| 摘要 |
PURPOSE: To improve the accuracy of an active range finder by positioning a second light receiving optical system for correcting contrast incorporating a second light receiving element and second light receiving lens near a light emitting optical system perpendicular to the length direction of a base line in addition to a light receiving optical system for measuring distance incorporating a first light receiving element and first light receiving lens. CONSTITUTION: Since an infrared-ray emitting diode(IRED) 16 and semiconductor position detecting element (PSD) 18 for measuring distance are separated from each other by the length of a base line, the image of the reflected spot of the IRED 16 on the PSD 18 moves in the length direction of the base line in corresponding to a subject distance. Since the distance between a PSD 2 for correcting contrast and the IRED 16 in the length direction of the base line is substantially zero, the image of the reflected spot of the IRED 16 does not move toward the base line in corresponding to the subject distance. Therefore, the length X2 of the PSD 20 becomes sufficiently long when the length X2 is equal to or longer than the maximum width of the image of the reflected spot. In addition, since the distance between the PSD 18 and IRED 16 in the direction perpendicular to the length direction of the base line is substantially zero, the width Y1 of the PSD 18 becomes sufficiently wider when the width is equal to or wider than the maximum width of the image of the reflected spot. |
