| 摘要 |
PURPOSE:To make the constitution of the gradational display circuit much simpler than before and to reduce the IC ship area of the gradational display circuit by reducing the number of stages of a shift register required for each picture element and the number of circuit elements for extracting display commands from stage outputs. CONSTITUTION:The shift register 10 is equipped with the stages corresponding to respective picture elements in a display range and also equipped with a counter 30 which receive count pulses CP generated by dividing a display period by the number of gradations and counts the gradations in the period. Then an adding circuit 40 receives the counted value of the counter CP and a display data value and supplies the sum of both the values to the initial stage of the shift register 10 while switching the output state according to whether or not the sum is larger than the number of the gradations. Then the output state is switched by an FF50 in synchronism with the counter pulses CP according to the state change of the stage outputs provided for the respective stages of the shift register 10. Consequently, the number of the stages of the shift register 10 required for each picture element and the number of circuit elements for extracting display commands from the stage outputs are decreased.
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