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Construe Widely and Face Invalidity – Construe Narrowly and Miss Infringements: The Dilemma of Interpreting Patent Specifications

Author: Michael Pendleton LLB, Dip Juris (Syd); LLM (Lon)
Professor of Law, Murdoch University
Issue: Volume 11, Number 3 (September 2004)

Contents

    I. Proper Construction of Patent Specifications

  1. Determining the proper construction or interpretation of a patent specification [1] is directly or incidentally involved in most issues of patent law. Construction or interpretation of a patent specification is vital to determining the validity of the patent as well as infringement of the patent. The claims in the patent specification, duly construed and interpreted, are tested against the relevant prior art base to determine whether the invention possesses the requisite novelty[2] and inventive step[3] for it to granted or pronounced valid. Duly construed and interpreted, the claims in the patent specification additionally define the scope of the patentee's monopoly in the context of an allegation of infringement.

  2. The method of construction the court or patent office employs to interpret a patent specification is crucial to the validity of the patent prior to and post grant in assessing novelty and inventive step.[4] The stricter the method of construction applied the easier it will be for a patent to be found to possess the requisite novelty and inventive step. Using the same method of construction will mean it will be correspondingly more difficult to prove infringement, eg. to show that a variant which does not definitively transgress the claims in a patent specification is an infringement. The corollary is that the more expansive and liberal the approach to construction the more difficult it will be for a patent to demonstrate novelty and inventive step yet easier to prove infringement, eg. by showing that a variant which does not definitively transgress the claims amounts to an infringement.

    II. Methods of Construction

  3. A number of methods of construction of a patent specification have evolved over time in various jurisdictions in the same way as have various methods of statutory construction.Methods of patent construction and statutory construction have tended to evolve in tandem[5] A patent specification is to be construed like any other document[6] having regard to the special role of the claims[7] the fact that a monopoly right is created, and that the document is to mark out the monopoly with sufficient clarity to serve the patentee's purposes and those of competitors. It is to be understood as addressed to a person skilled in the relevant art hypothetically applying their knowledge of the relevant art as at the priority date of the claims[8] Construction is a matter of law for the court and expert testimony is relevant only to the knowledge of the hypothetical person skilled in the art[9]

    III. Approaches to Construction

  4. Methods of construction of a patent specification which tend towards strict constructionism or literalism have been described metaphorically as "fence post" approaches to determining the proper scope of the monopoly and less strict or less literal methods, "sign post" approaches[10] The paradigm "fence post" approach is apparently regarded as that of the English courts under the Patents Act 1949. Paradigm "sign post" approaches are regarded as Civil Law approaches to patent construction[11] Like all paradigms selecting specific examples from the cases is far more problematic.

  5. Since the coming into force of the United Kingdom Patents Act 1977, questions of construction of a patent are to be resolved with regard to Article 69 of the European Patent Convention and its Protocol[12] Article 69 and the Protocol have been said to attempt to formulate a median position between the "sign post" and "fence post" paradigms of United Kingdom and European patent construction[13] . The following traces the doctrine of patent construction evolved in the United Kingdom, Australia and Hong Kong. There are inevitable implications for other jurisdictions.

    IV. Anglo-Australian Approaches to Construction of a Patent Specification Prior to the Seminal House of Lords Decision in Catnic v Hill & Smith

    [14]

    V. The Australian Patents Act 1990

  6. The Australian Patents Act 1990, like the Patents Act 1952 before it, is largely derived (leaving aside its so called "plain English drafting") from the Patents Act 1949 of the United Kingdom. Much High Court of Australia dicta on methods of interpretation and construction of a patent specification apply or approve relevant United Kingdom decisions. The United Kingdom approach to patent interpretation pre the decision of the House of Lords in Catnic v Hill & Smith[15] was of generally regarded as of the "fence post" variety though subject to the well established and easy to state, though more difficult to apply, "pith and marrow" doctrine (discussed below) to be applied in cases of non-textual infringement or colourable evasion. The Patents Act 1949 was repealed by the Patents Act 1977, an Act drafted to give affect to British obligations under the European Patent Convention. As stated above, Article 69 of the European Patent Convention and its Protocol attempts a marriage of the traditional British fence post approach to patent interpretation and the more liberal European sign post approach to patent interpretation.

    VI. Catnic v Hill & Smith in the United Kingdom

  7. The leading case in the United Kingdom is Catnic v Hill and Smith (Catnic)[16] where the patent in suit was governed by the Patents Act 1949. [17]The CIPA Guide to the Patents Act[18] states:

    "Catnic is currently the leading decision as to the criteria for patent infringement, relying on the newly introduced concept of purposive construction of the patent specification. The inter relation of Catnic and the long line of previous authorities on pith and marrow or equivalent (culminating in the Rodi and Wienenberger v Henry Showell decision has not yet been fully worked out.)

  8. In Catnic the relevant claim described a lintel of box girder construction in which the backplate extended vertically from the baseplate. In the defendant’s variant of the lintel the backplate was in one case 6 degrees and in another 8 degrees off vertical, ie. 90 degrees.[19] The House of Lords found the defendant’s variant infringed the patent.

  9. In delivering the unanimous decision of the House of Lords, Lord Diplock declared that there is only one method of patent construction and interpretation, the purposive approach[20]

    "My Lords, in their closely reasoned written cases in this House and in the oral argument, both parties to this appeal have tended to treat "textual infringement" and infringement of the "pith and marrow" of an invention as if they were separate causes of action, the existence of the former to be determined as a matter of construction only and of the latter upon some broader principle of colourable evasion. There is in my view no such dichotomy; there is but a single cause of action and to treat it otherwise, particularly in cases like that which is the subject of the instant appeal, is liable to lead to confusion."[21]

  10. Lord Diplock observed that all members of the Court of Appeal agreed that the applicable law was to be derived from Van der Lely N.V. v Bamfords Ltd (Van der Lely)[22] and Rodi & Weinenberger A.G. Henry v Showell Ltd (Rodi).[23] Both cases split the House of Lords and Court of Appeal respectively, and contain powerful dissents.

  11. In both, the intention of the patentee to claim a feature as an essential integer of the invention was held by the majority to be the test of whether an infringement had occurred. For infringement to exist there had to be copying of each and every such integer. This was the traditional formulation of the pith and marrow doctrine. However, this intention was to be imputed whenever a feature was included in a claim in clear language deliberately chosen. The essentiality of the feature in relation to the working of the invention as a whole was not considered as an aid in determining the patentee's invention. Thus in Van der Lely Upjohn L.J. said:

    As a matter of construction of claim 11 it seems to us clear that the appellants have deliberately chosen to make it an essential feature of the claim that the hindmost wheels should be detachable and, as we have already pointed out, the foremost wheels need not be. Why they so confined the claim is not for us to speculate.[24]

  12. Upjohn L.J.'s approach was followed by Buckley and Waller L.JJ., who constituted the majority of the Court of Appeal in Catnic and who had found no infringement by the defendant’s lintel with a backplate 6 and 8 degree off vertical. Function of a feature in an invention was not material to construction of the patentee's words. Whether an alleged infringer had taken the substance of an invention could only be considered if the relevant words of the specification were inessential as a matter of the intention expressed by the patentee, including oversights.

  13. The minority judgments in Van der Lely, Rodi and Catnic in the Court of Appeal took a quite different approach. It is submitted that these minority views have been adopted by Lord Diplock and were taken further in Catnic.

  14. In the Rodi case Lord Pearce (dissenting) held that an essential feature means essential in relation to the patentee's words in relation to the function of the feature of the invention:

    For the question is whether the essential part of the essential integer is taken although the unessential parts of it have been omitted.[25]

  15. More significant is the following passage from Lord Reid's dissenting judgment in Van der Lely, since it demonstrates the inadequacy of the majority approach in that case:

    Upjohn L.J. said that the appellants have deliberately chosen to make it an essential feature of the claim that the hindmost wheels should be detachable. If by there he meant that there is something in the specification to show that they deliberately refrained from including the foremost wheels or went out of their way to make the hindmost wheels an essential feature, I cannot find anything on which to base such a conclusion. But I do not think that he meant that, because he went on to agree with Lloyd-Jacob J. that apparently the appellants did not appreciate the possibility that the foremost wheels might be moved. So I think that he must have meant that the mere fact that they only mentioned the hindmost wheels was to make the limitation to the hindmost wheels an essential feature of the claim. But if that were right I cannot see how there could ever be an unessential feature or how this principle could ever operate. And I think that that principle is very necessary to prevent sharp practice.[26]

  16. It is submitted Lord Reid implied that if a patentee did not appreciate that he was creating a functionally unnecessary limitation, provided always that the claims will not be construed to comprehend variants having a material effect upon the way the invention works, the court should not hold the patentee (or his patent agent) to the oversight. It is suggested this test was explicitly adopted by Lord Diplock for this type of situation.

    VII. Lord Diplock's Test of Essentiality

  17. In a crucial but difficult paragraph, Lord Diplock outlines the application of the new functional orientated test of essentiality to circumstances where the effect of a variant is uncertain, having regard to the state of the art at the date of the specification.

    Where it is not obvious, in the light of then existing knowledge [presumably whether a variant will have a material effect on the way the invention worked], the reader is entitled to assume that the patentee thought at the time of the specification that he had good reason for limiting his monopoly so strictly and had intended to do so, even though subsequent work by him or others in the field of the invention might show the limitation to have been unnecessary.[27]

  18. It seems that in these circumstances the limitation will be held essential. It is hard to see how it could mean otherwise. But Lord Diplock says objective reasons will be required to confine narrowly the scope of the patentee's monopoly.

    No plausible reason has been advanced why any rational patentee should want to place so narrow a limitation on his invention. On the contrary, to do so would render his monopoly for practical purposes worthless, since any imitator could avoid it and take all the benefit of the invention by the simple expedient of positioning the backplate a degree or two from the exact vertical.[28]

  19. However, it would appear from the sentence immediately following the above quotation that a superfluous limitation will be held inessential in the following circumstances:

    It [the question of essentiality] is to be answered in the negative only when it would be apparent to any reader skilled in the art tat a particular word or phrase used in a claim cannot have been intended by a patentee, who was also skilled in the art, to exclude minor variants which, to the knowledge of both him and the readers to whom the patent was addressed, could have no material effect upon the way in which the invention worked.[29]

  20. Hence it appears that for the first time the Court will protect what the patentee might have claimed, provided that both the patentee and his readers would recognise, had they directed their minds to it at the priority date, that the minor variant was incapable of having any material effect on the way the invention worked.

  21. We have some indication of what constitutes a minor variant because, it seems, Lord Diplock has Van der Lely's facts in mind. This is evidenced by his analysis of the division of the House of Lords in that case, which he considers to be due to the lack of expert evidence on whether the dismountable foremost wheels would cause a material effect on the way in which the hay raking machine worked.

    My Lords, upon analysis of the speeches in this House in Van der Lely v. Bamfords the division of opinion between Lord Reid and the remainder of their Lordships appears to have been due to his thinking that it would be obvious to the informed reader that dismounting the `foremost' rather than the `hindmost' wheels was an immaterial variant, whereas the majority were not satisfied that this was even the fact, let alone that it was obviously so.[30]

  22. In Van der Lely the defendant was successful in defeating a large number of the patentee's claims due to anticipation or obviousness. The patentee was forced to rely largely on claim 11, which covered the dual function of the invention as both bay rake and swathe turner. This duality was facilitated by a mechanical movement, involving two parallel rows of cutting wheels, wherein the hindmost wheels were dismountable via a hinging arrangement attached to a divided supporting beam. The defendant's machine did not use a divided supporting beam, but instead used a fixed frame assembly in which the foremost wheels were dismountable. The patentee had provided in the claim for a fixed frame assembly as an alternative, but had not appreciated that, in this version, either foremost or hindmost wheels could be made dismountable.

  23. It is submitted that it is implicit in Lord Diplock's analysis of the decision in Van der Lely that the Court should have had regard in their judgment to expert evidence as to whether the defendant's machine utilising dismountable foremost wheels could have a material effect upon the way the patented hay raking machined worked. Once it was established that there could be no material effect, the court should then ask the relevant expert whether, either hypothetically or in fact, any rational patentee would have intended to exclude the defendant's variant from the scope of his monopoly. If not, it is a mere minor variant and will be held to infringe.

  24. It is submitted that in similar circumstances where the patentee has failed to think through the effect of minor variants which, to his and his readers knowledge at the priority date, can have no material effect on the way the invention works, the Court should, if Lord Diplock's principle is accepted, lend its assistance.

    VIII. Codex Corporation v Racal-Milgo

  25. In Codex Corporation v Racal-Milgo [31] the English Court of Appeal stated that it was unnecessary and undesirable to cite pre Catnic decisions:

    "On the question of infringement we were referred to a substantial number of authorities and heard much interesting and instructive argument on the proper construction of patent specifications and their claims; and upon the comparison or relation between textual infringement on the one hand and infringement by taking the `pith and marrow' on the other. Nevertheless, without any disrespect to the full arguments put before us by both sides, we do not now find it necessary to consider these in detail nor to refer to earlier decided cases in the light of the recent decision in the House of Lord in Catnic Components Limited v Hill & Smith Limited [1982] RPC 183 at 237. In that case, in our opinion, Lord Diplock, in a speech with which the other members of the House agreed, summarised the effect of the cases to which we have been referred and the general, legal approach which courts should adopt to cases in which it is alleged that a patent has been infringed. Indeed, in the light of the clear and authoritative summary of the relevant law in the speech of the learned Law Lord, we think that it will henceforth be unnecessary, and usually undesirable, for counsel to take the court through the previous decisions referred to in the speech and to which our attention was drawn in detail."

    yet:

    "We do not think that the decision in this recent case has had the far reaching effect that Mr Blanco White feared, or for that for which Mr Aldous, in the alternative, contended. For instance there is no suggestion in Lord Diplock's speech that one should look only to the essence or principle of a patent in suit and hold that there to have been an infringement merely because that essence or principle has been made use of by the alleged infringer. There may have been, or there may not. The question to be asked is one of construction, but of purposive or realistic construction through the eyes and with the learning of a person skilled in the art, rather than with the meticulous verbal analysis of the lawyer alone (at 381-82)."

    IX. Hong Kong Approaches to Construction of a Patent

  26. The question of whether Catnic applies to infringement was first considered by the Hong Kong courts in Improver v Raymond. The case concerned a ladies’ depilatory device for use in removing unwanted hair from the arms and legs. The Improver patent claimed essentially a device in which the plucking and removal of the hairs was achieved by a helical spring bent into an arcuate shape and rotated at very high speed. The rotation coupled with the arcuate form caused the windings of the spring to open and close at great speed, allowing them to grip and extract the hairs. The defendant’s device contained a flexible rubber rod with perpendicular slits along its length instead of a helical spring. The effect achieved by bending the rod into an arcuate form and rotating it very fast was substantially the same as in the patent. The main questions for the courts to consider at trial and on appeal were (1) how patents were to be construed under the Patents Act 1977, and (2) whether the defendant’s variant infringed.

  27. At the trial, [32] Mayo J held that the Catnic approach was entirely consistent with the Protocol to Article 69 of the European Patent Convention, relying on a number of English decisions to the same effect. The judge held in favour of the defendant principally on the basis that the defendant’s device worked in a manner materially different from the invention in the Improver patent. In the Court of Appeal,[33] Penlington JA (giving the judgment of the court) adopted the following formulation of the Catnic principles which had been framed by Hoffmann J in the corresponding English proceedings.[34]

    1. Does the variant have a material effect upon the way the invention works? If yes, the variant is outside the claim. If no –

    2. Would this (ie that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art. If no, the variant is outside the claim. If yes –

    3. Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention. If yes, the variant is outside the claim.

  28. The Court of Appeal also expressed agreement with the following comments on those principles by Hoffmann J in Improver.

    It is worth noticing that Lord Diplock’s first two questions, although they cannot sensibly be answered without reference to the patent, do not primarily involve questions of construction: whether the variant would make a material difference to the way the invention worked and whether this would have been obvious to the skilled reader are questions of fact. The answers are used to provide the factual background against which the specification must be construed. It is the third question which raises the question of construction and Lord Diplock’s formulation makes it clear that on this formulation the answers to the first two questions are not conclusive. Even a purposive construction of the language of the patent may lead to the conclusion that although the variant made no material difference and this would have been obvious at the time, the patentee for some reason was confining his claim to the primary meaning and excluding the variant. If this were not the case, there would be no point in asking the third question at all.

  29. The court held that the first Catnic question had to be answered in a general factual sense and not as a matter of construction of the patent. Applying that test, the court was not of the view that the defendant’s variant worked in a way materially different from the invention and held in the plaintiff’s favour on the first question.

  30. On the second question, the court agreed with Hoffmann J that the question supposes that the skilled man is told of both the invention and the variant and is asked whether the variant would obviously work in the same way. It was not appropriate to import any ‘inventiveness’ test into this question such as would be relevant in an attack on validity based on obviousness. Accordingly, this question merely needed to be answered by someone with sufficient technical knowledge to understand how the patent and the variant worked. The second question was also answered in the plaintiff’s favour.

  31. The court held that, on the third question, ‘the relevant question is whether persons with practical knowledge and experience would understand that strict compliance with a particular word or phrase appearing in the claim was intended by the patentee to be an essential requirement of the invention’. The court was of the view that, since the patentee had confined itself to describing the functions of a helical spring, it had made the helical spring an essential integer, in which case there was no question of any equivalent mechanical device infringing the patent. The court accordingly held in the defendant’s favour on the third question and upheld Mayo J’s finding of non-infringement.

  32. In PLG Research Ltd v Ardon International Ltd,[35] the English Court of Appeal compared the Catnic approach with that of the German courts in a number of cases and commented as follows:2

    In determining the extent of protection, they [the German courts] ask whether the variant embodied in the disputed device is one which is deducible by a person skilled in the art from the wording and drawings of the claims. This appears to us to be not quite the same as the third Catnic question, but to be arguably more in conformity with the requirements of the Protocol that the wording of the patent should be construed so as to afford a fair measure of protection for the patentee.

  33. In Canon v GCC,[36] Rogers J held that PLG v Ardon has released the courts from any over-meticulous examination of what was said in Catnic. The judge said that the relevant provisions of the 1977 Act and the Protocol say:

    ... no more than that a sensible and proper interpretation of the claims as defining the scope of the invention claimed as part of a document which describes and claims the invention should be given. In my view, the 1977 Act, art 69 and the Protocol, when taken together, are really saying the same thing as Lord Russell said in EMI v Lissen Ltd (1939) 56 RPC 23 at p 39 onwards. Although it has often been said that there was no majority of the House of Lords in favour of Lord Russell’s view, it seems to me that his approach is, in reality, the sensible approach to the question of construing a specification. The provisions to which I have referred amount to the same thing.

  34. In EMI v Lissen, Lord Russell said as follows:

    The Court of Appeal have stated that in their opinion no special rules are applicable to the construction of a specification, that it must be read as a whole and in the light of surrounding circumstances; that it may be gathered from the specification that particular words bear an unusual meaning; and that, if possible, a specification should be construed so as not to lead to a foolish result or one which the patentee could not have contemplated. They further have pointed out that the claims have a particular function to discharge. With every word of this I agree; but I desire to add something further in regard to the claim in a specification.

    The function of the claims is to define clearly and with precision the monopoly claimed, so that others may know the exact boundaries of the area within which they will be trespassers. Their primary object is to limit and not to extend the monopoly. What is not claimed is disclaimed. The claims must undoubtedly be read as part of the entire document and not as a separate document; but the forbidden field must be found in the language of the claims and not elsewhere. It is not permissible, in my opinion, by reference to some language used in the earlier part of the specification to change a claim which by its own language is a claim for one subject-matter into a claim for another and a different subject-matter, which is what you do when you alter the boundaries of the forbidden territory. A patentee who describes an invention in the body of a specification obtains no monopoly unless it is claimed in the claims. As Lord Cairns said, there is no such thing as infringement of the equity of a patent (Dudgeon v Thomson LR 3 App Cas 34).[37]

    I would point out that there is no question here of words in Claim I bearing any special or unusual meaning by reason either of a dictionary found elsewhere in the Specification or of technical knowledge possessed by persons skilled in the art. The prima facie meaning of words used in a claim may not be their true meaning when read in the light of such a dictionary or of such technical knowledge; and in those circumstances a claim, when so construed, may bear a meaning different from that which it would have borne had no such assisting light been available. That is construing a document in accordance with the recognised canons of construction. But I know of no canon or principle which will justify one in departing from the unambiguous and grammatical meaning of a claim and narrowing or extending its scope by reading into it words which are not in it; or which will justify one in using stray phrases in the body of a Specification for the purpose of narrowing or widening the boundaries of the monopoly fixed by the plain words of a claim.[38]

  35. In Assidoman v Mead,[39] Aldous J (now Aldous LJ) held that the comments of the Court of Appeal in PLG v Ardon were obiter and that the correct approach to construction under the 1977 Act and the Protocol is still that of Lord Diplock in Catnic. This approach was followed by Jacob J in Beloit v Valme[40] and by the Court of Appeal in Kastner v Ritzla.[41]

  36. It would appear that, unless and until a higher court says otherwise, the Catnic principles will continue to be applied. It would also seem that they will apply equally to the construction of patents under the Patents Ordinance. Section 125(1) of the Patents Act 1977 and its protocol on the interpretation of Article 69 of the European Patent Convention are mirrored in sections 76(1) and (3) of the Patents Ordinance.[42]

    X. Australian Approaches to Construction of a Patent Specification Post Catnic v Hill & Smith

    [43]

    XI. The True Status of Catnic and Purposive Construction in Australia

  37. The true status of Catnic and purposive construction in Australia is problematic. Catnic was approved and said to be followed by the Full Federal Court in Populin v HB Nominees[44] (Populin), and by the courts in Rhone-Poulenc Agrochimie SA v UIM Chemical Services Pty Ltd [45] Allsop Inc v Bintang Ltd[46] Windsurfing International Inc v Petit [47] Fisher & Paykel v Avion[48] Kimberly Clark Aust Pty Ltd v Arico[49] and Doric Products v Lockwood.[50] A more rigorous approach may now be found in Azurko v Old Digger [51] which refuses to pay even lip service to the continued survival of the doctrine of “pith & marrow” or mechanical equivalents.[52]

  38. One difficulty with the outward acceptance of Catnic[53] is that the Australian Courts have continued to analyse their decisions in terms of purposive construction as well as the "pith and marrow" doctrine notwithstanding Lord Diplock's insistence in Catnic that the latter was subsumed by the former. In Populin the Full Federal Court referred to the "pith and marrow" doctrine which it said was specifically recognised by the High Court in Olin Corporation v Super Cartridge Company (Pty) Ltd[54] thereby perhaps hinting that the doctrines subsumption in purposive construction could only be done by the High Court.

  39. Another difficulty with the apparent acceptance of Catnic is that Lord Diplock appears to endorse the minority judgments of Lord Reid in Van der Lely N.V. v Bamfords Ltd (Van der Lely)[55] and Lord Pearce in Rodi & Weinenberger A.G. Henry v Showell Ltd (Rodi)[56] rather than the majority judgments (authored by Lords Upjohn in Van der Lely). Yet it is these majority judgments which have enjoyed predominant support in Australia (and it should be said in England prior to Catnic). Professor Ricketson writes in Law of Intellectual Property[57]

    "So far as Australian courts are concerned, it seems accurate to say that the narrower view of the pith and marrow doctrine put forward by Lord Upjohn in Rodi and Wienenberger has been preferred, although occasional, broader statements are to be found." See for example Radiation Ltd v Galliers and Klaerr Pty Ltd (1936) 60 CLR 36 at 51 (Dixon J).

    XII. High Court of Australia and Purposive Construction

  40. A further difficulty is that the High Court of Australia has yet to express a view on Catnic. The highest authority on the issue at the date of writing are Full Federal court decisions. Words of disapproval of Catnic, albeit muted, are to be found. In Prestige Group (Australia) Pty Ltd v Dart Industries Inc[58] Gummow J stated in the Federal Court:

    "It should be said that the notion of purposive construction, championed by Lord Diplock in Catnic Components Ltd v Hill and Smith Ltd (1982) RPC 183 at 243 has had an uneven reception in this court; see the discussion of the authorities in Rehm Pty Ltd v Webster Security Systems (International) Pty Ltd (1988) 81 ALR 79 at 91-2, and see also Nicaro Holdings Pty Ltd v Martin Engineering Company (1990) 91 ALR 513 at 527-9."

  41. In both decisions referred to, Gummow J expressed the view that Catnic was not the revolutionary far reaching approach some had suggested and did not find it of application in either case.

    XIII. Populin v HB Nominees

  42. In Populin v HB Nominees[59] the facts were briefly as follows. The Appellant, Populin, owned the patent rights to a sugar cane planting machine. It seems that prior to the patent in suit planting machines were manually fed long sticks of sugar cane from a neat stock. The machine cut these sticks into appropriate lengths called billets and planted them in a trench. Populin developed a cane planting machine which planted the cut billets obtained from sugar cane harvesting machines. In order to dispense with the necessity of manually feeding the cane into the machine the Appellant designed a mechanism whereby cane billets dumped into the supply bin were sorted and fed regularly and efficiently into the planting mechanism in the machine. This sorting mechanism was crucial to the determination of the appeal. The Appellant's sorting mechanism consisted of a storage apartment in which the billets were dumped. This was connected by conveyor system to a small bin which accomplished the sorting. Sorting was achieved by keeping the relative small number of billets in the container in a state of agitation which, in conjunction with the floor of the small bin being steeply angled towards the conveyor, caused the billets to align. Upon alignment, they would be picked up by the flights conveyor and conveyed to the planting head. In the Defendant's machine no separate small bin and supply bin were incorporated. Instead a hopper received the dumped cane. The sorting mechanism consisted in the interaction of the hydraulic ram which raised the hopper and a trough containing fungicide into which the hopper billets were fed. Turbulence in the trough together with the steep angle of its floor towards the conveyor caused the billets to align and be picked up by the flights of the conveyor and carried to the planting head.

  43. In a joint judgment Bowen CJ, Deane and Elliot JJ found no infringement and dismissed the patentee's appeal. The Court's decision turned on the characterisation of the stated separateness of the small bin and the supply container in the patentee’s claims as essential to the invention. As these were merged in the defendants variant there was no infringement. The court referred to and approved the purposive approach to patent interpretation expounded by Lord Diplock in Catnic.[60]

    "A patent specification should be given a purposive construction rather than a purely literal one derived from applying to it the kind of meticulous verbal analysis in which lawyers are too often tempted by their training to indulge."

  44. It is arguable that read in isolation this dictum adds little to the dictum of Dixon J (as he then was) in Radiation Ltd v Galliers and Klaerr Pty Ltd[61] which was also cited by the Full Federal Court in Populin.

    But on a question of infringement, the issue is not whether the words of the claim can be applied with verbal accuracy or felicity to the article or device alleged to infringe, it is whether the substantial idea disclosed by the specification and made subject of a definite claim has been taken and embodied in the infringing thing.

  45. Similarly in Minnesota Mining and Manufacturing Company v Biersdorf (Aust) Ltd,[62] applied in Populin v HB Nominees,[63] a unanimous High Court stated:

    "It remains the law that a defendant may not take the substance of an invention unless the workings of the claims make it clear that the relevant area has been deliberately left outside the claim."

    and:

    "Lack of precise definition in claims is not fatal to their validity so long as they provide a workable standard suitable for intended use"[64]

  46. In order to infringe a patent a defendant must take each and every one of the essential integers of a claim. Non essential integers could be substituted or omitted entirely without infringing.[65] However, what is non essential is notoriously difficult to predict and has led to the celebrated dissents in the Van der Lely and Rodi cases.[66]

    XIV. A Summary of the Australian Position - Decor Corporation Pty Ltd v Dart Industries Inc

  47. In Decor Corporation Pty Ltd v Dart Industries Inc [67] Sheppard J, summarised the Australian law concerning construction of a patent specification as follows:

    1. The claims define the invention which is the subject of the patent. These must be construed according to their terms upon ordinary principles. Any purely verbal or grammatical question that can be answered according to ordinary rules for the construction of written documents is to be resolved accordingly.

    2. It is not legitimate to confine the scope of the claims by reference to limitations which may be found in the body of the specification but are not expressly or by proper inference reproduced in the claims themselves. To put it another way, it is not legitimate to narrow or expand the boundaries of monopoly as fixed by the words of a claim by adding to those words glosses drawn from other parts of the specification.

    3. Nevertheless, in approaching the task of construction, one must read the specification as a whole.

    4. In some cases the meaning of the words used in the claims may be qualified or defined by what is said in the body of the specification.

    5. If a claim be clear, it is not to be made obscure because obscurities can be found in particular sentences in other parts of the document. But if an expression is not clear or is ambiguous, it is permissible to resort to the body of the specification to define or clarify the meaning of words used in the claim.

    6. A patent specification should be given a purposive construction rather than a purely literal one.

    7. In construing the specification, the court is not construing a written instrument operating inter partes, but a public instrument which must define a monopoly in such a way that it is not reasonably capable of being misunderstood.

    8. The body, apart from the preamble, is there to instruct those skilled in the art concerned in the carrying out of the invention; provided it is comprehensible to, and does not mislead, a skilled reader, the language used is seldom of importance.

    9. Nevertheless, the claims, since they define the monopoly, will be scrutinised with as much care as is used in construing other documents defining a legal right.

    10. If it is impossible to ascertain what the invention is from a fair reading of the specification as a whole, it will be invalid. But the specification must be construed in the light of the common knowledge in the art before the priority date.

  48. With great respect Justice Shepherd, leaves open most possibilities of interpretation in this formulation thus giving very little guidance as to how to predict the likely manner of a court’s construction of a patent specification.

    XV. The Recent Move Towards True Catnic Style Purposive Construction in Australia

  49. In Azurko v Old Digger [68] the Full Federal Court appears to have endorsed Catnic style purpose constriction with a vigour found wanting in previous authority. Beaumont J, held as follows:

    As has been seen, Azuko's argument also focused upon Catnic and the "purposive" theory of specification interpretation, But, for present purposes, it is not necessary to consider, as the submissions of both sides sought to do, whether there is a real (or merely virtual) distinction between the "literal" and "purposive" approaches to construction in this connection. On either approach, it was open to his Honour to find, on the expert opinion evidence, that a "minor" variation did not avoid infringement of an essential feature of the SDS invention.

    Although Lord Diplock in Catnic made several important generalisations in this context, the particular circumstances of that case and the issues there should not be overlooked. The statement or the claim there used the following language:

    A lintel…, having a second rigid support member extending vertically from or from near the rear edge of the first horizontal plate...(Emphasis added)

    The defendants' product differed from the plaintiff's invention only in that the defendants' rigid support member, instead of being perpendicular to the base, was inclined 6° or so from the vertica1. It was held by the House of Lords that the question in each case of alleged infringement was whether persons of relevant practical knowledge and experience would understand that strict compliance with a particular descriptive word or phrase was intended by the patentee to be an essential requirement of the invention, so that any variant would fall outside the monopoly claimed, even though it could have no material effect upon the way the invention worked; that such question would only be answered in the negative when it would he apparent to a reader skilled in the art that such a descriptive word or phrase could not have been intended to exclude minor variants which would have no material effect upon the working of the invention; that no plausible reason had been advanced why a limitation should have been intended excluding a back plate not positioned at precisely 90° to both horizontal plates, yet close enough to make no material difference to the working of the lintel; that "extending vertically" was in context capable of meaning "near enough to vertical to enable the back plate to perform satisfactorily all the functions that it could perform if it were precisely vertical"; and that it would be obvious to a builder that the patentee did not intend to make exact verticality of the back plate an essential feature of the invention. The present primary judge referred to, and relied upon, Catnic, in my opinion correctly. It may be said of this case, by way of analogy, that the exact position of the sleeve was likewise not intended to be an essential feature of the SDS invention.

  50. His Honour also, properly relied upon observations of Menzies J in ClG. There, the letters patent was for an invention relating to mixer tubes for use in gas burners, to reduce flashback. Menzies J said (at CLR 167.-8; IPR 118):

    “The defendants admitted infringement of letters patent 202348 up to the middle of 1966, but deny it thereafter. What I find happened is that the defendants, having simply copied articles of the plaintiffs manufacture, upon receipt in the middle of 1966 of a letter from the plaintiffs patent attorneys alleging infringement of letters patent 202348, consulted their own patent attorneys and thereafter modified their own manufacture by drilling the mixer tube to a very slightly concave, rather than a perfectly flat, base. In my judgment the modification so made did not prevent equipment manufactured and sold thereafter from constituting an infringement of the letters patent. Patent rights arc not to be set at nought by such a subterfuge which I am satisfied added nothing to the equipment and was made merely in an attempt to take full advantage of the invention while avoiding infringement of the plaintiff's letters patent by a modification so small as to be insignificant. I find that the base of the mixer chambers, which the defendants manufactured and sold after the middle of 1966, was so close to the plaintiff’s specification in that the degree of concavity was so slight that such manufacture and sale continued to amount to infringement. Of course, CIG was decided before Catnic, but takes a similar approach - which, I think, is properly seen as analogous here.

    In short, I am of the opinion that Azuko's argument here very much depends upon satisfying the court that the primary judge failed to understand or apply the distinction, critical for infringement purposes, between essential and non-essential integers; yet when his Honour's reasons are read as a whole, it ) emerges that there is really no warrant for the assertion. The application of the distinction was necessarily a matter of characterisation, and thus of judgment and degree, in which a comparative assessment had to be made of claim I of the SDS patent and the Premier tools by reference to their respective essential features. Plainly, in my opinion, his Honour undertook that assessment, and, aided by an expert opinion, concluded that those respective features were, in substance, identical, the only departure being "minor", "trifling" and "of no mechanical significance". That approach was, I think, sound in principle, and its application was justified as being in accord with expert testimony, which his Honour was entitled to use in reaching his conclusion. It follows, in my opinion, that the appeal against the finding of infringement or claim I ought to be dismissed.”

    XVI. Root Quality Pty Ltd v Root Control Technologies Pty Ltd

  51. In perhaps the most significant Australian case involving interpretation of the patent, Root Quality Pty Ltd v Root Control Technologies Pty Ltd[69] Finkelstein J, canvassed the Australian and English law in some detail. He points out that in Catnic, Lord Diplock was addressing the proper policy to interpretation in the light of a balancing of interests to patentee, competitor and the public. He also makes plain that “pith and marrow” or mechanical equivalents no longer have application in Australia despite many cases suggesting it does[70] It appears inescapable from this that his Honour is rejecting so much of the High Courts decision in Olin v Super Cartridge [71] that states “pith and marrow” is still good law. Finkelstein J states the position in Australian law is as follows[72]

    “Before Catnic the subject matter of a patent was defined in accordance with a literal meaning of the claim. Nevertheless, if the substance (pith and marrow) or mechanical equivalent of the claim was taken, there would be infringement. The rules were made necessary to render patents useful. The change brought about by Catnic was that a patent specification is to be given a purposive construction and not a literal construction. The question is to be determined under this approach is whether the patentee intended strict compliance with an element of the invention to be an essential requirement of the invention. On this basis the former approach, that is, whether the “pith and marrow” or substance of the claim has been taken, is no longer necessary.”

  52. The patent in suit involved a planting device where recesses might end in a hole. This was the preferred embodiment, the specification stated in its unamended form. The specification was subsequently amended to require each recess to end in a hole. The defendant’s variant had recesses which had recesses not terminating in a hole, and thus was alleged not to infringe. Finklestein held the affect of the amendment was not necessarily to make the recesses ending in a hole an essential requirement. Other factors had to be taken into account. The judge stated evidence of intention from the inventor was not applicable as the addressee of the specification is the public.

  53. In this light Finkelstein J applies the two Improver[73] questions to the patent in suit. He concludes on the second Improver question that the person skilled in the art, that is the person with a practical interest as in Catnic’s builder, would agree the defendant’s variants in this case could not have been intended to be excluded from the plaintiff’s patent. On the first improver question, Finklestein J takes the view that the variant, at the priority date, could have no effect on the way the invention works. He is thus able to find non literal infringement of the patent. This was so even though the absence of holes in the defendant’s variant was accepted by the court as a useful feature.

  54. It is submitted this represents a true purposive construction. The essentiality of the feature is decided by reference to importance or otherwise of the function of the feature in the invention as a whole.

    XVII. Conclusion

  55. With questions of patent construction it is submitted public policy requires some degree of additional latitude in construction of claims ought to be extended to patentees. Their monopoly rights have been subject to far greater examination and circumspection than other forms of intellectual property without, until the recent US Free Trade Implementation Act amendments, any presumption of validity. The balance provided is the corresponding difficulty such latitude entails on patentees surmounting the requirements of novelty and inventive step in order to obtain a patent in the first place.

Notes

[1] The patent specification consists of two parts, the description and the claims.

[2] s.18(1)(b)(i) Patents Act 1990 (Cth).

[3] s.18(1)(b)(ii).

[4] Either in determining the proper scope of the subject patent application or in determining the state of the prior art base by construing prior published patent applications. The method of construction or interpretation is equally relevant to an attack on the validity on the granted patent under section 40 of the Patents Act 1990 (Cth).

[5] Professor Cornish, writing in Intellectual Property (1989) Sweet & Maxwell 2nd ed at p14 observes: "The tendency to proliferate detail and to make complicated cross references has a long history. It is rooted in the assumption that the judges cannot, will not, or should not work out the implications of statutory directives for themselves... Today, however, there are forces at work - and nowhere more so than in the intellectual property field - that may lead to change'.

[6] Ingersoll Sergeant v Consolidated Pneumatic (1908) 25 RPC 61 at 82 (HL).

[7] EMI v Lissen (1938) 56 RPC 23 at 39 (HL).

[8] Rhone-Poulenc Agrochimie SA v UIM Chemical Services Pty Ltd (1986) 6 IPR 607 at 610, Multiform Displays v Whitemarley (1957) RPC 260.

[9] Boyd v Horrocks (1891)

[9] RPC 77.

[10] W.R. Cornish, Intellectual Property p245, 2nd Edition, 1989. Sweet and Maxwell, London.

[11] For a discussion of German approaches to patent construction see Improver Corp v Raymond Industrial (1991) FSR 233 (CA, Hong Kong).

[12] s124 Patents Act 1977 (UK).

[13] Cornish, Intellectual Property

[14] (1981) FSR 60, (1982) RPC 183.

[15] Fn. 12 above.

[16] Fn. 13 above.

[17] Quite a literature has been generated on the effect and significance of Catnic, see BC Reid, The Catnic Decision: the construction of patent claims (1981) EIPR 56 TA, Blanco White, the Catnic Case: the test for infringement of a patent (1981) EIPR 90, W R Cornish and M Vitoria "Catnic in the House of Lords: a new approach to infringement" (1981) JBL 136, M D Pendleton "Catnic: signpost to where?, The Purposive Approach to Patent Construction: A Divergence in Anglo Australian Judicial Interpretation 91983) MULR 75, (1982) EIPR 79, B C Reid "Catnic Further Case Notes" (1984-5) 14 CIPA 254, P Prescott "Improver Corporation: v Remington Consumer Product Ltd" (1989) EIPR 259, and Terrell on the Law of Patents, 13th ed, Aldous Young Watson and Thorley, Sweet and Maxwell 1982.

[18] Chartered Institute of Patent Agents, 3rd ed, Sweet and Maxwell 1990 125.01-125.21

[19] "Between this design [the allegedly infringing lintel] and that described in Claim 1 of the patent, the difference which is relied upon by Hill and Smith to save it from being an infringement, is that the back plate is not precisely vertical but is inclined at a slight angle to the vertical, viz., 60 in the case of the three course module and 80 in the case of the two course module" per Lord Diplock at p.64

[20] Purposive construction was a term first coined by Lord Diplock in Kammins Ballrooms Co Ltd v Zenith Investments (Torquay) Ltd (1971) AC 850 at 881.

[21] At p187. Author's emphasis.

[22] [1963] R.P.C. 61 (House of Lords).

[23] [1963] R.P.C. 369 (House of Lords).

[24] [1961] R.P.C. 296, 313 (Court of Appeal). Approved by Viscount Radcliffe and Lord Jenkins in the House of Lords.

[25] [1963] R.P.C. 367, 389.

[26] Van der Lely, supra 76-77.

[27] Ibid. 66. Author's words in brackets.

[28] Catnic, supra 67.

[29] Ibid. 66. Author's words in brackets.

[30] Ibid. 66.

[31] (1983) RPC 369 at 380.

[32] [1990] 1 HKLR 33.

[33] [1991] 1 HKLR 251; [1990] 2 HKC 28.

[34] Improver Corp v Remington Consumer Products [1990] FSR 181.

[35] [1995] FSR 116; [1995] RPC 287.

[36] At pp 132–133, and 309.

[37] At p. 39.

[38] At p.41.

[39] [1995] FSR 225; [1995] RPC 321.

[40] 2[1995] RPC 705; [1997] RPC 489 (CA).

[41] [1995] RPC 585

[42] (1981) FSR 60, (1982) RPC 183.

[43] (1982) 41 ALR 471.

[44] (1986) 6 IPR 607 at 610

[45] (1989) 15 IPR 685.

[46] (1984) 2 NSWR 196.

[47] (1991) 103 ALR 239.

[48] (2001) 207 CLR 1.

[49] (2001) 53 IPR 270.

[50] (2001)52 IPR 75.

[51] See par. XIII, below.

[52] McKeough & Stewart, Intellectual Property in Australia (1991) Butterworths, write at p252 "The purposive approach to interpreting patent specifications is now firmly established in Australia".

[53] In this case Gills J had approved the test of pith and marrow as formulated by the House of Lords in Van Der Lely v Bamfords and Rodi and Wienenberger v Showell.

[54] [1963] R.P.C. 61 (House of Lords).

[55] [1963] R.P.C. 369 (House of Lords).

[56] (1984), Law Book Company Ltd

[57] (1990) 19 IPR 275 at 286. Author's emphasis.

[58] See above.

[59] p 324.

[60] (1983) 60 CLR 36 at 51.

[61] (1980) 29 ALR 29 at pages 52-53.

[62] (1982) 41 ALR 471.

[63] At p43.

[64] Minnesota Mining and Manufacturing Company v Biersdorf (Australia) Ltd 1980 144 CLR 253 29 ALR 29.

[65] Van Der Lely v Bamfords (1963) RPC 61 and Rodi and Wienenberger v Showell (1969) RPC 367, both House of Lords decisions.

[66] (1988) 13 IPR 385 at 400. This must be read in the light of Rhone-Poulenc Agrochimie SA v UIM Chemical Services Pty Ltd, Allsop Inc v Bintang Ltd Windsurfing International Inc v Petit, and Fisher & Paykel v Avion cited in fns 35-38.

[67] (2001)52 IPR 75.

[68] (2000) FCA 980. 177 ALR 231.

[69] Populin v HB Nominees cited above, at 475-7.

[70] (1977) 180 CLR 236.

[71] Root Quality v Root Control, at p 242

[72] Improver v Remington [1990] FSR181

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