Patent US 5,481,401

Light from a mercury lamp is focused by an objective lens system and is incident on a specimen to be examined. A focusing optical path of light reflected by the specimen is split into an optical path of an ultraviolet ray and an optical path of visible light by a dichroic mirror having wavelength selectivity. The ultraviolet ray is guided to an ultraviolet CCD camera. The ultraviolet CCD camera supplies a monochrome picture signal to a monochrome display through a first picture processor. On the other hand, the visible light is guided to a color CCD camera. The color CCD camera supplies a color picture signal to a color display through a second picture processor. Therefore, an ultraviolet picture of the specimen is displayed on the monochrome display at a high resolving power and a large magnification. At the same time, a color picture of the specimen is displayed on the color display.