Patent ID: 7477407
Filing Date: 2009-01-13
Classification: G01B,G02B

Abstract:
1. A confocal optical device in which an objective lens concentrates a beam of light emitted from a light source upon the inside of a sample on a sample board, a detection lens concentrates a beam of light reflected from the sample so that the beam of light passes through a pinhole, and a photo-detector detects the beam of light, comprising: a drive mechanism which moves either of the objective lens and the sample board so that the distance is changed between the objective lens and the sample board; a spherical-aberration correction section which is disposed between the light source and the objective lens; a reference-position detection section which, based on a detection result by the photo-detector, detects the position of the objective lens or the sample board when the focal position of the objective lens coincides with the surface of the sample; a movement-distance derivation section which, based on a detection result by the photo-detector, calculates a distance by which the objective lens or the sample board is moved until the focal position of the objective lens coincides with an object to be measured inside of the sample, and derives the depth at which the measured object is located in the sample; and a correction control section which controls the spherical-aberration correction section according to the inside-sample depth of the measured object based on a predetermined ratio, which is based on a correlation between a movement distance of the objective lens or the sample board and the spherical aberration obtained in advance, to the movement distance of the objective lens or the sample board.