| 摘要 |
PURPOSE:To obtain an image picture operating device which has no cables and does not require the pen pressure, by providing a light pen having a driving power frequency selecting means and a frequency detecting means in the receiving face side. CONSTITUTION:An AC oscillator 8 using a battery 10 as the power source oscillates a frequency f1 different from a flickering frequency f3 of a fluorescent lamp to flicker a light emitting element 7. Coordinates are detected in accordance with the fact that a ratio of the current flowed to a counter electrode is proportional to the distance from a light spot to each electrode. When a switch 9 is depressed, a frequency f2 different from frequencies f1 and f3 is set. The signal f3 due to external diffused light of illumination or the like is eliminated from the output signal of a semiconductor optical position detecting element by a filter 31, and the output signal passes an F/V conversion circuit 4 to become an output of a voltage V1 corresponding to the frequency f1 and a voltage V2 corresponding to the frequency f2. This output passes an A/D conversion circuit 5 to discriminate whether the light pen switch 9 is depressed or not by a microcomputer.
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