Nikon has ended a four-year battle with Sigma after Nikon accused Sigma of infringing a patent for vibration reduction in DSLR lenses.

The two firms remained at loggerheads despite a Tokyo district court ordering Sigma to pay 1.5 billion yen to Nikon following a lawsuit over six lenses in May 2011.

It is unclear why the case continued for four more years but there is speculation that Sigma appealed the court ruling.

In a statement, Nikon said it had reached a judicial settlement with Sigma on 21 April 2015.

It added: ‘After receiving the Intellectual Property High Court’s recommendation for settlement, Nikon has decided to make a judicial settlement, since it saw that swiftly resolving this matter through settlement would be the best way after its comprehensive examination of the progress of the lawsuit including the Tokyo District Court’s decision.’

Nikon said it stands to receive settlement money from Sigma, but additional terms of the deal remain confidential.

In a separate statement, Sigma said both parties had ‘amicably reached a settlement on this issue’.

Sigma added: ‘However, Sigma would like their customers and users of Sigma products to understand that the settlement will not have any impact on [Sigma’s] operating activities.

‘Sigma would like to take this opportunity to thank their customers for their continued support.’

Sigma statement in full:
Tokyo, Japan– April 21, 2015– SIGMA Corporation (hereafter referred to as “SIGMA”) and Nikon Corporation (hereafter referred to as “Nikon”) have reached a settlement at the Intellectual Property High Court which includes a patent infringement lawsuit against SIGMA.
On May 25, 2011, Nikon filed a patent infringement lawsuit against SIGMA to the Tokyo District Court alleging SIGMA had infringed patent rights owned by Nikon and sought for an injunction and compensation for SIGMA’s manufacture and sale of infringing interchangeable lenses for single lens reflex cameras.
In the proceedings of the trials, based on the recommendation of the Intellectual Property High Court, in order to enable an early and amicable resolution of the issue, both parties have reached a mutually agreed settlement on the disputed patents.
As mentioned above, both parties have amicably reached a settlement on this issue.
The terms and conditions of the settlement agreement are to be kept confidential between both parties and are not allowed to be disclosed to a third party.
However, SIGMA would like their customers and users of SIGMA products to understand that the settlement will not have any impact on the SIGMA’s operating activities. SIGMA would like to take this opportunity to thank their customers for their continued support.

Nikon statement in full:
Nikon Corporation (Kazuo Ushida, President, Tokyo, hereafter referred to as “Nikon”) announces that it reached a judicial settlement as of April 21, 2015 with regard to the patent infringement lawsuit (hereafter referred to as “Lawsuit”) filed by Nikon against Sigma Corporation (hereafter referred to as “Sigma”) in the Tokyo District Court on May 25, 2011.
After receiving the Intellectual Property High Court’s recommendation for settlement, Nikon has decided to make a judicial settlement, since it saw that swiftly resolving this matter through settlement would be the best way after its comprehensive examination of the progress of the Lawsuit including the Tokyo District Court’s decision.
Nikon will receive settlement money from Sigma. Additional terms and conditions of the settlement, including the amount of settlement money, are subject to confidentiality obligation between Nikon and Sigma.
Nikon estimates that the financial impact of this settlement is minimal.