Optical microscope with variable magnification

Abstract

An optical microscope including a revolver for mounting a plurality of objective lenses having different magnifications, a stage for holding a specimen to be inspected and being movable in a plane perpendicular to an inspection optical axis, a television camera for picking-up an image of the specimen by means of an objective lens which is indexed into the inspection optical axis, and a television monitor for displaying an image of the specimen on a display screen. In order to select an objective lens having a desired magnification and to move the stage with respect to the inspection optical axis automatically, a desired region is denoted on the image displayed on the display screen by operating a mouse. Then, a necessary magnification is calculated in accordance with a division ratio obtained by dividing an area of the desired region by a full area of the display screen. An objective lens having a magnification which is equal to the necessary magnification or which is closest to the necessary magnification, but is smaller than the necessary magnification is selected and is automatically indexed into the inspection optical axis. At the same time, a moving amount of the stage is calculated and the stage is automatically moved such that a center point of the desired region comes into a center point of the display screen.