Microsoft Corp (MSFT.O) lost a round in a potentially costly patent battle when a U.S. International Trade Commission judge on Monday found that the software giant used InterDigital Inc’s technology in its mobile phones without permission. The judge, Theodore Essex, said that Microsoft infringed two wireless cellular patents owned by InterDigital (IDCC.O), a patent licensor, and said it would not be against the public interest to ban the Microsoft devices from being imported into the United States.