(Reuters) – U.S. solar panel maker First Solar (NASDAQ:) has notified several large rivals that it believes they are infringing on its patents on a leading solar technology, executives said on a conference call with analysts on Tuesday.

First Solar said it has sent letters, through its attorneys, to Canadian Solar (NASDAQ:), JA Solar, Longi, Jinko Solar and Trina Solar, according to a slide presentation on its web site.