OPTICAL COORDINATE INPUT DEVICE

摘要

PURPOSE:To attain the input of coordinates with high stability and accuracy by using a correction data storage means and a correction means for correction of the output variance of each photoreceptor. CONSTITUTION:A ROM 32 storing the correction data serves as a correction data storage means. A microprocessor 26 delivers a read address to the ROM 32 with the timing synchronous with the reading of output of each photoreceptor. The correction data read out of the ROM 32 is supplied to a subtractor 36 serving as a correction means via a D/A converter 34. The subtractor 36 subtracts the correction data from the output signal of the photoreceptor supplied via an amplifier 28. This value of subtraction is supplied to a microprocessor 26 via an A/D converter 30 as the data obtained after correction. Thus the output signal of the photoreceptor free from variance is supplied to the processor 26. This secures the stable and accurate detection of the coordinate value.