| 摘要 |
PURPOSE:To vary a combination of magnification extremely easily under the control of a computer by a magnification combination selection switch without any need to change driving cams and driving gears of an optical system. CONSTITUTION:When magnification is varied from 100% magnification, a switch 32 judges which combination of magnifications is set. When a 80% magnification button 30 is pressed, the number 200 of pulses corresponding to 81% is read out of an address 506 of an ROM25 and stored in an address 1002 of an RAM26 and a magnification display lamp 31 for 81% is turned on. A preset counter 27 sets the difference 210 between the number 410 of pulses in an address 1,000 of the RAM26 and the number 200 of pulses in the address 1002 and also outputs a rotational-direction command signal to stepping motor driving parts 33 and 34 to output a pulse signal until the set value 210 attains to zero. Stepping motors 15 and 16 rotate in the specified direction according to the number 210 of pulses to move mirrors 12 and 13 to an optical position where 81% magnification is obtained. |
