| 摘要 |
PURPOSE:To obtain a new apparatus driven by an electrostrictive element from which alignment error caused by the influence of hysteresis is eliminated by a method wherein the electrostrictive device is vibrated by application of an AC voltage and a driven member is aligned by the one side peak position of the vibration. CONSTITUTION:One end of an electrostrictive element 1 is fixed to a shutter base plate 3 by a fixing member 2. Also, a shutter wing 5 and a symmetrical shutter wing are supported by a shaft 6b on the back side of the shutter base plate 3. If an AC voltage is applied to the electrostrictive element 1, the rate of distortion of the element 1 increases in accordance with the increase of the output amplitude of the AC amplifier and the shutter wing 5 opens an aperture 4 every time the electrostriction element 1 vibrates. When the charging level of a capacitor 31 reaches the level determined by the divided voltage between a variable resistor VR and a resistor R1, the output level of a comparator 33 is reversed to L level and makes a transistor 13 conductive through an inverter 34. Therefore, the electrostriction element 1 is discharged through the transistor 13 and restored from the striction state to the original state. With this constitution, accurate alignment can be achieved. |
