| 摘要 |
PURPOSE:To obtain the functions of a theodolite by specifying the conditions of an optical system which has a front group with positive refracting power and a rear group with negative refracting power, a dichroic prism for separating infrared light and visible light between both groups, and an erecting prism behind the rear group. CONSTITUTION:The front group consists of three elements in two groups, i.e. a positive single lens and a cemented lens of a positive and a negative lens, and the rear group consists of two elements in one group, i.e. a cemented lens of a negative and a positive lens; and they satisfy inequalities I -IV. In the equations, (f) and (f1, 2, 3) are the focal length of the whole system and the composite focal length of the front group, and nuDi (i=1, 2, 3) is the Abbe number of the line (d) of the (i)th lens; and thetaj (j=1, 2) is the partial dispersion ratio of the infrared area of the (j)th lens defined by theta=(nc-n1014)/(nF-nC) using the refractive index nC of a line C, refractive index nF of a line F, and refractive index n1014 to a light beam with 1014nm wavelength, and ri (i=1, 2) is the radius of curvature of the (i)th surface. |
