Patent ID: 6674574
Filing Date: 2004-01-06
Classification: G02B

Abstract:
A reflected illumination fluorescence microscope comprising:an objective lens; a sample stage; a reflected illumination system for irradiating excitation light on a sample via said objective lens to excite the sample, said reflected illumination system having a reflected illumination light source, a first collector lens for collecting light from said reflected illumination light source, a shutter for selectively intercepting light from said reflected illumination light source, an excitation filter for extracting a specified excitation wavelength of light, and a first dichroic mirror for directing excitation light to an axis of said objective lens and transmitting a wavelength of fluorescence emitted from the sample and a wavelength region of light longer than said wavelength of fluorescence; an absorption filter disposed in an optical path through which light transmitted through said first dichroic mirror passes; an image plane for capturing a fluorescence image; a transmitted illumination system for illuminating the sample by using said wavelength region of light longer than said wavelength of fluorescence, said transmitted illumination system having a transmitted illumination light source disposed on the opposite side of said objective lens, a second collector lens for collecting light emitted from said transmitted illumination light source, a first band-pass filter for extracting said wavelength region of light longer than said wavelength of fluorescence, and a condenser lens; a second dichroic mirror disposed in an optical path through which light transmitted through said absorption filter passes, said second dichroic mirror reflecting and directing to said image plane light including said wavelength of fluorescence and excluding said wavelength region of light longer than said wavelength of fluorescence; a transmitted differential interference optical system having a polarizer and a differential interference prism disposed between said first band-pass filter and said condenser lens, having a second differential interference prism disposed between said objective lens and said first dichroic mirror, and having a first analyzer and an imaging sensor disposed in an optical path through which light transmitted through said second dichroic mirror passes; a focus detecting section for detecting a focusing level of a sample image by operating on an evaluation value of said focusing level on the basis of a signal output from said imaging sensor; a focusing driver for moving at least one of said objective lens and said sample stage to focus on the sample on the basis of said focusing level; a shutter driver for opening and closing said shutter; a controller for controlling said imaging sensor, said focus detecting section, said shutter driver, and said focusing driver, said controller carrying out an automatic focus under condition that said shutter is closed; an image forming lens disposed in an optical path through which light transmitted through said absorption filter passes; an optical path dividing element disposed in an optical path through which light transmitted through said image forming lens passes; an ocular lens disposed in an optical path divided by said optical path dividing element; a first low-pass filter disposed in front of said ocular lens, said first low-pass filter transmitting said wavelength of fluorescence and stopping said wavelength region of light longer than said wavelength of fluorescence; a second analyzer operatively disposed between said second dichroic mirror and said image plane, said second analyzer being removable from an optical path between said second dichroic mirror and said image plane; and a third analyzer operatively disposed between said optical path dividing element and said ocular lens, said third analyzer being removable from an optical path between said optical path dividing element and said ocular lens; wherein said first band-pass filter is removable from an optical path of said transmitted illumination system, and a transmitted differential interference image and said fluorescence image are imaged and observed at once, under a condition that said first band-pass filter is removed from said transmitted illumination system, said second analyzer is inserted in said optical path between said second dichroic mirror and said image plane, and said third analyzer is inserted in said optical path between said optical path dividing element and said ocular lens.