Japanese PV manufacturer Kyocera has filed a patent infringement complaint against Germany's Hanwha Q Cells
The action in the Tokyo District Court relates to Kyocera's Japanese patent for a "three-busbar electrode structure" - patented in March 2012 - that increases energy conversion efficiency in modules.
Japanese units of foreign players such as Hanwha Q Cells - a unit of South Korean conglomerate Hanwha - have been making substantial progress in Japan's solar market, where domestic brands such as Kyocera have traditionally been first choice.
Foreign-made panels accounted for 4.8GW of the 8.63GW of PV kit shipped in Japan in the year to 31 March.
Kyoto-based Kyocera says it is "in negotiations with other parties regarding the patent". Hanwha Q Cells, which is based in Saxony-Anhalt, was unavailable for comment.