Irvine-based VIZIO, the maker of HDTVs, has signed another patent license deal, this time with Seiki Digital, the company said Tuesday. VIZIO said that Seiki has agreed to make royalty payments to VIZIO for sales of licensed products. Financial details of the license were not announced. VIZIO has been aggressively signing up companies as licensees to its patent portfolio, which it describes as a "substantial worldwide patent portfolio directed to digital television technology." VIZIO has not been shy about asserting its patent rights in court, and has so far signed up such companies as Sony, ON Corporation/RCA, and others to its portfolio of patents.