CH 1995 H No. 3456
Neutral Citation Number: [1997] EWHC 370 (Pat)
IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT
Date: February 6, 1997
Before: THE HON. MR. JUSTICE LADDIE

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B E T W E E N

HOECHST CELANESE CORPORATION
										Plaintiff

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(1) BP CHEMICALS LIMITED
(2) PUROLITE INTERNATIONAL LIMITED
										Defendants

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Mr. Antony Watson QC and Mr. Andrew Waugh instructed by  Taylor Joynson Garrett for the Plaintiff
Mr. David Young QC and Mr. Guy Burkill instructed by Bird & Bird for the Defendants

Hearing dates: 20 - 24, 28 January, 1997

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JUDGMENT

Mr. Justice Laddie: In this action, the plaintiff, Hoechst Celanese Corporation, sues the defendants, BP Chemicals Limited and Purolite International Limited, for infringement of European Patent (UK) No. 0,196,173. The defendants have counterclaimed for a declaration of non-infringement and for revocation. At the beginning of the trial there was also before the court an application to amend the patent by limiting the scope of the claims. Because of possible problems related to the provisions of s. 63 of the Patents Act 1977, Mr. Watson QC, who appeared on behalf of the plaintiff, invited me to consider the issue of amendment separate from the other issues in these proceedings. That course was not objected to by Mr. Young QC who appeared on behalf of the defendants. Neither the defendants nor the Comptroller, who was not represented before me, raised any objection to the amendments sought and, having read all the relevant material, I gave leave to amend. All the witness statements, experts reports and skeleton arguments dealt with the issues in this case on the assumption that the patent would be amended. Save where otherwise expressly stated, in this judgment all references to the patent will be to the amended form.

The patent is concerned with the removal of alkyl iodides from acetic acid. Originally it had been concerned more generally with the removal of iodides from non-aqueous organic media. In certain, but not all, processes for the manufacture of that acid, the product will contain very small quantities of iodide compounds. One of the major uses for acetic acid is the production of vinyl acetate (“VA”). The manufacture of the latter compound is conducted in the presence of a catalyst made of palladium. It has been found that the catalyst is poisoned or deactivated in an irreversible manner by even very low levels of iodide compounds in the feed reagents. Removal of iodide from those sources of acetic acid which contain it as a very low level contaminant therefore makes the acid suitable for use in VA manufacture. In essence the method of iodide removal which is the subject of the patent consists of passing the contaminated acetic acid through a bed containing a particular type of synthetic resin which has been loaded with silver or mercury. The effect of the bed is to protect or guard against iodide coming through into the acetic acid final product. It is therefore frequently referred to as a “guard bed”.

The first defendant employs at its Hull plant a process for making acetic acid in which small amounts of iodides are unwanted contaminants. A guard bed containing silver-loaded resins has been in use since at least 1990. Those resins are identified by the code numbers CT 145 and CT 175. It is not in dispute that, if the patent is valid, the latter resin infringes some at least of the claims. Infringement by CT 145 is disputed. Furthermore the defendants say that the patent is invalid. By the time of the trial, the attack of invalidity was restricted to an argument of obviousness based on an article which was referred to throughout the trial as “Hingorani” after the name of one of its authors, and common general knowledge. Consistent with the thrust of the defendants’ witness statements and expert reports, Mr. Young confirmed on the first day of the trial that the defendants were not alleging obviousness on the basis of common general knowledge alone. 
Technical background.
To understand the issues which arise in this action it is useful to have in mind some of the technical background. An ion exchange resin is a polymer containing ionic functional groups, that is to say active groups of atoms which together carry an electrical charge. The functional groups are bound to atoms or groups of atoms called counterions by electrostatic forces. When the resin is placed in a fluid medium containing different counterions, those bound to the polymer can be exchanged for those in the fluid medium. This process is called ion exchange. When the functional groups on the resin carry a negative charge (called “anionic”), they will bind ions which carry a positive charge (called “cationic”). Such a resin will therefore enable the exchange of the cationic ions and, as a consequence, is called a “cationic exchange resin”. On the other hand if the resin contains cationic functional groups, it will bind, and allow the exchange of, anionic ions. It is called an “anionic exchange resin”. A well known example of the use of ionic exchange resins is in domestic water softeners. The purpose of such softeners is to take out of the water supply those molecules which make the water “hard”. These are various calcium salts. If water containing calcium (cationic) ions is trickled through an ion exchange resin which contains sodium ions (which are cationic) bound to anionic functional groups, the calcium ions are exchanged with the sodium ions. The calcium salts are thereby turned into equivalent sodium salts. The sodium salts are soluble in water, so the water is now “soft”. Eventually most of the sodium ions on the resin will be exchanged for calcium ions and the resin will not work any more. At that stage the water softening capacity of the system can be regenerated by passing a very strong brine solution (i.e. a strong solution of Sodium Chloride) through the resin. Now the preponderant sodium ions replace the calcium ions. The waste from this washing operation is discarded and the resin once again contains a large amount of ionic sodium ready to soften the next charge of water passed through it. It will be seen that the ions are exchanged over and over again. Ion exchange can only take place if the ions to be exchanged can reach the sites on the ion exchange resin where the exchange will take place. If the resin is in the form of a bead, the overwhelming majority of the sites will be located inside. Therefore the efficacy of the resin will depend on the ions being able to get to the inside so as to get close to the functional sites. 

The resin itself is made from a synthetic polymer. That is to say a mass of very long, frequently interconnected, molecules which themselves are built up by connecting together by chemical reaction large numbers of smaller chemical building blocks. In the 1940's a new class of polymers was developed which employed as the major building block molecules of a chemical called styrene. The manufacture of these polymers also involved the use of minor proportions of a chemical called DVB. This chemical causes cross-linking. That is to say the individual polymer molecules are, to a greater or lesser extent, attached to each other. These resins are amorphous substances with no internal pore structure. If they are made to swell in a solvent, the spaces in the molecular structure also grow. If the resin swells enough, these spaces will grow large enough to allow ions to pass through the molecules. The larger the spaces, the larger the ions which can migrate through the resin. These amorphous resins have been referred to for many years as “gel resins” and, as explained above, their effectiveness is dependent upon being swollen enough to allow the ions to wriggle their way right into and out of the inside of the resin bead. This is essential to their operation.

The extent to which a gel resin can swell and its molecular cavities open up to facilitate ion access is controlled to a significant extent by the degree to which the resin is cross-linked by the DVB. The cross-linking fixes resin molecules in relation to each other. They are braced together. The higher the level of cross-linking, the less the molecules are able to swell on exposure to a solvent. The result is that high levels of cross-linking will prevent a gel resin from being effective for ion exchange. In the worst cases, the ions in the fluid to be treated may only reach the outer surface of the resin beads. Only a trivial fraction of the active sites in the resin are located on its surface. The result is that for all practical purposes the resin will not work. 

There is another way of allowing ion-bearing fluid to gain access to the active sites on the inside of a resin bead. The resin beads can be manufactured in such a way that they are riddled with inter-connecting holes rather like a sponge. The beads may still be made of the same polymer as those used for the manufacture of gel type resins however the interconnected pores built into the beads can facilitate access to the inside. This was described as follows by Dr. Albright, the defendants’ expert, as follows;

“[Another] major breakthrough came in the 1950's when various resin  manufacturers, including Rohm & Haas, developed processes by which  the resin beads were made with an inherent internal pore structure.  These processes are essentially the same as that [used for making styrene-DVB crosslinked gel resins] except that an inert precipitant or  porogen  is added to the  reaction system.  Alcohols are examples of typical porogens.  The  addition of the porogen leads to precipitation of microgel particles  of polymer in the form of  microspheres  during the polymerisation.   The formation and clustering of these microspheres creates a resin  bead containing an inherent continuous pore phase (macroporous phase)  and a continuous gel phase. At Rohm & Haas, this process was called a macroreticular process, and  the resins made from it were called macroreticular resins.”

Professor Dasgupta, the plaintiff’s main expert, agreed. He said;

“I agree that what distinguishes a macroreticular/macroporous resin from a gel resin is the fact that a porogen is used in the manufacture of the macroreticular/macroporous resins.”

As the parties agreed, other  resin manufacturers such as Dow, Bayer and Purolite referred to resins  made by this process as macroporous resins. By the time of the application for the patent in suit, the terms macroreticular and macroporous had become interchangeable. 

It is significant that the polymer used to make the macroreticular resin may be the same as that used in a gel-type resin. However, because the macroreticular resins are made by the porogen process to have an inherent internal pore structure to assist in resin permeability, they can be made of more highly cross-linked polymer than can be used in gel resin manufacture. Even when the polymer itself is significantly more rigid, the existence of the macropores may permit the ions to gain access to the inside of the resin bead. Therefore resins made with a higher DVB content can make effective macroreticular resins even if they are incapable of making good gel resins. 

Since the continuous gel phase of a macroreticular resin is made of the same type of polymer as is used to make gel-type resins, it can expand on exposure to a suitable solvent just as the equivalent gel-type resin would. Such expansion will have the effect not only of expanding the molecular gaps in the gel phase itself (just as it does in gel resins), but will also cause the porogen-generated macropores to expand as well. This is illustrated below;

The permeability of the swollen macroreticular resin is contributed to both by the increase in the size of the porogen-generated pores (so called “macropores”) but also by the increased size of the molecular cavities in the gel phase.

Needless to say, if the solvent is removed from a macroreticulated resin it will shrink in size just as a gel resin would do. That would have the effect of reducing the size of the macropores. However the extent to which the macropores shrink can also be affected by the type of solvent from which they are being dried. If a highly polar solvent such as water is used it tends to bring in the walls of the pores on drying more than if a less polar solvent, such as acetic acid, is used. As a result the dried macroreticulated resin will still have pores, but they will be much smaller than if the resin was dried from a less polar solvent. This extra shrinkage of the pores is sometimes referred to as pore collapse. However, as Dr. Albright confirmed, although the term “collapse” is used, what is really happening in this type of drying is that the pores shrink more but they still exist.

The patent in suit - issues on construction
Claim 1 of the patent reads as follows;

“A method for removing iodide compounds from a non-aqueous organic  medium comprising contacting the medium containing the iodide compounds with  an ion exchange resin characterised in that the resin is a  macroreticulated strong-acid cation exchange resin which is stable in the organic medium and has at least one percent of its active sites in the silver or  mercury form and further characterised in that the organic medium is acetic acid and the iodide compounds comprise alkyl iodides.” 

When this case was opened it was apparent that two points on the construction of this claim  were in issue. The defendants were asserting that CT145 was not “macroreticulated” nor “stable” as those terms were to be understood in the context of the specification. Much of the evidence, both witness statements and experts’ reports, and many of the experiments were directed at these two issues and they were also set out in the parties’ respective skeleton arguments. Once the trial started, much of the cross-examination went to these issues and, in particular, to the question of the meaning of “macroreticulated”. However in Mr. Young’s speech after the close of evidence, the defendants changed tack. They had always accepted that the word “macroreticulated” in claim 1 and the specification was indistinguishable from “macroporous” and now they did not suggest that it had any meaning other than that commonly used in the art, as explained above. In particular, a resin made with a porogen so as always to have pores built into its structure was macroreticular/macroporous. As a consequence it was also accepted that CT145 is macroreticulated within the context of claim 1 of the patent. The result is that the only issue of construction left extant is that concerning the meaning of the word “stable”. 

The patent defines relevant stability in the following words:

“A final characteristic of the resin when used to remove iodide compounds from acetic acid non-aqueous, organic media, and one that is inherent in most ion exchange resins meeting the foregoing requirements, especially when the resin is specifically indicated to be designated for non-aqueous applications, is that the resin is stable in the acetic acid organic medium from which the iodide compounds are to be removed. By the term “stable”, it is meant that the resin will not chemically decompose, or change more than 50 percent of its dry physical dimension upon being exposed to the acetic acid organic medium containing the iodide compounds.” (underlined words added by amendment, struck through words deleted)

The radius ‘r’ of a sphere is related to its volume ‘v’ by the mathematical expression; v = r3. In other words the volume of a sphere increases by the cube power of the amount by which the radius increases. Thus if the radius is doubled, then the volume goes up by 23, i.e. 8-fold. If the radius is quadrupled, then the volume goes up by 43, i.e. 64-fold. If the radius goes up by 50% (i.e. x 1.5), then the volume goes up by 1.53 = 3.375 fold.  An increase in the radius of a sphere will inevitably result in a corresponding increase in the volume of the sphere and vice versa. The crucial question of construction to be answered is what is meant by the patent when it refers to a change of not more that “50 percent of its dry physical dimension”. Is this a reference to changes in the linear dimensions of the resin, i.e. the radius or diameter of the resin microspheres, or is it a reference to changes in the volume of the resin? The difference is of particular importance where CT145 concerned. The claims of the patent are concerned with the stability of the resin as used in the guard bed. That is to say the stability of the resin when loaded with silver or mercury. In one of the defendants’ experiments in reply to measure the change in CT145 in its silvered form when exposed to acetic acid, it swelled in volume by some 86% from its most condensed form. However the change in the linear dimensions, that is to say the diameters or radii, of its microspheres or beads will be much below 50% because of the cube relationship explained above. It follows that if “dry physical dimension” means radius and diameter, CT145 infringes whereas if it means volume, and the method of measurement used in the reply experiment is correct, it does not. 

It is not in dispute between the parties that the task of the court is to construe what the patent and its claims mean to the skilled man in the art. As the defendants put it, the patent is addressed to acetic acid producers as well as VA producers. The skilled addressees accordingly will be chemists or chemical engineers. The patent and its claims are directed to those addressees in language which they are supposed to understand. Unless it is clear from the context that some special and different meaning is intended, the terminology used should be construed to have its normal and generally accepted meaning to that audience. The evidence given by Professor Dasgupta in his first report was as follows;

“Generally understood meaning of "dimension" 
61.  It is a scientific fundamental that "dimension" does not describe a  measurement of volume.  In the case of a spherical resin, dimension  refers to the diameter of the resin.  Contrary to what I understand  the Defendants to be saying, there is no such thing as volume  dimension.  "Dimension" is a specific word.  In Freshman Physics,  students do dimensional analysis.  There are only three dimensions:  distance or length (L), mass (M), and time (T).  All other  measurements are derived from these, for example force equals length  times mass over time squared (LM/T2).  Volume is not a dimension, it  is a measurement of capacity.  All of the fundamental dimensions (length, mass, time) when specified, represent  unique quantities that can only be uniquely arrived at.  A volume of  8 cm3, for example, may represent innumerable possibilities: a cube  of 2 cm on each side, a sphere of 2.48 cm diameter, a sheet of 1 cm  thickness and a 8 cm x 1 cm face, and so on.  In contrast, a  dimension of 8 cm means a length of 8 cm that is uniquely specified.” 

He went on to say that at his office he had two dictionaries which he referred to from time to  time.  They are Webster's New Collegiate Dictionary and  the CRC Handbook of Chemistry & Physics. They both  support Professor Dasgupta’s understanding that “dimension” means a linear measurement,  not a measurement of volume. In addition to this, the plaintiffs’ solicitors conducted a search of dictionary definitions. Every one of the technical dictionaries they consulted supported the Professor’s understanding of the word “dimension”. In fact only two dictionaries were found which defined “dimension” in a way which would have included volume. These were general dictionaries in the Oxford series and in relation to one of these, the Concise Oxford English Dictionary, the 1995 edition deleted “volume” from its definition of “dimension”. None of this evidence, and in particular Professor Dasgupta’s view that it was a scientific fundamental that “dimension” does not describe a measurement of volume was challenged in cross-examination. Furthermore, Dr. Albright did not put forward a contrary view as to the technical meaning of the expression either in his original report or in his supplementary report - which answered and challenged a number of Professor Dasgupta’s views but not those referred to above. Prima facie, and in the absence of any compelling material within the specification itself for coming to a different view, the generally accepted technical words must be given their normal technical meaning. 

However in his first report Dr. Albright set out reason; 

“why I believe the patent in  suit intended the change in  dry physical dimension  of a resin to be  determined by reference to change in volume rather than change in  diameter.”

First he, and Mr. Young in argument, referred to a general passage on page 3 of the specification which reads;

“It is important in the practice of the present invention to use an ion exchange resin with suitable properties. The ion exchange resin should not be of the gel-type. As is known, gel-type polymers are characterized by the fact that their porosity essentially depends upon the volume increase which they exhibit upon exposure to a given solvent system. Ion exchange resins which depend essentially upon swelling for their porosity are not suitable for the practice of the present invention.”

Since in this description of resins which are not within the scope of the invention reference is made to volume increases it is suggested on behalf of the defendants that claim 1 must mean or be referring to the same thing, i.e. volume changes. As explained above, the well-known interrelationship between radius or diameter of a sphere and its volume means that one can easily be calculated from the other. It is schoolboy physics. The fact that the patent in another place refers to volume says nothing about the units used for defining the scope of the patent monopoly. The draughtsman of the patent could have defined permissible swelling of the resin by reference to volume changes  or diameter changes. They would be equally easy to understand and determine. They would be equally consistent with the wording of the specification. Although Dr. Albright says that measuring changes in diameter of a resin bead “directly is not a straightforward matter in itself” (my emphasis), he notes that the plaintiffs have determined it by extracting the cube root of the measured change in volume. He does not suggest, nor could he, that there is anything difficult, surprising or unusual in determining increases in diameter this way.  

Therefore, even if I accept the suggestion that the passage quoted above lies behind the 50% change limitation in claim 1, it throws no light on which are the units chosen by the patentee for measuring or defining that change. In other words the passage relied upon would be equally appropriate whether the patentee had used “change in dimension” to mean changes in volume or changes in diameter. Because of the cube relationship referred to above, either would have been acceptable units for measuring or defining permissible swelling of the resin.

Dr. Albright also says that volume must have been intended because the customer or user of the resin is only interested in volume changes because it is the volume change in going from either  the dry state to the solvent saturated state or between different solvent states that determines the size of the column or bed in which a resin is to be used. However, even if this is so, once again it says nothing about the way in which the patentee has chosen to define the permissible swellability of the resins within his claim.  

Secondly, Mr. Young, again relying on Dr. Albright’s views on construction, pointed to the fact that the patent only referred to one preferred resin,  Amberlyst 15, a resin commercially available from Rohm and Haas, and that the characteristics of that product set out on page 4 of the specification refers to the percentage swelling. Once again I find this neutral. The specification actually refers both to swelling, presumably by volume, and the diameter of beads of Amberlyst 15, expressed as mesh sizes. This again throws no light on the issue of which units the patentee used to define the permissible extent of expansion of the resins within his claim. 

Thirdly, Dr. Albright says that a change in diameter of 50% corresponds to a change in volume  of about 240% (incidentally emphasising the ease with which volume changes relate to diameter changes and vice versa).  He says that although there are some resins which will swell  to that extent in a good swelling solvent, he is unaware of any  commercial strong acid cation exchange resin which will swell  to that extent in acetic acid or any other organic solvent. The burden of this argument is carried by the word “commercial”. It is clear from the evidence put before the court that the range of strong acid cation exchange resins will cover a significant number which will swell more than 240% by volume. The fact that none or few of those have been commercially exploited is of little relevance. Furthermore, to the extent that this is a point at all, it seems to me to help the patentee. It will be noted that the definition of stability in the patent quoted above explains that it is a characteristic which is “inherent in most ion exchange resins” of the macroporous type. It follows that the fact that the plaintiff’s construction would leave within the scope of the patent most relevant resins is consistent with the teaching in the specification. On the other hand if the defendants’ construction is right it would exclude large numbers of resins, which is less compatible with the teaching.

None of these arguments persuades me that the words used in the specification should bear anything other than their proper technical meaning. It follow that the limit in the specification to a resin which does not change more than “50 per cent of its dry physical dimension” on being exposed to the acid, refers to changes in the only relevant physical dimension, namely diameter. If that is so, the defendants concede that CT145 infringes.

Validity
The only document pleaded as prior art for the purpose of the obviousness attack is Hingorani. This short document, published in Chemical Engineering World in May 1977, records some experiments carried out by Dr. S. B. Hingorani and Mr. K. S. Venkateswarlu. for ease of reference, I will treat the document as if it had been written only by one author, Dr. Hingorani. He was concerned to find a way to remove radioactive iodine and methyl iodide from a gaseous environment. However the paper records certain experiments which were carried out in an attempt to remove iodine and iodides from water. Water, unlike acetic acid, is not an organic solvent. The paper sets out certain data and hypotheses relating to how iodide is removed in this system. How the paper, and in particular the data and hypotheses, would or should have been understood and reacted to by a man skilled in the art at the priority date was the subject of a stark difference of opinion amongst the witnesses. Both sides agreed that the paper was poorly written and in parts wrong. The plaintiff said that, having read the data and hypotheses, a notional skilled man would not only not be lead in the direction taken by the patent in suit but would have been discouraged. The defendants referred to the same data and hypotheses and came to precisely the opposite conclusion. Which of these is right is a matter I will return to later. 

During the course of the trial evidence was also given relating to a brief précis of the Hingorani paper which was published in a journal called “Chemical Abstracts”. That document contained none of the relevant data or hypotheses. It was only a few lines long. Although it was published before the priority date of the patent, it was not pleaded as a piece of prior art nor was any attempt made to amend the pleadings to add it as a citation. The possible significance of this document to some of the arguments in this action will become apparent. 

Before considering in detail the obviousness attack, it is necessary to remember what is in issue, what part evidence can play in its resolution and what evidence is probative. The court has the task of determining whether it would be obvious to a notional skilled but uninventive person in the art at the priority date to make or do something falling within the scope of the patent. This is an objective test. In many cases it is also a test which can be viewed as somewhat removed from reality. The defendant identifies particular pieces of prior art and asserts obviousness of the patent over them when considered in the light of the common general knowledge in the art or industry involved. This is the inquiry which s. 3 of the Act imposes. The reason why this is likely to be removed from reality is that in very many fields of technology, developments are in the hands of research teams. The members of those teams do not look at particular pieces of prior art in the light of common general knowledge only. They normally bring to bear not only the common general knowledge but also their experience or knowledge of the results of a large amount of earlier research efforts, most of it highly confidential, conducted by them or other research teams engaged by their employer. One of the advantages of having a research department is that its members can learn from and build upon earlier research which others in the same art are not aware of. Of course if  a third party research team actually hits upon something within the scope of the patent and publishes it, the patent will be invalid, at least to the extent of the overlap. On the other hand if its success is not published, it may provide the third party with a personal defence to infringement proceedings as a result of the somewhat limited provisions of s. 64 of the Act. Furthermore the exercise may well be removed from reality in the sense that the prior art relied on may consist, for example, of a document which none in the art were likely to find. It may be written in a little used language and located in an obscure library. But it is well established law that such a document must be given the same weight in an obviousness attack as any other piece of prior art. The notional man in the art must be assumed to have read and understood it, even if the real man in the art would have done neither.

When the court is considering obviousness, the parties frequently rely upon two types of witness, experts and witnesses of fact. The relationship between the evidence given by these witnesses was considered recently by the Court of Appeal in Glaverbel SA v. British Coal [1995] RPC 155 in which the then Vice Chancellor said:

“The Act requires the court to make a finding of fact as to what was, at the priority date, included in the state of the art and then to find again as a fact whether, having regard to that state of the art, the alleged inventive step would be obvious to a person skilled in the art.

In applying the statutory criterion and making these findings the court will almost invariably require the assistance of expert evidence.  The primary evidence will be that of properly qualified expert witnesses who will say whether or not in their opinions the relevant step would have been obvious to a skilled man having regard to the state of the art.  All other evidence is secondary to that primary evidence.  In the past, evidential criteria may have been useful to help to elucidate the approach of the common law to the question of inventiveness.  Now that there is a statutory definition,  evidential criteria do not form part of the formulation of the question to be decided.

In the nature of things, the expert witnesses and the court are considering the question of obviousness in the light of hindsight.  It is this which may make the court's task difficult.  What with hindsight, seems plain and obvious, often was not so seen at the time.  It is for this reason that contemporary events can be of evidential assistance when testing the experts' primary evidence.  For instance, many people may have been industriously searching for a solution to the problem for some years without hitting upon the allegedly obvious invention.  When this type of evidence is adduced, the court can quickly find itself caught up in an investigation of what was or was not obvious to certain identified individuals at certain dates during the history of the development of the product or process involved.  This gives rise to complications because the state of knowledge of these individuals, though skilled, may not correspond to the statutory definition of the state of the art.  A particular inventor may have been unaware of some aspect of the state of the art as defined in section 2(2). and may therefore have genuinely taken what was actually an inventive step, but nevertheless be unable to claim a patentable invention since the step was, in the terms of the statute, obvious.  Further, this type of evidence invites the court to speculate whether particular individuals were of an inventive disposition, because the earlier making of the same invention by another or others does not necessarily mean that at a later date the invention was obvious.  Yet again, evidence of the commercial success of the invention can lead into an investigation of the reasons for this success; there may be commercial reasons for this success unrelated to whether the invention was or was not obvious in the past. 

Secondary evidence of this type has its place and the importance, or weight, to be attached to it will vary from case to case.  However, such evidence must be kept firmly in its place.  It must not be permitted, by reason of its volume and complexity, to obscure the fact that it is no more than an aid in assessing the primary evidence.”

Evidence of what are said to be contemporary events is not infrequently relied on by patentees and defendants. The former adduce evidence to show that others in the art have sought to find an answer to the same problem as faced the inventor and failed. The latter adduce evidence of others at or about the priority date who found the same or essentially the same answer. The statement from Glaverbel in the passage quoted above that “contemporary events can be of evidential assistance” is subject to the important qualification that its importance and weight will depend on the circumstances of the case. The primary purpose of such secondary evidence is to help the court answer the fundamental question; was it obvious to go from the pleaded prior art to the invention covered by the patent. Unless it throws relevant light on that question, it is at best of little value and at worst potentially misleading. This case included good examples of evidence which failed to assist the court. In both sides’ written statements reference was made to the activities, or assumed activities, of a number of workers in this field at about the priority date of the patent in suit. Notwithstanding indications from me that I had concerns about the relevance of this material, it was relied on during the trial and was the subject of cross-examination. 

The plaintiff suggested that a research team in a company called Halcon Scientific Design Co. which was trying to find an answer to iodide contamination in acetic acid, probably had the Hingorani article before it and failed to come up with the particular combination of silvered or mercurised  macroporous resin which is the subject of the patent. Even if this was true, it was likely that that team was not simply working from Hingorani and common general knowledge. Furthermore, the only evidence touching upon the central question of whether that team had Hingorani consisted of evidence given by way of Civil Evidence Notice by a Dr. Moy. He was given the task of carrying out a literature search by Halcon. He has no document showing that he obtained Hingorani or its abstract, nor does he recall finding either of them. All that he was able to say was that he was confident that he would have seen and retrieved the abstract and that it is very probable that  he would have ordered and studied the full Hingorani article. He says:

“Assuming I did see the article, or the Abstract, I can only think that I did not consider the article of help in solving the contamination problems we were dealing with.”

In view of the fact that this witness’ evidence is so speculative and that the defendants were not able to challenge it by cross-examination, I have come to the conclusion that the plaintiff has failed to prove on a balance of probabilities that the team did have the full Hingorani article in front of it. This episode is therefore inadequate even as secondary evidence in relation to the obviousness issue.

The second category of evidence relied on by the plaintiff consisted of the results of a patent search which was directed at showing that a number of other companies in the art had at about the priority date put forward a number of proposals for the reduction of iodide levels in acetic acid and none of them suggested the use of silvered or mercurised macroporous resins. It was not suggested that any of the inventors of these patents had Hingorani in front of them. It was not shown what other material they had at their disposal. This is quite incapable of being even secondary evidence of value to the determination of the obviousness issue before the court.

The defendants also relied on historical evidence of what had been done at about the priority date in support of their case of obviousness. They asserted that a Dr. Kurland of UCC had developed the same idea as Dr. Hilton, the inventor of the patent in suit, at about the same time. They asserted that this was done “apparently with knowledge of Hingorani”. It is not necessary to consider what Dr. Kurland did or did not do because it is clear that the only Hingorani material which he had in front of him was the abstract, which contains none of the critical data in the paper itself and, as noted above, was not cited as relevant prior art in these proceedings. The fact, if it be one, that a particular researcher working from an unpleaded piece of prior art, arrived at the invention in suit is of no assistance to the court.

The other piece of historical evidence relied on by the defendants consisted of the steps taken by Dr. Hilton, the inventor, to reach the invention. Dr. Hilton was called by the plaintiff and was cross-examined. From time to time the courts have said that the way in which the inventor reached his invention is immaterial. He may think that he has made a marvellous invention or he may have worked out his development by a process which, to him, was entirely logical. But to use what he did and thought he had achieved as evidence for or against obviousness is to put the cart before the horse. Once the court has decided whether the step was obvious it can then assess whether what the inventor did was what the notional man in the art would have done from the pleaded art or not. Evidence from the inventor that he took a long time to make the invention and thought he was very clever is no evidence that he was. Similarly analysis after the event of the logical steps he took to arrive at the invention is no evidence that it is obvious. If he is an inventive man he will no doubt see things more clearly than his notional non-inventive colleague. It would be strange if the fact that the inventor got to the invention was used as evidence that others would also. These propositions seem to me to be supported by cases such as Re I.G. Farbenindustrie A.G.’s Patent (1930) 47 RPC 289 and Allmanna Svenska Elektriska A/B v. The Burntisland Shipbuilding Co. Ltd. (1952) 69 RPC 63. In addition to this, for the same reasons as are set out above, the evidence of what the inventor did or thought is even more irrelevant if he never had before him the prior art on which the defendant is relying. In this case, it is quite clear that Dr. Hilton did not have the Hingorani document at the time he made his development. It appears that he did have the results of a literature search which included a number of documents, including the Hingorani abstract, none of which is relied on by the defendants for the purpose of their obviousness attack.

In the light of these considerations, I have come to the conclusion that all the historical evidence of what individuals did or are thought to have done at or about the priority date is of no assistance in determining whether or not Dr. Hilton’s development was obvious. Furthermore, although there was extensive discovery, including discovery of Dr. Hilton’s research work, very little of it was referred to in court and even the small number of documents which were took the case no further.  This is a great pity because it has meant that the parties have spent much more on this litigation than was necessary and the trial lasted longer than it ought. In saying this, I do not mean to direct any criticism at the lawyers involved. In the absence of clear guidance from the court as to what is or is not admissible or of probative value, the parties and their advisers can not be blamed for covering all the possibilities. Furthermore, in view of what was said by the Court of Appeal in SKM SA v. Wagner Spraytech (UK) Ltd [1982] RPC 497, the fact that the plaintiff felt obliged to give discovery of its research and development leading to the making of the invention can not be faulted. 

However, there is much pressure now to reduce the cost of litigation in general and patent litigation in particular. Parties and the court must be astute to prevent the expenditure of time, effort and money on the filing and challenging of unnecessary evidence and discovery. As the Vice Chancellor said in Glaverbel, secondary evidence on the issue of obviousness must be kept firmly in its place. If the evidence is of no weight it should be excluded from the outset. Evidence that others in the art did or did not make essentially the same development at or before the priority date of the patent should not be given unless it can be shown that those others were starting from or had brought to their attention all or some of the prior art pleaded in the case or the evidence is in some other way really relevant to the issues in dispute. Similarly, although the SKM case provides that documents relating to the inventor’s research and development are discoverable, it may well be that that blanket approach needs refinement. It seems to me that there may well be strong arguments for holding that discovery should not be given of research or development work carried out by the inventor or anyone else if that work did not start from or involve consideration of the pleaded prior art. This is a matter which may need to be considered properly in some future case.

I can now turn to the issues on obviousness. There are two questions which need to be answered: (i) what would the pleaded prior art document convey to the notional skilled man - i.e. what does it mean and promise and (ii) what would be his reaction to it.

Hingorani was looking for a technique which might be used to remove radioactive iodine and methyl iodide from gases circulating in spent fuel reprocessing plants. What was wanted was an “effective and economical means of control to assure negligible exposure from the release of” those radioactive species. It seems to me that the notional reader would assume that he was concerned to obtain the best results possible in the shortest time possible bearing in mind the limitations, if any, of the equipment available to him. After all, he wanted “negligible” iodine or iodide to get past the scrubbing process. The experiments he conducted were not conducted on a contaminated gaseous phase. Instead he used radio-labelled iodine and methyl iodide in water and he exposed this medium to silver impregnated Amberlite IR-120, a readily available gel resin (i.e. not a macroporous resin as required in Dr. Hilton’s patent). The way in which he carried out his experiments is not clearly described, as both parties agreed. The results he got are set out in three tables. The first plots the percentage of iodine absorbed against time. It records, inter alia, that 57.7% of the iodine was removed in the first five minutes, 62.4% in 2 hours, 89.6% in 20 hours and 92.4% in just under 3 days. The table with results for methyl iodide records, inter alia, that 20.4% was removed in the first 5 minutes, 35% was removed in 2 hours, 56.3% in 20 hours and 96.2% in 6.25 days. The author’s comments on the results are very short. He picks out for particular mention the fact that, in the case of iodine, “the adsorption is almost complete in 25 hrs. (1500 min.) and further increase in the time of contact has negligible effect on adsorption”. He then compares that with the adsorption of methyl iodide and notes that the time taken to achieve almost complete equilibrium “as in the case of iodine, is nearly 150 hrs.” It is clear that he is comparing the 25 hrs. for iodine with the 6.25 days for methyl iodide. This poorer performance in relation to methyl iodide is explained as follows:

“This is probably because methyl iodide is not easily hydrolysed in aqueous solution. ATKINS et al., (1966) have also indicated a similar trend for the adsorption of methyl iodide by vegetation.”

No one offered any support for the second of these sentences. Indeed no one could suggest what it meant. However the first sentence appears to be an attempt by the author to explain the comparatively poorer performance of the resin in picking up methyl iodide. The article finishes with a table which compares the percentage adsorption of iodine and methyl iodide by the gel resin with the equivalent adsorption by activated charcoal. Although the resin seems to have worked better than the charcoal, the author notes again;

“The adsorption is however, less for methyl iodide than iodine on Ag-impregnated resin.”

The overall impact of this paper, at least at first reading, is that silvered gel resin removes both iodine and methyl iodide from water but at rates which are quite slow and at an efficiency which only reaches 90 - 95%. Furthermore, as noted above, the performance in relation to methyl iodide is significantly inferior to that with iodine. 

This is to be compared with what was required by those seeking a candidate for a guard bed in acetic acid manufacture. Here very high adsorption rates and removal of about 99.9% of the iodine species are required. In my view there is nothing in this document which would have encouraged a notional man skilled in the art to try what Dr. Hilton did if he was trying to solve the problem faced by acetic acid manufacturers wishing to supply to VA customers. There was no doubt that if the notional skilled worker had considered applying Hingorani’s teaching to the removal of iodide from acetic acid, he would have realised that he was trying to extract from an organic medium. He would also have known that for such mediums a macroporous resin was preferable to a gel resin. But I do not think that the defendants have proved that he would have decided that it was a step worth trying. Both parties agreed that the Hingorani paper was poorly written with a number of significant errors in it. Furthermore, the acetic acid manufacturer would be particularly concerned to reduce the level of methyl iodide in his product, there being at the priority date a number of techniques available for removing iodine itself. Not only are the results of Hingorani discouraging, they are particularly discouraging in relation to methyl iodide. 

In coming to this conclusion I have borne in mind the evidence of Professor Dasgupta and Dr. Albright. They engaged in a minute examination of the Hingorani paper. For example Professor Dasgupta suggested that Hingorani’s hydrolysis explanation for the comparatively poor results achieved with methyl iodide would have particularly put him off trying the same type of process in an organic medium. He said the equivalent reaction in the latter medium, called solvolysis, would be expected to run much more slowly than hydrolysis in water. Therefore if hydrolysis was a rate determining step in the adsorption of methyl iodide in Hingorani’s aqueous experiments, the equivalent solvolysis would have made the adsorption of methyl iodide even slower and less efficient from an organic medium. This was countered by Dr. Albright who said that he thought Hingorani’s hydrolysis explanation was clearly wrong. These issues were then disputed by these experts at every greater levels of complexity. In a somewhat similar vein, Dr. Albright analysed the data in the first two tables in the document and, by reference to some graphs which he produced based on the data in them, suggested that in fact the rate of removal achieved by Hingorani was very fast for both iodine and methyl iodide in the first 5 minutes of the experiments and that the long time taken to get to even the 90% removal level was due to poor experimental technique by Hingorani. This also resulted in an ever deepening and more complex dispute between Dr. Albright and Professor Dasgupta, with the latter pointing out that some of the data in the tables is obviously unreliable and challenging the former’s views as to the speed of the initial adsorption. In my view neither witness was trying to mislead the court. Both were very highly regarded scientists in their respective fields. If Professor Dasgupta exhibited an almost evangelical self confidence, it did not mean that I doubted the honesty or accuracy of his evidence. Similarly Dr. Albright accepted that some of his calculations were in error. But his great competence and honesty were not, and could not be, challenged. However neither of these witnesses really helped me to decide what the notional skilled addressee would have thought. Both came to Hingorani well knowing the issues in dispute between the parties. Both were far better qualified than the notional addressee. Both put forward their views of Hingorani after an immensely detailed analysis of it. Their evidence did not help me one way or the other to decide what the notional skilled worker, unaware in advance of the significance of Hingorani, would have understood its teaching to be. For the reasons set out above, I have come to the conclusion that he would have found the teaching discouraging and would not have thought it suggested a possible way forward to solving the acetic acid problem faced by Celanese and others in the art. 

This conclusion receives some support from the evidence of Dr. Porcelli, one of the plaintiff’s witnesses. He is a chemical engineer who was employed by Halcon between 1970 and 1976. Amongst other tasks he participated in Halcon's activities in developing acetic  acid,  acetic  anhydride and VA processes including economics, research and  commercial development tasks. I found him to be a thoroughly fair and credible witness. He had not seen the Hingorani paper before becoming involved in this action. He gave evidence that the title to the paper “Removal of Radioactive Iodine and Methyl Iodide by use of Silver-impregnated Resin” would have leapt out at him if it had been included in a literature search while he was employed to consider removal of iodides from acetic acid. His reaction to the document once he read it is illustrated by the following passages from his cross-examination;

“A.  My management was expert enough in technology that they probably would have come to the same conclusion that I did. They would have looked at Hingorani and said, "This is not very encouraging.  Try something else."  We are not like  some of the larger companies which have hundreds of people.  We  are a small company.  It was important to choose what we did carefully because we have limited resources.  You cannot  waste it. 
Q.  I understand.  Overall, Dr. Porcelli, we are all trying to  do this with hindsight. 
A.  I realise that.  To tell you the truth, I am probably one  of the most qualified in this room to do it in hindsight  because I did not see this until December.  My impressions, which I  am giving you here, are the same things that I saw in December. Nobody told me what the case was when I saw this article  and asked for my opinion. I am giving you the same opinion  right now.” 

and;
  
“Q.  ...  Looking back, are you not now being far more critical about Hingorani than the more open minded approach which Halcon took in 1984/1985?   The negative demolition  job which is now being done on Hingorani is not the way you  were thinking of. 
A.  No.  If anything, it is because you are causing me to give more attention to it than I would have.  If I had seen it then, I would have dismissed it and that would have been  the end of it.  It was not the first thing we dismissed and not the last thing. The reason I am showing impatience in my  voice is because we are dealing with this dead horse on so many times, and that is why it sounds the way it is. I tell you that in December, when I saw this for the first time, I thought it was a ludicrous article.  I am surprised that it was published because the results are so poor and the method is so poor and inconsistent.  Really,  you do not understand what is going on here.  I do not  understand what "equilibrium" means.  I do not know whether it is "stirred" for sure, or "unstirred".  As to the data, if  you look at the shape of the curve, it is a little bit weird as you have amply pointed out.  It is a strange shape curve  for a kinetic curve.   There are lot of strikes against this  which would make me not too encouraged to try it, the least of  which is that this is methyl iodide from water and my problem is organic iodide from acetic acid.” 

and;

“A.  ...  If I looked at this data in its entirety I would  say this is not very exciting because the rate is 20 per cent  in five minutes, but then not doing anything else and not  really achieving the kind of removal in any kind of reasonable  time; we are talking about 9,000 minutes.  If I proposed that experiment to my boss, he would say, "Do you not have  better things to do than that?" 
Q.  That is 9,000 minutes leaving it.  You are not going to be sitting watching it, I assume, for six days. 
A.  No, but to propose that a system needs that kind of  reaction time to get only 96% when I am looking for a much higher  level of conversion, that is not very encouraging.  Furthermore, when I look at that data, compare it with the iodine data, which you are correctly pointing out looks pretty good,  then hear Hingorani's explanation that methyl iodide needs hydrolysis, that is why it is lower, and I say, "Gee, there  is not too much water in the acetic acid I am going to treat"; that is not very encouraging, is it?” 

Mr. Burkill, who cross-examined Dr. Porcelli also tried to suggest that he would have been embarrassed if he had had Hingorani in front of him and had missed Dr. Hilton’s answer. He also put it to him that carrying out an experiment using macroporous resin would not have involved a large budget. Dr. Porcelli’s evidence was;

“Q.  The expense of heating Hingorani and acetic acid with a  bottle of resin and a bottle of silver nitrate, how much are you going to ask management to budget for that? 
A.  That is not the point. 
Q.  It is your point. 
A.  It is what you are not doing with that time which may be  more productive. 
Q.  But you are not going to sit and watch it, in any event,  are you? 
A.  No.  You have misunderstood.  It is the fact that he has to spend his time trying to duplicate this experiment, which  has poor results, instead of trying an idea that, maybe, would  be more fertile. It is more the cost of not doing something because you are doing this. 
Q.  Looking at it the other way round, let us assume that in  1984 somebody did have Hingorani and showed it to you and you  said, "No, forget that".  Then Hilton comes along, sticks it on Celanese, and Union Carbide comes along and sticks it on  the Union Carbide plant and management calls you in and says, " You had Hingorani, why did you let it go?", how are you going  to justify it? 
A.  They would have said to me, "The Hilton work is very remarkable, is it not?", to which I would have said, "Yes, especially when you look at this article that we found  which shows such poor results.  I am very surprised with Hilton's work.  Maybe Celanese is full of balloney".  I do not know what my management would say.  It is very speculative.”

This evidence can not be taken too far. Dr. Porcelli, like any other witness drawn from the art, could not help but give his answers in the light of his own personal knowledge of this area of technology including the results of research work done by his employers. He admitted this was so;

“A.  I am certain he will.  All I know is that you are asking me  to look closely at this, much more closely than I would have  had I done it at the time.  I cannot do it in a vacuum.  I know what other information I have had.  I have the information  of my industrial practice at Halcon which showed that methyl iodide reaction is slow in organic media.  I have my experience where metals on resins are slower than metals in solution.  I have tried methyl iodide in solution with  silver and it is slow.  It is not a fast reaction.  I know putting metals on supports makes those reactions slower.  To see  this data at face value, I say he has bad rates of reaction.  He never gets complete conversion.  This is perfectly  consistent with the experience I have had at the time that I would  have seen this article, had I done it.” 

  and;

“Q.  What I am putting to you, Dr. Porcelli, is that there are numerous practical approaches to have a look at this, and  say, "Hey, it is a bit slow but rather than throw it away, the obvious thing to do is to have a look and see how I can  speed it up."  Would that not be the case in a practical  laboratory? 
A.  Yes, but if the data was slightly more encouraging; not slightly, if the data was more encouraging.  It is not just one problem.  This is methyl iodide from water.  As I said before and will repeat it again, I  have experience of  silver in solution reacting, trying to react with methyl iodide.   I have experience of silver in water, silver in acetic.  If I do ionic iodide and silver in aqueous solution, the reaction  is almost instantaneous.  That is something I remember doing  in college chemistry in a laboratory.  It was one of the first things we did in the 1970s.  Everyone thinks of silver  first. Silver is very, very obvious.  No one is going to argue  about that.  We tried silver in acetic acid with methyl iodide  and it was terrible.” 

The court cannot surrender its decision on this objective question to the personal approach of one witness. Nevertheless I have come to the conclusion that Dr. Porcelli’s view of Hingorani, reached without preconditioning by knowing what the issues in this action are, is very similar to  the view that the notional skilled addressee would have had at the priority date. Furthermore the extensive and impressive theorising in which Professor Dasgupta and Dr. Albright engaged was a reflection of the fact that the Hingorani article was so unclear as to the experimental technique used and so short on explanations of what was achieved. Its message was so unclear that it left a lot of room for such speculation.

For these reasons I have come to the conclusion that the defendants have not proved that the notional non-inventive skilled addressee who had read Hingorani and was faced with the problem of reducing to very low levels the iodine and iodide content of acetic acid destined for use in VA manufacture would have arrived at a solution within the scope of claim 1 of the patent in suit.

However this is not an end to the argument on obviousness. One of the major failings of Hingorani is that it would not suggest to the notional reader that high levels of removal could be achieved at high speeds in water. It therefore does not suggest that such levels or speeds could be achieved if it was modified by the use of macroporous resins to achieve iodine and iodide removal from acetic acid. That was the problem facing the manufacturer of acetic acid destined for use in VA manufacture. Hingorani did not suggest a solution to that problem. However claim 1 is not limited to such high rates and levels of removal. It is not limited to use in a column or in an agitated solution. It covers precisely the same levels and rates of removals which Hingorani achieved in his aqueous environment. It was not in dispute between the parties that it would have been obvious at the priority date to use a macroporous resin instead of a gel resin once it was decided to apply Hingorani’s technique to organic media, such as acetic acid. 

Since this is so, Mr. Young advanced an alternative argument as follows. Assume, as I have held, that Hingorani would not be used as a starting point for a solution of the problem faced by the manufacturers of acetic acid for use in VA manufacture. That means that Hingorani would not direct the addressee to the bull’s-eye represented by that particularly demanding application for iodide removal. However the target represented by claim 1 in the patent is much larger than that. It would be obvious to go from Hingorani to the ‘magpie’ or ‘outer’ on that target. In other words it would be obvious to go from Hingorani to achieving equivalent rates and levels of removal from acetic acid, and such rates and levels, although of no use where VA manufacture is concerned, is still within claim 1.  If the patentee has defined his monopoly too widely he cannot complain if it encompasses lower levels of technical achievement which are obvious. This argument, if effective, does not address the validity of some of the subsidiary claims in the patent which are more narrowly defined. 

This is a most attractive argument. Mr. Young is clearly right that a patentee who claims widely opens himself up to additional attacks of obviousness. But the onus is still on the party attacking the patent to show why it is obvious to do something even within the outer areas of the monopoly. Prima facie a granted patent is valid. Does the fact that the notional skilled worker would have no difficulty in deciding to use macroporous resins instead of gel resins in applying Hingorani to an equivalent organic system and for the purpose of achieving similar results mean that this is obvious?

Mr. Watson referred me to the decision of the Court of Appeal in Hallen Co. v. Brabantia (UK) Ltd. [1991] RPC 195 in which consideration was given to precisely what was the test for obviousness. At page 212, Slade LJ, giving the judgment of the court, said;

“We nevertheless accept the plaintiffs’ submission that, for the purpose of testing obviousness, one cannot assume that the skilled man simply makes technical trials for the same of so doing.”

Then having referred to three previous authorities, he continued;

“These three last-mentioned decisions, together with some decisions of the Technical Board of Appeal of the European Patent Office which were cited to us, support the proposition that the notional skilled man should not be expected to try all combinations unless he has a problem in mind and particular combinations might assist him in solving it.”

The three authorities referred to were Technograph Printed Circuits Ltd. v. Mills & Rockley (Electronics) Ltd. [1972] RPC 346 (HL), Beecham Group Ltd.’s (Amoxycillin) Application [1980] RPC 261 and Hickman v. Andrews [1983] RPC 147. In Beecham Buckley LJ had said that to prove obviousness over the prior art;

“It must, in my opinion, be shown to be worth trying [the alleged inventive step] in order to solve some recognised problem or meet some recognised need.”  

Similarly in Hickman, Goff LJ said;

“”There is another preliminary question and that is what the expert is supposed to be doing. It cannot be that he is to look to the whole store of his imaginary knowledge and see if it is obvious to turn something therein to better account. He must I think have some definite object in view.”

All of these passages are consistent with the Object/Solution approach to obviousness adopted in the Technical Board of Appeal of the EPO. Even if the step from the prior art is a small one, to prove obviousness it is necessary to demonstrate that there is some reason for taking it. If, in a chemical case, the inventor shows that he reacted A with B to obtain a product which had some extremely desirable properties, that will not be rendered obvious simply by showing that a man in the art knew of A and B and would have realised that they were capable of reacting with one another. It would need to be proved that he would have bothered doing it. 

However in their closing submissions the defendants referred to the decision of the Court of Appeal in Windsurfing International v. Tabur Marine [1985] RPC 59 and, in particular, the following passage;

“No doubt, the philosophy behind sub-paragraph (f) [of the Patents Act, 1949 s. 32(1)] is different to this extent, that a patent is granted only for an invention and that which is obvious is not inventive, but it also must, we think, take into account the same concept as anticipation, namely that it would be wrong to prevent a man from doing something which is merely an obvious extension of what he has been doing or of what was known in the art before the priority date of the patent granted.”

From this the defendants argued that the correct approach is to ask on what principle could Dr. Hingorani (or any of his readers) now be prevented from using a silvered strong acid cation resin in acetic acid, this being a natural extension of his concept. They say that, having looked at Hingorani’s paper, one has to go on to consider what obvious modifications there are, and in particular, whether its application to the removal of methyl iodide from acetic acid is an obvious variant thereof. Although Mr. Young did not put it exactly in this way, there was at least a suggestion that the approach adopted in Windsurfing would render a step obvious even if there was no particular reason for taking it. 

It appears to me that there is nothing in Windsurfing which is inconsistent with the subsequent decision of the Court of Appeal in Hallen. In fact Windsurfing was cited to and quoted from by the court in Hallen. What the court in Windsurfing was dealing with was an argument it believed had been put forward by the plaintiff, namely that it should not assume that the notional addressee has any interest in the cited prior art. It understood the plaintiff to be arguing that even workshop modifications of the prior art would not be obvious;

“If, he suggests, there was no reason for considering Darby to be of any interest, the improvement of Darby, even by what might be considered mere workshop trial and error, would not have been obvious. ...

What he challenges, or what we understand him to challenge, is that Darby would have led to any further inquiry at all, even of a routine or workshop kind ...

... Thus, the argument proceeds, there would not have been any reason for developing Darby and hence no development, even of a routine nature, would have been obvious or even have occurred to the skilled man, who would merely have dismissed Darby as a not very practical toy. It is from this foundation that he goes on to submit that the learned judge asked himself the wrong question and wrongly accepted as evidence of what was obvious the evidence of witnesses as to how Darby might have been improved, for, in suggesting improvements to or embellishment upon that which called for no improvement or embellishment, they were doing so in response to an invitation to treat Darby as a springboard to further development and invention and were in fact suggesting inventive steps.” 

It went on to dismiss this argument and held that what has to be determined is whether what is claimed as inventive would have been obvious, “not whether it would have appeared commercially worthwhile to exploit it.” None of this is inconsistent with or in any way qualifies Hallen. Before a step from the prior art can be held to be obvious there must be some reason why the man skilled in the art would wish to take it. If he has a problem and the step would occur to him as a solution to it, then he has a reason. But there is no requirement that it be demonstrated that the step would have been expected to produce significant commercial advantages. The problem might be very small. The courts will assume that he may just want an alternative way of achieving essentially the same result as in the prior art. Thus mere workshop modifications, none of which would be expected to produce significant technical or commercial benefits are still obvious. To adopt an example sometimes given by Jacob J., if it is known to make a 5 inch plate, it is obvious to make a 51/4 inch plate. Technicians and businessmen frequently want to make trivial variations in established or known products. Similarly if the prior art discloses two wooden parts held together by screws it would be obvious to glue them, even if so doing would not be expected to advance the industry. The notional addressee is likely to want to use materials readily at hand to make essentially the same thing as is disclosed in the prior art. That is sufficient motivation and the use of those materials is, accordingly, obvious. When the defendants argue that Hingorani or any of his readers is entitled to use any “natural extension” or “obvious variant” of his concept, they are correct if by that they mean the type of workshop modification or alternative discussed above. But it was not and could not be suggested by any witness that changing the medium from aqueous to organic and changing the resin was a mere workshop variant of what is set out in Hingorani. 

The fact that Claim 1 is wide enough to cover uses of silvered or mercurised macroporous resin well beyond those necessary for curing the VA supply problem means that the patentee takes the risk of covering uses which are obvious for some other reason. It was not suggested let alone proved that there was any reason why anyone in the art would have wanted to or been lead towards doing anything in the peripheral areas of claim 1. If the claims are wide enough to cover areas which are of no interest to the art, that does not make them bad for obviousness.

In the circumstances I reject this alternative attack on the validity of claim 1. It follows that it is not necessary to consider the attacks made on those subsidiary claims which the plaintiff asserted had independent validity. The patent is valid and infringed and, subject to the effect of s. 62(3) and  63(2) of the Act, the plaintiff is entitled to full relief. 
Framed in good faith and with reasonable skill and knowledge. 
The claims of the patent as originally filed were not limited to extracting iodides from acetic acid. It covered extraction from any organic medium. The plaintiff accepts that a piece of prior art, referred to as “Emken”, anticipated some of the original claims. I have made no finding to that effect and have not been asked to by either side. In any event, it is because of Emken that the plaintiff sought leave to amend the claims and specification. As mentioned at the beginning of this judgment, I gave leave. The plaintiff’s entitlement to relief will be restricted by the provisions of s.63 of the Act unless it can prove that the specification was framed in good faith and with reasonable skill and knowledge. The plaintiff asserted, and the defendants did not dispute, that the specification of the patent was drafted in good faith. There is no material upon which to doubt that. The only question which arises is whether it was also drafted with reasonable skill and knowledge. The meaning of these words was considered in General Tire & Rubber Co. v. Firestone Tyre & Rubber Co. Ltd. [1975] RPC 203, Hallen Co. v. Brabantia (U.K.) Ltd [1990] FSR 134 and Chiron Corporation v. Organon Teknika Ltd. [1994] FSR 458. In particular, in General Tire, in which the same words in the 1949 Act were considered, the Court of Appeal said;

“On this question of good faith in framing a specification one is, we apprehend, basically in a field of inquiry whether the patentee or his agent knew something detrimental to the patent, as applied for in the form in which the patent was framed, which escaped the eagle eye of the examining officer in the Patent Office. If a patent agent puts forward something of which he has no knowledge, which suffers from some fatal imperfection in the patent field, we do not consider that, when the Patent Office accepts it without demur, it can be said that it was framed otherwise than in good faith. It is, after all, the function of a patent agent to argue in honesty for the width of the application.”

Then, in relation to the words “with reasonable skill and knowledge” it said;

“It was argued that even so this showed a lack of reasonable skill ... a patent agent’s office should, it was said, have a foolproof system of checking ‘copying errors’. Here is, we consider, a fallacy in approach. Section 59(3) does not speak of ‘reasonable care’ but of ‘reasonable skill and knowledge’. This we take to be limited to the field of expertise peculiar to those concerned with framing specifications, in no way to refer to mere commonplace slips which are from time to time the fate of those in many fields remote from patent expertise. A particular lack of reasonable care may in any given case exhibit a lack of reasonable relevant skill, but not in every case by any means, and certainly not in the case suggested.”

As Aldous J. said in Hallen, this imposes on the patentee a duty to prove on the balance of probabilities two things; first that the specification was framed in good faith and secondly that it was framed with reasonable skill. The first of these is a test of honesty. It is assessed by reference to what the patentee or his agent actually knew. The fact that there is something detrimental to the patent which a competent patentee would have found out about, but this patentee did not, does not mean that the latter lacks honesty or that the specification is not framed in good faith. Furthermore, taking into account what the patentee knows, the court has to decide whether its framing was carried out with reasonable skill and knowledge. Carelessness is not, per se, enough. The court must ask whether, in the circumstances existing at the time, including what was known about the prior art, a competent patentee or, more usually, patent agent would or could have been expected to frame the specification in the way it was in fact framed.

With that in mind, I can turn to the events surrounding the grant of this patent. The application for this patent originated in the United States of America. The application was sent by the plaintiff to Mr. De Minvielle-Devaux (Mr. Devaux) of Carpmaels & Ransford, the firm appointed as agents for the prosecution through the European Patent Office (EPO). He  carried out an essentially editorial job of rewording the specification so far as necessary to comply with the formal requirements of a patent application being made through the EPO. Once an application has been filed with the EPO, it is subject to a search. The results of that search are then communicated to the applicant or his agent. The search report is a short and formal document. It identifies documents which, at that stage, the examiner has concluded are relevant to the further progress of the application. On the report each of the cited documents is categorised. The report states that category X covers documents which the examiner considers are “particularly relevant if taken alone”. In other words it covers documents which appear to be anticipations. The report also states that category Y is for documents thought to be “particularly relevant if combined with another document of the same category”. It therefore covers documents which, when read with others, appear to give rise to an obviousness attack. There are other categories as well. For example, category A relates to documents which are thought to relate to the technological background of the invention. The search report not only categorises the cited documents but it also identifies the passages in the citations which the examiner at that stage considers to be particularly relevant. The search report does not set out the examiner’s thinking in relation to the citations. Thus if there are five documents in category Y, there is no explanation of which ones should be read together with which others, nor the reasons why the examiner thinks that there may be an obviousness problem. The search report, together with copies of the cited documents, is then sent to the applicant or his agent. That was done in this case. The search report cited four documents. Three of them were identified as category Y citations. One of those was the Emken patent. In other words Emken was not cited by the EPO as a possible anticipation. 

The search report and the citations were forwarded by Mr. Devaux to Mr. Cassady, an Associate General Counsel with the plaintiff who at that time was responsible, inter alia, for the prosecution of patent applications relating to Dr. Hilton’s work both in the United States and abroad. It is not in doubt that neither Mr. Cassady nor Mr. Devaux examined the Emken patent. Furthermore it is not in dispute that the only passage in Emken identified in the search report as relevant to the application’s scope or validity does not constitute an anticipation. On the other hand the plaintiffs accepted for the purpose of these proceedings that had the Emken patent been considered by them or their agents on or shortly after receiving copies, it would have been realised that Example I anticipated some of the claims. 

What the applicant did was to request substantive examination of the application. When that is done the application, citations already found on the search report and any other relevant material which may come to the attention of the EPO is considered by an examining group consisting of three examiners who are experts in the field of technology covered by the invention. One of those three will act as the primary examiner. However his draft report is considered by all of them and the report as finally sent to the applicant has to be acceptable to at least two of the examiners. Once that report is received, and assuming that it contains objections to the allowability of the application, the applicant and its agent are given an opportunity to try to persuade the examiners that the defects do not exist or, where appropriate, to amend the specification so as to remove problem areas or to restrict the claims. In this case the examiners must have considered all the available material, including in particular the Emken patent, and decided that they did not raise an attack of obviousness, let alone anticipation, against the application because they passed the application. Needless to say, with that clean bill of health neither Mr. Devaux nor Mr. Cassady considered the Emken patent at that stage either.

It seems to me that in considering whether this application was framed with reasonable skill and knowledge, it is convenient to consider two periods namely the period from the receipt of the search report until the substantive examination and the period after examination. I can deal with the latter easily. Once it became clear that the examiners, who must have considered the Emken citation, thought that it did not raise any validity issues against the application, it could not have been unreasonable for the applicant to proceed on the basis that it was irrelevant. In fact Mr. Devaux who gave evidence and was cross-examined on this issue said that although he has prosecuted many hundreds of applications through the EPO since it opened for business in 1978, he has never experienced or heard of a case where a piece of prior art which was in fact an anticipation and which had been unearthed during the EPO search was subsequently dropped. Of course the EPO frequently abandons objections based on citations in the search report when, on further consideration, it realises that the objections are unmeritorious. The fact that the examiners decided not to rely further on any of the category Y citations, including Emken, would have led any applicant or agent to the reasonable conclusion, absent knowledge to the contrary, that the citation was not of significance. No criticism can be levelled at the plaintiff in respect of this period.

The heart of the issue is whether the specification can be shown by the plaintiffs to have been framed with reasonable skill and knowledge having regard to the failure by Mr. Devaux and Mr. Cassady or anyone else within the plaintiff to consider Emken after it had been cited in, and copied with, the search report but before the examination stage. 

On this both Mr. Devaux and Mr. Cassady gave evidence. Both were clear, straightforward witnesses who gave their evidence as dispassionately as possible. Mr. Cassady was prepared to accept that he took a risk by not looking at the Emken citation. But neither he nor Mr. Devaux accepted that the system which they adopted in relation to the prosecution of EPO cases was in any way unreasonable. On the contrary, they said that they thought their conduct had been reasonable. 

Mr. Burkill argued that the EPO clearly expects that the patentee will review the citations at the time of sending out the search report as evidenced by the practice of attaching copies of them to the report and precisely identifying relevant passages in them by page and line number. He said that there are sound reasons why a prudent patentee should review the citations when the search report is received. He said that course would save money if the claims are hopeless because it would enable the applicant to abandon his application before the examination stage. He also referred to what were clearly highly theoretical, but in practice, almost completely illusory benefits of amending early following the provisions of EPC rule 86. Finally he said that a patentee who chooses not to review the art himself but relies solely on the EPO Examination Division is taking a risk. That risk may be small, but it is nevertheless a risk, voluntarily assumed. 

I was not persuaded by any of these arguments. There is no doubt that the procedure of supplying a search report first and an examination later provides an opportunity to the applicant to consider the cited prior art early and to make amendments early. In many cases that might be a reasonable course to adopt. But that does not mean that it is not reasonable to take the alternative course of waiting until the outcome of the examination before tackling any problems with the prior art which the EPO may raise. Mr. Devaux gave evidence that it was very rare indeed for him to examine the documents cited in the search report in advance of the examination. He said that there are no clients now, whether large or small, who require him to do that. The reason for that is clear. Some or all of the citations may be dropped as irrelevant by the examiners at the examination stage. That is what happened in this case. It is perfectly sensible and reasonable for the applicant and its agents to decide that the most efficient use of professional time is to reserve investigation of the prior art until the EPO has decided what documents it intends finally to rely upon at the examination stage to attack the validity or scope of the application. If this was not a reasonable course to follow it would mean that all applicants would need to analyse and consider the search report citations even though much of the work involved in doing that would be wasted since it would involve considering citations which the EPO itself would subsequently decide, as in this case, were irrelevant. That would put a quite unnecessary cost burden on applicants. This view applies with particular force to the Y citations. As I have mentioned, the search report does not set out which Y citations are to be read in the light of which other citations nor does it set out the examiner’s reasons for believing the citations give rise to an obviousness attack. That is very different to what happens when an obviousness argument is raised by the EPO at the examination stage. Even if, contrary to my view, it was unreasonable for an applicant and its agents to fail to consider the contents of an X category citation before the examination stage, it is entirely reasonable for them to defer consideration of Y category citations until the examination stages. At that point they will know not only whether the citation is still being relied upon but also why it is said to support an argument of obviousness. It is significant that not only did Mr. Devaux say that it was now his invariable practice not to examine the citations in the search report but to await the outcome of the examination, but the defendants did not call any witness to challenge the reasonableness of taking this course.

Even though Mr. Cassady accepted that there was a risk involved in not looking at the citations on receipt of the search report, that also does not mean that the specification was framed without reasonable skill and knowledge. The risk was that the EPO might cite a clearly invalidating piece of prior art at the search stage and then, after due consideration by an examination team, come to the mistaken view that it was in fact irrelevant. Mr. Burkill described the risk as small. In my view it was minute. The risk of that happening does not mean that the approach adopted by Mr. Devaux and Mr. Cassady was not reasonable. 

It is unfortunate that the EPO, having initially underestimated the importance of the Emken patent, then compounded the problem by jettisoning it as irrelevant. But I have no doubt that it was reasonable for the applicants and their agents to proceed without looking at the Emken patent. The specification in suit was framed with reasonable skill and knowledge.