| 摘要 |
PROBLEM TO BE SOLVED: To make a retaining means corresponding to all light beams accurately retain control values at a time when control signals of a voltage source are to be corrected by a single correction system for a plurality of light beams. SOLUTION: To correct the voltage of the voltage source 76 of a driving circuit 26 by a correction control voltage, previously the base of the voltage of the voltage source 76 was used as a driver GND reference. The reference base of a voltage, however, is separated from the driver GND, an independent reference offset terminal 72 is provided and a correction voltage is supplied to the reference offset terminal 72. Consequently, since there is no fluctuation in the correction voltage due to the fluctuation of the driver GND and the base of the voltage generated in the voltage source 76 is increased or decreased, stable correction control becomes possible. Since the signal GND of a correction means 50 is electrically separated from the ground of the driver GND in a IC package 52, and extended out of the IC package 52, and is connected to the LD-GND of a light emitting element 14A at a low impedance, the signal GND can be made to follow the fluctuation of the LD-GND of the light emitting element 14A during the setting of the correction voltage and accuracy can be further improved. COPYRIGHT: (C)2005,JPO&NCIPI |
