Instrument Detection with an Optical Touch Sensitive Device

摘要

An optical touch-sensitive device detects touch events caused by instruments (e.g., pens, styluses) and distinguishes these events from touch events caused by fingers. In some embodiments, different instruments can also be distinguished. The optical touch-sensitive device includes multiple emitters and detectors. Each emitter produces optical beams which are received by the detectors. The optical beams preferably are multiplexed in a manner so that many optical beams can be received by a detector simultaneously. Touch events disturb the optical beams, for example due to frustrated total internal reflection. Information indicating which optical beams have been disturbed is analyzed to detect one or more touch events. The analysis also distinguishes instrument touch events from finger touch events.

主权项

1. A method for detecting an instrument touch event on a touch-sensitive surface, the surface having emitters and detectors arranged around its periphery, the emitters producing optical beams received by the detectors, the instrument touch event disturbing the optical beams, the method comprising:
receiving information indicating which optical beams have been disturbed; analyzing the received information to detect one or more touch events; and based on said analysis, identifying at least one of the touch events as an instrument touch event rather than a finger touch event, wherein the instrument is an active instrument.