| 摘要 |
PURPOSE:To improve the precision of position detection by generating a detection signal when a primary detection signal by a microswitch and a secondary detection signal by a photosensor are both inputted. CONSTITUTION:Primary detection for the position of an optical system supporting body directly by a microswitch and secondary detection by a photosensor are carried out in combination and only when position detection signals of the both are generated, a position detection signal is generated. For example, when a ball screw 2 fitted in the optical system supporting body 1 is turned by a motor 3- said supproting body 1 moves as shown by an arrow and a cam surface 7 energizes the microswitch 8. Simultaneously, a disk also rotates and a transmission type photosensor 5 provided so as to match with a hole 5 on the disk generates a pulse. Then, only when the microswitch 8 is energized and the sensor 6 generates the pulse, a detection-signal generating means 9 generates a pulse. |
