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	England and Wales High Court (Patents Court) Decisions
You are here: BAILII >> Databases >> England and Wales High Court (Patents Court) Decisions >> Zeno Corp (Formerly Known As Tyrell Inc) & Anor v BSM-Bionic Solutions Management GmbH & Anor [2009] EWHC 1829 (Pat) (29 July 2009) URL: http://www.bailii.org/ew/cases/EWHC/Patents/2009/1829.html Cite as: (2009) 32(10) IPD 32070, [2009] EWHC 1829 (Pat)

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IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT

		Royal Courts of Justice Strand, London, WC2A 2LL
		29 July 2009

Mr. Justice Lewison:

Introduction

1. In September 2007 Boots plc began to sell Zeno, a device manufactured by Tyrell Inc. In February 2008 patent attorneys acting on behalf of Riemser Arzneimittel AG wrote to Boots, drawing attention to Riemser's patent EP (UK) No. 1 231 875, and expressing the view that Zeno had adopted the same technical solution. The invention claimed in the patent is a hand-held unit for the treatment of insect stings and insect bites. But Zeno is not used for that purpose. It is used for the treatment of acne; and the instruction leaflet that comes with it says in terms that it should not be used for insect or spider bites or stings. Boots stopped ordering Zeno, although they were later persuaded to reorder. This action is a claim (technically a counterclaim) by Riemser for infringement of its patent. Predictably, Tyrell say that the patent is invalid; and that anyway they do not infringe it. They also say that the letter from Riemser's patent attorneys amounted to a threat of infringement proceedings.

The experts

2. Tyrell's medical expert was Dr Ronald Behrens. He is a consultant in Tropical and Travel Medicine at the Hospital for Tropical Diseases. He directs the Hospital for Tropical Disease's Travel Clinic; and is also Senior Lecturer at the Department of Infectious and Tropical Diseases at the London School of Hygiene and Tropical Medicine, a postgraduate school in the University of London. His research interests include malaria and its prevention, particularly on studies on identifying measures that travellers should take to avoid malaria, and also on the effectiveness and toxicity of malaria prophylactic drugs. He has been involved in evaluating and assessing the effectiveness of bite prevention strategies and products available for bite prevention. He has also conducted studies on imported infectious diseases including malaria, hepatitis A and tuberculosis. He has been closely involved in the diagnosis and treatment of insect bites and diseases related to insect bites such as leishmaniasis and dengue fever.
3. Riemser's medical expert was Professor Peter Friedmann. He is Emeritus Professor of Dermatology at the University of Southampton. Since 1998 his main areas of research have been the immune mechanisms underlying allergic reactions to chemicals experienced by skin contact or as therapeutic medicinal drugs. He has continued to work on the environmental impact on the skin, in particular the mechanisms of the effects of ultraviolet light and noxious environmental chemicals on the skin.
4. Dr Behrens' view was that the patent in suit was addressed to a team of people including those with experience in the design and manufacture of medical devices together with those with medical or first aid experience in the treatment of insect bites and stings. The team would also have included an engineer capable of actually making the device that the patent in suit describes. Professor Friedmann's view was that it was addressed to researchers and doctors with practical knowledge and experience of the physiology of the skin and the treatment of skin conditions. This group of people would include, but not be limited to, researchers and doctors with a particular interest in the physiological reactions to, and the treatment of, insect bites and stings. However, this specific topic is not routinely studied by any one, well-defined group of specialists, but rather overlaps the areas of interest and experience of different groups of researchers and doctors, in particular research dermatologists and allergologists. The patent in suit would also be of interest to manufacturers of electrical healthcare devices, but they would have sought the advice of a dermatologist or allergologist.
5. In the end, this minor disagreement did not matter. Both experts agreed that the addressee would be a team consisting of a medically qualified person and an engineer. The first aid experience to which Dr Behrens referred was not the sort of first-aider trained to deal with minor workplace accidents or a boy scout, but a GP or similar; and Professor Friedmann accepted that a GP would be adequately qualified to read and understand the patent in suit. Moreover, despite their minor disagreement on the makeup of the team, both experts were agreed on the common general knowledge that such team would possess.

Common general knowledge

6. Generally insect bites and stings cause distress and discomfort rather than danger. In most cases they can be self-treated in the field; but in other events the consequences and complications are much more significant and medical expertise will be required. The patent in suit is concerned with treatment in the field.
7. Venomous insects attack as a defence mechanism injecting toxic venom through their stings. Because a sting is part of an insect's defence mechanism, it is meant to hurt. Stings hurt because they contain a small amount of venom that triggers a histamine response resulting in swelling, burning and itching. In most patients, this is the extent of the response. In a small number of cases the victim may suffer a more severe reaction, in which case urgent medical advice should be sought as the victim may require adrenaline injections. The current standard treatment for stings is as follows. First, the stinger should be removed using the edge of a dull knife or a fingernail. The wound should be cleaned and treated with a topical (or oral) analgesic together with an antiseptic cream. The application of ice or a cold wet compress can help reduce itching and swelling. Some individuals benefit from oral anti-histamine medication.
8. In contrast to stinging insects, biting insects use their bite as a means to feed. Their aim is to go unnoticed during the feeding process, and therefore, insect bites are (generally speaking) not painful at the time of the bite itself. When insects bite, they inject saliva into the skin. It is the constituent elements of insect saliva (e.g. anticoagulants, amines, peptides, enzymes, etc.) that cause the inflammatory and allergic reactions to insect bites, in a similar way to the venoms of stinging insects.
9. Itching is the main symptom associated with insect bites. Topical antihistamines can alleviate itching. The bite should also be cleaned and treated with antiseptic. If there is significant pain, this can be alleviated with oral analgesics. Any systemic reaction including facial swelling, shortness of breath or wheezing, difficulty swallowing, light-headedness or fainting should be managed by a doctor urgently. Systemic treatment with adrenaline and steroids are the standard management of anaphylaxis.
10. During biting and stinging the insect is not usually observed and/or recognised and so when patients present with symptoms relating to a bite, the causative insect is usually unknown. Accordingly, treatment is generally symptom dependent rather than relating to the insect except where there is a clear syndrome such as bee or wasp sting or acute anaphylaxis.
11. Thermolabile poisons were not part of the common general knowledge of the skilled person as at 1999. Even now Professor Friedmann was only able to identify one such poison, phospholipase (although he did not know what insect injected phospholipase) and accepted that he did not even have this limited knowledge as at 1999. Nor would the skilled person know the actual temperatures at which the poisons are denatured.
12. Thermal burns are injuries that result from exposing the skin to heat sufficient to cause damage and death of cells and tissues. The effects of the heat will depend upon the intensity (temperature), duration of exposure, type of heat source and its contact with the skin (whether wet or dry), as well as the thickness of the skin and the surface area exposed. Delivery of such a heat "insult" to the skin will cause pain which may vary from tolerable to extreme. Depending on the depth to which the skin tissues are damaged, thermal burns may have a variety of appearances and consequences.
13. Contact with hot water at 45^oC causes minimal damage that results in redness (erythema), and tissue swelling. Water between 50°C and 55°C can cause blistering and loss of the surface layers of skin, depending on the duration of contact. Dry contact, such as with metal or air, transfers heat into the skin much less efficiently, so higher temperatures can be tolerated before the tissues are damaged. However the precise temperature and duration of exposure to dry heat sufficient to cause damage to the skin was neither part of common general knowledge nor readily available in the literature.
14. The medical community was also aware of folkloric methods of treating stings and bites. These included "bicarb for bees and vinegar for wasps". They also included hot baths to reduce itching.
15. However these "remedies" have no proven scientific basis. Chinese culture had a long tradition of using heat to treat a vast range of symptoms and conditions but, again, these practices were (and are) not generally accepted as scientifically sound by Western medicine. In many cases, if inflamed skin is heated up to temperatures as would typically be used in a hot bath (e.g. up to about 40°C - 45°C), then the inflammation can be exacerbated because of the increased blood-flow to the inflamed area. As at 1999 there was no theory for the treatment of stings and bites by the application of heat that was generally accepted in the medical world. On the contrary, the classical response to inflammation was (and is) the application of cold and soothing material such as a flannel or ice to relieve swelling and discomfort. Local application of heat is in direct contrast to this standard of practice.
16. Thus the view of the western medical community was that it was likely that these remedies work (if at all) as placebos. However, the placebo effect is not to be underestimated, especially in the treatment of itch, the most common symptom in response to an insect bite. Itch is as much a sensation as a physical discomfort and so is particularly prone to psychosomatic manipulation.

The patent in suit

17. The patent in suit begins by saying that:

"The invention relates to a hand-held unit that is used to treat the consequences of insect stings and insect bites."

18. Having considered methods of preventing stings and bites in the first place (which are not wholly effective) it then goes on to describe features of the prior art. It acknowledges devices that work by the application of heat, including one device (referred to in this case as Lombal) which it acknowledges as having all the integers of the pre-characterising part of claim 1. The disadvantage of the prior art is that:

"the heat introduced cannot be precisely dispensed either in regard to the level of the temperature or in regard to the duration of exposure, but depends on the skill and the experience of the user. As a result, lack of success or transgression of the harmlessly tolerable temperature and, consequently, additional skin irritations may easily occur."

19. It then sets out the object of the invention as follows:

"The object of the invention is therefore to provide a device for the thermal treatment of insect stings and bites with which, regardless of the external conditions, the amount of heat necessary for the neutralization of the thermolabile insect poisons is introduced without, at the same time, skin irritations occurring that are attributable to the exposure to heat."

20. The patent in suit goes on to describe the device. In essence it consists of a hotplate and a control which regulates both the temperature of the hotplate and the time for which it remains heated. By activating a key, the device begins a "heating up phase". During this phase the hotplate heats up to a specified maximum temperature. Once the hotplate has reached the required temperature, a second phase called the "heating phase" begins; and the time control is triggered. This control consists of both a time regulator and a temperature regulator. During the specified duration of the heating phase, which corresponds to the duration of treatment, the temperature regulator ensures the maintenance of the maximum temperature and, at the same time, prevents it from being exceeded. After the expiry of the heating phase, the heating operation is terminated; and the temperature of the hotplate returns to the ambient temperature.
21. The specification continues:

"The hotplate 2 is heated in the heating-up phase to a maximum temperature in a range from 50 to 65^oC, preferably 55 to 60°C, a tolerance of ± 3^oC being maintained. In the heating phase that follows the heating-up phase and that corresponds to the treatment duration, the maximum temperature is maintained for a time interval of 2 to 12 seconds, preferably 3 to 6 seconds. In this connection, the duration of the heating phase is inversely proportional to the level of the maximum temperature. At the end of the heating phase, the heating operation is terminated and the cooling phase starts."

22. The patent in suit goes on to give examples of different temperature and time curves. Temperatures are specified in multiples of 5^o C. Time is measured in seconds to one or two decimal points. The patent in suit says:

"The amount of heat is introduced into the puncture independently of the ambient temperature and of the surface temperature of the skin since the heating phase starts only when the maximum temperature is reached and the temperature of the hotplate is constantly maintained over the entire duration of the heating phase by the temperature regulator. In this way, an exact introduction of the amount of heat necessary to neutralize the thermolabile poisons is possible in a temperature range in which damage to the skin by said heat introduction is not to be feared."

23. It points out that:

"The duration of exposure is not critical at a temperature of 55(C, with the result that the treatment can be repeated several times, if necessary, at said temperature. In addition, as a consequence of the anaesthetic action of insect poison, a heat treatment of the skin at the puncture point is felt to be markedly less unpleasant than in other regions.

At a maximum temperature of about 60(C, the heating phase should not exceed 5 s since skin reactions otherwise occur on sensitive areas of skin as a consequence of the introduction of heat.

If the maximum temperature is 65(C, the heating phase should not exceed 3.5 s since skin reactions otherwise occur as a consequence of the heat introduction."

24. Having described the device, the patent in suit sets out the claims:

"1) Device for the local thermal treatment of insect stings and insect bites that acts on the puncture point by means of the introduction of heat,

a) the device comprising a heating element (1) that is designed as an electrical hotplate (2) supplied by a voltage source (3),

b) the hotplate (2) being heatable in a heating-up phase to a maximum temperature in a range from 50 to 65ºC, preferably 55 to 60ºC, and the maximum temperature being maintainable in a heating phase for a time interval ranging from 2 to 12 s, preferably 3 to 6 s,

c) a temperature sensor (4) and a control device being connected to a heating element (1), the electrical signal generated by the temperature sensor (4) being routed to the control device (5),

characterized in that the control device controls the heating-up of the hotplate (2) to the maximum temperature and the duration of the maintenance of the maximum temperature."

Disputes of construction

25. A number of integers of the claim have disputed constructions. There is, however, no dispute about the principles of construction that I must apply. The principles were summarised by Jacob LJ in Mayne Pharma Pty Ltd v Pharmacia Italia SPA [2005] EWCA Civ 137 and refined by Pumfrey J in Halliburton Energy Services Inc v Smith International (North Sea) Ltd [2005] EWHC 1623 (Pat) following their general approval by the House of Lords in Kirin-Amgen v Hoechst Marion Roussel [2005] RPC 9. An abbreviated version of them is as follows:

i) The first overarching principle is that contained in Article 69 of the European Patent Convention;

ii) Article 69 says that the extent of protection is determined by the terms of the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.

iii) It follows that the claims are to be construed purposively—the inventor's purpose being ascertained from the description and drawings.

iv) It further follows that the claims must not be construed as if they stood alone—the drawings and description only being used to resolve any ambiguity. Purpose is vital to the construction of claims.

v) When ascertaining the inventor's purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.

vi) Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol—a mere guideline—is also ruled out by Article 69 itself. It is the terms of the claims which delineate the patentee's territory.

vii) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements.

viii) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context.

ix) It further follows that there is no general "doctrine of equivalents."

x) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.

xi) Finally purposive construction leads one to eschew the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge.

Device for local thermal treatment of insect stings and insect bites

26. The received wisdom is that the use of the word "for" in a patent claiming a product means that it covers any product that is "suitable for" the particular purpose specified in the claim. It was common ground that this was the case here. The origin of this principle of construction is, according to Mr Burkill, the decision of Parker J in Adhesive Dry Mounting Co Ltd v Trapp & Co (1910) 27 RPC 341. The patent in that case contained a process claim of mounting photographs etc on cardboard consisting of interposing between the two surfaces a thin layer of material capable of becoming adhesive under the action of heat. Another claim claimed:

"For the carrying into practice of the process hereinbefore described a pellicle which is adhesive when hot …"

27. The question was whether that claim claimed the pellicle itself or merely the use of the pellicle for the process claimed in the earlier claim. Parker J said:

"I think the former is the right construction for if the latter be adopted the second Claiming Clause is already included in the first."

28. That was the only reason he gave for that construction. Likewise in Coflexip SA v Stolt Comex Seaway MS Ltd [2000] IP & T 1332 a patent claimed both a process and a device "for operating the process according to one of the preceding claims". It was argued that this limited the claim to a device when used for the claimed process. The Court of Appeal rejected that argument. Aldous LJ said:

"The patent, as the title and specification state, relates to a method and a device. To construe claim 3 in the way suggested by Stolt would in effect mean that there was no device claim. At page 5 lines 30-32 it is stated "The characteristics of the method of the present invention form the objects of claims 1 and 2. The characteristics of the device in accordance with the present invention form the objects of claims 3 to 9." Clearly the patentee had in mind both method claims and device claims. His intention is carried through into the claims. For example claim 4 claims "A device according to claim 3…". That also indicates that claim 3 is a claim to a device not to a device when used."

29. As a question of construction of those particular patents these decisions are unexceptionable, because it will seldom be right to construe a claim so that it is entirely redundant. But it seems to me, with all respect, to be a slender foundation for the wider rule of construction applicable across the board that has been subsequently developed with no further explicit reasoning in any of the cases that have subsequently referred to or applied the supposed rule. Moreover, as Lord Hoffmann pointed out in Merrell Dow Pharmaceuticals Inc v H.N. Norton & Co Ltd [1996] RPC 76, 92 this sits uneasily with the decision of the EPO Board of Appeal in MOBIL/Friction reducing additive Decision G02/88 [1990] E.P.O.R. 73. Since a patent is a unilateral document, written in words of the patentee's choice, one might also reasonably ask: if he meant "suitable for", why did he not say it? In Folding Attic Stairs Ltd v The Loft Stairs Company Ltd [2009] EWHC 1221 (Pat) Mr Peter Prescott QC, sitting as a judge of the Patents Court, said:

"There is an old prejudice or tradition in patent law that words of intent should not be used in patent claims (see Eli Lilly & Co's Application [1975] RPC 438, 444). It was said to go back to the early nineteenth century; but whether that is the law now under the 1977 Act and the European Patent Convention must be questionable. We have seen an abandonment of the concept in many pharmaceutical patents whose claims are in so-called "Swiss" form. What they really mean (and nobody pretends otherwise any more) is "The use of known ingredient X for making a medicine for treating disease Y", meaning for the purpose of, or with the intention of, treating disease Y. In this instance the law has moved on, and there is no doubt about it. In a recent decision of the Court of Appeal it was not even the intention to treat a different medical complaint that was the key point, but the intention to do so with a different dosage regimen (Actavis UK Ltd v. Merck & Co Inc [2008] EWCA Civ 444). The real reason that such claims are allowed is that, were it otherwise, the inventor would be quite unable to protect his invention at all. But they imply a test of purpose or intentionality on the part of the manufacturer. If that is permissible in pharmaceutical cases, I do not see why it could not be so in other industries. I believe the words 'predetermined' or 'preset' have long been used by patent draftsmen for the purpose of indicating intentionality, albeit rather covertly. Why not admit it openly?" (Emphasis in original)

30. Nevertheless in FNM Corporation Ltd v Drammock International Ltd [2009] EWHC 1294 (Pat) decided a few days later Arnold J considered the position in some detail including the decision of the Court of Appeal in Actavis UK Ltd v. Merck & Co Inc; and affirmed the "the principle that the word "for" in a patent claim means "suitable for"". So despite my own doubts, and in view of the common ground, I will assume that the emperor is clothed and apply the received wisdom that "for" a purpose means "suitable for" that purpose. In this case the specified purpose is the "local thermal treatment" of insect stings and bites.
31. However, that still leaves the question: if the manufacturer of a product does not design or intend it to be used for the specified purpose, how does one judge whether it is "suitable" for use for that purpose? Is it simply a question of whether something is capable of being used for a specified purpose? After all, Terrell is capable of being used as a doorstop or a paperweight; and a popular cartoon book of a few years ago was entitled "101 Uses for a Dead Cat". Was it "suitable" for all those uses? Closer to home, some of the feedback relating to Riemser's own product extolled the efficacy of a hot mug of tea or a lit cigarette end in applying heat to the site of insect bites. But are these "suitable" things to use?
32. Bühler AG v Satake UK Ltd [1997] R.P.C. 232 concerned a claim to "a roller mill for the milling of cereal". Jacob J said:

"The parties were agreed that this phrase constituted words of limitation: a device is only covered by the claim if it is capable of milling cereals or the like. The dispute at one point seemed to be, how capable? Cereal mills themselves differ depending upon the stage of milling and a device suitable for only one or some stages would be "suitable for milling". However in the end Mr. Waugh took the position that if a mill could be shown to be suitable for milling cereal - without alteration to make it so - then it would be covered as a matter of interpretation. The real dispute arising from this phrase was whether the sole piece of prior art cited, Linden, was capable of milling cereals."

33. This suggests that a device will be suitable for a specified purpose if it is capable of being used for that purpose without adaptation. On this test (which was apparently not disputed in the end) a hot mug of tea would be suitable for treating insect bites. The EPO's Guidelines for Examination (April 2009 edition) which Arnold J quotes in FNM Corporation Ltd v Drammock International Ltd suggest a more nuanced test. They say (section C-III § 4.13):

"Apparatus which otherwise possesses all of the features specified in the claims but which would be unsuitable for the stated purpose or would require modification to enable it to be so used, should normally not be considered as anticipating the claim. Similar considerations apply to a claim for a product for a particular use. For example, if a claim refers to a 'mold for molten steel', this implies certain limitations for the mold. Therefore, a plastic ice cube tray with a melting point much lower than that of steel would not come within the claim. Similarly, a claim to a substance or composition for a particular use should be construed as meaning a substance or composition which is in fact suitable for the stated use; a known product which prima facie is the same as the substance or composition defined in the claim, but which is in a form which would render it unsuitable for the stated use, would not deprive the claim of novelty. However, if the known product is in a form in which it is in fact suitable for the stated use, though it has never been described for that use, it would deprive the claim of novelty."

34. The first sentence of this quotation appears to envisage that something may be unsuitable for the specified purpose even if it contains all the features of the claim, since that is put forward as an alternative to modification. Again, despite my doubts, I am content to proceed on the basis that something is suitable for a specified purpose if it is capable of being used for that purpose without modification.
35. Mr Vanhegan QC said that there were two possible constructions of the specified purpose. The first (narrow) construction was that the product had to be suitable for the treatment of bites and stings, in the sense of providing effective treatment by neutralising the thermolabile poison injected by the insect. The second (and wider) construction was that the product must be suitable for applying heat to the site of an insect bite or sting. He said that the narrow construction was the correct one.
36. Although the theory advanced in the specification is that the invention works by neutralising thermolabile poisons, the theory is, in the view of both medical experts, at best dubious. But, as Mr Burkill submitted, the theoretical underpinning does not form part of the claim itself, which is a claim to a product rather than to a process. Based on Terrell § 7-104 and Auchinloss v Agricultural & Veterinary Supplies [1999] RPC 397, 402 he submitted that as long as there was a "real effect" on the consequences or symptoms of insect bites and stings it did not matter what caused that effect. I agree with this, as long as the real effect in question is a beneficial one, otherwise it cannot realistically be called "treatment".
37. I therefore accept that a device "for … treatment" must be capable of having some real beneficial effect on the symptoms experienced by one who has been bitten or stung by an insect, but I do not consider that it matters why it works (assuming that it does). This is a little narrower than Mr Vanhegan's wide construction, but not as narrow as his narrow one.

The temperature ranges

38. Claim 1 refers to:

"a maximum temperature in a range from 50 to 65ºC, preferably 55 to 60ºC".

39. The question under this head is the precision with which those temperatures must be interpreted. Mr Vanhegan relies on the decision of Mr Peter Prescott QC, sitting as a judge of the Patents Court, in Auchinloss v Agricultural & Veterinary Supplies [1997] RPC 649 at 689-90 in which he said:

"Where the patentee has expressed himself in terms of a descriptive word or phrase there may be room for supposing that he was using language figuratively, and did not intend to restrict himself to the purely literal meaning. But where the patentee has defined an integer of his claim in terms of a range with specified numerical limits at each end, his purpose must be taken to have been to claim thus far and no further. His reason for doing so may not be apparent, but it may exist all the same, for instance it may lie 'buried in the prior art'. Further, in this case I believe that there are evident reasons of convenience and certainty which would have led him to claim in this way, as I have observed."

40. This part of the deputy judge's judgment was not affected by the appeal. Mr Burkill, on the other hand relies on the decision of Aldous J in PLG Research Ltd v Ardon International Ltd [1993] FSR 197 in which the claim required a junction to have a thickness of "not less than 75 per cent" of the thickness of the mid-point of a strand passing through the junction. Aldous J said:

"There is no evidence that the 75 per cent limitation, as opposed to, say, 76 per cent or 74 per cent, was crucial, nor that it would be seen to be crucial by the skilled addressee. Thus, variants close to 75 per cent limitation for a minor part of the junctions would not have a material effect upon the way the invention worked and that would have been obvious to the skilled addressee. Further the patentee would not be thought to have intended to exclude such variants from his monopoly. The skilled addressee would realize that the manufacture of plastics net structures by biaxially stretching was a process in which variations of thickness were certain and that the edges of the junctions could not be vertical. Thus, there would be some variation apparent when measuring the strands and the junctions, and also the measurements taken at the extreme edge would not be the place contemplated for the patentee."

41. Terrell § 6-138 gives other examples where numerical limits have been interpreted with some flexibility, in particular by applying the scientific convention that numbers are given to the number of figures that are significant. Thus 10 will cover a range from 9.5 to 10.4; 10.1 will cover a range from 10.05 to 10.14 and so on. In the end I think that both sides agreed with the statement in Terrell:

"It is submitted that the correct consideration in each case is to determine whether on its true construction the stated limit has to be read as exactly (X) or as about (X), determination of which possible meaning is correct being approached in the same way as for any other form of claim limitation."

42. It is plain that the temperatures are expressed as whole degrees (i.e. 65ºC rather than 65.0ºC). So it is not difficult to understand that a range between 64.5^oC and 65.4^oC would be encompassed in 65ºC. Mr Burkill points to two additional features of the specification. First he refers to the passage in which it says that the hotplate is heated to:

"a maximum temperature in a range from 50 to 65^oC, preferably 55 to 60°C, a tolerance of ± 3^oC being maintained."

43. Mr Burkill argues that the stated tolerance applies to all values mentioned in claim 1. Thus 65^oC would encompass 68^oC. In fact the logic of this argument goes further. If both 65^oC and 3^oC are expressed to two significant figures, then 65^oC in the claim can encompass 68.4^oC. Second, he says, where the specification refers to illustrative figures, the temperatures are presented in multiples of 5^oC. On this basis, therefore, 65^oC can encompass 70^oC (or possibly 70.4^oC or even, if the 3^oC tolerance point is also right, 73.4^oC).
44. In evaluating this argument, it must be remembered that what the claim is talking about is applying heat to human skin. Moreover, it is talking about applying heat to human skin for a predetermined length of time. The minimum duration specified in the claim is 2 seconds, and the preferable minimum specified is 3 seconds. Professor Friedmann's evidence was that if heat is applied to human skin at 65^oC a burn will be caused after half a second, and that at 65.49^oC a burn would be caused even more quickly. It follows that the application of heat at 68^oC would cause an almost instant burn; and if applied for the minimum specified period of 2 seconds the burn is likely to be serious. The application of heat at 70^oC would be extremely dangerous. I must also bear in mind that the precise combination of temperature and duration of exposure to heat sufficient to cause real damage was not part of common general knowledge. Nor was the method of treatment proposed by the patent in suit part of common general knowledge. Accordingly the skilled reader would not have had any "feel" for the effects of straying outside the explicit parameters of the claim. Thus the skilled reader would have been very cautious, since both experts agreed that safety would have been his paramount consideration. In those circumstances I do not consider that the skilled reader would read the specified temperatures as unimportant or imprecise. He would not understand that a maximum temperature of 65^oC could extend beyond 65.4^oC. What goes for the maximum temperature must also go for the minimum temperature. There are two additional points that reinforce this conclusion. First, the specification says:

"At a maximum temperature of about 60(C, the heating phase should not exceed 5 s since skin reactions otherwise occur on sensitive areas of skin as a consequence of the introduction of heat.

If the maximum temperature is 65(C, the heating phase should not exceed 3.5 s since skin reactions otherwise occur as a consequence of the heat introduction."

45. If these temperatures are read with a tolerance of ± 3^oC then it would mean that the specification is saying that at 63^oC (60^oC + 3^oC) the heating should not exceed 5 seconds otherwise skin damage might occur; and at the same time is saying that at 62^oC (65^oC – 3^oC) the heating should not exceed 3.5 seconds otherwise skin damage might occur. This would be self-contradictory teaching; and given that the duration of heating is measured with an accuracy of half a second, it seems to me to be unlikely that the skilled reader would interpret this teaching as loosely as Mr Burkill suggests.
46. Second, claim 6 claims:

"Device according to Claims 1 to 5, characterized in that the maximum temperature is maintained during the heating phase with a tolerance of ± 3°C".

47. If the tolerance of ± 3°C is already incorporated into claim 1, then claim 6 is entirely pointless. Moreover the fact that the tolerance is expressed as ± 3°C clearly shows that the patentee was being more precise than the separation of temperatures by multiples of 5^oC.
48. I hold, therefore, that the temperatures given in the claim are to be read as accurate to two significant figures, with the consequence that the minimum temperature specified in claim 1 is to be read as 49.5^oC and the maximum temperature is to be read as 65.4^oC (or 49.50 and 65.49 respectively).

Time intervals

49. Claim 1 refers to:

"the maximum temperature being maintainable in a heating phase for a time interval ranging from 2 to 12 s, preferably 3 to 6 s".

50. The question under this head is whether 12 seconds is the maximum duration of the heating phase.
51. Mr Vanhegan starts with the object of the invention. This has twin goals: first to deliver the amount of heat necessary to neutralise poisons; and second to achieve that goal without causing skin irritations. Accordingly, precise control over both time and temperature will be necessary to achieve these goals. If the temperature is precisely controlled, but the time of exposure to heat is not, then the user of the device suffers an increasing risk of burns the longer he uses the device. This is reinforced by a passage in the specification that says:

"The amount of heat is introduced into the puncture independently of the ambient temperature and of the surface temperature of the skin since the heating phase starts only when the maximum temperature is reached and the temperature of the hotplate 2 is constantly maintained over the entire duration of the heating phase by the temperature regulator. In this way, an exact introduction of the amount of heat necessary to neutralize the thermolabile poisons is possible in a temperature range in which damage to the skin by said heat introduction is not to be feared." (Emphasis added)

52. Unless both temperature and duration are strictly controlled, an exact introduction of heat is not possible; and without such exactness damage to the skin will certainly be feared. Moreover, when the specification and the claims deal in times, they do so with precision. Thus, for instance, the defect in the prior art to which the specification draws attention is that:

"the heat introduced cannot be precisely dispensed either in regard to the level of the temperature or in regard to the duration of exposure."

53. Likewise claim 4 speaks of maintaining a temperature for a duration of 5.5 seconds, and claim 5 a duration of 3.25 seconds. Where the patentee descends to quarters of seconds it is clear that precision is intended.
54. Mr Burkill on the other hand says that the patent teaches that the duration above which damage will be caused to the skin depends on the temperature. It follows therefore that at lower temperatures the duration of the application of heat can be longer than the claimed range. The skilled reader would thus understand that the claim meant "at least about 2 to 12 seconds" for efficacy but he would appreciate that it could be longer, subject to not compromising safety.
55. I prefer Mr Vanhegan's argument. If Mr Burkill is right, then "ranging from 2 to 12 seconds" means the same as "at least 2 seconds". Moreover, the same considerations that would have led the skilled reader to have been cautious about straying outside the temperature ranges referred to in the claim would have made him equally cautious about straying outside the durations given in the claim. Mr Burkill also relied on passages in the evidence in which the experts said that a duration of application at the maximum temperature for longer than 12 seconds inevitably maintains the maximum temperature for 12 seconds. In the first place this is a question of construction for the court, rather than a matter for the experts. Second, the claim does not speak of a period of 2 to 12 seconds. Rather, it speaks of a "time interval" of 2 to 12 seconds. The ordinary meaning of an "interval" is that it intervenes between two other things. In other words it has a beginning and an end. In addition the specified time interval is one "ranging from" 2 to 12 seconds, which again shows that the period has both a beginning and an end. In my judgment Mr Burkill's construction involves a drastic rewriting of one of the integers of the claim. In the context of the patent in suit I hold that a time interval of 2 to 12 seconds means a period that is not less than 2 seconds and not more than 12.

Heatable and maintainable

56. Claim 1 refers to:

"the hotplate… being heatable in a heating-up phase to a maximum temperature in a range…, and the maximum temperature being maintainable in a heating phase for a time interval…"

57. Mr Burkill says that the claim uses the words "heatable" and "maintainable" in order to make it clear that this is a product claim. If it had used the words "heated" and "maintained" then there would only be an infringement when an otherwise infringing device was switched on. I do not think that Mr Vanhegan seriously dissented from this. In essence his submission was that "heatable" and "maintainable" meant that when in use the device was "heated to" the maximum temperature and "maintained at" that temperature for the designated period. This coincides with my own understanding of this integer.
58. Mr Vanhegan potentially had a point about added matter; but in the light of my construction of the claim it does not arise.

Infringement

59. As I have said, the Zeno device is marketed as a treatment for acne. It is a hand held, battery operated device designed to apply heat to an acne lesion at a controlled temperature for a metered duration of treatment. The device is manufactured for a US company and marketed extensively in the US. One consequence of this is that temperatures are measured in degrees Fahrenheit rather than Celsius. I have used the Celsius equivalents. The way the device works (so far as relevant to the question of infringement) is broadly as follows. It is activated by pressing a power button. After about a minute a green flashing light is seen. The green flashing light is pressed to initiate treatment. The metal treatment tip is placed on the acne spot and held there for the 2 ½ minute treatment cycle.
60. The function of the metal treatment tip is to act as a hotplate. It is heated by heat producing resistors powered by the batteries; and a thermistor measures the temperature of the metal treatment tip to within 0.28^oC. Unless the device fails the maximum temperature of the metal treatment tip during each of the treatment cycles is 48.33^oC. The temperature of the metal treatment tip at the time the green light starts flashing is designed to be approximately 46.67^oC. After the green flashing light is pressed the temperature of the metal treatment tip gradually rises during the first 60 seconds of the treatment cycle. After the first 60 seconds of the treatment cycle the power to the heat producing resistor is interrupted for a short period so as to reduce the temperature of the metal treatment tip by 0.56^oC. When the heat supply is resumed the temperature of the metal treatment tip initially rises rapidly and then maintains a more or less constant temperature for the remaining 90 seconds of the 2 ½ minute treatment cycle. The temperature to which the metal treatment tip rises (and at which it remains more or less constant) is approximately 0.28^oC lower than the maximum temperature during the first 60 seconds of the treatment cycle (i.e. approximately 46.4^oC). During the 10 second interval between the end of the first treatment cycle and the start of the second, the temperature of the metal treatment tip rises by about 0.56^oC.
61. Thus, during the second treatment cycle the temperature of the metal treatment tip is higher than in the first treatment cycle, both at the start of the cycle and at any corresponding point in the cycle. However, the second treatment cycle follows the same pattern as the first. A third treatment cycle follows the second. Again, during the third treatment cycle the temperature of the metal treatment tip is slightly higher than the temperature attained in the second treatment cycle.
62. The rather imprecise language of the product description was supplemented by temperature graphs which were more precisely measured and drawn. The Zeno device is set so that the temperature of the metal treatment tip cannot exceed 119^oF (48.3^oC). However, as measured by Mr Yee there were occasions on which this limit was exceeded (albeit by a very small margin). Typically the device operated at temperatures between 47.5^oC and 48.3^oC.
63. On the basis of my construction of the claim, the Zeno device maintains its temperature for longer than 12 seconds and thus falls outside the claim. It also operates at too low a temperature to fall within the claim.
64. Mr Vanhegan also submitted that it had not been demonstrated that at the temperatures at which the Zeno device operated it had any beneficial effect at all on the consequences or symptoms of insect stings or bites. On the contrary the evidence was that the application of wet heat (i.e. a hot bath) at 40^oC to 45^oC can exacerbate an inflammation. The Zeno device operates at only two or three degrees above that bracket. Moreover Professor Friedmann said that the application of dry heat rather than wet heat was less efficient at transferring heat to the skin. So it cannot be assumed that the application of dry heat at a temperature of two or three degrees above the range of temperatures at which wet heat can exacerbate symptoms would have any different effect. Mr Burkill accepted that the evidence that the Zeno device had any beneficial effect on the consequences or symptoms of insect stings or bites was thin. In fact it was non-existent. Neither expert had addressed the question. The best Mr Burkill could do was to show that one of the pieces of prior art was marketed as an "itch stopper" on the basis that the user could select a temperature of operation which could be as low as 45^oC and as high as 51.5^oC. But there was no evidence that the prior art device worked at that low temperature. In effect Mr Burkill invited me to infer that the Zeno device would have a beneficial effect at its operating temperature. In view of the relative lack of knowledge about the precise temperatures at which the application of heat can produce a beneficial effect (and in view of the experts' scepticism about the whole theory on which the patent in suit is based) I think it would be foolhardy to draw any such inference. The fact is that Professor Friedmann did not himself suggest that the Zeno device would have any beneficial effect on the consequences or symptoms of insect stings or bites; and there was no other positive evidence to that effect. It is for Riemser to discharge the burden of proving infringement; and I hold that they have failed to do so. It has not been proved that the Zeno device is capable of treating the consequences or symptoms of insect stings or bites.
65. Accordingly the Zeno device does not infringe.

The prior art: novelty

66. There was only one piece of prior art relied on as anticipating the invention claimed by the patent in suit: a patent application (CN 1,113,747A) made by Dr Li in 1995 ("Li"). The test for anticipation is whether the prior inventor's publication contains a clear description of, or clear instructions to do or make something that would infringe the patentee's claim if carried out after the grant of the patentee's patent. To anticipate the patentee's claim the prior publication must contain clear and unmistakeable directions to do what the patentee claims to have invented: General Tire and Rubber Co v Firestone Tyre and Rubber Co Ltd [1972] RPC 457.
67. The principal issue arising in relation to Li was whether it disclosed a timer. As I have said, Li was a patent application. The original was in Chinese and we all worked from a translation. The quality of the English was not of the highest, and that made the task of understanding the details of Li more difficult. The object of Li was:

"to provide a high effective thermal skin itch-relieving and therapy apparatus which can generate temperatures of 52^oC – 59^oC and heat discontinuously so as to overcome the above defects."

68. The technical solution proposed was an apparatus for relieving itch by heating including a power supply inside a case, including a heater at a port of the case, a temperature controlling electronic heating device which consists of a thermal probe inside the heater, a temperature selection switch, a temperature controlling circuit "and can cause the heater to generate temperatures of 52^oC – 59^oC and heat discontinuously". The heater is a triode transistor and the thermal probe is a thermistor provided inside the triode transistor. The heater is of PTC heating material, and the thermal probe is an electric contact thermometer and provided in the PTC heating material. The specification continues:

"In the technical solution of the invention, a net can be provided at the port of the case and a connecting rod system can be provided inside the case consisting of a connecting rod connected with the heater, a cam, a transmission means and a control circuit."

69. The specification then describes the general method of operation of the invention:

"In the invention higher temperatures of 52^oC – 59^oC or 53^oC, 55^oC, 57^oC, 59^oC are employed. However, the heater heats discontinuously, i.e. heats to 1 – 3 seconds and then stop[s] heating for about 1 second every time. Thus the skin will not feel sharp pain, and the surface layer of the skin (the layer where the mast cells exist) can be heated to a desired temperature rapidly in ¼ second. The desired temperature can be maintained for a period so that the mast cells temporarily [lose] an ability to release the itch factors and swelling factors, and thus the itch can be relieved. Meanwhile deep [tissues] of the skin (deeper than Dermis) are still maintained at a safe temperature and will not be hurt. When the invention is applied to heat discontinuously for about 20 seconds, the skin itch can be relieved immediately."

70. The specification continues by referring to a number of figures. Two of the figures are described as a circuit diagram of one of the embodiments of the invention. The specification proceeds to describe the first embodiment of the invention. It first describes how the heater is controlled and activated, concluding this part of the description by saying:

"When the triode T₁ as the heater reaches a selected temperature and maintains constant (± 0.5^oC), a light emitting diode LED₁ lights up, indicating a set temperature is reached."

71. The grammar of that sentence is obscure. It continues:

"A net can be provided at the upper port of the case 7, and the triode T₁ is positioned inside the net. A connecting rod system is also provided inside the case 7 which consists of a connecting rod connected with the triode T_1, a cam, a transmission means and a control circuit. The connecting rod can cause the triode T₁ to extend to the net automatically and be heated for 3 seconds when the triode T₁ reaches a set temperature and contracts back into the case for 1 second when triode T₁ drops below the set temperature. This process is repeated. If the triode T₁ does not reach the selected temperature, it cannot extend to the net."

72. It was common ground that the circuit diagram which Li said described this embodiment did not show any means of discontinuous heating for pre-determined periods. As Mr Yee put it in his second report:

"However, there is nothing in the circuit diagram shown at Figure 3 that would enable discontinuous heating of the sort envisioned by Li (other than by manually switching the circuit on and off)."

73. Professor Ivey agreed. He said:

"In fact, the temperature controlling circuit in Li has no concept of the passage of time: it is a purely analogue circuit that switches the heater on and off depending on its temperature."

74. But at that point the experts' views diverged. Mr Yee said:

"However, Li specifically states that discontinuous heating must be achieved. Li is therefore telling the skilled person that the device should additionally include a timer circuit to work alongside the bridge circuit set out in Figure 3. Such electrical time controlling circuits were readily known and widely used by medical device technicians as at 1999. The workings of such timer controls would not need any explanation to a technician as they could readily be acquired from a number of suppliers and/or wholesalers "off the shelf". Time controllers of this type were as at 1999 and indeed had been for many years widely used in medical devices."

75. Professor Ivey on the other hand said:

"As a result, there is no device in Li that controls either the duration of the heating/cooling phases of the heater (which is dictated by the properties of the circuit components and operating conditions), or the duration of maintenance of the working temperature of the heater: that temperature would fluctuate between the lower and upper thresholds (as described above) for as long as the device is switched on."

76. Mr Vanhegan put a rather different case in cross-examination, which focussed on the description of the net, the connecting rod and the cam mechanism. Professor Ivey agreed that this described a mechanism by which once the triode has reached a set temperature it is extended to the net for three seconds and then contracts back for one second when the triode drops below the set temperature. However, he did not agree that this would be achieved by a timing circuit. He envisaged a circuit that measured temperature in the way that the illustrated circuit did, and then in some way operated a motor and a cam that allowed the heater to go in and out. But he did agree that whatever circuit operated the connecting rod and cam would have to be a different circuit from that illustrated in Li. So far as the period of 3 seconds on and three seconds off were concerned, Prof. Ivey thought that what Li was reporting was merely what he observed when he switched it on given the particular choice of components that he had made rather than the intended duty cycle on/off period.
77. Mr Yee did not refer to this passage of the specification in either of his two reports. In the course of his cross-examination he did, however, give some evidence about it. The net, he said, could be any substance that would hold heat (e.g. a piece of cloth or nylon mesh). The net was not the same as the triode, so that the net was not itself the heater or hotplate. His reading of the relevant passage in the specification was that the triode was moved forward to the net and the net itself was heated for a period of three seconds, following which the triode contracted back into the case for one second. His cross-examination continued:

"A. T₁ is maintaining a relatively constant temperature, as we discussed, but from my reading the net is apparently receiving heat for 3 seconds and not receiving heat for 1 second.

Q. So you are saying effectively that when the triode is hot it goes out and heats up the net?

A. That is my reading.

Q. Then it retracts and gets cool again?

A. The net cools when T₁ is retracted.

Q. The net is varied in temperature depending whether the triode is touching it or not?

A. That is my reading of the text."

78. He added that "the temperature of T₁ … should be relatively constant as controlled by the control circuit." A later passage of his evidence went like this:

"Q. Although the net may get hotter and cooler. The heater is maintained at a constant temperature but it is going to be like dabbing it off your hand?

A. I believe, to use Dr. Ivey's good analogy, it is like somebody taking an iron on and off of your shirt.

Q. But the iron is going to remain at a constant temperature?

A. I believe so."

79. There are, in my judgment, two real difficulties in holding that Li anticipates the patent in suit. The first is that the reading now relied on was not one that seems to have occurred either to Mr Yee or to Professor Ivey when they prepared their reports. If it did not occur to either of these experts it is difficult to say that the skilled reader would understand that Li contains "clear and unmistakeable directions" to make something that would infringe the patent in suit. Second, the reading now relied on envisages the net being heated for 3 seconds and cooled for 1 second, with the heater being maintained at a relatively constant temperature. The length of time for which the heater remains heated is determined by the user rather than by the device itself. However, the claim in the patent in suit requires the hotplate (or heater) to be maintained at the maximum temperature for 2 to 12 seconds. Li does not disclose this feature.
80. I conclude, therefore that Li does not anticipate the patent in suit.

The inventive concept

81. Mr Vanhegan argued that it is the dual control of maximum temperature with time that is the heart of the alleged invention. I agree that this is undoubtedly part of the invention; but in my judgment the inventive concept of the patent in suit is that both the temperature at which heat is applied and the duration of the application of heat are controlled by the device itself rather than by the user. As Mr Burkill put it, it has both a thermostat and a timer. The prior art relied on the user to control the length of time for which heat was applied. He or she would apply heat until either the itch stopped or the pain caused by the heat became too great for comfort (what Professor Friedmann called "the ouch reflex").
82. The cited prior art was Li (already mentioned), a device manufactured by Dr Li called the Itch Stopper and a patent application (FR 2 746 296 A1) ("Lombal"). They all worked in much the same way as the device described in Li, that is by applying heat and relying on the "ouch reflex" to limit the duration of the application. It is not, I think, necessary to describe them further.
83. The short question is: would it have been obvious to add a timer to the prior art? It is not disputed that if the idea of adding a timer had occurred to the skilled reader confronted with the prior art, and he had decided to implement it, the implementation of that idea would have been simple and would have used well-known technology. So the real question is: would the idea of adding a timer and the decision to implement that idea have been obvious?
84. Both the medical experts agreed that, although the treatment of insect bites and stings by the application of heat was not an accepted method of treatment they would not have dismissed the prior art out of hand as being the medical equivalent of a perpetual motion machine. They would have been interested in the prior art.
85. The first limb of the obviousness attack was the allegation that the claimed invention was completely useless or, if not completely useless, was a backward step in relation to the prior art. For the legal underpinning of this submission Mr Vanhegan referred to a passage in Blanco White: Patents for Inventions which reads as follows:

"A wrong theoretical explanation in the specification of the working of an invention will not itself invalidate a patent, provided that persons wishing to make practical use of the invention are not misled by it. This is so notwithstanding that the untrue statements might to a scientist amount to a promise of results that he would know would not be fulfilled, or that they might (with later spreading of more accurate knowledge) become at some later time misleading to practical men.

The position is different, however, if the whole theoretical substratum of the invention is wrong, so that the invention is nonsensical. It seems best to regard such cases as akin to "selection" cases: i.e., cases where all the patentee has done is to select one special form of, or make a minor alteration to, an old article or process. If, as his specification suggests, some unexpected advantage results, then his patent may be good though at first sight the invention seems trivial; but if his explanation of the superiority of his invention is nonsense, then the patent will be bad even though there is no definite promise to be unfulfilled, because if the theory goes nothing is left but a trivial "invention"."

86. However, this passage was written in the context of the Patents Act 1949 under which lack of utility was a ground of objection. In any event, "nonsense" sets the bar high; and neither expert went that far so far as the underlying theory of heat treatment was concerned. Moreover even if the explanation of the mechanism by which the treatment worked (i.e. the neutralisation of poisons) was wrong that would not, as Mr Burkill submitted, have prevented or deterred anyone from making or using the device claimed. But Mr Vanhegan had another way of putting this point. He said that the narrower theory underlying the claim was that a device operating within the time and temperature parameters claimed in claim 1 was stated in the specification to be a product that was both effective in treating bites and stings and also safe to use. In fact the evidence was that if the device operated at some of the temperatures claimed in the claim (e.g. 65^oC for 2 seconds) it would be very likely to burn the user. Thus it failed to achieve one of its twin objectives, viz. to be safe (or, in the language of the specification, "without, at the same time, skin irritations occurring that are attributable to the exposure to heat").
87. One of the grounds on which a patent may be revoked is that the invention is not a patentable invention: Patents Act 1977 s. 72 (1) (a). Bundled up in this description are a number of different features. For example an invention may not be patentable because it is not new; or because it is not capable of industrial application or because it does not involve an inventive step. If, in Mr Blanco White's words, an invention is "nonsensical" it would, I think, be disqualified from being a patentable invention not because it did not involve an inventive step, but because it was not capable of industrial application. That is the ground on which applications to patent perpetual motion machines are rejected. The mere fact that a claim fails to achieve its object as set out in the specification does not, in my judgment, prevent what is claimed from being patentable. Nor, in my judgment, does the law prevent someone from claiming an invention that is not safe to use. In my judgment, therefore, this ground of objection fails.
88. The other limb of Mr Vanhegan's attack, based on a more conventional approach to obviousness, was diametrically opposed to the first. Far from saying that it was useless to add a timer, he said that it was obvious to do so. As mentioned the prior art relied on the "ouch reflex" to prevent users from burning themselves. If a timer were added its only utility in the majority of cases would be to override the "ouch reflex", because if the user felt pain before the timer cut out he would simply remove the device from the skin. Dr Behrens thought that adding a timer might itself be dangerous because it might encourage users to use the device for too long. As he explained in his oral evidence:

"If you tell an individual that this must be used for this specific time, they would use it even against their pain and discomfort for that specific time as per instruction by the individual. Theoretically, it could work the other way and certainly there are times that I have seen people injured because they have misfollowed an instruction and not done the sensible thing, which was to stop the treatment when pain and discomfort has occurred."

89. He also explained that given the length of time that the application of heat would need to cause damage was itself uncertain, it would be difficult to predetermine the length of time that a timer would have to operate. He added:

"My real question is whether a timer is at all necessary with the concept that the [ouch] factor in the control and the benefits of total duration of dose have not been shown and that they may have been working perfectly well without a timing mechanism and therefore it was an unnecessary step."

90. He summarised his position in the following exchange:

"MR. JUSTICE LEWISON: Can I just make sure I have understood this. One of your concerns about adding a timer to a device like Lombal is that for some people, it will override your ouch response whereas if you are reliant entirely on the ouch response in using Lombal, then it will work.

A. It will work. Well, it will provide the maximum heat without causing damage.

Q. So there is no reason at all to add a timer to Lombal. It detracts from it.

A. Yes, I accept that."

91. In the light of that evidence it seems to me that if anyone had had the idea of adding a timer to the prior art it would not have been obvious to put the idea into practice. There would have been no motive to do so. In so far as the prior art worked at all, it worked without a timer, relying solely on the "ouch reflex" to prevent damage to the users of the devices; and the introduction of a timer might have had serious deleterious effects. Whether it did or not would depend on the temperatures and the durations for which the timer was set. These dual parameters were not part of common general knowledge and the prior art gave little guidance. Mr Vanhegan put to Professor Friedmann some classes of user who might be assisted by a timer (the stoical, the masochistic and the elderly) and to some extent Professor Friedmann accepted that for these classes of user a timer might be a good idea. But that, to my mind, came nowhere near establishing that it was obvious to add a timer to the device. As Mr Burkill put it, there would have been pros and cons in adding a timer.
92. In my judgment therefore the obviousness attack fails.

Unjustified threats

93. The action began in response to a letter sent by Riemser's German patent attorneys (who were not acting on behalf of the First Defendant BSM-Bionic). It was sent to a large number of Boots stores who were stocking the Zeno device; and to other retailers in Europe. The letter set out the patent in suit and continued:

"Our client has now found out that your company offers in the United Kingdom under the trademark Zeno a medical device for the treatment of acne which is also based on the principle of the application of heat over a specific period of time …

Up to this point we cannot see any difference to the technical solution for which our client was granted protection, all the more so since the temperature range is also within the limits of the range that is protected by the patent, and the patent discloses a lower limit in respect of the period of time.

…

For this reason, we should like to request you to let us know why you are of the opinion that you need not take into consideration the patent of our client when marketing the product Zeno."

94. Section 70 of the Patents Act 1977 as amended provides (so far as relevant):

"(1) Where a person (whether or not the proprietor of, or entitled to any right in, a patent) by circulars, advertisements or otherwise threatens another person with proceedings for any infringement of a patent, a person aggrieved by the threats (whether or not he is the person to whom the threats are made) may, subject to subsection (4) below, bring proceedings in the court against the person making the threats, claiming any relief mentioned in subsection (3) below.

(2) In any such proceedings the claimant or pursuer shall, subject to subsection (2A) below, be entitled to the relief claimed if he proves that the threats were made and satisfies the court that he is a person aggrieved by them.

(2A) If the defendant or defender proves that the acts in respect of which proceedings were threatened constitute or, if done, would constitute an infringement of a patent –

(a) the claimant or pursuer shall be entitled to the relief claimed only if he shows that the patent alleged to be infringed is invalid in a relevant respect;

(b) even if the claimant or pursuer does show that the patent is invalid in a relevant respect, he shall not be entitled to the relief claimed if the defendant or defender proves that at the time of making the threats he did not know, and had no reason to suspect, that the patent was invalid in that respect.

…

(5) For the purposes of this section a person does not threaten another person with proceedings for infringement of a patent if he merely –

(a) provides factual information about the patent,

(b) makes enquiries of the other person for the sole purpose of discovering whether, or by whom, the patent has been infringed as mentioned in subsection (4)(a) above, or

(c) makes an assertion about the patent for the purpose of any enquiries so made."

95. It is common ground that Tyrell qualifies as a "person aggrieved". It is also common ground that whether a threat has been made depends on how the communication would be understood by an ordinary reader in the position of the recipient of the communication. It is also common ground that a threat may be explicit or implicit. In L'Oreal (UK) Ltd v Johnson & Johnson [2000] FSR 686 Lightman J said that a threat may be "veiled or covert, conditional or future". These propositions are established by authorities that pre-date the amendment to section 70. Sub-section (5) was one of the provisions introduced by the amendment. The reasonable reader must now, I think, be taken to be aware that communications will not amount to threats if they do no more than is permitted by that sub-section. On the other hand, the very fact that subsection (5) is an exception carved out of section 70 (1) leads to the conclusion that, if a communication does not fall within that subsection, the meaning of "[threatening] proceedings" must be a wide one. On the basis of my construction of the patent in suit, Riemser has not proved infringement, so that subsection (2A) does not apply.
96. In the present case:

i) The letter did not mention proceedings or explicitly threaten them;

ii) The letter asserted that "up to this point" the writer could see no difference in the technical solution; but contained a request for the reason why the recipient thought that it need not "take into consideration" the patent;

iii) The writer of the letter was not an English lawyer to whom the conduct of proceedings about patent infringement in England would usually be entrusted.

iv) On the other hand, the letter was not addressed to the manufacturer of Zeno, nor even to Boots head office. It was sent to the stores that were actually stocking the product.

97. The packaging in which the Zeno product was sold displayed the name and address of the manufacturer in Houston Texas and its UK distributor.
98. The writer of the letter knew who had manufactured the Zeno device; who had imported it and who was offering it for sale. So the purpose of the letter cannot have been to discover who was infringing the patent (if indeed it was being infringed).
99. Was the "sole purpose" of the letter to discover whether the patent had been infringed? If the writer of the letter were genuinely concerned to ask about some technical characteristic of the Zeno device that would point out a difference between that device and the device described in the patent the obvious person to write to would be the manufacturer. Why should the retailer know the technical details of what it sold? And even if the retailer did know, surely the relevant person would be someone in head office responsible for Boots' corporate decision to stock it rather than any individual store manager. Why, then, were the letters sent to the retailers? The only answer must be to persuade them to stop selling the Zeno device. It partially succeeded in that objective. In my judgment that means that it cannot be said that "the sole purpose" of the letter was to discover whether the patent had been infringed.
100. It is true that the letter made assertions about the patent; but it also made assertions about the Zeno device.
101. Mr Burkill objected that no evidence had been called from Boots to show how they interpreted the letter. I do not think that matters. In Mannai Investment Co Ltd v Eagle Star Life Assurance Co Ltd [1997] AC 749 the question was whether a notice given by a tenant to a landlord was valid to terminate a lease. Lord Steyn said:

"The question is not how the landlord understood the notices. The construction of the notices must be approached objectively. The issue is how a reasonable recipient would have understood the notices; and in considering this question the notices must be construed taking into account the relevant objective contextual scene."

102. In my judgment the same applies here. It is not a question of how Boots understood the letter; but how a reasonable person in the position of Boots would have understood it. Read in context, through the eyes of a retailer, the letter amounted, in my judgment, to a veiled threat of infringement proceedings.

Result

103. The patent in suit is valid but not infringed.
104. Riemser (but not BSM-Bionic) is liable for unjustified threats.
105. I will hear discussion on the form of relief to be granted. In principle I am prepared to grant a declaration of non-infringement; a certificate of contested validity; and an order for an inquiry into damages.