15 September 2010

Amendments: Can a Mistake that Nobody Noticed Be "Obvious"?

Expo-Net Danmark A/S v Buono-Net Australia Pty Ltd [2010] FCA 983 (7 September 2010)

Amendment – obvious mistake – allowability under s 102 of the Patents Act – discretion

Philosophical musings aside, when a tree falls in the forest, physical laws dictate that it makes a sound, whether or not anyone is there to hear it, or if someone who is there is listening to loud music through their iPod, or if they are hearing-impaired, or if they are just not paying attention!  As the tree falls, vibrational energy is generated through abrasive and percussive contact, and the release of stresses in overburdened timber.  The vibrational energy is transferred to the surrounding air, to generate what we call "sound".

What has any of this to do with amendment of patent specifications, you ask?

Well, in light of this decision of Justice Bennett in the Federal Court of Australia, we ask the question: if a mistake occurs in a patent claim, but nobody sees it, can it be said to be "obvious"?  Is the law on this point objective, like the laws of classical physics, or is it capricious and observer-dependent in the manner of some pop-science rendering of quantum theory?


We have written before (eg in A Tale of Four Amendment Requests) about the requirements for a post-grant amendment to be allowable under the provisions of section 102 of the Patents Act 1990.  In particular, these provisions prohibit any amendment that would broaden the scope of the patent monopoly.

There are, however, limited exceptions to these restrictions on amendments.  Specifically, sub-section 102(3) provides that the usual restrictions will not apply when an amendment is requested "for the purpose of correcting a clerical error or an obvious mistake made in, or in relation to, a complete specification."  It would not be unusual for an error in a claim to result (on a literal interpretation) in scope that is not broader than, or equivalent to, the intended scope of the claim.

As the court noted, at [13]:

The onus to establish that the error is a clerical error or obvious mistake lies with the patentee. As pointed out in Bodkin C, Patent Law in Australia (Thomson Lawbook Co, 2008) at [13460], an obvious mistake is one such that ‘the instructed public can, from an examination of the specification, appreciate the existence of the mistake and the proper answer by way of correction’ (citing General Tire and Rubber Company (Frost’s) Patent [1972] RPC 259, not considered further in the Court of Appeal).
The more detailed reasons of Graham J in the General Tire case appear at 278:

The interests of the public demand that something which was not originally an infringement should not be made so by amendment except in a very clear case. Such an amendment is only justifiable where, from the nature of the mistake, it is obvious to the instructed reader of the specification itself, who it is presumed may be intending to do something which lies outside of the apparent scope of the unamended claim, that he will be taking the risk of a successful action against him because it is also obvious to him that the specification can probably be amended to cover what he is intending to do. In such a case it can properly be said that the reader has notice that the apparent scope of the claim is too narrow.
We consider that these words are worth bearing in mind when considering the present case, particularly with regard to the nature of the hypothetical "instructed reader".


The patentee, Expo-Net Danmark A/S ("Expo-Net") sought to make a number of amendments to the specification and claims of Australian Standard Patent No. 2006226731 and Innovation Patent No. 2007100339, most of which were uncontentious.  Indeed, all were uncontentious in the sense that none were opposed by the respondent, Buono-Net Australia Pty Ltd.  We are concerned with only one of the amendments, which the court did not consider to be entirely clear-cut.

As the court interpreted the patents (at [6]):

In general terms, the invention the subject of both patents is for a method of producing contact filter blocks in which a foaming agent is used for creating a microscopically uneven (and thus rough to touch) outer surface, resulting in a larger surface area of the contact filter blocks. In the method, an apparatus is used having a reservoir for storing granulate material, a heating and pressurising unit, an extruder with rotating heads for extruding the material and a cooling unit for cooling the extruded element. Relevantly for the purpose of the motion, it is apparent from the drawings in each patent that the “reservoir” has an inlet for receiving the granulate material and an outlet for transferring the material to the heating and pressurising unit. The outlet, as drawn, appears continuous, as a structure, with the inlet to the heating and pressuring unit.

The claims, however, erroneously referred to a reservoir "having a first inlet and a second inlet" (emphasis added).  They also referred to a heating and pressurising unit having a "second inlet in communication with said first outlet" (emphasis added).  It therefore seems reasonably apparent that the initial reference to "a second inlet" should in fact have referred to "a first outlet".


The court ruled that the error in relation to the "first outlet" was not a relevantly obvious mistake, noting that not one of the patentee's Danish patent attorney, Mr Nielsen, "nor any other patent attorney, nor any Patent Office examiner perceived the mistake when examining the patent applications.  Mr Nielsen has been unable to provide any explanation for the principal error. I am not prepared to conclude that this was an obvious mistake within the meaning of s 102(3)."

Fortunately for Expo-Net, the court determined that the requested amendments did not offend any of the restrictions normally imposed by section 102, and were therefore allowable in any event.  Furthermore, it was appropriate in the circumstances for the court to exercise its discretion, under section 105, to allow the amendments.


With all due respect to Justice Bennett, who is arguably the Federal Court's most highly-regarded patent judge, we are not convinced that it is appropriate to dismiss a request to amend on the basis of an "obvious mistake" simply because the error in question was not identified earlier by people involved in the drafting and prosecution of the patent application.

Firstly, any request to amend a patent specification in order to correct an error is necessarily predicated on the error in question not having been identified and corrected at an earlier stage.  The facts in this case are therefore entirely unexceptional in the circumstances.  A lack of any explanation for the original error is also to be expected, since it passed unnoticed at the time and it may therefore be presumed that all of the persons involved were genuinely of the belief that there was no error present.

Secondly, the hypothetical "instructed reader" posited by Graham J in General Tire is not a patent attorney or examiner.  While not wishing to admit it out loud, the patent professionals among our readers will be well aware that errors of this type do slip past attorneys and examiners from time-to-time.  There would be no need for corrections if they did not!

Justice Graham's "instructed reader" is someone "who it is presumed may be intending to do something which lies outside of the apparent scope of the unamended claim, that he will be taking the risk of a successful action against him because it is also obvious to him that the specification can probably be amended to cover what he is intending to do." 

We consider that objectivity and consistency in the application of the General Tire test requires that the hypothetical instructed reader be credited with infallible diligence!  In the present case, it beggars belief that someone examining the claims for the purpose of assessing whether on not some proposed activity may infringe would fail to recognise that the reservoir must have, as well as an inlet, an outlet feeding the inlet of the heating and pressurising unit.  Otherwise, the apparatus simply will not work as intended.  There is clearly a mistake in the claims, and the appropriate correction is plainly apparent from the context and a reading of the specification as a whole.

This decision provides ammunition for any party opposing a request to amend a patent for the purpose of requesting correction of an "obvious mistake."  For patentees finding themselves in a similar position, it may be necessary to take great care in arguing for amendments to be allowed.  The facts of any case will inevitably show that at least one patent attorney and at least one examiner failed to notice the allegedly obvious mistake prior to the patent being granted.


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