| 摘要 |
Correction lenses (21,22) are provided to correct jitter movement of focused image. Lenses are driven with stepping motors (133,134). Difference of angle position data of optical axis of double telescope and of drive amount of correction lenses is determined. The device determines the different of the angle position data of the optic axis of the double telescope and of the drive amount of the correction lenses. If the difference overshoots a positive threshold value, the stepping motor is activated in clockwise direction. If the difference undershoots a negative threshold value, the stepping motor is activated in anticlockwise direction to compensate the difference. If the difference lies between the positive and negative threshold values, the stepping motor is not activated. Threshold value is a quarter of the drive amount of correction lenses corresponding to turn of stepping motor
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