| 摘要 |
<P>PROBLEM TO BE SOLVED: To exactly align the optical axis of a transmitter with that of a receiver when a light-receiving element for optical axis adjustment is covered with an optical cover. <P>SOLUTION: A level correction operating section 36 adjusts light-receiving levels of quartered PD1-PD4 of a second light-receiving means corresponding to the direction of the second light-receiving means 6 with respect to an exterior 24 or an optical filter 25. An optical axis adjustment control unit 35 moves the second light-receiving means so that the difference between each of the adjusted levels is eliminated, and aligns the optical axes. Also, refractive indexes of an outer covering and an optical filter are made symmetric with a rotational axis of the second light-receiving means to reduce by half the memory capacity of a level correction coefficient. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
