Nikon Corporation

Nippon Kogaku K.k.

Yoshiyuki Shimizu

Toshiro Ishiyama

Yutaka Suenaga

Masashi Tanaka

Kiyoshi Hayashi

Kazuo Ushida

Ikuo Mori

Norio Murayama

Yasuhiro Oomura

Kei Tomimatsu

Takeshi Sudo

Reiko Ohyama

Takashi Mori

A particularly constructed objective lens unit is provided for reflective fluorescence that transmits excitation light well, generates little self-fluorescence, and can correct for various aberrations. The objective lens unit has a front lens group closer to a specimen side than a rear lens group. Among the lens components forming the front lens group, at least the lens components arranged on the specimen side are formed from a prescribed optical material. This optical material has a higher transmissivity for excitation light and generates less fluorescence due to the excitation light than the other lens components forming the objective lens unit. The excitation light, fed into a position path between the front lens group and the rear lens group, is guided through the front lens group to the specimen. An image of the specimen is formed, based on the fluorescence from the specimen, through the front lens group and the rear lens group.

Objective lens unit for reflective fluorescence and reflective fluorescence microscope having an objective lens unit for reflective fluorescence

A small, light weight wide angle photographic lens has attachment size of less than approximately 3.5 times the focal length and has a field angle of approximately 100.degree.. The wide angle photographic lens includes a first lens L.sub.1 having a negative refractive power and a concave surface facing the image side; a second lens L.sub.2 with a positive refractive power having the convex surface facing the object side; a third lens L.sub.3 having a negative refractive power cemented to the second lens L.sub.2 and having a surface with a larger absolute value of index of refraction on the image side; a fourth lens L.sub.4 having a positive refractive power cemented to the third lens L.sub.3 and having a surface with a larger index of refraction on the object side; and a plurality of lenses on the image side of the fourth lens L.sub.4, wherein the concave surface of the first lens L.sub.1 is an aspherical surface with a conical constant .kappa. greater than 0.3 and less than 0.3 with a curvature of the concave surface decreasing monotonically with increasing distance from the optical axis. The wide angle photographic lens also satisfies conditions 0&lt;n.sub.4 -n.sub.3 &lt;0.15 and 0.2&lt;r.sub.5 /f&lt;0.7 where n.sub.3 and n.sub.4 denote the index of refraction of the third lens L.sub.3 and the fourth lens L.sub.4, respectively, r.sub.5 denotes the radius of curvature of the boundary surface between both lenses L.sub.3 and L.sub.4, and f denotes the focal length of the total lens system.

Wide angle photographic lens

A microscope objective, and microscope incorporating same, are disclosed. A representative embodiment of the objective comprises, arranged on an optical axis, a front lens group having positive refractive power disposed on the object side, a rear lens group having negative refractive power disposed on the image side, and a corrective lens group interposed between the front and rear lens groups. The corrective lens group is axially movable and comprises a pair of meniscus lens elements each of which having a convex surface oriented toward each other. The corrective lens group serves to correct aberrations arising from a cover glass or other refractive body situated between the specimen being observed and the objective lens. To such end, the objective preferably satisfies the conditions:

Microscope objective lens and a microscope incorporating same

A first partial optical system including a first group of lenses having a positive refractive power, a first concave reflection mirror and a second group of lenses having a positive refractive power, for forming a primary reduced image of an object, a second partial optical system including a second concave reelection mirror and a third group of lenses having a positive refractive power, for further reducing the primary reduced image and refocusing it, and a reflection mirror arranged between the first partial optical system and the second partial optical system, for deflecting a light path are arranged in a sequence as viewed from the object. A good image-forming ability as a projection optical system for fabricating a semiconductor device is attained with a simple construction.

Catadioptric reduction projection optical system

A super-wide field eyepiece comprises, in succession from the incidence side of light, a first lens unit including a meniscus lens having its convex surface facing the incidence side and having positive or negative weak refractive power as a whole, a second lens unit including at least one lens surface having negative refractive power and having positive refractive power as a whole, and a third lens unit including at least two positive lenses and having positive refractive power as a whole, and an intermediate image is formed between the first lens unit and the second lens unit.

Super-wide field eyepiece

An inverse telescopic wide angle lens comprises a diaphragm; a front lens group of an integral positive or negative refractive power, positioned in the object side in front of the diaphragm and having a first lens group of a negative refractive power including a negative lens of which an image-side air-contacting surface is formed as an aspherical surface concave to the image side, and a second lens group of a positive refractive power positioned between the first lens group and the diaphragm; and a rear lens group of an integral positive refractive power, positioned behind the diaphragm and having plural lenses. The negative lens in the first lens group is so constructed that the absolute value of the refractive power of the concave surface on the optical axis is larger than that of the refractive power of the surface at the object side on the optical axis, that the curvature of the concave surface decreases monotonously with the distance from the optical axis, and that the form of the concave surface of the negative lens at the image side satisfies a particular condition. The effective diameter of the lens closest to the object in the first lens group is so constructed as to satisfy a particular condition.

Inverse telescopic wide angle lens

An inverse telescopic wide angle lens comprising:

An imaging optical system has a first objective lens movable along the optical axis thereof for focus adjustment and for forming the image of an object at infinity, and a second objective lens for forming the image again at a predetermined position at a predetermined magnification. The second objective lens comprises, in succession from the object side, a positive single lens, a negative single lens and a positive single lens disposed with an air space therebetween, and satisfies the following conditions:

Imaging optical system

A microscope whose enlargement magnification is changeable includes a plurality of interchangeable first objective lenses of different focal lengths for changing a divergent light flux from an object on a stage into a parallel light flux, a first interchanging device for moving the first objective lenses and interchangeably installing them on a predetermined optic axis, a plurality of interchangeable second objective lenses of different focal lengths for condensing the parallel light flux from the first objective lenses and forming an enlarged image of the object at a predetermined position, an eyepiece for observing therethrough the enlarged image of the object formed by the second objective lenses, a prism for directing the light flux from the second objective lenses to the eyepiece, and a second interchanging device provided between the first interchanging device and the prism for moving the second objective lenses and interchangeably installing them on the predetermined optic axis.

Microscope whose enlargement magnification is changeable

A microscope objective lens which, in spite of having a great numerical aperture and a high magnification, can always maintain an excellent imaging performance even if the thickness of a parallel flat plate such as a cover glass disposed between the object surface and the objective lens is greatly varied. The microscope objective lens has, in succession from the object side, a first lens group of positive refractive power for converting the light flux from an object into a convergent light flux, the first lens group having a positive meniscus lens component with its concave surface facing the object side and having a cemented lens component, a second lens group having a cemented lens component of negative refractive power disposed in the convergent light flux, and a third lens group of negative refractive power having a meniscus lens component with its convex surface facing the object side and having a succeeding negative lens component. The second lens group is movable on the optical axis relative to the first and third lens groups to correct deterioration of imaging performance due to variation in thickness of the parallel flat plate.

Microscope objective lens

An objective lens for microscope of low magnification is of a two-group structure and is composed, in the order from the object side, of a converging front lens group having a meniscus lens component convex toward the object and a converging rear lens group including a positive lens component having a stronger curvature at the image side and a biconvex lens component. The meniscus lens component in the front lens group is composed of a biconvex positive lens and a biconcave negative lens adhered together at an adhered interface convex toward the image side. The lens surface at the object side of the meniscus lens component of the front lens group is convex toward the object side and has a positive refractive power, while the lens surface at the image side of said meniscus lens component is concave toward the image side and has a negative refractive power.

Objective lens for microscope of low magnification

A microscope objective lens of medium or high magnification having a great working distance and yet having an excellent imaging performance comprises, in succession from the object side, a first lens group of positive refractive power for converting a light flux from an object into a convergent light flux, the first lens group having a positive meniscus lens component having its concave surface facing the object side and a cemented lens component, a second lens group having a cemented lens component of small refractive power disposed in the convergent light flux, and a third lens group having a meniscus lens component having its convex surface facing the object side and a succeeding negative lens component. The objective lens satisfies the following conditions:

A condenser optical system for a microscope comprises, in order from the light ray entrance side, a forward group and a rearward group. The forward group includes a negative lens component and a positive lens component either cemented to or separated from the negative lens component. The rearward group consists of a plurality of lens components and has a totally positive refractive power. The air separation between the forward group and the rearward group is smaller than the total center thickness of the rearward group. The front focus of the rearward group lies in the air separation. The condenser optical system is of high magnification and yet can perform good optical compensation for the light source.

Condenser optical system for a microscope

An epidark illumination system for use with a microscope in which a sample is illuminated from around an objective by a ring-shaped light flux having its center coincident with the optic axis of the objective to enable the sample to be observed in a dark field of view comprises a ring-shaped condenser lens member disposed adjacent to the forward end of the objective with the center of the lens member being coincident with the optic axis of the objective to condense the light flux upon the sample, and a scattering member for scattering the ring-shaped light flux disposed in the light path before the ring-shaped light flux reaches the ring-shaped condenser lens member.

Epidark illumination system

A parfocal low-magnification microscope objective lens system comprises, in succession from the object side, a positive first lens member, a negative second lens member and a positive third lens member. The first lens member has its concave surface facing the object; the second lens member includes at least one negative meniscus lens component with its concave surface facing the object; and the third lens member includes a positive lens component with that surface thereof sharper in radius of curvature facing the image plane side. The lens system satisfies the following four conditions: d.sub.A &lt;f.sub.A &lt;d.sub.A + .vertline.f.sub.B .vertline.; d.sub.A &lt;d.sub.B ; .vertline.f.sub.B .vertline.&lt;.vertline.f.sub.A .vertline.; and .vertline.d.sub.B .vertline.&gt;.vertline.f.sub.B .vertline.; where f.sub.A and f.sub.B are the focal lengths of the first and the second lens member, respectively, d.sub.A is the distance from the rear principal plane of the first lens member to the front principal plane of the second lens member, and d.sub.B is the distance from the rear principal plane of the second lens member to the front principal plane of the third lens member.

Growing community of inventors

Miura, Japan

Yoshiyuki Shimizu