| 摘要 |
PROBLEM TO BE SOLVED: To stabilize correction accuracy regardless of difference among devices, environmental variation, and the like, by using a control circuit commonly at the time of individual control and simultaneous control, and to easily deal with intricate control mode, e.g. increase in light beam or correction of uneven quantity of light of the light beam, through a simple device configuration. SOLUTION: Since a circuit performing individual control is made identical to a circuit performing simultaneous control, difference due to characteristics of the device is eliminated and accurate APC can be attained. In order to express the control voltage V2 at the time of simultaneous control in terms of the control voltage of each individual light beam, a difference holding capacitor 62 is connected in series with a sample hold capacitor 52, opposite ends of the difference holding capacitor 62 are short-circuited at the time of individual control and the short circuit is released at the time of simultaneous control. Since the control voltage V2 is divided by a combined impedance so that the control voltage V1 of each individual light beam is stored in the sample hold capacitor 52, the circuitry is simplified and thereby the device configuration can be simplified. COPYRIGHT: (C)2005,JPO&NCIPI
|
