Patent ID: 7884928

Claim:
A cup attaching apparatus for attaching a cup as a processing jig to an eyeglass lens, comprising: an illumination optical system comprising an illumination light source and arranged to illuminate the lens from a side of a front surface of the lens by illumination light from the light source; an imaging optical system comprising an imaging device and a retroreflection member placed on an opposite side from the light source with respect to the lens, the imaging optical system being adapted such that the retroreflection member returns the illumination light passing through the lens back to its incoming direction, and the imaging device receives the returned illumination light, and the imaging optical system being adjusted to focus on a point near a surface of the lens; an image processing device adapted to process an image signal from the imaging device to detect at least one of a mark point provided on a unifocal lens, a small lens portion of a bifocal lens, and a progressive mark provided on a progressive focal lens and obtain a position of the detected one; an arithmetic control device adapted to determine an attaching position of the cup based on the position obtained by the image processing device; and an index projection and light receiving optical system comprising an index plate formed thereon with a predetermined pattern and a two-dimensional photo-receiving element which receives measurement light passing through the index plate and the lens and has a light receiving surface on which an image of the pattern is to be formed, wherein the arithmetic control device is arranged to determine optical characteristics of the lens based on output from the photo-receiving element, and the retroreflection member includes a first retroreflection member placed on an optical path of the index projection and light receiving optical system and a second retroreflection member placed surrounding the optical path.