Construing relative terms in Australian patent claims: when expert evidence does not assist

Dr Victoria Longshaw and Dr Nigel Parker

In a recent decision, Fei Yu trading as Jewels 4 Pools v Beadcrete Pty Ltd [2014], the Federal Court of Australia dismissed an appeal by Fei Yu trading as Jewels 4 Pools, and it distributors (“the Appellants”), against the primary Court’s decision to uphold Beadcrete Pty Ltd’s (“the Respondent”) Australian Patent No. 733668, and confirmed infringement by Fei Yu, and it’s distributors.

This decision provides a useful construction of the relative term “average” as used in the claims of the patent at issue. The way in which the court approached the interpretation of this relative term is relevant to Applicants prosecuting Patent Applications in Australia.

The Patent

Australian Patent No. 733668 relates to surface finishes for pathways, walls, swimming pools and other structures. The claimed invention is directed to aggregate mixes which include glass beads mixed in a matrix of cementitious material. Beadcrete Pty Ltd had observed difficulty in using glass beads, either alone or with other aggregate materials such as semiprecious stones etc. in such aggregate mixes, as the glass beads tended to lack the required porosity or toughness to establish an effective bond with a matrix material. The glass beads also tended to impart alkalinity.

In solving this problem, Beadcrete Pty Ltd had claimed an invention having glass beads of varying sizes with an average particle size within the range of 1.5 to 4.5 mm, and having a size distribution defining a major component of beads within a relatively large incremental size range and a minor component of beads in a smaller incremental size range, the weight of the beads in the larger incremental size range being greater than those within the small incremental size range.

Validity Issues

On appeal, the Appellants argued that the majority of the claims were unintelligible, incapable of infringement, and invalid because the claim referring to the particle size distribution did not identify a “specified midpoint.” The appellants also argued that the claims lacked novelty in light of prior art which, it was asserted, disclosed the addition of large beads within the size distribution cited in the claims.

Expert evidence was submitted as to the meaning of the word “average.” This evidence was provided by an engineer who specialised in the construction of swimming pools. However, the Appellants did not suggest that the expert’s evidence was directed to the meaning of technical or scientific terms, or to unusual or special meanings.

The Respondents adopted an approach to claim construction which depended upon the term “average particle size,” submitting that the meaning of the word “average” had to be determined within the context of the definition of the particle size distribution. That is, that there were to be larger and smaller glass beads. Four meanings of the word “average” were advanced, each meaning providing a possible method for assessing the average size of particles in a sample of aggregate.

The primary judge had not been convinced that the expert for the appellants was a skilled addressee in the art, and further considered that the term “average particle size” was not a technical term requiring expert evidence, stating that it was for the Court to construe the claim. The judge concluded that an average particle size could easily have been determined by a person skilled in the art by simply identifying the weighted average particle size based on the weight distribution of different sizes of particles. The primary judge observed that “it would have been inconceivable to those skilled in the art of mixing an aggregate into a cementitious matrix to form a surface finish that they would concern themselves with the absolute number of glass beads or the absolute size of any particular glass bead, be it the largest or smallest, in any given matrix.”

The primary judge also held that the prior art did not anticipate the claimed invention because it failed to teach that there could be a particle size distribution in which there were more larger sized beads than smaller sized beads.

The Court of Appeal agreed with the primary judge’s conclusions, and upheld the patent.

The Appellants construction case, alleging that the integer citing “a particle size distribution” must be construed in isolation from other integers in the claim, was considered by the Court of Appeal to be fundamentally flawed. The Court reiterated that the meaning of each claim must be determined by reference to the words, in the context of the specification as a whole.

The infringement order was also upheld, and infringement by the respondents confirmed pursuant to section 117 of the Patents Act 1990. Section 117 provides that patent infringement occurs where a product is supplied by one person to another, in circumstances where the use of that product by that person would infringe that patent.

Take-home message

This case is a useful reminder to Patent Applicants and Patentees in Australia, that although experts may give evidence as to the meaning which those skilled in the art would give to technical or scientific terms and phrases, it is for the Court to interpret words bearing ordinary meanings. Furthermore, integers cited in a patent claim will be interpreted within the context of other integers in that claim, and within the context of the specification as a whole. In such circumstances, the submission of expert evidence as to the meaning of a relative term used in the claims, and which has an ordinary meaning, will not assist.