Patent Document ID: 20090279051
Application ID: 12432626
Patent Status: 0

Claim One:
1. A fundus camera comprising: an illumination optical system including an illumination unit configured to illuminate a fundus of a subject's eye; a fundus photographing optical system including an image-recording image sensor configured to capture a fundus image via an objective lens and a focusing lens; a focus target located in the illumination optical system at a position conjugate with the fundus of the subject's eye and configured to have a plurality of regions for forming light fluxes respectively passing through different areas of a pupil of the subject's eye to form a plurality of focus target images on the fundus; an observing images sensor located in the photographing optical system at a position conjugate with the fundus of the subject's eye and configured to capture the plurality of focus target images reflected from the fundus; a focus drive unit configured to drive the focus target and/or the focusing lens; a target image position detection unit configured to detect positions of the plurality of focus target images on the observing image sensor; a first focus detection unit configured to calculate a first driving amount of the focus drive unit based on the positions of the plurality of focus target images detected by the target image position detection unit; a drive control unit configured to drive and control the focus drive unit based on the first driving amount calculated by the first focus detection unit; and a second focus detection unit configured to detect a change in the focus target images based on an output of the observing images sensor during a driving operation of the focus drive unit and to calculate a second driving amount of the focus drive unit based on the detected change.