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Facebook Wins Against Voxer In Patent Infringement

by | Sep 7, 2021

Facebook vsFacebook has had some bad press in recent times. However, in this recent patent infringement case, Facebook v Voxer [2021], the High Court judgement sided with Facebook. The decision is interesting to look at in more detail and discuss, because it continues the development of two important points of UK case law which have arisen from the landmark doctrine of equivalents decision in Actavis v Eli Lilly [2017].

These two points are:

  1. To what extent can the scope of a claim be affected by the actions of the patentee, and
  2. How do you deal with possibly infringing equivalents which are obvious in view of the prior art.

In this Facebook v Voxer [2021] patent infringement decision, Lord Justice Birss handed down a judgement that Facebook did not infringe Voxer’s European Patent (UK) No. 2 393 259, and that also the patent was invalid. A bad day for Voxer.

In coming to this conclusion, the judge firstly found that Facebook’s system did not infringe the patent under the normal (literal-ish) construction of the claims. The judge found that Facebook’s system had two differences to claim 1 of the patent.

Therefore, the judge went on to consider whether Facebook’s system nonetheless infringed under the doctrine of equivalents, despite these differences.

To do this, the famous three Actavis questions were considered for each of these two differences in turn.

These questions are effectively:

  1. Notwithstanding that it is not within the normal meaning of the relevant claim of the patent, does the variant achieve substantially the same result in substantially the same way as the invention, i.e. the inventive concept revealed by the patent?
  2. Would it be obvious to the person skilled in the art, reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention?
  3. Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim of the patent was an essential requirement of the invention?

By considering these three questions, the first difference between Facebook’s system and claim 1 was found not to be an equivalent, and therefore Facebook’s system did not infringe the patent.

However, in any case, the judge went on to consider whether the second difference was an equivalent.

The first two Actavis questions were found in favour of Voxer (basically, that the second difference worked in the same way as the equivalent feature in the claim, and that a skilled person would understand this to be the case).

To answer the third question, the judge needed to decide whether the patentee had effectively excluded the possibility of equivalents for this second difference.

1. To what extent can the scope of a claim be affected by the actions of the patentee?

This concept is commonly known as file wrapper estoppel. The patentee is held to their arguments or amendments in prosecution of the patent to grant, or during court proceedings. This stops the patentee being inconsistent – i.e. arguing that the patent is valid for a reason, and then ignoring that reason when they come to argue for infringement.

This concept is only a recent introduction to UK law. It is still not clear how wide ranging it could be. To date, it has only been modestly applied in equivalents cases.

The use of file wrapper estoppel was recently developed in the UK in Akebia v Fibrogen [2020]. Here Lord Justice Arnold found that Akebia did not infringe by equivalence a claim which Fibrogen had narrowed by a validity-saving amendment. The limitations which Fibrogen had included by amendment to keep the claim valid could not be ignored when considering infringement.

Facebook tried to argue that this principle applied to Voxer’s claim. Voxer had earlier tried to make an amendment post grant which was broader than that which was supported by the original patent application. This was found to be added matter by the UK Intellectual Property Office (UKIPO), and so was not accepted. Voxer had to back-track on this amendment to a narrower position.

If Facebook’s system was to be considered to have an equivalent feature, then the claim scope needed to be construed to have the broader (rejected-for-being-unsupported) meaning.

Facebook argued that this was not acceptable – how can the claim be construed to have the same scope as an unallowable claim?

The judge disagreed, saying that the amendment was to do with internal validity, and since it had nothing to do with prior art, it had nothing to do with claim scope.

But what is interesting to me is that, in answering the third Actavis question, the judge at least considered amendments which were proposed but not accepted. In my opinion, this subtly goes beyond the application of file wrapper estoppel in the Fibrogen case. The final claim itself was not being assessed, rather the UKIPO’s opinion on an intermediate claim. Even though the judge found in this instance that the rejection of the intermediate claim did not affect the claim scope, it at least raises the possibility that more relevant amendments and opinions could do.

This just emphasises the importance of being careful with what is submitted to the UKIPO. It seems likely that file wrapper estoppel is going to have greater importance in equivalence cases in the future.

2. How do you deal with possibly infringing equivalents which are obvious in view of the prior art?

The second development in this case was due to Facebook arguing that they could not infringe under the doctrine of equivalents, because their system was obvious in view of the prior art for the Voxer patent.

The question is, by the doctrine of equivalents for infringement purposes, can the scope of a claim be construed so broadly that it includes systems/devices/methods which (if claimed) would not have been granted a patent in the first place?

It would seem logical that a claim should not be construed so broadly. Otherwise, it gives patentees a backdoor to gaining protection over uninventive “inventions” – and why should a patentee have protection over something which is uninventive?

This reasoning is sometimes known as the Formstein defence, named after a case in the German courts.

However, in the UK, it has not yet been necessary for a judge to apply such reasoning to come to a decision. So, it currently does not form part of UK law.

Lord Justice Birss in the present case also did not need to consider the question, because he had already found no infringement. However, he did comment that this approach would be the right way to proceed.

Therefore, patentees and potential infringers should be aware that it seems most likely that the Formstein defence will enter UK law at some point in the future.

At that point, we may well see a fourth question be added to the three Actavis questions, to cover the Formstein approach.

Potentially, the fourth question could be formulated as simply as:

Is the variant novel and inventive over the prior art at the priority date of the patent?

This question would require a “yes” to result in infringement – if the variant is novel and inventive over the prior art then the claim is arguably not being construed too broadly by covering the variant.

However, this formulation might not account for the variant being novel and inventive for tangential reasons separate to the inventive concept of the patent.

Therefore, the fourth question might instead be linked back to the wording of the first question, as per the below:

Is said way the variant achieves said result novel and inventive over the prior art at the priority date of the patent?

This question would again require a “yes” to result in infringement.

Although, I am sure, that a judge considering such a case in the future will likely phrase this concept more elegantly and accurately.

The patent infringement judgement in Facebook v Voxer [2021] therefore develops, but did not decide, two outstanding points of UK patent case law – and we wait to see how they further develop in future cases.


If you have any patent, design or trade mark queries, please contact us via email, by telephone: +44 (0) 1242 691 801, or using the form below and we will be happy to advise and guide you. 



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