Abstract: An immersion microscope objective includes a first lens group that consists of a first cemented lens consisting of a planoconvex lens and a first meniscus lens, the first meniscus lens having a thickness that is greater than a radius of curvature of a lens surface on an image side of the first meniscus lens, a second lens group that includes a plurality of second cemented lenses, a third lens group that consists of a third cemented lens, and a fourth lens group that includes a fourth cemented lens consisting of a plurality of meniscus lenses. The objective satisfies the relationship 2?h1/h2?4, where h1 indicates an axial marginal ray height at a lens surface of the third cemented lens that is closest to an object, and h2 indicates an axial marginal ray height at a lens surface of the third cemented lens that is closest to an image.

Abstract: An immersion microscope objective includes: a first lens group that includes a meniscus lens component that is the closest to an image in the first lens group, the meniscus lens component having a convex surface facing an object; and a second lens group, the objective satisfying the following conditional expressions: 1.4<NAob?1.51??(1) 1.30 mm?Yreso×NAob8??(2) Ltotal?65 mm??(10) where NAob indicates the numerical aperture of the objective; Yreso a maximum object height within a region on a plane orthogonal to an optical axis that crosses a position on the optical axis at which an RMS wave aberration in a d line is minimized, the region having an RMS wave aberration in the d line that is 0.1?d or less provided therewithin; ?d, the wavelength of the d line; Ltotal, a distance on the optical axis from an object surface to the lens surface that is the closest to the image.

Abstract: An immersion microscope objective includes: a first lens group that consists of a first cemented lens consisting of a planoconvex lens and a first meniscus lens, the first meniscus lens having a thickness that is greater than the radius of curvature of the lens surface of the image side of the first meniscus lens; a second lens group that includes a plurality of cemented lenses; a third lens group that consists of a second cemented lens; and a fourth lens group that includes a third cemented lens consisting of a plurality of meniscus lenses. The objective satisfies the following: 2?h1/h2?4??(1) where h1 indicates an axial marginal ray height at a lens surface that is the closest to the object in the second cemented lens, and h2 indicates an axial marginal ray height at a lens surface that is the closest to the image in the second cemented lens.

Abstract: An immersion microscope objective includes: a first lens group that includes a meniscus lens component that is the closest to an image in the first lens group, the meniscus lens component having a convex surface facing an object; and a second lens group, the objective satisfying the following conditional expressions: 1.4<NAob?1.51??(1) 1.30 mm?Yreso×NAob8??(2) Ltotal?65 mm??(10) where NAob indicates the numerical aperture of the objective; Yreso a maximum object height within a region on a plane orthogonal to an optical axis that crosses a position on the optical axis at which an RMS wave aberration in a d line is minimized, the region having an RMS wave aberration in the d line that is 0.1?d or less provided therewithin; ?d, the wavelength of the d line; Ltotal, a distance on the optical axis from an object surface to the lens surface that is the closest to the image.

Abstract: A phase contrast microscope includes a light source, an illumination optical system configured to irradiate an observation object with the light from the light source, and a magnifying optical system configured to magnify and project the observation object, the illumination optical system includes a ring slit, the magnifying optical system includes an objective provided with a phase film, the ring slit is disposed at a pupil position of the illumination optical system, the phase film is disposed at a position conjugate to the pupil position of the illumination optical system, and the following conditional expression (1) is satisfied: r/I?0.25??(1) where r is a central part radius of the phase film, and I is a radius of a pupil of the objective.

Abstract: A microscope includes a condenser lens that is arranged removably and insertably with respect to a light path of light from a light source, and an objective that collects the light from the light source, which has been transmitted through a sample. A conditional expression below is satisfied when b is an exit pupil diameter of the objective and adet is a diameter of an area in a state in which the condenser lens has been removed from the light path, the area being included in an exit pupil plane of the objective and being an area through which the light from the light source, which has entered the objective through one point on the sample, passes: 1/20?adet/b?1/2 ??(1).

Abstract: A microscope illumination apparatus includes: a dark-field illumination unit including a light source that is arrangeable in an outer periphery of an observation light path of a microscope, the dark-field illumination unit being removably provided in the outer periphery of the observation light path; a detector that detects that the dark-field illumination unit has been arranged in a prescribed position of the outer periphery of the observation light path, and outputs a turn-on signal; and a controller that controls the light source to be turned on in accordance with the detection of the detector.

Abstract: A microscope includes a condenser lens that is arranged removably and insertably with respect to a light path of light from a light source, and an objective that collects the light from the light source, which has been transmitted through a sample. A conditional expression below is satisfied when b is an exit pupil diameter of the objective and adet is a diameter of an area in a state in which the condenser lens has been removed from the light path, the area being included in an exit pupil plane of the objective and being an area through which the light from the light source, which has entered the objective through one point on the sample, passes: 1/20?adet/b?1/2 ??(1).

Abstract: A microscope illumination apparatus includes: a dark-field illumination unit including a light source that is arrangeable in an outer periphery of an observation light path of a microscope, the dark-field illumination unit being removably provided in the outer periphery of the observation light path; a detector that detects that the dark-field illumination unit has been arranged in a prescribed position of the outer periphery of the observation light path, and outputs a turn-on signal; and a controller that controls the light source to be turned on in accordance with the detection of the detector.

Abstract: A phase contrast microscope includes a light source, an illumination optical system configured to irradiate an observation object with the light from the light source, and a magnifying optical system configured to magnify and project the observation object, the illumination optical system includes a ring slit, the magnifying optical system includes an objective provided with a phase film, the ring slit is disposed at a pupil position of the illumination optical system, the phase film is disposed at a position conjugate to the pupil position of the illumination optical system, and the following conditional expression (1) is satisfied: r/I?0.25??(1) where r is a central part radius of the phase film, and I is a radius of a pupil of the objective.