Two more companies leapt on the smartphone lawsuit merry-go-round as Sony filed a complaint seeking to block LG Electronics from shipping phones to the US.
The patent infringement filing is the latest case in a frenetic 18 months of legal activity for the industry. Companies including Apple, Nokia, Motorola, Microsoft and Google could all see the inside of the court room in 2011.
Sony filed its complaint on Wednesday to the International Trade Commission (ITC), a body that is seeing an increasing number of smartphone suits.
Carolina Milanesi, an analyst at Gartner, said: "It's a strange move by Sony because they have little share of the smartphone market in the US. LG is really eating into their market share in Europe." She added: "We can now wait for LG's countersuit - that's the way these cases have normally gone."
Sony said the phones, which include the Encore, LG Accolade and the Rumor Touch, have technology that infringes its patents and would violate trade rules. It also filed a suit against LG in the Los Angeles.