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Patent claim construction: a red hot issue

7 minute read

Bitech Engineering v Garth Living Pty Ltd [2009] FCA 1393

The crucial role of patent claims, and the importance of the interpretation given to them by a Court, are highlighted in this decision of Justice Foster in the Federal Court of Australia. The surprising construction given to the claims by the Court in this case reminds us that, in some circumstances, the extent of the contribution a feature makes to an apparatus or process will be taken into account when interpreting patent claims.

Facts of the case

Bitech Engineering (Bitech) brought patent infringement proceedings against a number of parties, including Garth Living Pty Ltd, Bunnings Group Limited, Flameglow Pty Ltd and Hotpoint (Aust) Pty Ltd (the Respondents) for infringement of its Australian Patent entitled “Apparatus for Simulating Flames” (Patent). The claimed device simulates flames in electric and gas fired room heaters, making it appear as if flames arise from burning wood or coal. Although some of the Respondents brought cross-claims for revocation of the Patent, the Court’s findings on the crossclaims are unsurprising and not of note. The primary issue in the proceedings was whether the Respondents’ heaters infringed the Patent.

The decision

The Court concentrated its attention on the interpretation and infringement of claim 1 of the Patent, which was directed to an:

“Apparatus for simulating flames, the apparatus comprising:



  • a source of light;





  • simulated flame effect means for reflecting said light to simulate flames;





  • simulated fuel means to simulate a bed of combusting fuel; and





  • screen means on which to view an image of the simulated flames,

    said screen means being positioned between said flame effect means and said simulated fuel means, said screen means being capable of diffusely transmitting light reflected by said flame effect means and also being capable of reflecting light from said simulated fuel means so that the simulated flames appear to emanate between the simulated fuel means and an image of the latter means reflected in said screen means. (emphasis added).”



The structure of this claim suggests that at the time it was drafted, the feature of the apparatus which was considered to be different from the prior art was the nature of the “screen means”. However, this feature was not in issue in this case, and the Court’s consideration of the scope of this claim related to the “simulated flame effect means” feature.

The Court considered that the “simulated flame effect means” in the claim is a flame effect means which “reflects light from the light source to the viewing screen through which that reflected light is diffusely transmitted in order to create flame images on the screen.” That is, “the essence of the way in which light from the light source is ultimately used to create the images of flames on the screen is reflection“. (emphasis added)

The Court’s emphasis on reflection as being an essential part of the operation of the flame effect means is unsurprising given the use of the word “reflecting” in the part of the claim describing the simulated flame effect means.

The question that needed to be answered to determine whether the Respondents’ products infringed claim 1 was: did the Respondents’ products have all of the features of the claim, including a “reflective” flame effect means?

The Respondents’ heaters used a flame effect means which caused a flame effect on a screen by virtue of both reflection and direct emission. Unsurprisingly, the evidence in the case was primarily directed to whether the Respondents’ devices had a “reflective” flame effect means. That is, whether a substantial part of the flame effect was caused by reflected light.

Although the Court would be expected to determine what falls within and outside the scope of a “reflective” flame effect means, it went a step further and defined the devices that would fall outside the scope of the claim by reference to whether those devices had a “direct emission” flame effect means:

“Claim 1 does not contemplate, in my opinion, that the flame effect means will substantially rely upon or involve to any significant degree a process whereby light is directly emitted from that means to the viewing screen so that the images viewed on the screen are substantially or predominantly the result of the transmission of light directly emitted from the flame effect means.(emphasis added).”

Although the Court found that:

  • the images created from reflected light in the Respondents’ devices contributed to the observable flame effect “to some extent”; and
  • the reflected light “results in the formation of flame shapes on the viewing screen and other images which are visible to the users of the Respondents’ heaters when those heaters are put to their ordinary use”,

the Respondents were held not to infringe the Patent because the “substantial and predominant contributor” to the light which was the source of the flame shapes observable on the screen was light which was directly emitted and not reflected.

While the Court’s reasoning on this issue is not explicit, it appears that the Court considered that the presence of a flame effect means that relied substantially upon directly emitted light, that light being the dominant source of simulated flames, precluded the presence of a flame effect means that relied on reflected light as claimed.

Choice of experts

Also of note in this case is the selection of expert witnesses by the parties.

As indicated above, the issues in the case related to whether the simulated flame display was primarily caused by reflection or direct emission. This involved consideration of:

  • how much of the display was the result of reflection;
  • how much of the display was the result of direct emission; and
  • to the extent any part of the display was the result of reflection, did that part of the display result from the operation of a “flame effect means” which simulated flames.

The parties chose to engage University professors in physics to act as expert witnesses. Although the Court commented that “none of the experts had ever been involved in the design or manufacture of heaters or devices endeavouring to simulate flame effects”, the Court was not critical of the selection of experts. It simply did not rely heavily on the expert evidence, preferring to place reliance on its own observations of demonstrations conducted in the Court using examples of the Respondents’ heaters.

In retrospect, it seems that evidence from such highly qualified experts was unnecessary, especially as there was no controversy about whether the Respondents’ devices had “direct emission” flame effect means or whether direct emission was responsible for the strongest and brightest simulated flames. In addition, the experts were unsuitable for providing any evidence directed to whether the claimed invention involved an inventive step, as the patent is directed to people who design and manufacture room heaters, not academic physicists.


It appears that the reasoning behind the decision in this case was a surprise to the parties. Presumably being of the view that the controversy related to whether or not the Respondents’ heaters had the claimed feature of a “reflective” flame effect means, the parties adduced evidence from highly qualified experts in physics. However, the Court identified the controversy as relating to whether or not the Respondents’ heaters primarily relied upon a “direct emission” flame effect means, rendering much of the expert evidence of little assistance. Thus, the importance of a claimed feature to the ultimate product appears to have informed the Court’s views on whether a product containing that feature infringes the claim.

This case serves as a reminder that claims should be drafted to be clearly inclusive of recited features or steps, and that claim interpretation is a crucial aspect of patent litigation that deserves significant time and attention.

Bitech has appealed this decision to the Full Court of the Federal Court of Australia.