Recent case law confirms the priority date of a divisional
patent application is the priority date of the parent patent
Patents provide 20 year monopolies over inventions. However, to
be granted a patent, the invention must be new. This means that use
or disclosure of the invention to the public before the patent is
filed can be fatal to the patent application. Traditionally, a 12
month 'grace period' was allowed and that 12 months was
back-dated from the date that a patent application was filed.
In Mont Adventure Equipment Pty Limited v Phoenix Leisure
Group Pty Limited  FCA 1467, which involved a subsequent
divisional patent application, the issue before the Courts was
whether that grace period for the divisional patent application
should be back-dated from the parent application (which is earlier
in time) or the divisional application (which is later in time and
therefore could potentially jeopardise the patent).
Before the first instance decision was handed down in November
2008, it was commonly assumed that the grace period for publication
or use of the invention was back-dated from the date of filing of
the parent patent application and that this grace period also
applied to the patent's divisional application, even though the
divisional application would be filed later than the parent
application. Contrary to the expectations of many in the industry,
the first instance decision overturned this commonly held
assumption. On appeal the Full Federal Court has, however,
confirmed that the grace period of a divisional application begins
from the priority date of the parent application.
The decision turned on the interpretation of regulation 2.2(1A)
of the Patent Regulations 1991 (Cth). Regulation 2.2(1A),
coupled with section 24(1)(a) of the Patents Act 1990
(Cth), provides that the person making the decision about whether
an invention is novel or involves an inventive or innovative step
must disregard any information made publicly available (by
publication, disclosure or use of an invention) within 12 months
before 'the filing date of the complete application'.
The issue before the Court was whether, for divisional
applications, the priority date (the date that the grace period
commenced) was one year prior to the filing date of the parent
application or one year prior to the filing date of the divisional
application. The Full Court confirmed on appeal that the Act and
its Regulations are intended to ensure 'that the requirements
of novelty and inventive step or innovative step for the claims
within the divisional application (which are essential determinants
of the validity of the patent application) are assessed by
reference to a priority date established by the date of the earlier
(or parent or original application), rather than the later (or
divisional) specification' (per Jagot J at 76). In other words,
the priority date of a divisional patent application is the
priority date of the parent patent application.
For Mont Adventure, this meant that the disclosure of its
invention by public sale less than 12 months before the filing date
of its parent application did not affect the novelty, and thus the
validity, of its divisional patent application, even though the
public sale of the invention occurred more than 12 months prior to
the filing date of its divisional application.
The Full Federal Court has made it clear that, in the case of
divisional applications, the priority date is one year prior to the
filing date of the parent application not one year prior to the
filing date of the divisional application, as illustrated by the
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This publication is intended as a first point of reference and
should not be relied on as a substitute for professional advice.
Specialist legal advice should always be sought in relation to any
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