| 摘要 |
PURPOSE:To improve the range finding accuracy by accomplishing the peak reception of light clealy while holding under a preset condition the relationship between a projector and a receiver. CONSTITUTION:An object is scanned by the irradiating surface 6 having a diameter D1, which has come from a light emitting element 3 having an effective diameter of d1 through a condensing lens 2 having a focal length of f1. The reflected light from the object, which comes from a light receiving surface 7 of diameter D2 and which is determined by a condensing lens 4 of a focal length f2 and a light receiving element 5 of an internal effective diameter d2. If the condition d1/f1=d2/f2 is satisfied while effecting such selections that the diameters of the elements 3 and 5 have the relationship of d1=d2 and that the focal lengthes of the lenses 2 and 4 have the relationship of f1=f2, then the sizes of the irradiating surface 6 and the light receiving range 7 become equal. As a result, the detected signal curve upon the light reception of the element 5 takes such a shape as has a steep value appearing when the surface 6 and the range 7 become coincident while generating no flat portion. As a result, the range finding accuracy can be improved by the peak detection. |
