The Principles of Patent Claim Interpretation in the UK
A recent decision in the high court highlights the principles applied to interpreting patents and their claims as well as infringement in the United Kingdom.
The decision (2018 EWHC 173 (Pat); L’Oréal Société Anonyme and L’Oréal (UK) Limited v RN Ventures Limited) concerned the infringement by a facial cleansing brush of European Patent 1 772 669 B1 and certain Community Registered Designs relating to apparatus for treatment of acne.
The central issue related to the movements produced on the skin by brushes of different stiffness arranged in concentric circles within an oscillating head in the facial cleansing brush.
The Patent described an apparatus in which skin contacting elements (for example, brushes) moved in one or more of three distinct modes.
In one mode, described as the “single set mode” the skin contacting elements moved in unison.
In another mode, described as the “shear mode”, the skin contacting elements moved in a vertical direction relative to each other.
In a further mode, described as the “tension compression mode” the skin contacting elements moved in a horizontal direction relative to each other.
In still another mode, described as a mixed mode, the skin contacting elements moved in a vertical and horizontal direction relative to each other.
The claims of the Patent referred to moving a contacting element bi-directionally through a neutral position relative to an adjacent contacting element to produce alternating tension and compression of the skin.
The movement had to have the effect that when the apparatus is positioned so that the end faces of the contacting elements contact the skin, an action on the skin in the plane of a skin area to be treated for acne is produced to remove sebum plugs from skin pores, permitting removal of the plugs from the skin.
It was not alleged that the facial cleansing brush used the tension and compression mode. The question of infringement related to whether the claims of the Patent encompassed the single set mode or the shear mode and to whether the facial cleansing brush produced a shear mode when it was used.
RN Ventures argued for the exclusion of the single set mode on the basis that the expression “neutral position” referred to the starting or rest position of the contacting element rather than the relaxed state of the skin between the contacting elements.
It also argued that the relative movement had to refer to a movement at the base of the brushes because the Patent did not disclose brushes of different flexibility and relative movement between the base and the skin contacting end on adjacent tufts is different.
Mr Justice Henry Carr considered that, on a purposive interpretation, the relative movement had to be at the skin contacting end. The claim required that the contacting elements produce alternating tension and compression of the skin.
The judge said that where there is a difference in the behaviour of the base and tip of the contacting elements it would not be consistent with the Patentee’s purpose, nor fair to the Patentee, to disregard movement of adjacent contact elements which produces the claimed effect.
However, he also found that, on a purposive interpretation, the neutral position referred to the starting or rest position of the contacting elements.
The judge said that not everything disclosed in the specification of a patent necessarily falls within the scope of its claims, which may have been amended during prosecution.
The claims required relative movement between the contacting elements and it was explicable that it should do so because the Patent discloses that “applying bidirectional reciprocating motion via a single set of contact elements is generally not as effective as using adjacent contacting elements arranged to apply tension/compression or shear between them.”
Purposive interpretation does not allow the language of the claim to be disregarded. The Patentee’s purpose in choosing this language is, as indicated in the Patent, to exclude an arrangement which is generally not as effective as that which is claimed.
RN Ventures also argued that the expression “alternating tension and compression of the skin” excluded the shear mode and limited the scope of monopoly to the tension compression mode.
After taking expert evidence, Mr Justice Henry Carr agreed that RN Ventures confused the movement of the contacting elements and the effect of the movement and concluded that the claims encompassed the shear mode.
The judge noted that the shear mode was expressly stated as preferred over the tension and compression arrangement. And said that although not everything disclosed in the specification of a patent necessarily falls within the scope of its claims, this did not mean that the Patentee’s preferred arrangement should be excluded from the claims.
The document should be read as a whole and exclusion of all the preferred embodiments would not be a sensible reading. Nor would it accord with the inventor’s purpose. It would be neither fair to the Patentee, nor provide reasonable certainty to the public.
The inventive concept was not confined to the tension compression mode when it stated that the present invention provides either mechanical energy in a shear mode or a tension compression mode or a combination (elliptical) in order to loosen the adhesion between the sebaceous plug and the walls of the pore.
Whilst it is not appropriate to substitute this language for the words of the claim, this summary indicates that an interpretation which excludes the shear mode from the scope of the claims would be unduly narrow.
RN Ventures also argued that reference to the prosecution history was appropriate because it would be contrary to the Public Interest for the contents of the file to be ignored.
The file showed that the Examiner had gained the impression that the Proprietor was choosing to exclude the shear mode from the claims when he had amended to require that the contacting element produce alternating tension and compression of the skin. It added that the Proprietor should have told the Examiner that this was not the case.
The judge disagreed with RN Ventures saying that the Proprietor was satisfied by the text, and its interpretation is a matter for the national courts, not the Examiner. The Proprietor was not under a duty to correct any misunderstanding about the scope of the claims on the part of the Examiner.
He added that the prosecution history was inadmissible and, in any event, was of no assistance. He emphasised that reference to the prosecution history is the exception, and not the rule, and warned that Parties should think carefully in future before incurring additional costs in arguing about the prosecution history.
After taking video and further expert evidence, the judge identified four movements within the facial cleansing brush and that two of these movements, although not described in detail in the Patent, involved a shear mode.
The judge also found that there was sufficient disclosure in the Patent saying that the skilled person would be able to make a product falling within the claims of the patent using common general knowledge and the information in the patent.
It would be common sense for the skilled addressee to implement the general teaching of the patent by using bristle tufts of different stiffness to achieve the necessary differential force, which could then be tested on the skin.
He concluded that the Patent was infringed upon a literal interpretation of the claims.
Although not required to decide upon infringement by equivalence of the shear mode with the tension compression mode, the judge commented that, in that case, he would not have found infringement.
He said that the shear variant produced substantially the same result in the same way, and obviously so, as the Patent makes clear that this is its preferred arrangement.
However, on this hypothesis, having discussed the shear variant at great length in the specification, the Patentee nonetheless chose to exclude it from the claims.
The skilled addressee would have assumed that he intended to do so, possibly in the light of prior art cited during the prosecution.
And that consequently the variant was not an equivalent (that infringed the Patent).
If you would like help with the interpretation of claims or dealing with patents, please do not hesitate to contact an attorney at TLIP Ltd. We should be glad to be of assistance.