| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent ghost light due to reflected light by using a graded index lens for an objective lens. <P>SOLUTION: The objective lens 2 is arranged between a photographing diaphragm 10 and the pupil Ep of the eye to be examined, and the second surface of the objective lens facing the diaphragm 10 is the recessed spherical surface of a radius R2 of curvature having a curvature center in the center of the diaphragm 10. The diaphragm 10 conjugately forms an image on the pupil Ep by the objective lens 2. The first surface on the side of the eye to be examined E of the objective lens 2 is the recessed spherical surface of a radius R2 of curvature having a curvature center at this image-forming point. Consequently, all of the light beams passing through the center of the diaphragm 10 enter vertically to the first surface and second surface of the objective lens, and all of the light beams reflected by these surfaces return along their incoming optical paths. The refractive index of the glass of the objective lens 2 is the highest in the vicinity of an optical axis, and is gradually lowered toward its periphery. Unlike a normal lens, the light beams is not bent at the surface of the objective lens 2 but is bent gradually inside the objective lens 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
