AuthorStanley LAI SC LLB (Hons) (Leicester), LLM (Cantab), PhD (Cantab); Barrister-at-Law (Lincoln's Inn), Advocate and Solicitor (Singapore); Head of Intellectual Property Practice, Allen & Gledhill LLP, Singapore.
Citation(2012) 24 SAcLJ 599
Date01 December 2012
Published date01 December 2012

The determination of inventive step in the law of patents is most frequently framed in terms of its interface with novelty; ascertaining the state of the art for the purposes of testing the requirement; the traits or attributes that a skilled addressee is expected to possess; and how to know if an invention is obvious to the skilled person. This article traverses these issues and considers the various legal tests (including the European “problem and solution” approach) that have evolved in different jurisdictions. The article suggests a revised prescriptive test for inventive step that may be of assistance in specific situations.

1 The policy underlying the requirement of inventive step in patent law favours the need to show inventive merit by reaching a sufficiently high level of innovative activity in order for an applicant to be deserving of a patent monopoly. Section 15 of the Patents Act1 provides:

An invention shall be taken to involve an inventive step if it is not obvious to a person skilled in the art, having regard to any matter which forms part of the state of the art by virtue only of section 14(2) and without having regard to section 14(3).[2]

2 The section is in pari materia to section 3 of the UK Patents Act 1977,3 with equivalent provisions to be found in Article 56 of the Convention on the Grant of European Patents (European Patent Convention)4 (“EPC”). These formulations prima facie mandate that the public should not be prevented from doing things that are simply “obvious” extensions of what is already in play, in terms of existing technology. Yet the concept of inventiveness remains a challenge – and more often, a mystery – to litigants who call into question or defend the validity (or lack thereof) of a patent in the course of infringement litigation or de novo patent revocation proceedings.

I. The challenge defined

3 The challenge may be defined and approached from a number of fronts, most commonly: (a) the interface between the requirements of inventive step and novelty; (b) what the state of the art for the purposes of testing the requirement is; (c) what traits or attributes is the person skilled in the art expected to possess; and (d) how to know if an invention is “obvious” to the skilled person.

4 This article engages a discussion on each of these main questions and related sub-themes, which include alternative legal tests and prescriptions for the determination of inventive step. What may appear to be rudimentary at times has morphed into a salutary reminder in the course of the research for this article. The discussion will focus primarily on UK and EU patent laws, with peripheral references to Australian and US laws, and how the principles from various decisions can be best applied by the Singapore courts in the future.5

5 It is the author's view that the EU's “problem and solution” approach is one that may be considered within a conventional structured test that has often been applied by the Singapore courts. This article concludes with the suggestion of a revised prescriptive test for inventive step that incorporates the two (apparently divergent) approaches, interwoven with other sub-questions that have also evolved in jurisprudence, which may be applicable in specific situations.

II. The interface between inventive step and novelty

6 The relationship between the concepts of novelty and inventive step in patent law is perhaps best captured by Lord Hoffmann in Synthon BV v Smithkline Beecham plc (“Synthon”):6

If performance of an invention disclosed by the prior art would not infringe the patent but the prior art would make it obvious to a skilled person how he might make adaptations which resulted in an infringing invention, then the patent may be invalid for lack of an inventive step but not for lack of novelty.

7 The quotation above is illustrative of the inherent difference between the two concepts. For novelty, a single instance of prior art must, in terms, anticipate the patentee's invention. It is not possible to combine or mosaic different documents of prior art in order to say that an invention is not novel. A mosaic may be applied for the determination of inventive step. As Lord Reid most notably said in Technograph Printed Circuits Ltd v Mills & Rockley (Electronics) Ltd (“Technograph”):7

When dealing with obviousness, unlike novelty, it is permissible to make a ‘mosaic’ out of the relevant documents, but it must be a mosaic which can be put together by an unimaginative man with no inventive capacity.

8 What is often forgotten, which can lead to some imaginative incorporations of readings of the art, is the failure to appreciate that the mosaic must be the result of a consolidating exercise undertaken by an unimaginative person who is devoid of inventive capacity. In other words, if connections have to be made across different fields and more documents would have to be put together by a skilled (but unimaginative person) to arrive at the invention, there is a likelihood that the invention may be found not to lack inventive step.8 This exercise is undertaken by the application of different factors, which include: (a) the age of the documents; (b) the role of cross-references in linking one document to others; (c) the proximity of the fields from which the prior art comes; (d) the amount of effort or analysis required of the skilled person in identifying the relevant features in the prior art; and

(e) the ubiquity of some documents in the field such that they form part of the common knowledge.9
III. What is the state of the art for the purpose(s) of evaluating inventive step?

9 Section 15 of the Patents Act10 provides that the state of the art for the inquiry as to obviousness is, broadly, not unlike that of novelty, with a notable difference whereby unpublished patent applications with a priority date that is earlier than the invention are to be disregarded. This difference highlights how the obviousness inquiry differs from that of novelty, with the former recognising that a diligent researcher11 is not expected to take into account unpublished patent applications (albeit with an earlier application date) for the purposes of investigating inventiveness. The distinction fortifies what was said in Synthon and the reality that the criterion of inventive step is something of a “movable feast”: its application is very field-specific, and resolution usually turns on the particular technical features of each case.12

IV. Attributes of persons “skilled in the art”

10 The attributes of persons skilled in the art would naturally include the extent and degree of knowledge that reside in their arsenal as at the priority date. Most often, there is field-specific knowledge to

consider in the determination of inventive step, and the diligent researcher draws on this. Common general knowledge, by contrast, is a feature of the state of the art that is not necessarily field-specific. The courts will assume that certain features in science are so obviously self-evident that they do not to be specified but can be taken to reside within the intellectual arsenal of the skilled person.

11 The numerous references made in case law to the diligent researcher stem from a skilled but unimaginative addressee who, as on the priority date, is imputed with the knowledge of prior art that merely falls within the domain of common general knowledge. The second step of the test in Windsurfing International Inc v Tabur Marine (Great Britain) Ltd13 (“Windsurfing”) makes reference to this. By reason of the mention of “common general knowledge” in this formulation, the descriptor of “diligent researcher” has evolved to suggest that the skilled addressee is entitled to disregard prior art of which he did not know or for which he was not likely to have any regard. Obscure information would be omitted from the arsenal of what the diligent researcher is taken to know. Notwithstanding the judicial pronouncements advocating the “diligent researcher” test,14 it has also been observed that the evaluation of common general knowledge runs counter to the definition of the “state of the art” in section 14 of the Patents Act.15 In First Currency Choice Pte Ltd v Main-Line Corporate Holdings Ltd (“First Currency Choice”) the Court of Appeal recognised that knowledge that is unavailable to the public should be excluded from the common general knowledge that the notional skilled person is deemed to possess for the purpose of assessing obviousness.16 However, V K Rajah JA further stated that “such knowledge is nonetheless taken into account in assessing whether an invention is novel under [section] 14 of the [Patents Act]”.17 The “diligent researcher” approach has been criticised by Lord Diplock in Technograph.18 His Lordship clearly preferred a more – and often, punishingly – exact standard of treating the state of the art in the same manner for assessing obviousness as that for novelty (save for the special case of subsequently published applications), which was required under the statutory prescription. By contrast, in the same

decision, Lord Reid preferred to limit the state of the art for obviousness to the prior art that a diligent researcher could have uncovered.19

12 Section 14(2) of the Patents Act20 defines “state of the art” for the purposes of assessing obviousness in the same way as that for novelty; any prior use or disclosure that has been made available to the public is relevant prior art for the purposes of the novelty/inventive step inquiry, even if its availability was not known to the skilled person. The reference is to “all matter”, “whether a product, a process, information about either, or anything else”.21 The exhaustive nature of this definition has led commentators to prefer the persona of the “diligent researcher”, who cannot be reasonably taken to know about all matter, and therefore represents a more realistic view. By contrast, in Australia, the concept of...

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