NZ Patent Oppositions – Why do I need expert evidence?

Date: 2013-02-13
Author: Tracey Hendy

In our continuing series of articles on New Zealand patent oppositions, we look at the topic of expert evidence and why it is critical to establishing obviousness.

Where a difference exists between the invention and the prior art, the opponent will need to rely upon the ground of obviousness to establish invalidity.

Test for obviousness/inventive step

The approach adopted by New Zealand courts in assessing obviousness is the same as that adopted in England under the UK Patents Act 1977 as laid out by the Court of Appeal in Windsurfing International Inc. v Tabur Marine (GB) Ltd. [1985] RPC 59.

The court set out a four-fold test for assessing inventive step:

  1. Identify the inventive concept embodied in the patent;
  2. Impute to a normally skilled but unimaginative addressee what was common general knowledge in the art at the priority date;
  3. Identify the differences, if any, between the matter cited and the alleged invention; and
  4. Decide whether those differences, viewed without any knowledge of the alleged invention, constituted steps which would have been obvious to the skilled man or whether they required any degree of invention.

Without expert evidence, the New Zealand Patent Office has held that it is unable to come to a conclusion of obviousness. So evidence becomes crucial in any case relying on obviousness.

The importance of common general knowledge

At the very minimum, evidence should be provided to establish the state of common general knowledge in the field in New Zealand as at the priority date (step 2). One way of establishing the state of common general knowledge in the field is through the testimony of an “expert witness” who is typically a person skilled in that field. Another way of establishing the state of common general knowledge may be through textbooks, standard reference materials and articles in relevant international journals. But even so, these materials are usually obtained through the assistance of an expert and confirmation of the expert’s awareness of knowledge contained in the reference materials is also beneficial to the case.

In some cases, patent specifications may fall within the realm of common general knowledge although this is usually confined to industries where skilled workers in the field would typically review patent specifications to monitor developments in their field. Again, expert evidence may be required to show that monitoring of patents is prevalent in the field.

In our earlier article NZ Patent Oppositions – Why oppose?, we discussed why it is more difficult to succeed under obviousness where all the features of the invention can only be found in a mosaic of two prior art documents, compared to the situation where a single prior art document and the common general knowledge contains all the features of the invention.

So, in practice, the evidence tries to establish that any differences between the invention and a prior art document are part of the common general knowledge.

Expert Witnesses

Such evidence is usually obtained from one or more “expert witnesses” in the field in New Zealand. The expert witness usually has a specialized knowledge in that particular field in New Zealand and is able to testify as to the state of the common general knowledge in New Zealand. The hypothetical skilled addressee referred to in step 2 is considered to be “unimaginative”. However, in practice, the expert witness may be an expert in the field and little attention is paid as to whether the expert is over-qualified or too inventive.

The expert’s evidence should establish independence from the parties to the dispute.

The more the expert departs from the ideal, the greater the likelihood that the evidence will be held to have low probative value.

Expert’s view on obviousness

Generally speaking, the expert’s view as to whether an invention is obvious or not (step 4) is not appropriate in evidence since this is a matter for the court or the hearing officer to determine.

It may be useful to have the expert’s interpretation of any prior art documents. In particular, the expert may point to where claimed features can be found in the prior art. Additionally, the expert, as a skilled reader of the prior art document may understand it differently from a non-skilled reader and thus shed light on otherwise unclear passages or elucidate features that might be inherent only to a skilled reader.

Perhaps, the expert can be shown the prior art and can provide testimony as to what alternative solutions might have presented themselves to the expert as at the priority date. If the alternative solution includes the invention then this would strongly suggest a lack of inventive step. Such evidence could be particularly persuasive if the expert is not aware of the invention and can testify as being unaware of the claimed invention.

Ideally, the expert should explain his reasoning as much as possible. The conclusions are not so important as the his reasoning.

Thus, expert evidence, particularly on matters of common general knowledge and interpretation of prior art plays a crucial role in opposition proceedings.

Further articles in this series

This is the fourth instalment of a multi-part series on New Zealand patent oppositions. Other articles include: