Abstract: An objective has lens units, each of which is constructed with single lenses, and a numerical aperture of 0.7 or more, comprising, in order from the image side, a first lens unit including a positive meniscus lens with a convex surface facing the image side, at least two negative lenses, and at least two positive lenses, and having negative power as a whole; a second lens unit including a negative lens and a positive lens so that the radius of curvature of the surface of the negative lens, adjacent to the positive lens, is smaller than that of the opposite surface thereof; a third lens unit including biconvex positive lenses and biconcave negative lenses which have different media, so that two of the biconvex positive lenses are arranged on the object side and the image side, and having positive power as a whole; and a fourth lens unit including a negative meniscus lens and at least one positive meniscus lens, and having positive power as a whole.

Abstract: An objective lens includes a first lens group, a second lens group having a lens pair, a third lens group having a lens pair, a fourth lens group having a lens pair, a fifth lens group having a lens pair, and a sixth lens group. The objective lens is configured so as to satisfy the following conditional expressions: d/L<0.025 0.58<Rp/Rn<1.65 where L(mm) is the overall length of the objective lens; d(mm) is the air gap of each of the lens pair; Rp is the radius of curvature of each of positive refractive power surfaces opposing each other with the air gap therebetween; and Rn is the radius of curvature of a negative refractive power surface. Whereby, chromatic aberration can be corrected and resolution is exponentially improved without using a cemented lens, providing a deep ultra-violet objective lens with a high NA capable of auto focussing instantaneously.

Abstract: A two-wavelength antireflection film to prevent light in two-wavelength regions of a deep-ultraviolet region and a region from a visible region to the near-infrared region on a surface of a substrate by coating the two-wavelength antireflection film on the surface of the substrate which penetrates light from the deep-ultraviolet region to the near-infrared region, comprising a first thin film which is formed on the substrate, and has a refractive index of 1.6 to 2.0 and optical film thickness of 0.4&lgr; to 0.7&lgr; for design main wavelength (&lgr;), a second thin film which is formed on the first thin film, and has a refractive index of 1.35 to 1.55 and an optical film thickness of 0.05&lgr; to 0.6&lgr; for the design main wavelength &lgr;, a third thin film which is formed on the second thin film, and has a refractive index of 1.6 to 2.0 and an optical film thickness of 0.1&lgr; to 0.

Abstract: A two-wavelength antireflection film to prevent light in two-wavelength regions of a deep-ultraviolet region and a region from a visible region to the near-infrared region on a surface of a substrate by coating the two-wavelength antireflection film on the surface of the substrate which penetrates light from the deep-ultraviolet region to the near-infrared region, comprising a first thin film which is formed on the substrate, and has a refractive index of 1.6 to 2.0 and optical film thickness of 0.4&lgr; to 0.7&lgr; for design main wavelength (&lgr;), a second thin film which is formed on the first thin film, and has a refractive index of 1.35 to 1.55 and an optical film thickness of 0.05&lgr; to 0.6&lgr; for the design main wavelength &lgr;, a third thin film which is formed on the second thin film, and has a refractive index of 1.6 to 2.0 and an optical film thickness of 0.1&lgr; to 0.

Abstract: An objective has lens units, each of which is constructed with single lenses, and a numerical aperture of 0.7 or more, comprising, in order from the image side, a first lens unit including a positive meniscus lens with a convex surface facing the image side, at least two negative lenses, and at least two positive lenses, and having negative power as a whole; a second lens unit including a negative lens and a positive lens so that the radius of curvature of the surface of the negative lens, adjacent to the positive lens, is smaller than that of the opposite surface thereof; a third lens unit including biconvex positive lenses and biconcave negative lenses which have different media, so that two of the biconvex positive lenses are arranged on the object side and the image side, and having positive power as a whole; and a fourth lens unit including a negative meniscus lens and at least one positive meniscus lens, and having positive power as a whole.

Abstract: An objective lens includes a first lens group, a second lens group having a lens pair, a third lens group having a lens pair, a fourth lens group having a lens pair, a fifth lens group having a lens pair, and a sixth lens group.

Abstract: An objective lens includes a first lens group, a second lens group having a lens pair, a third lens group having a lens pair, a fourth lens group having a lens pair, a fifth lens group having a lens pair, and a sixth lens group.

Abstract: The invention provides an objective system for use on a single objective type binocular stereomicroscope which, albeit having a parfocal length thereof shorter than a focal length thereof, can reduce various aberrations as much as possible, and a single objective type binocular stereomicroscope system which can be well manipulated while the viewing position is invariable even when objective lenses are interchanged. The objective system for use on a single objective type binocular stereomicroscope comprises an objective lens for converting light from an object into an afocal light flux and two viewing optical units for receiving light emanating from the objective lens to form left and right images, which satisfies condition: 1.0<FL/L<1.6 where FL is a focal length of the objective system, and L is a distance from a first lens surface of the objective system on an image point side to a sample surface.

Abstract: A high-magnification objective optical system for binocular stereomicroscopes, each having two observation optical systems for forming light from an object into left and right images through an objective lens, is provided with an optical member placed to be removable or replaceable between the object to be observed and the objective lens and satisfies the following condition: 0.2<|NA·m|<1.2 where NA is a numerical aperture on an object side of the objective lens and m is the magnification of the objective lens. In this way, a stereoscopic observation is obtained, holding good performance of image formation at high magnification and NA.

Abstract: An incident-light fluorescence microscope including: (i) a transmission illuminating optical system which has a first optical member for receiving light emitted from a light source and extracting transmitted light and which irradiates the transmitted light onto a sample, and (ii) an observation optical system which has an objective lens and a second optical member and which is positioned closer to the objective lens than the sample. An incident-light fluorescence illuminating optical system is provided in the observation optical system, wherein the first optical member has a peak of transmittance at a wavelength longer than the fluorescent wavelength, and the second optical member selectively modulates only a wavelength transmitted through the first optical member.

Abstract: The invention provides an objective system for use on a single objective type binocular stereomicroscope which, albeit having a parfocal length thereof shorter than a focal length thereof, can reduce various aberrations as much as possible, and a single objective type binocular stereomicroscope system which can be well manipulated while the viewing position is invariable even when objective lenses are interchanged. The objective system for use on a single objective type binocular stereomicroscope comprises an objective lens for converting light from an object into an afocal light flux and two viewing optical units for receiving light emanating from the objective lens to form left and right images, which satisfies condition: 1.0<FL/L<1.6 where FL is a focal length of the objective system, and L is a distance from a first lens surface of the objective system on an image point side to a sample surface.