Bloomberg: As Lucas mentioned in comments, Intellectual Ventures (IV) sues Nikon over 4 patents infringement, 2 of them being image sensor related:
US6,221,686 "Method of making a semiconductor image sensor" originally filed by Motorola in 2000, issued in 2001, and
US6,979,587 "Image sensor and method for fabricating the same" originally filed by Hynix in 2002, granted in 2005
The two patents are a subset of the image sensor patents mentioned in IV lawsuit against Canon filed in court a month and a half ago.
According to the complaint filed Oct. 26 in federal court in Wilmington, Delaware, IV initially approached Nikon in 2008 about taking a license to the patents. Nikon declined to meet with the technology-licensing company at that time, according to court papers. In 2011, IV said it made a second approach to Nikon and its “good-faith efforts to negotiate a license” with the camera company failed.
The case is Intellectual Ventures I LLC v. Sendai Nikon Corp., 11-cv-01025, U.S. District Court, District of Delaware (Wilmington).