| 摘要 |
PURPOSE:To rapidly set a laser light amount to a target value by obtaining the displacement position of a specific optical element necessary to set the quantity of a light emitted from a light quantity regulating unit to a target value based on the transmission characteristic of the unit, and driving the optical element. CONSTITUTION:The target value IS of a laser light quantity is read from a target setter 15 by a calculating discriminator 22, and the present light quantity IO of a light emitted from a light quantity regulating unit 4 is read from a counter 14. Maximum light quantity IMAX is read from a maximum light quantity memory 27, and light quantity ratios IS/IMAX, IO/IMAX are calculated. The transmission characteristic of the unit 4 is read from a transmission property memory 26. When the numbers NS, NO of steps of a pulse motor 5 corresponding to the light quantity ratios are obtained, the magnitudes are compared, a pulse output is applied from the discriminator 22 to a motor driver 17, and a polarizing filter 3a is set to the vicinity of a deviation angle corresponding to the target light quantity. A feedback control is conducted in response to a deviation between the detected light quantity and the target value to set a deviation angle corresponding to the target light quantity to the filter 3a. |
