US Patent 7348969 Passive light stylus and user input device using same

The present disclosure provides a passive light stylus that produces a defined intensity profile detectable by a user input device when at least a portion of a tip of the stylus is proximate an input surface of the user input device. In some embodiments, the stylus includes a housing including an entrance aperture configured to collect ambient light and an exit aperture configured to emit the collected light, where the exit aperture is proximate a tip of the stylus. The stylus also includes a light guide disposed within the housing, where the light guide is in optical communication with the entrance aperture and the exit aperture such that the light guide directs collected light from the entrance aperture to the exit aperture.