Abstract: An illumination optical system for a microscope is provided wherein the illumination state can be successively changed between Koehler illumination and critical illumination while ensuring one or more conditions are satisfied so that the image of the light source illuminates an appropriately large region of the field of view of the microscope during critical illumination. Preferably, no cemented lens elements are used so that degradation of the cement caused by ultraviolet light sources is avoided, thereby enabling an appropriate illumination type to be provided at will and without degradation of the optical components of the illumination optical system over time.

Abstract: A fluorescent microscope comprises a light source, an optical illumination system which forms an optical path to irradiate a specimen with a light beam from the light source, an objective lens which condenses the light beam of the optical illumination system onto the specimen, an optical device which is disposed on the optical path of the optical illumination system and which decenters the light beam by decentering an optical axis of the optical path, and a slit which passes the light beam decentered by the optical device through a total reflection illumination region on an emission pupil surface of the objective lens.

Abstract: An illumination optical system for a microscope is provided wherein the illumination state can be successively changed between Koehler illumination and critical illumination while ensuring one or more conditions are satisfied so that the image of the light source illuminates an appropriately large region of the field of view of the microscope during critical illumination. Preferably, no cemented lens elements are used so that degradation of the cement caused by ultraviolet light sources is avoided, thereby enabling an appropriate illumination type to be provided at will and without degradation of the optical components of the illumination optical system over time.

Abstract: A differential interference optical system includes an illumination source, a first polarizing element for converting a ray of light emitted from the illumination source into linearly polarized light, a first polarizing member for separating the linearly polarized light converted by the first polarizing element into two linearly polarized components which vibrate perpendicular to each other and travel at a slight separation angle, a lens system for illuminating and observing an object to be observed, a second polarizing member for combining the two linearly polarized components on the same path after passing through the lens system, and a second polarizing element for converting a ray of light combined by the second polarizing member into linearly polarized light.

Abstract: A differential interference contrast microscope including an illuminating light source 61, a polarizer 62 for converting an illumination light ray into a linearly polarized light, a polarized light separating means 63 for dividing the linearly polarized light ray into two linearly polarized light rays having mutually orthogonal vibrating directions, an illuminating optical system 64, 65 for projecting the two linearly polarized light rays onto an object 66 under inspection, a polarized light combining means 69 for combining the two linearly polarized light rays on a same optical path via an inspecting optical system 67, 68, an analyzer 70 for forming a differential interference contrast image on an imaging plane 71.

Abstract: A differential interference contrast microscope including an illuminating light source, a polarizer for converting an illumination light ray into a linearly polarized light, a polarized light separating means for dividing the linearly polarized light ray into two linearly polarized light rays having mutually orthogonal vibrating directions, an illuminating optical system for projecting the two linearly polarized light rays onto an object under inspection, a polarized light combining unit for combining the two linearly polarized light rays on a same optical path via an inspecting optical system, an analyzer for forming a differential interference contrast image on an imaging plane.

Abstract: A differential interference contrast microscope including an illuminating light source, a polarizer for converting an illumination light ray into a linearly polarized light, a polarized light separating unit for dividing the linearly polarized light ray into two linearly polarized light rays having mutually orthogonal vibrating directions, an illuminating optical system, for projecting the two linearly polarized light rays onto an object under inspection, a polarized light combining unit for combining the two linearly polarized light rays on a same optical path via an inspecting optical system, an analyzer for forming a differential interference contrast image on an imaging plane.

Abstract: The invention provides a microscope objective having a working distance longer than achieved so far in the prior art even at more than 100 magnifications. The objective comprises a lens group A that comprises a positive meniscus lens concave toward an object side thereof and a plurality of cemented lenses, has positive refractive power and converts light rays from an object to a converging light beam, and a lens group B having negative refractive power, and satisfies condition (1):5<.vertline.f.sub.A /f.sub.B .vertline.<20 (1)where f.sub.A is a focal length of said lens group A and f.sub.B is a focal length of said lens group B.

Abstract: A semiconductor device includes a semiconductor chip; leads including first inner leads and second inner leads extending substantially radially from a central point of the semiconductor chip; electrical conductors electrically connecting the semiconductor chip to the lead frame; and an encapsulating resin encapsulating the semiconductor chip, the electrical conductors, and the inner leads, Each of the first inner leads has a first inner end located proximate the central point and each of the second inner leads has a second inner end located farther from the central point than the first inner ends. The first and second inner leads are alternatingly arranged. Thus, at least some of the inner leads extend under the semiconductor chip, providing heat conducting paths. The lead frame includes a frame and leads supported by the frame and including first inner leads and second inner leads extending substantially radially toward a central point of the frame.