Aperio Technologies Inc. of Vista, Calif., a digital pathology services provider, has filed a lawsuit against Hamamatsu Photonics KK, Hamamatsu Corp. and Olympus America Inc. for infringement of US Patent Nos. 6,917,696, 7,457,446 and 7,518,652. Filed in the US District Court for the District of Delaware, the lawsuit alleges that Hamamatsu’s NanoZoomer, a digital pathology system distributed by Olympus America, infringes the three patents.