Jane Lambert

What is meant by an "Inventive Step"?

15 May 2001

One of the requirements of patentability is involvement of an "inventive step". Those words are defined negatively in art 56 of the European Patent Convention ("the EPC") and s. 3 of the Patents Act 1977. An invention shall be considered as having an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art. That definition introduces two related, but separate, concepts, namely the "state of the art" and " a person skilled in the art.".

"The State of the Art"

The "state of the art" is the antithesis of novelty: "an invention shall be considered to be new if it does not form part of the state of the art."   Art 54 (2) defines the state of the art as comprising

"everything made available to the public by means of a written or oral description, by use or in any other way, before the date of filing of the European patent application."

For the purposes of novelty, but not inventiveness, the state of the art also includes the contents of European patent applications filed before, but published after, the date of filing of an application for a European patent for the invention in question where both applications design ate the same contracting state.   A disclosure of the invention to the public made less than 6 months before the date of filing of a European patent application is disregarded in two circumstances.   The first is where the disclosure was due to and in consequence of an evidence abuse in relation to the applicant or his legal predecessor. An obvious example of such abuse would be a disclosure in breach of confidence.  The second exception is where the applicant or his predecessor in title has displayed the exhibition at an official, or officially recognized exhibition.  That exception is conditional upon the applicant's stating that the invention has been so displayed at the time of filing and supporting his application with a certificate in the form specified by the Implementing Regulations. The reason for this exception is that art 11 of the Paris Convention for the Protection of Industrial Property requires member countries of the Union for the Protection of Industrial Property to grant temporary protection to patentable inventions, utility models, industrial designs and trademarks in respect of goods exhibited at officially recognized exhibitions held in the territory any of any member of the Union.

"The Person skilled in the Art"

A "person skilled in the art" is not, as Laddie J observed in Pfizer Ltd.'s Patent [2001] FSR 16, at paragraph 62, "a real person" but "a legal creation."  His function is "to offer an objective test of whether a particular development can be protected by a patent."  The reason for the test is that anything that is obvious over what is available to the public should not be the subject of a monopoly.   The artificiality of the concept is clear from considering the skilled man's attributes.   In the words of Laddie J:

"He is deemed to have looked at and read publicly available documents and to know of public uses in the prior art. He understands all languages and dialects. He never misses the obvious nor stumbles on the inventive. He has no private idiosyncratic preferences or delights. He never thinks laterally. He differs from all real people in one or more of those characteristics. A real worker in the field may never look at a piece of prior art - for example he may never look at the contents of a particular public library - or he may be put off because it is in a language that he does not know. But the notional addressee is taken to have done so." (paragraph [62]). 

A skilled man may in some circumstances be a notional team, which can include a forensic engineer in cases like PCME Ltd. v Goyen Controls UK Ltd. [1999] EWHC Patents 264, [1999] FSR 801 where a manufacturer has taken steps to inhibit reverse engineering.  In Pfizer Ltd.'s Patent, for instance, Laddie J concluded that the skilled addressee in a case concerning a substance for treating penile dysfunction "would have relevant but unimaginative expertise and knowledge in the fields of pharmacology, chemistry and urology" which would include knowledge for most of the relevant treatments and non-inventive expertise in relation to the naturally occurring agents of such dysfunction.  In Kirin-Amgen Inc.'s Patent, where the patent in suit concerned the synthesis of a hormone that stimulates red blood cell production, Neuberger J held that the notional team would include three PhD’s with several years experience in gene technology, molecular biology and cell biology, respectively, at least one of whom would have had experience of proteins in general and glycoproteins in particular, as well as two laboratory technicians well acquainted with gene technology and biochemical techniques.

The Windsurfing Test

In Windsurfing International Ltd. v Tabur Marine (Great Britain) Ltd. [1985] RPC 59, Oliver LJ proposed the following four-point test of obviousness at page 73:

• the court identifies the inventive concept embodied in the patent in suit;

• assuming the mantle of the person skilled in the art as at the relevant date, the court will impute to him the common general knowledge as at that date;

• it will then identify what (if any) differences exists between the matters cited as being "known and used" and the alleged invention; and

• he court will then decide whether, viewed without any knowledge of the alleged invention, those differences constitute steps which would have been obvious to the skilled man or whether they required any degree of invention.

This test refers to yet another concept, namely that of "common general knowledge" supposedly possessed by the notional skilled addressee. 

Common General Knowledge

Common general knowledge is not the same as the "state of the art" and it serves a different purpose.   It is part of the toolkit of the notional person or team of persons skilled in the art which the court will assume when determining the third and fourth questions of the Windsurfer test. Lord Diplock referred to common general knowledge as "practical knowledge and experience of the kind of work in which the invention was intended to be used" in Catnic Components Ltd. v Hill & Smith Ltd. [1982] RPC 182, 242.  Laddie J amplified the expression in relation to a notional addressee in Raychem Corporation's Patents [1998] RPC 31:

"It includes all that material in the field he is working in which he knows exists, which he would refer to as a matter of course if he cannot remember it and which he understands is generally regarded as sufficiently reliable to use as a foundation for further work or to help understand the pleaded prior art. This does not mean that everything on the shelf which is capable of being referred to without difficulty is common general knowledge nor does it mean that every word in a common textbook is either. In the case of standard text books it is likely that all or most of the main text will be common general knowledge." 

Evidence of what was common general knowledge at the date of the application of a patent has to come from expert witnesses but that gives rise to two problems that Neuberger J identified in Kirin-Amgen at paragraph 68:

"The first is that they are giving evidence about the state of knowledge as at a date significantly earlier than that on which they are considering the matter; particularly in an area where the science and technology are advancing very fast, as in the present case, that is a particular difficulty. Secondly, the court will normally be hearing from experts who are considerably more skilled, considerably more informed, and indeed inventive, than the notional addressee." 

Such experts will, as Laddie J said in Pfizer at paragraph 64, have acquired additional, private knowledge that they will have gained from their own research much of which may have been confidential.   Personal knowledge forming part of the witness's personal toolkit would not be part of the notional addressee's.  

 The EPO Approach

Some of these conceptual difficulties arguably result from the British approach to obviousness developed with regard to the previous patent legislation.   The approach of the Boards of Appeal of the European Patent Office appears to be slightly different.   In Yushiro Chemical Industries Co. Ltd.'s Application T-9876/96, unreported 3 March 2001, the Technical Board explained that for deciding whether or not a claimed invention involves an inventive step, the Boards of Appeal consistently apply what the Board called "the problem and solution" approach.   That approach, involves essentially:

(a)  identifying the closest prior art,

(b)  assessing the technical results (or effects) achieved by the claimed invention when compared with the closest state of the art established,

(c)   defining in the light thereof the technical problem which the invention addresses and successfully solves,

(d)  verifying that the defined technical problem is solved by the embodiments encompassed within the claimed solution, and

(e)  examining whether or not a skilled person starting from the closest prior art would arrive at something falling within Claim 1 by following the suggestions made in the prior art in the sense of Article 54(2) EPC. 

If the technical results of the invention provide some improvement over the closest prior art, the problem can be seen as providing such improvement, provided this improvement necessarily results from the claimed features for all that is claimed. If, however, there is no improvement, but the means of implementation are different, the technical problem can be defined as the provision of an alternative to the closest prior art."

This approach does not dispense with the need to consider what was common general knowledge altogether, but it may limit the scope, and concentrate, the enquiry. For instance, in the particular case before it, once the solution embodied in the invention had been identified, the  Board readily concluded  with only a passing reference to common general knowledge that such solution would have been obvious to the skilled addressee at the relevant time.  The relative brevity of many Board decisions certainly suggests that the EPO's approach is simpler and more efficient than the Windsurfing approach.   However, appearances may be deceptive. In comparing decisions of the Boards of Appeal with judgments of English courts it is important to remember, first, that each case depends on its own facts and, secondly, the questions listed by the Technical Board in Yushiro are essentially the same as those of Oliver LJ in Windsurfer, albeit in a different order.  It could be added that it is not clear how the closest prior art can be identified before the inventive concept. 

Changes to the EPC

The Act Revising the Convention on the Grant of European Patents made no change to article 56 but it has changed the definition of the "state in the art" in two respects.  The first change, which affects novelty but not affect inventiveness for the reason set out above, is the deletion of paragraph (4) of article 54.  The inclusion in the state of art of the content of European patent applications filed before but published after the application in question will no longer be conditional upon the designation of the same contracting states in the previous filing. The second change, which will affect inventiveness, is the insertion of new paragraphs (4) and (5) into article 54 that make it clear beyond peradventure that a second medical or veterinary use of a known substance or composition may be patentable.