07 August 2018 | Audrey Horton Professional Support Lawyer

The Court of Appeal has held that a patent for a composition of glass fibres with numerical ranges was valid and infringed.


A patent may only be granted for an invention which is new (section 1, Patents Act 1977). An invention is new if it does not form part of the state of the art. A patent is invalid for lack of inventive step if the invention claimed in it was obvious to a person skilled in the art having regard to the state of the art at the priority date (section 3, 1977 Act).

The two requirements for a claim to be anticipated by a prior document are disclosure and enablement (Synthon BV v SmithKline Beecham Plc (No 2) [2005] UKHL 59). A broad generic disclosure in the prior art does not take away the novelty of a claimed more specific one (Dr Reddy's Laboratories (UK) Ltd v Eli Lilly & Co Ltd [2009] EWCA Civ 1362).

The principles applicable to the construction of numerical limits were reviewed by the Court of Appeal in Smith & Nephew Plc v Convatec Technologies Inc ([2015] EWCA Civ 607).

In Actavis v Eli Lilly, the Supreme Court considered the scope of protection of a claim for infringement ([2017] UKSC 48).


J planned to import fibre glass products into the UK and applied to revoke O’s European patent in order to clear away any potential objection to such importation. J admitted its products would infringe O’s patent if it was valid. 

J argued that O’s patent lacked novelty and inventive step over one item of prior art: a US patent N disclosing a glass composition for producing glass fibres. The ranges for the constituents of glass fibre set out in tables in N either overlapped or fell within the corresponding ranges in the relevant claims of O’s patent. J argued that the skilled person reading N would have seriously contemplated applying the teaching of its tables across the entirety of the ranges set out. O submitted that the relevant figures in the patent would be understood by the skilled person to be exact values.

The Intellectual Property Enterprise Court held that O’s patent was valid and infringed. The relevant figures in the patent would be understood by the skilled person to be exact values, rather than adopting a broader whole number convention. A skilled person reading N would not seriously contemplate applying its teaching in the area of overlap, and so the patent did not lack novelty. None of the patent's claims were obvious over the examples in the N tables. The N tables did not contain an individualised description of any fibre glass falling within the patent, and nothing in N directed the attention of the skilled person to the area of overlap with the patent. 

J appealed.


The court dismissed the appeal. It held that O’s patent was valid and infringed.

In considering the construction of numerical limits, it was necessary to consider the relevant claim in the light of the disclosure of the patent, the common general knowledge and all other relevant circumstances. Smith & Nephew did not establish a rule of law as to how numerical ranges should be interpreted in all cases. 

A mere reference to a prior patent did not necessarily require the addressee of the patent to study it in detail before understanding the meaning of the language used in the claims. Although O’s patent undoubtedly recognised N as prior art, it went considerably further. It specifically referred to and reproduced examples in N, using them as a comparison. That was a compelling point in favour of adopting a narrower construction of the end points of the ranges in the instant case. In comparing the composition of the comparative example from N with the ranges in O’s patent claims, the skilled person would conclude that the patentee's ranges were exact and not meant to be broadened by whole number rounding. 

The question was whether the prior document N contained a disclosure of the invention. In general, a broad generic disclosure in the prior art did not take away the novelty of a claimed more specific one. There may be circumstances where a prior disclosure of a numerical range, such as a range of temperatures to be used in a process, may include an implicit disclosure that the skilled person may choose any value within the range.  Here there was no implicit disclosure of making every possible combination of compositions within the ranges specified in the N table. N did not tell the skilled person that they could choose indiscriminately any combination of values from its tables. In light of the common general knowledge, there was no disclosure in N which deprived the claim of novelty. The invention of the claim remained concealed or hidden in the disclosure of N.

It was possible to identify differences between the examples in N and the patent claim. For it to be obvious to proceed from the information in the N tables to a composition within the patent claim there would have to be evidence that the skilled person would make the relevant choices of values in the combination necessary to do so, while at the same time not taking other constituents out of range. In the absence of such evidence the obviousness attack on O’s patent was also rejected.


This decision clarifies the UK position on overlapping numerical ranges. The UK’s approach is now in line with that of the European Patent Office's Technical Board of Appeal as regards the test for the disclosure of an overlapping range in the prior art. To be novel, an overlapping range should not have been seriously contemplated by a skilled person in view of the prior art. The serious contemplation test was merely a way of distinguishing between matter which was properly regarded as hidden in the prior document and matter which was made available and disclosed. On that basis it did not differ materially from the conventional approach to novelty, as set out in Synthon.

Interestingly the court chose not to address the application of the principles of equivalence in the context of a claim involving numerical limits. Following Actavis v Eli Lilly, the question of whether the scope of protection of a claim for infringement, including by equivalents, is the same as the claim's scope for validity, remains unresolved.

Case: Jushi Group Co Ltd v OCV Intellectual Capital LLC [2018] EWCA Civ 1416.

First published in the August 2018 issue of PLC Magazine and reproduced with the kind permission of the publishers. Subscription enquiries 020 7202 1200.

About the Author

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Audrey Horton
Professional Support Lawyer
As the knowledge and development lawyer in our Intellectual Property Group based in London, I play a key part keeping the IP team up to date with legal developments and case law, scanning the horizon to ensure we are at the forefront of new trends.

Direct: +44 (0)20 7415 6000

[email protected]

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