Dometic discharged? Federal Court clarifies the relevant date for assessing best method

Best method requirement

Section 40(2)(aa) of the Australian Patents Act 1990 requires that a complete specification must disclose the best method known to the applicant of performing the invention. This requirement is intended to raise the standard of the social contract behind the grant of a patent: to provide the public with the full benefit of an invention, the applicant discloses the most effective means of performing the invention in exchange for a temporary monopoly. For best method, an additional good faith disclosure is required over and above the obligations towards sufficiency and enablement of the claims. Failure to disclose the best method of performing the invention can invalidate an entire patent, and has proven to be a powerful ground of invalidity attack in Australia.

In Dometic Australia Pty Ltd v Houghton Leisure Products Pty Ltd [2018] FCA 1573 (Dometic), the Court confirmed that the relevant date for assessing the best method known to the applicant is the filing date of the complete specification. However, it further considered that in the case of a divisional application, the relevant date is the date of filing the divisional application, and not the effective filing date (i.e. the date from which the patent term runs).

Following Dometic, despite having the same effective filing date (and patent term), parent and divisional applications have different dates as at which the best method known to the applicant is to be identified – which could be many years after the date at which the patent term commenced. This created a ‘best method divisional dilemma’, where applicants wishing to file divisional applications needed to include in the specification at filing any improvements to the best method developed since the effective filing date, creating not only potential added matter issues but an onerous obligation on both applicants and attorneys alike.

NOCO case

In NOCO, the patents in suit were three Australian patents (the NOCO patents) directed to portable jump starters for charging a depleted or discharged battery (e.g. a car battery) with enhanced safety features addressing risks associated with sparking, short circuits, and potential damage or injury if the jumper cables were connected incorrectly. The patents were filed as a series of divisional applications from PCT/US2014/045434 (PCT434) filed on 3 July 2014, being the effective filing date. The patents were the subject of infringement proceedings, with a cross-claim for revocation on numerous grounds. All the asserted claims were found to be invalid, despite surviving the best method challenge.

Relying on Dometic, the respondent argued that the NOCO patents failed to disclose the best method known to it as at the filing date of each divisional application, insofar that after the original PCT434 filing, the applicant had launched an improved jump starter in September 2014, the details of which were not included in any of the later filed divisional specifications.

The relevant date

In NOCO, Moshinsky J offers the view that the relevant date as at which the best method known to the applicant is to be identified is the filing date of the patent application from which the patent term runs (i.e. the effective filing date, namely the earliest complete/PCT filing date).

In arriving at this view, the previous decisions of Rescare Ltd v Anaesthetic Supplies Pty Ltd (1992) 111 ALR 205 and Pfizer Overseas Pharmaceuticals v Eli Lilly & Co [2005] FCAFC 224 were considered by Moshinsky J to be in agreement as to the date as at which the best method known to the applicant is to be identified—this date being the date from which the patent term runs.

In consequence, the best method known to the applicant at the time of the PCT filing, should be included in the PCT specification at the time of filing.

Time for reform

While Moshinsky J refused to comment on whether Dometic was plainly wrong, his judgment in NOCO constitutes a strong judicial signal that many will see as reflecting common sense. While the best method requirement remains part of Australian patent law, this decision will be welcomed by patent applicants and attorneys.

Despite this welcome decision, there remains wide support from within the profession to repeal the best method requirement. A best method requirement in Australia (and New Zealand) still makes us a global outlier in requiring such a high and arguably unfair obligation on patent applicants to disclose ongoing developments that extend beyond accepted enablement and support requirements.