Davies v Lazer Safe Pty Ltd  FCAFC 65
Patents – construction – infringement – validity only if primary judge’s construction was wrong
Justices Greenwood, White and Burley addressed an appeal by Kevin Davies from a finding by McKerracher J in May last year that Lazer Safe Pty Ltd did not infringe various claims of his patent for “A Safety System” applied to machinery with moving parts such as a press brakes – stopping the movement of the parts when an obstacle is detected in the path of the moving part. Justice McKerracher had also dismissed a cross-claim by Lazer for invalidity of the asserted claims, which Lazer cross-appealed, but only if the Full Court found McKerracher J had erred in finding the asserted claims were not infringed.
The primary issue in the appeal concerned the findings made by McKerracher J in relation to the construction of claim 1 of the Patent, which construction meant Lazer did not infringe. While the Full Court agreed with his Honour’s conclusion as to infringement of claim 1, they disagreed with some aspects of how his Honour reached that conclusion. Those errors are the focus of this note.
The patent commenced by identifying how prior art safety systems included the use of light beams which, when disturbed by an obstacle, would cause the moving parts of a machine to stop moving. The difficulties identified with such prior art systems included “the need to re-align the light beams when tools are changed, and the possibility that an operator may move his or her hand under the tool just as the beams are deactivated. Also, as with light curtains, all parts of the work must be kept clear of the beams, because operator confirmation is required every time a new obstruction is encountered.” The patent stated that the invention sought to overcome at least some of these difficulties.
Claim 1 (with the various integers identified by numbers) was to:
“(1.1) A safety system for use with a machine having a moving part arranged to move through a known path of movement, the safety system characterised by comprising: (1.2) at least one light emitting means arranged to emit light; (1.3) the axis of the emitted light being generally perpendicular to the path of movement of the part such that a region including at least a portion of said path is illuminated; (1.4) at least one light receiving means arranged to receive light from the or one or more of the light emitting means which has passed through said region; and (1.5) a processing and control means arranged to receive image information from the light receiving means and thereby recognise the presence of one or more shadowed regions on the light receiving means cast by obstructions in the region; (1.6) wherein the illumination of the region is such that the processing and control means has sufficient image information to determine the boundaries of the or each shadowed region and control movement of the part dependent on said image information.”
The debate on infringement concerned the construction of integers 1.5 and 1.6. Readers may recall from our note on the primary judge’s decision that Davies asserted that claim 1 did not require the shape of an obstruction to be determined and did not require a comparison with a stored image. Lazer’s position, accepted by McKerracher J, was that the claim required the system to determine the shape of any obstruction and compare that against stored images and thereby control the movement of the part based on the determination of identification of the shape of the obstruction. His Honour did so by noting that his preferred dictionary meaning of “recognise” is “to know again; perceive to be identical with something previously known” and then pointed to descriptions of systems in the patent which required identification of specific shapes of the obstruction.
However, as the Full Court observed, to adopt that meaning is to set to one side the words “the presence of” that immediately follow the word “recognise”. That is, if one recognises the “presence of” something, that does not necessarily mean one recognises what that thing is. Their Honours therefore preferred another dictionary meaning of “recognise” being simply “to perceive as existing” rather than as inviting comparison with something previously known. Furthermore, the Full Court considered that the primary judge relied on a preferred embodiment of the invention to construe the claim, when the patent made clear there were four methods by which a shadow of the obstruction might be perceived, only two of which required the shape of the shadow to be recognised. Accordingly, McKerracher J fell into error by adding limiting glosses to the clear and broad words of the claim.
However, luckily for Lazer, that was not the end of the matter. There remained one issue of construction of integer 1.6, where McKerracher J held that, even if the system need not recognise the shape of an obstruction, because a “boundary” must enclose “a region or area, extending around the entire perimeter of an object”, claim 1 “requires the boundary determination of an obstruction claimed by recognising a realistically substantial portion or part of the shadowed region, so as to determine a sizable portion of the outline or shape of the obstruction, in contrast to a dot, spot, point or edge of any such region.” Lazer’s product did not determine a sizable portion of the outline of any obstruction.
The Full Court identified the construction issue in relation to this aspect of integer 1.6 as: what is meant by the requirement that the illumination of the region is such that the processing and control means has “sufficient image information to determine the boundaries of the or each shadowed region”? The Full Court concluded that the processing means must have sufficient information to be capable of controlling the movement of the part dependent on identifying the bounds or limits of the shadowed region. Put another way, integer 1.6 required the system to first determine the boundaries of the, or each, shadowed region, and secondly, control movement of the part dependent on the image information. The word “boundaries” had no antecedent in the language of the specification and was to be understood as requiring identification of a realistically substantial portion or part of the shadowed region so as to determine the outline or shape of the obstruction.
Finally, the Full Court reiterated that, even if a construction leads to redundancy with respect to other dependent claims, that does not mean the construction must be wrong – the latter claims may simply be poorly drafted.