Luminance, an artificial intelligence technology company, recently opened its U.S. headquarters in Chicago and some law firms in the city have already signed on to use it.Founded by researchers at the University of Cambridge in Great Britain, Luminance is a web-based technology that can read and understand legal language in contracts.Luminance and competitors Ravn Systems, eBrevia and Chicago-based NexLP are part of a trend of using AI to handle brainwork and paperwork normally handed to the legal team.“It’s …