OPTICAL PROXIMITY SENSOR FOR TOUCH SCREEN AND ASSOCIATED CALIBRATION TOOL

摘要

A proximity sensor including a housing, light emitters mounted in the housing for projecting light out of the housing along a detection plane, light detectors mounted in the housing for detecting amounts of light entering the housing along the detection plane, whereby for each emitter-detector pair (E, D), when an object is located at a target position p(E, D) in the detection plane, corresponding to the pair (E, D), then the light emitted by emitter E is scattered by the object and is expected to be maximally detected by detector D, and a processor to synchronously activate emitter-detector pairs, to read the detected amounts of light from the detectors, and to calculate a location of the object in the detection plane from the detected amounts of light, in accordance with a detection-location relationship that relates detections from emitter-detector pairs to object locations between neighboring target positions in the detection plane.

主权项

1. A calibration tool for calibrating parameters of a proximity sensor strip comprising a plurality of emitters E and detectors D, wherein the emitters and detectors are arranged such that the emitters project light out of the strip along a detection plane and the detectors detect light entering the strip along the detection plane, and for each emitter-detector pair (E, D), when an object is located at a target position p(E, D) in the detection plane, corresponding to the pair (E, D), then the light emitted by emitter E is scattered by the object and is expected to be maximally detected by detector D, the calibration tool comprising:
a reflective object placed parallel to the proximity sensor strip in the detection plane, the reflective object spanning the length of the proximity sensor; a mechanism for incrementally moving said reflective object towards or away from the proximity sensor along the detection plane; and a processor coupled with the proximity sensor strip and with said mechanism operable to (i) activate a plurality of the emitter-detector pairs (E, D) at each incremental move of said reflective object, (ii) measure detections detected by detector D of each activated pair, and (iii) calibrate the target positions p(E, D) in the detection plane according to the distances between the sensor strip and the reflective object at which maximum detections are measured.