Secret use
211 By virtue of par 18(1)(d) of the Act, an invention will not be patentable if it was secretly used in the patent area before the priority date of the claim by, on behalf of or with the authority of the patentee. However par 9(a) provides that to use the invention for the purpose of reasonable trial or experiment only is not secret use. Her Honour apparently accepted the evidence given by Mr Mansur (the inventor) as to the relevant use and concluded that the appellant had failed to establish that the trial "was unreasonable in duration". The appellant criticized this decision upon two bases, namely:
• that her Honour proceeded upon the basis that the onus of proving secret use was upon the appellant; and
• that on a proper assessment of the evidence, the alleged trial period was too long to be reasonable for the purposes of s 18.
212 Before addressing these issues, it may be helpful to refer to the discussion of secret use by Gyles J (Beaumont J concurring) in Azuko Pty Ltd v Old Digger Pty Ltd [2001] FCA 1079. His Honour observed that the rationale behind the prohibition upon issue of a patent following secret use is that the inventor should not, by using the invention for a periodof time prior to disclosing it, derive greater advantage from it than is contemplated by the Act. The terms "secretly used" in par 18(1)(d) and "secret use" in par 9(a) are not defined, but it is likely that secret use and public use are mutually exclusive. The word "use" is found in the definition of "exploit". In relation to an invention which is a product that definition includes:
"Make, hire, sell or otherwise dispose of the product, offer to make, sell, hire or otherwise dispose of it, use or import it, or keep it for the purpose of doing any of those things; …"
213 As Gyles J pointed out in Azuko, "use" is only one aspect of the definition of "exploit" and so presumably has a narrower meaning than that term.
214 The appellant submitted that the learned trial Judge erred in finding that the appellant was obliged to prove secret use and to exclude the operation of par 9(a). Her Honour relied upon the decision of Gibbs J (as his Honour then was) in Montecatini Edison SpA v Eastman Kodak Co (1971) 45 ALJR 593 at 595 - 596 and the decision at first instance in Azuko ([2000] FCA 676) in which von Doussa J followed the decision in Montecatini. Gibbs J was concerned with an appeal from a decision of the Deputy Commissioner granting an application for letters patent. At 595 - 596 his Honour said:
"Both parties before me agreed that I ought not to find in favour of the appellant on the issue of want of novelty, or that of obviousness, unless I were satisfied that the appellant's case had been clearly made out; it was said that I should adopt a similar approach to that which must be followed in considering whether to accept an application and specification, namely, that the application should only be rejected in a clear case where it is obvious that a patent cannot be granted: see Commissioner of Patents v Microcell Ltd (1958-59) 102 CLR 232 at 236, 244-245. I was not referred to any Australian authority that establishes a similar rule in opposition proceedings, but it has been held under the different provisions of the statute in force in England that in such proceedings the jurisdiction to refuse a patent, at least on the ground of obviousness, should be exercised only in clear cases … ."
215 Whether this approach should also be taken in revocation proceedings is a different question. In Azuko, Heerey J (in the Full Court) observed in his dissenting judgment:
"Section 9 postulates particular circumstances, necessarily within the knowledge of the patentee, which on ordinary principles are matters for the patentee to aver and prove. But in the circumstances of the present case the onus of proof is not in my view determinative."
216 The other members of the Court did not find it necessary to address the question. The appellant submitted that her Honour's reliance upon Montecatini was inappropriate because it was "a decision on the benefit of the doubt in a patent opposition and not relevant to a patent revocation action." It conceded that it bore the overall burden on the issue of validity (whatever that may mean) but nonetheless argued that the burden of proof shifted in the course of the trial because "… the facts giving rise to any reasonable trial or experiment only are peculiarly within the knowledge of the patentee on whom the burden of proof on the issue should rest …". In written submissions, counsel referred to International Paint Co Ltd's Application [1982] RPC 247 at 275 as supporting this proposition. Curiously enough, that case also concerned opposition proceedings. If Montecatini should be disregarded because it dealt with such proceedings, then it is a little difficult to see why International Paint should be of assistance. There is another reason for doubting the helpfulness of that decision. Anthony Walton QC was there sitting as an additional Judge in the Patents Court. At 275 he observed:
"The onus of establishing that an established user was experimental must rest on the applicant for a patent, because the facts are peculiarly within his own knowledge and his disclosure thereof must be uberrimae fidei. Nevertheless, this jurisdiction is a preliminary jurisdiction in which the benefit of any doubt must be given to the applicant."
217 There was an application for leave to appeal. This is reported under the same citation at 278 - 280. Concerning the burden of proof, Buckley LJ (Eveleigh & Brightman LJJ concurring) said at 280:
"In opposition proceedings it is well established that the standards of proof and the burden of proof differ from the standards of proof and the burden of proof which is required in infringement and revocation proceedings. Consequently it appears to me that considerations arising under section 51 or section 52 [concerning prior use] in opposition proceedings should be dealt with in just the same way as other considerations arising in opposition proceedings, and to the extent that the Court protects the applicant against being prevented from going on to obtain a grant of his patent and then to attempt to protect it against revocation proceedings, the same approach should be applied to questions of proving any relevant facts in relation to sections 51 and 52. In revocation proceedings those two sections will come into play as qualifications upon the grounds for revocation which are set out in section 32 of the Act, and in such proceedings, which are tried with the full panoply of pleadings, discovery, oral examination and cross-examination of witnesses and so forth, those issues will be dealt with in the same way as any other issues arising in revocation proceedings; that is to say, that any matters which have to be proved will have to be proved in accordance with the ordinary civil standard of proof."
218 It is difficult to avoid the conclusion that his Lordship was seeking to eradicate any perceived heresy in the observations made at first instance. The Court of Appeal had only recently addressed the question of burden of proof in Dunlop Holdings Ltd's Application [1979] RPC 523 (in the Court of Appeal, at 537). Those proceedings also involved opposition to the grant of a patent. Buckley LJ said at 542 - 543:
"There appears, however, to be no positive authority on the question of where the legal burden of proof lies. It seems to me that in principle that burden should lie on the opponents to prove all the necessary elements of a valid ground of opposition and that accordingly, in the case of an opposition under section 14(1)(d) the opponent must establish that there has been previous use which was not secret. It should be appreciated that that use may have been use by the opponents themselves, or use by the applicants themselves, or use by some third party or indeed some co-operative use by more than one user. Knowledge of the relevant facts may lie mainly, or exclusively, with either the opponents or the applicants, or be to a greater or lesser degree available to either of them. Notwithstanding that the legal burden may lie upon the opponents, the evidential burden may shift according to the state of the evidence from time to time. The ease with which it may do so may depend upon the circumstances of the case and the likelihood of the facts being within the knowledge of, or more readily available to, one side or the other. Thus, if the relevant facts are likely to be within the exclusive knowledge of the applicants - if, for instance, the alleged prior use is a use by the applicants themselves - very little evidence on the opponent's side might be sufficient to shift the evidential burden on the issue of secrecy to the applicant. Failure to produce convincing evidence of secret or non-secret use at any stage at which the evidential burden rests on the party who fails to do so, may prove fatal to that party's case; but when all the evidence has been adduced the question must be whether it has been established that the prior use was non-secret. Although in my view the legal burden of proof of non-secret prior use rests on the opponents, if the secrecy of the prior use is not put in issue either on the pleadings (if I may so call the opponent's statement and the applicant's counter-statement in opposition proceedings) or in the written evidence placed before the Court, it is not in my judgment incumbent upon the opponents to come armed with evidence directed to establish an aspect of the case which has not been put in issue; in other words, if prior use is established, but secrecy of that prior use is not raised as an issue, the opponents should be taken to have discharged the burden resting upon them without having to prove that the prior use was non-secret."
219 Bridge LJ said at 546:
"As a matter of principle it seems to right that in opposition proceedings … the legal burden of proving every element necessary to make good his ground of opposition must rest upon the opponent. But situations may nevertheless arise, in my judgment, in the course of evidence relating to a section 14 opposition where the evidential burden in relation to some subordinate issue arising as relevant to the particular ground relied upon, shifts in the course of the proceeding."
220 At 547, Waller LJ said:
"But in my view, once the issue of secrecy is raised, it will be for the opponent to prove the absence of secrecy. The overall burden remains on him, just as it would in a criminal case. For example, if self-defence were raised, or if there were an alibi defence, the burden would remain on the prosecution to prove the case and to disprove whichever of those defences was being put forward."
221 Clearly, the structure of the relevant English legislation differed from that of the current Australian legislation. As a result, this decision cannot definitively resolve the present issue. Nonetheless, the general approach taken by the Court of Appeal is, with respect, entirely consistent with principle. Further, it is consistent with the approach taken by the High Court in Watts v Rake (1960) 108 CLR 158 and Purkess v Crittenden (1965) 114 CLR 164. I see no reason why the same approach should not be applied for present purposes. Whilst there may have been an evidential onus upon the present respondent to raise the issue of reasonable trial or experiment, and perhaps even to address that issue in so far as it lay within its knowledge, it did so by calling Mr Mansur to give relevant evidence. In the end, however, the onus remained upon the appellant to satisfy the Court that there had been a disqualifying secret use, having regard to the combined operation of ss 9 and 18. Proof of use which may have been for the purpose of trial or experiment only would not have discharged that onus. It is worth observing that in virtually all cases, the invention in question will have been secretly used for necessary experimental and/or trial purposes. It cannot have been intended that in proceedings for revocation, the inventor should be put to proof of the reasonableness of such use simply because the applicant for revocation alleges disqualifying secret use. Such an outcome, if intended, would surely have been directly addressed.
222 Before considering the evidence, I should deal with one other matter arising from the appellant's submissions. It asserted that at the trial, counsel for the respondent conceded secret use. This is said to have occurred at TS 1595 and 1610. It is quite clear that counsel was conceding only that there had been a use which was said (by the appellant) not to be a secret use for the purposes of s 18 by virtue of the operation of par 9(a). I do not consider that this so-called concession has any relevance for present purposes, save to clarify the precise limits of the issue with which the Court is concerned.
223 Her Honour concluded that the appellant had not established that the trials were "unreasonable in duration", and that therefore the ground of revocation was not made out. She considered that:
"Mr Mansur's evidence explained the need for testing (the invention) over almost one year which is to say two seasons. He needed to assess its performance over that period and in the changing conditions which occur throughout the seasons."
224 This observation was apparently open on the evidence, and if I am correct in upholding her Honour's view as to the burden of proof, then I would have thought the above conclusion to be beyond challenge. However the appellant disputed the correctness of her Honour's assessment of the evidence. In par 4 of the notice of appeal it asserted that:
"The learned primary Judge should have found on the evidence, in any event, that both the Petty and Standard Patents each were invalid by reason of the admitted prior (secret) user by Mr Mansur as inventor … ."
225 This ground appears after discussion of the question of burden of proof. The words "in any event" suggest that the intention was to challenge the finding regardless of where that burden lay. The difficulty faced by the appellant in so doing lies in the absence of any evidence concerning this issue, other than that of Mr Mansur. That evidence may not have been conclusive of the issue, but it was certainly relevant. In the absence of evidence to the contrary, there was no reason to reject it. The approach taken by the appellant in argument was to rehearse the evidence (or parts of it) and to invite us to assess it by reference to undefined standards as to reasonable trial or experiment. This resulted in little more than an assertion that such use as there had been must have been beyond the bounds of par 9(a).
226 Mr Mansur used the invention on his farm from about September 1992 until December 1993. This period of a little over a year included two growing seasons. Her Honour appears to have treated Mr Mansur as a generally reliable witness. At TS 1609 (in re-examination) he was asked about the purpose of the relevant use and said:
"Well the purpose was to prove the concept or prove the - yes, whether it would work or not and be a successful implement and I think the - the significance in the length of time that it takes to do something like that is that the conditions when we start at the beginning of the seasons, the things that we're trying to achieve with that first cultivation - it may be more delicate and the weeds get bigger later and it has to be stronger and the ground - we go from conditions that are very wet that we need to cultivate in to conditions that are very dry and so we need to see if they perform in all those instances. I suppose the other thing that comes to mind is we - in the country that's out there there still is timber in some of the country that's buried in the ground, and the first trial in the field you may not hit any but that doesn't prove that its strong enough, that the blades will respond properly when you do hit it so it does take a fair amount of time to - to prove the product and see if any changes are needed in it."
227 Counsel for the appellant challenged this explanation, asserting that it was inconsistent with other evidence given by Mr Mansur, in particular a statement in cross-examination that once he had developed the third prototype (which is the relevant piece of equipment for present purposes) he knew that he had something which was going to work (TS 1579). The appellant pointed out that this was at some time prior to September 1992 and that Mr Mansur then manufactured eighteen to twenty tools which he installed on two row cultivators, retaining some as spares. The equipment was then used throughout the two following seasons. Mr Mansur said that during the period of the trial:
"I varied the weights, heights and angles of the blades (which were swept back and up) to best adapt them to travel just below the soil in the furrow and to maintain adequate trash clearance. For trialling purposes I set up two cultivators with detachable blades. These were used on the farm for a full year." (AB 792)
228 I see no inconsistency in these various statements. A statement that an inventor "knows" that something will work may reflect his or her belief but does not lead to the conclusion that trials are unnecessary.
229 The appellant also pointed out that the use was in connection with the cultivation of commercial crops. This was no doubt true, but it is difficult to conceive of any field trial of the invention which would not involve such use. If the true purpose of the use is for trial, and the trial is reasonable, any collateral commercial advantage to the inventor is irrelevant. As to the question of reasonableness, Mr Mansur's explanation of his objectives must be a relevant consideration. It was said that there was no evidence that his trials addressed the problems identified in the patent and that there were no experimental notebooks or other records. While all of this may be true, it does not necessarily follow that the trials were unreasonable. The appellant pointed out that in Longworth v Emerton (1950 - 1951) 83 CLR 539 at 550, the High Court said:
"The use was not experimental except in the possible but vague sense that the appellant might not have been quite satisfied that the qualities of the machine had been fully tested and might have remained uncertain whether some further improvements might not be effected to make it more efficient."
230 However the Court had previously observed:
"On the facts of the present case it appears to be reasonably plain that the appellant used his invention freely in the district in which he and his brother and brother-in-law lived, taking no precautions to keep its character secret or to confine its use to those who were in confidential relations with him, and that he did so without any view to definite improvement or experiment of a specific character and not for the purpose of developing the actual invention applied for."
231 It is also relevant for present purposes that in Longworth the Court was considering only the question of experiment whereas par 9(a) speaks of both trial and experiment. The structured and specific research processes often adopted in experimentation will not necessarily be relevant in trials. The latter process may simply involve "seeing how it goes", when the invention is employed in the field. In such a situation adjustment and fine tuning may not be recorded as would be the results of laboratory experiments.
232 In assessing what might be reasonable for present purposes, it is necessary to keep in mind the nature of the equipment in question, the tasks for which it was designed, and the conditions under which it is to be used. Clearly, a row cultivator or a tool for a row cultivator will have to be very robust to enable it to resist the rough nature of its likely employment. It will be expected to perform in a wide variety of conditions, both of weather and terrain. It is easy to accept that such a piece of equipment could not be subjected to reasonable trials in anything less than a year, particularly given the seasonal nature of its employment.
233 If, as I have concluded, the onus of excluding reasonable trial and experiment was upon the appellant, then there can be no basis for challenging the inference drawn by her Honour that such burden was not discharged. However, even if the burden lay upon the respondent to prove the reasonableness of the trials and that the use was only for the purpose of such trials, I see no reason to reject Mr Mansur's evidence. Clearly, her Honour did not do so. That being the only evidence directly bearing upon the matter, and there being nothing improbable about it, any such onus was discharged. The appellant must fail on this ground.