Practice and Procedure – whether extent of discovery may be limited by reference to the parties’ contended claim construction
As many readers – and particularly those from common law jurisdictions – will be aware, ‘discovery’ (or ‘disclosure’) is the process by which the parties to a legal dispute are able to obtain relevant evidence from each other prior to the commencement of the main trial.
Discovery can be vital in patent infringement proceedings, because sometimes it is not possible to demonstrate that a particular accused product or process infringes a patent without access to technical information known only to the alleged infringer. Often the patentee will seek discovery of a wide range of material, while the accused infringer will resist extensive discovery on the basis that much of what is being sought will not be relevant, and the patentee is merely engaging in a ‘fishing expedition’.
Of course, an apparatus or process will only be infringing if it falls within the scope of one or more claims of the patent. Consequently it is possible, in principle at least, that the legitimate extent of discovery may depend upon the proper construction (i.e. interpretation) of the patent claims. In Australia, disputes over claim construction are decided by the court during the main trial, and not at some preliminary stage (such as the ‘Markman hearings’ normally held for this purpose in the US).
So what happens if the parties disagree on the proper construction of the claims in the course of discovery?
DISPUTED DISCOVERYIn this particular case, before Justice Jagot in the Federal Court of Australia, the patentee (Siemens) is seeking discovery of documents in the possession of the alleged infringer (GE Betz) relating to methods and apparatus for periodically cleaning hollow fibre membranes by backwashing. GE Betz disputed discovery of certain categories of documents sought by Siemens, on the basis that they are not relevant according to a construction of the claims proposed by GE Betz. Siemens has rejected this construction, but has thus far not put forward any specific competing construction of its own.
GE Betz resisted discovery of documents relating to:
- the velocity and direction of permeate flow throughout its backwash process;
- the direction and magnitude of any transmembrane pressure gradient throughout its backwash process;
- the presence and magnitude of any pressure wave(s) generated during its backwash process;
- instructions for use of or inducements to use the GE Betz systems;
- advertisements dealing with the operational parameters of the backwash process; and
- the use or uses to which the GE Betz systems have been put by customers.
RELEVANCE OF PROPOSED CLAIM CONSTRUCTIONGE Betz argued that its ‘analysis of the patent shows that the novel aspect of the claimed invention is limited to the integer of the “rapid reversal of liquid flow”, sufficient to cause what is described as “water hammer”. For this reason, the respondents take the view that the issues between the parties are effectively limited to those relating to rapidity of flow.’ (At .)
In the time-honoured manner, GE Betz characterised these aspects of Siemens’ discovery as a ‘fishing expedition’.
On the question of the relevance of the disputed claim construction, the court found in favour of Siemens (at ):
Construction of the claims of a patent is ultimately a matter for the Court, and experience shows that there might be many competing constructions available. In these circumstances I cannot see any proper basis upon which the applicants should not obtain discovery in relation to the whole of the backwash process …. If only part of the backwash process is disclosed, there is a real risk that an incorrect impression of that process may be obtained, not only by the applicants but also by the Court. There is also a risk that the parts disclosed may make little sense without an understanding of the whole.
COMMENTThe key factor here is that, as Justice Jagot has stated, the correct construction of patent claims is a question of law, rather than fact, which is ultimately a matter for the court.
Proposed constructions of the claims put forward by one or other party at an early stage of proceedings are no basis to limit discovery, since the court will require all relevant facts in order to reach a decision on the matters before it – including the question of claim construction.