| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve accuracy in light quantity adjustment when using a light source emitting multiple laser beams. <P>SOLUTION: Light quantity adjustment processing includes steps of: as a first adjustment portion, adjusting a driving current of a light source in a light source unit 1, measuring emission power Pm_ch as an adjustment result and monitor voltage Vm_ch for each channel and writing the measured ones in a memory; as a second light quantity adjustment portion, emitting only a laser beam of a representative channel ch<SB POS="POST">R</SB>, executing APC so that an image surface light quantity P<SB POS="POST">2</SB>becomes equivalent to a setup target light quantity P<SB POS="POST">1</SB>, and measuring the image surface light quantity P<SB POS="POST">2</SB>; and using tentative light use efficiency η<SB POS="POST">1</SB>, the target light quantity P<SB POS="POST">1</SB>and the image surface light quantity P<SB POS="POST">2</SB>to obtain real light use efficiency η<SB POS="POST">2</SB>and writing the obtained one in the memory. The APC is executed for each channel through a step of using the light use efficiency η, the emission power Pm_ch and the monitor voltage Vm_ch to calculate a reference value V<SB POS="POST">REF</SB>_ch of each channel ch for executing control so that the image surface light quantity P<SB POS="POST">2</SB>becomes equivalent to the target light quantity P<SB POS="POST">1</SB>. <P>COPYRIGHT: (C)2013,JPO&INPIT |
