based on EP 3 883 277 which is a Unitary Patent that relates to an electronic label for a sales floor.

    The court considered how feature 7, “a printed circuit board housed in the case on the side of the back of the case”, and feature 8.4, “the antenna of the radio frequency device being disposed on or in the housing on the side of the front of said electronic label” should be construed (cf. Reasons II.3.c). In other words, the key point was how the printed circuit board and antenna are arranged relative to each other within the housing of the electronic label.

    The MUC LD found that:

    Already the set of claims as originally filed, which may be used as an aid in construing the amendments made during the prosecution proceedings, made a direct connection between the chip provided on the printed circuit board and the antenna (cf. Reasons II.3.c)).

    This finding was also highlighted in the first headnote translated from German as:

    A European patent’s set of claims as originally filed may be used as an aid in construing the amendments made to the set of claims during the prosecution proceedings.

    The local division using the wording of claim 1 as originally filed, i.e. the chip arranged on the printed circuit board and the antenna should be at a distance from each other ("...à distance de..."), to interpret the amended claim in a way that requires the antenna to be wholly located at the front of the housing, and the printed circuit board is arranged wholly at the rear of the housing.

    This was decisive in the question of infringement, which is essential for a preliminary injunction to be granted, as the alleged infringing devices use antennas where a part of the antenna is in contact with the rear of the housing. Thus, the claims of the application as originally filed were used to interpret the amended claims of the granted patent in a way that led to a finding of non-infringement.

    In practice, the decision and headnote may be stating the obvious: that the content of a patent application as originally filed can be used to interpret the claims of the patent as granted. This is already directly implied by the strict prohibition on the addition of new matter (or scope) to a patent or patent application after the application was filed. However, the headnote singles out the original claims of the application as being used in the interpretation of the amended claims of the granted patent and raises the question of how much more important the claims of the application as originally filed may be.

    Concluding Thoughts on the Present State of Prosecution History Estoppel in Europe

    Prosecution history estoppel (PHE) in the United States, of course, involves issues relating to amendments and statements made by the applicant during prosecution which can operate to limit the scope of claims during enforcement proceedings. For example, PHE can prevent the patent proprietor from using the Doctrine of Equivalents (DoE) to cover subject matter that was surrendered or disclaimed during the prosecution proceedings to obtain the patent. In case an applicant makes narrowing amendments to their application to accommodate patent law, they may be precluded from invoking the DoE to broaden the scope of their claims to cover subject matter ceded by the amendments.

    The question of whether or to what extent the prosecution history should be considered when determining the extent of protection of a patent also arises in Europe and now especially before the UPC. In our view, the present decision does not introduce PHE per se to the UPC. If anything, the decision may point in the opposite direction, potentially reducing rather than increasing the limiting effect of amendments made during prosecution.

    Since we are still in the early days of the UPC it will be important to follow how PHE law develops over time.


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