| 摘要 |
PROBLEM TO BE SOLVED: To provide a light guide body that can smoothly change an emission light quantity distribution and causes neither an increase in the number of components nor an increase in the cost.SOLUTION: A width F of an emission light quantity adjustment part 71e in a direction orthogonal to a length direction of a light guide body 71 is made gradually narrower substantially toward light incidence surfaces 71b at both ends of the light guide body 71 so as to correct an emission light quantity distribution of the light guide body 71. The emission light quantity distribution of the light guide body 71 tends to increase toward the light incidence surfaces 71b at both the ends of the light guide body 71 and to decrease toward the center of the light guide body 71, and further a transmission light quantity of an imaging lens 46 tends to decrease toward both ends of the imaging lens 46 and to increase toward the center of the imaging lens 46. The emission light quantity distribution of the light guide body 71 is corrected under the conditions, so a deviation of the emission light quantity distribution and a deviation of the transmission light quantity distribution excellently cancel each other and a reception light quantity distribution of light reception by a light reception surface of a CCD 47 becomes constant. |
