| 摘要 |
PROBLEM TO BE SOLVED: To prevent performance from being lowered because of unstable control in an optical axis direction and the adjustment error of an optical axis even when a beam splitter having angle dependency is used in convergent luminous flux or divergent luminous flux. SOLUTION: The luminous flux emitted from a laser diode light source 21 is reflected from the polarized light separating plane 20a of a composite prism 23, transmitted and sent toward an opposed device from a lens group 25 having positive power after the spherical aberration thereof is corrected by a lens 22 having positive power and a lens 23 having a negative power. On the other hand, received light from the opposed device is made incident from the group 25 having the positive power, transmitted through the light intensity distribution correcting plane 20b of the prism 20 and received by a four-divided sensor 24 after the symmetry of light intensity distribution thereof is secured. By transmitting the received light through both of the planes 20a and 20b, the asymmetry of the light intensity distribution occurring when the received light is transmitted through the plane 20a is negated. Thus, the light intensity distribution of the beam spot of the received light on the light receiving surface of the sensor 24 can be made symmetric as for two orthogonally crossed axes. |
