Canadian Patents which are overbroad by reason of “mistake, accident, or inadvertence” can be unilaterally disclaimed at any time by filing a Disclaimer with the Canadian Intellectual Property Office. In Hershkovitz v. Tytco Safety Products Canada Ltd. 2010 FCA 190 the Federal Court of Appeal has given guidance as to what happens when the disclaimer is subsequently challenged as being invalid.
The Court held that Disclaimers must be narrowing in effect. Adding ‘inventive elements’ into the patent claim will result in the disclaimer being Save Now held invalid. Whether an addition is ‘inventive’ (not allowed) or a narrowing ‘essential element’ is a question of claim construction, contrasting the original claim and the amended claim as properly construed with the help of expert evidence.
If the disclaimer was broadening in effect, it will have no effect. The original claim will remain, but so will the patent owner’s claim made when submitting the Disclaimer that the claim was defective overbroad. With the disclaimer invalid, all that is left is the admission by the patentee that the original claim was defective. Consequently, the Court will hold the claim invalid automatically as a matter of law.
The relative ease of filing a disclaimer and lack of examination are attractive features to cure mistakes made in prosecution, but care must be taken to ensure they do not cause more harm than good.
By James Wagner