| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an object lens for a parallel system entity substance microscope, the objective lens being provided so as to restrain the upward curving phenomenon of an image due to asymmetrical distortion aberration, by using an aspheric face. <P>SOLUTION: An object lens 102 (102a) comprises, in order from a variable power optical system side to an object surface side; a first lens group G1 including a negative lens (indicated by L12 in FIG. 1) whose concave face is oriented toward a variable power optical system side and having negative refractive power as a whole; and a second lens group G2 including cemented lenses (a cemented lens composed of lenses L21 to L23 and a cemented lens composed of lenses L24 and L25 in FIG. 1) and having positive refractive power as a whole. At least one face of the lens faces composing the second lens group G2 is aspheric (the 13th and 14th faces in FIG. 1). The aspheric surface satisfies the following conditional expression: 3.5<¾ho/hi¾<7.5, in which ho is the height of the principal ray of an outer luminous flux at the maximum field angle of the aspheric face, and hi is the height of the principal ray of an inner luminous flux at the maximum field angle of the aspheric face. <P>COPYRIGHT: (C)2012,JPO&INPIT |
