| 摘要 |
PURPOSE:To obtain an automatic leveling instrument of simple constitution free of an error in correction due to fluctuations of temperature by suspending a correcting reflective member, equipped with a reflective surface for upside-down inversion, on some point on an optical axis as a fulcrum in one body, and setting this fulcrum at a position a half as far as the focal length of an objective lens. CONSTITUTION:For example, an interval between a correction system 9 and an objective lens 4 is l1, an interval between the correction system 9 and a center point 2 of rotation for inclination is l2, and an interval between the correction system 9 and an index 7 is l3; and a main body slants around the point 2 by a fine angle alpha. In this case, the objective lens 4' is displaced downward by (l1-l2)alpha on the basis of an optical axis 1, and the correction system 9 is also displaced upward by l2alpha. Then, luminous flux which travels horizontally from the body to be collimated and strikes the objective lens 4' travels l1alpha lower than the optical axis 1 in parallel to the optical axis 1 to illuminate the correction system 9. Therefore, the luminous flux of collimation displaced downward by (l1+l2)alpha is incident to the correction system 9. On the other hand, the index 7 is displaced upward by (l2+l3)alpha on the basis of the optical axis 1, so correction meeting a requirement (l1+l2)alpha=(l2+l3)alpha, i.e. l1=l3 is achieved. |
