| 摘要 |
PROBLEM TO BE SOLVED: To enable the using of a wider range of variable display speed when a variable display device is constituted of a variable display member rotated with a motor. SOLUTION: Larger fluctuations occur at one or a plurality of points (resonance points) in the speed over 30 ms/step but the differentiation of drive voltage causes a change in the location of the fluctuations. Therefore, the resonance points can be avoided at any level of speed by altering the drive voltage for changing torque. For example, at the drive voltage of 5V, a resonance point exists near the 22 ms/step but at the drive voltage of 11V, no resonance point exists near the 22 ms/step. Hence, in using the speed of 22 ms/step, the drive voltage should not be given 5V. The generation of the drive voltage by a PWM waveform allows easily changing of torque (current) by varying the frequency of a PWM signal. |
