| 摘要 |
PURPOSE:To prevent a decrease in detection sensitivity due to variance in electrode capacity inherent to each touch electrode, by making the frequencies of retrieval signals supplied from an oscillator to the retrieval touch electrodes different in correspondence to the inherent electrode capacity of each touch electrode. CONSTITUTION:The inherent electrode capacities CY1-CY3, and CX1-CX3 of the touch electrodes Y1-Y3, and X1-X3 and contents corresponding to the resonance frequency of a resonance circuit consisting of respective resonance circuit 2 are stored in a storage element 3a. Touch electrode selecting signals for selecting the electrodes Y1-Y3, and X1-X3 successively are inputted to the storage element 3a of the oscillator 3, whose output is inputted to a D/A converter 3b. The output of the converter 3b is supplied to a voltage frequency converting circuit 3c. Consequently, when some touch electrode is selected, the selected touch electrode is supplied with a retrieval signal of frequency coincident with the resonance frequency of a resonating circuit 2 including the electrode capacity of the touch electrode from the oscillator 3. Thus, a decrease in detection sensitivity due to variance in electrode capacity inherent to each touch electrode is removed. |
