Apparatus for investigation of fluorescence characteristics of microscopic objects

Claim 1

Apparatus for investigation of fluorescence characteristics of microscopic objects and for distinguishing between modified and unmodified objects, comprising: a fluorescence microscope having an amplitude modulated irradiation source and a movable stage which carries a microscopic object emitting fluorescent radiation under the action of said irradiation source; a beam-splitting plate having an interference coating, adapted to reflect a short-wave component of said fluorescent radiation and to pass a long-wave component of said fluorescent radiation, said plate being located in the path of said fluorescent radiation; a first recording channel to register a respective component of said fluorescent radiation from said microscopic object said channel being located in the path of the fluorescent radiation reflected from said beam-splitting plate, said channel having an output; a second recording channel to register a corresponding component of said fluorescent radiation, said channel being located in the path of said fluorescent radiation passed by said beam-splitting plate, said channel having an output; means for determining a relationship between said components, said means comprising a cathode-ray tube having its horizontal deflection plates coupled to the output of said first recording channel, and having its vertical deflection plates coupled to the output of said second recording channel; a level discriminator comprising a light-sensitive detector having an input which is connected to the screen of said cathode-ray tube, and an output forming a signal which is indicative of the presence of a modified microscopic object; said light-sensitive detector being fixed on the screen of said cathode-ray tube in a movable relation to said screen at a point which determines the boundary of presence of modified microscopic objects when the detector is intersected with a luminous line corresponding to said relationship between said components of said fluorescent radiation from the object; a control unit having an input and an output, whose input is coupled to the output of said light-sensitive detector; means for stopping said stage in compliance with a signal from said control unit when a modified object is detected, said means comprising an electric motor having an input coupled to the output of said control unit and an output coupled to said stage.