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Construing the (almost) un-construable - 16 September 2013


Recent authority[1] continues the Australian tradition of refusing to hold claims invalid for lack of clarity. This authority nonetheless demonstrates:

  • lack of clarity can lead to non-infringement;
  • the role of the skilled person’s common general knowledge in claim interpretation; and
  • that Australian Courts “try to give effect to the construction which affords the patentee protection for the invention”[2].

The invention

Justice Jagot’s decision in Beadcrete  Pty Ltd v Fei Yu trading as Jewels 4 Pools (No 3) [2013] FCA 187 concerned an invention relating to “surface finishes for pathways, walls; swimming pools and other structures”. The invention was defined (in claim 1) in terms of glass beads in a matrix of cementitious material,

“said beads having an average Particle size within the range of 1.5-4.5 millimeters and a particle size distribution defining, major component of said beads within a relatively large incremental size range and a minor component of said beads within a smaller incremental size range wherein the weight of beads in the large incremental size range is greater than the weight of beads within the small incremental size range”.

Common general knowledge in claim interpretation

It is well settled that Australian patent claims should be construed from the point of view of the “hypothetical skilled addressee having regard to both the common general knowledge and the specification”[3].

The applicants proffered four methods of ascertaining the average particle size, three of which were ruled out as nonsensical because they involved the consideration of individual particles. The remaining method was described as:

“identify the weighted average particle size based on the weight distribution of different sizes of particles (a weighted average, unlike an average, takes into account the frequency[4] at which each size is represented)”[5] (our emphasis).

Her Honour notes that the remaining method should not be accepted by default[6] and goes on to survey various Australian Standards (government-issued documents defining acceptable test procedures) and the patent specification for clarification of the claim language.

The Australian Standards describe the use of sieves and the weighted average particle size. Her Honour concludes:

  1. “…it was common general knowledge that the appropriate method for determining the size and weight distributions of the glass beads to be used in surface finishes was test sieves. It also would have been common general knowledge at that time that test sieves functioned by the selection of appropriate sizes of sieves which were then required to be assembled in a particular way (most basically, so that they descended in a decreasing size from the largest sieve at the top to the smallest sieve at the bottom)”[7], and
  2. certain methods (consistent with the weighted average particle size) are standard methods well known to those skilled in the art[8].

From there, her Honour finds in the patent specification confirmation of 1 and 2 above and further indication of the meaning to be given to the average particle size (which meaning is consistent with the weighted average particle size). The specification:

  • includes “[t]he average particle size, as referred to here, is the weight averaged particle size of the beads based upon the distribution of beads in the mixture”[9], and
  • specifies the average particle size of an exemplary formulation of beads which is consistent with her Honour’s calculation of the weighted average particle size of that formulation,

but does not mention sieves or specify the calculation procedure more precisely.

After this analysis, the weighted average particle size is determined to assess infringement.

Construe to afford patent protection

The claim does not specify a midpoint separating the two incremental size ranges, nor does it specify that the two incremental size ranges meet at a midpoint.

“The respondents submitted that the claims lacking any specified midpoint, claims 1 to 9 and 23 to 26, were thereby unintelligible and thus incapable of infringement (and invalid). In any group of beads there may be large and smaller beads resulting from an arbitrary definition of where the boundary between the two groups is to be drawn.”[10]

This submission is quickly dispatched:

“Further, the relatively large incremental size range and the smaller incremental size range are to be identified by reference to the weighted average particle size. No other means of identification is reasonably practicable having regard to the claims as they would be read by the skilled addressee. On this basis, it is clear that beads larger than the size of the average are in the relatively large range and beads smaller than the average are in the smaller size range.”[11]

Claims not invalid for lack of clarity

Very few Australian patent claims are held invalid for lack of clarity. This decision suggests that the requisite degree of clarity is so low that, to fail, a claim “must be one that cannot be given meaning”[12].

Lack clarity can lead to non-infringement

Whilst her Honour was able to give the claim meaning and thus held the claim valid, difficulties applying this meaning to the impugned products led to the conclusion that the patentee had not proved infringement in respect of various of those products.

The impugned products included different mixes of beads having differing particle size distributions.

To show infringement, the patentee had samples of four of the impugned products analysed (by a third party) using sieve sizes in accordance with an Australian Standard. These sieve sizes were found to differ too widely to provide a meaningful indication of the particle distribution. Accordingly, the patentee had additional testing performed with sieves of narrower size increments.

Despite these narrower size increments, in two of the four mixes tested, the average particle size fell within a range of sizes captured by a sieve that also captured a “material proportion” of the beads whereby infringement turned on the unknown size distribution within that material proportion:

“The problem, accordingly, is that a material proportion of the beads, 30%, are in the size range of 1.7 mm to less than 2 mm. The sizes within that range are unknown. As the applicants bore the onus of proof it cannot be inferred that any of those beads are greater than 1.72 mm. All of those beads might be 1.7 mm, which is less than the average particle size for the clear beads. If that 30% is allocated to the smaller size range then the integer is not satisfied as the major component of the beads is not within a relatively large incremental size range and the minor component of the beads is within a smaller incremental size range and the weight of beads in the large incremental size range is not greater than the weight of beads within the small incremental size range. It follows that the applicants have not proved any infringement…”[13].

The decision is on appeal

The other two of the four mixes tested were found to infringe the claim. The respondents (infringer) have appealed this decision and a further hearing is scheduled for 20 November 2013.



Patent attorney manufacturing 

Ben Mott - Principal

Mechanical Engineer & Patent Attorney

[1] Beadcrete  Pty Ltd v Fei Yu trading as Jewels 4 Pools (No 3) [2013] FCA 187

[2] Beadcrete at 13

[3] Beadcrete at 33

[4] In the context of the decision, it is clear that the calculation procedure contemplated is based on the particle size captured in each of a set of sieves being mathematically-weighted by the combined weight of the particles retained in that sieve (as opposed to by the number of particles in that sieve).

[5] Beadcrete at 24

[6] Beadcrete at 40

[7] Beadcrete at 35

[8] Beadcrete at 43

[9] Beadcrete at 46

[10] Beadcrete at 23

[11] Beadcrete at 50

[12] Beadcrete at 72

[13] Beadcrete at 139