| 摘要 |
PURPOSE:To automatize work to find out a focus setting range by providing a height detecting means to detect the height of an object, and controlling the amplitude of a waveform signal corresponding to the output of the height detecting means. CONSTITUTION:A signal obtained by a height measuring instrument 80 is converted to a position signal at the highest point of the object by a height signal generation circuit 81, and a switch SW1 is closed. Thereby, a Z travel part 7 starts descent advancing the right just above position of the highest point of the object 1 from the highest position of a movable range. When an error signal is detected on the middle way of descent, a switch SW2 is switched, and focusing servo is applied. When no error signal is detected on the middle way of descent, the switch SW1 is opened again, and the Z travel part 7 is saved to the highest position of the movable range. In such a way, it is possible to perform automation without generating the collision of an objective lens 17 with the object 1 even when no focus setting range can be found out. |
