| 摘要 |
A force-sensing data input device of very high accuracy and a method for operating such a force-sensing input device. An input surface is provided having a transparent faceplate which conforms to the display surface of a display device, such as a cathode-ray tube display, with which the input device is used. A flange of the input surface is separated from a rigid, conductive reference surface or frame by force-sensing piezoelectric transducers, preferably constructed of lead-zirconium titanate. At least portions of the piezoelectric transducers which are sensitive to electromagnetic interference are located within wells formed in the frame so as to be shielded. Preferably, four piezoelectric transducers are provided, one at each corner of a rectangular opening formed in the frame. To determine the point of application of force on the input surface, the outputs of the four transducers are first summed. To constitute a valid data entry attempt, the sum must exceed a first threshold while the user is pushing on the input surface. When the user releases his finger, a peak of the sum is detected, which is of opposite polarity from the polarity of the sum for the pushing direction. The individual outputs of the four sensors at the time that the peak of the sum occurs are used to calculate the point of application of the force.
|
