摘要 |
For providing an optical digitizer without expensive parts and for minimizing the device, a variation timing of an output of a linear image sensor in an optical unit is detected as a time data by using a comparator. A variation timing measuring circuit detects a variation timing of the output of the comparator. A pointed position of a position pointing device is detected from the output of the variation timing measuring circuit by obtaining an incident angle of light or shadow from the position pointing device to the optical unit.
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