Fuji Photo Optical Co., Ltd.

Yoshikazu Doi

Yutaka Sakai

Kenzo Sado

Kazunori Ohno

Nagayoshi Hirano

Yasumasa Sunaga

Toshiro Kishikawa

Hiroshi Yamada

Hitoshi Miyano

Masane Suzuki

Kazuo Yoshikawa

Katsuo Katagiri

Yasuo Honda

Kazunori Ohono

Takaaki Uchida

An objective optical system for an endoscope comprises a retrofocus objective lens assembly consisting of a front-stage diverging lens unit, an aperture diaphragm, a rear-stage converging lens unit, and a prism positioned in this sequence, and a self-scanning solid state image pickup device positioned at the image formation surface of said objective lens assembly. The objective lens assembly satisfies the conditions 0.8&lt;.vertline.f1.vertline./f.ltoreq.1.5, 1&lt;f2/f.ltoreq.1.5, and Np&gt;1.7, where f denotes the resultant focal length of the whole assembly, f1 denotes the resultant focal length of the front-stage diverging lens unit, f2 designates the resultant focal length of the rear-stage converging lens unit, and Np designates the refractive index of the prism.

Objective optical system for endoscope

A holographic endoscope transmits light to an object and receives and transmits the image of that object. The light transmitted is used to illuminate an object with one of two beams which are derived from a single laser, while the image received is transmitted from the object. The light from the image transmitted passes through a field lens, and a second beam or reference beam is made to interfere with this light. The resulting interference pattern is recorded on a photographic plate, forming the hologram.

Holographic endoscope

A mechanical compensation type zoom lens system capable of improving performances of large diameter lenses, wide angle lenses and highly variable magnification zoom lenses. This zoom lens system comprises a convergent lens group fixed during zooming, movable lens groups for zooming and an image-forming lens group. The movable lens groups comprise three groups including a first movable divergent lens group, a second movable convergent lens group and a third movable convergent lens group as arranged in the forward order. In the movable lens groups, an interval between the second movable convergent lens group and the third movable convergent lens group is increased on the wide angle side, whereby the movement value of the first movable divergent lens group is decreased. As the result, an entrance pupil position on the wide angle side is hardly changed, so that the distortional aberration can be corrected.

Zoom lens system

A compact wide angle zoom lens comprising front and rear lens groups which are moved in opposite directions along the optical axis of the lens system to vary the magnification. The front lens group comprises a concave meniscus lens, a concave lens and a concave lens and the rear lens group comprises a convex lens, a first convex meniscus lens, a concave lens and two convex meniscus lenses, in the order mentioned from the object side.

Wide angle zoom lens

A television camera system using any television lens and camera in combination achieves automatic video control. The television camera actually used in the television camera system has an erasable memory having memorized therein optical and/or electrical regulation values of the television camera with respect to a standardized television lens for forming the best images or the intended images. Similarly, the television lens actually used in the television camera system has an erasable memory having memorized therein optical and/or electric regulation values of the television camera with respect to a standardized television camera for forming the best images or the intended images. The regulation values read out from these memories are used to control the amount of regulation of the camera control unit.

Television camera system

A rear stop type lens with highly corrected comatic flare is constituted of one convex meniscus lens, two concave lenses and one biconvex lens arranged in the order mentioned from the object side.

Rear stop type lens system

A compact rear stop type zoom lens suitable for use with a camera having an electronically controlled shutter. The rear stop type zoom lens is comprised of two lens groups which effect variation in magnification when moved in opposite directions on the optical axis of the entire lens.

Rear stop type zoom lens

A zoom lens system having a wide angle of view, a large diameter and a large zooming ratio in which the distortion is well corrected. The zoom lens system includes a movable lens group and a fixed lens group for zooming. A relay lens is provided behind the zooming lens group. A compensating lens having a small refractive power is inserted between the movable lens group and the fixed lens group and is moved in association with the zooming operation. The compensating lens consists of an aspherical lens of small refractive power or a group of spherical lenses having a small refractive power as a whole. The compensating lens is located at a position between the movable lens group and the fixed lens group where the light flux advancing along the optical axis of the zoom lens system converges to the image side.

Zoom lens system with a movable distortion-correcting element

A zoom lens system consists of a front lens group A comprising a negative meniscus lens L1 convex to front (i.e. object side) and a positive lens L3 having the face of greater curvature faced to front, and a rear lens group B comprising a positive lens L4 having the face of greater curvature faced to front, a positive menisucs lens L5 convex to front, a negative lens L6 having the face of greater curvature faced to rear and a positive lens L7. The front and rear lens groups A and B are moved in the opposite directions along the optical axis thereof to vary the focal length thereof. The above zoom lens system satisfies the following conditions where the focal length of the front lens group A is fA, the radius of curvature of the concave face of the negative meniscus lens L1 is r2, the radius of curvature of the front face of the positive lens L3 is r5, the radius of curvature of the convex face of the positive meniscus lens L5is r9 , the radius of curvature of the rear face of the negative lens L6 is r12 and the Abbe dispersion number of the positive lens L3 is .nu.3; -2.3&lt;fA&lt;-1.5, 0.45&lt;r2&lt;0.65, 0.5&lt;r5&lt;1.0, 0.4&lt;r9&lt;0.6, 0.3&lt;r12&lt;0.55, .nu.3&lt;40.

An optical system for a color television camera includes an interchangeable taking lens, a color separating prism block located behind the taking lens and three image pick-up tubes for different color images located behind the prism block. Between the prism block and at least one of the pick-up tubes an optical element which is capable of varying the optical path length is inserted. The optical path length varying element may be a plane parallel plate or a combination of two optical wedges having parallel opposite end faces. The plane parallel plate changes the optical path length by its thickness. The combination of the two optical wedges varies the optical path length by sliding the wedges with respect to each other to vary the distance between the opposite end faces.

Optical system for color television cameras

An inverted telephoto lens having a super-wide angle of view is composed of a negative meniscus lens L1 convex to the front as numbered consecutively from front to rear, a biconvex lens L2, a negative meniscus lens L3 convex to the front, a cemented positive doublet of a negative lens L4 and a positive lens L5, a biconvex lens L6, a biconcave lens L7 the rear surface of which has radius of curvature greater than that of the front surface thereof, a positive meniscus lens L8 convex to the rear, and a positive lens L9 arranged in this order. The Abbe dispersion number of the biconvex lens L6 is more than 53 and less than 61. The difference between the Abbe number of the negative lens L4 and that of the positive lens L5 of the doublet is more than 10 and less than 16.

Inverted telephoto type super-wide angle lens

A zoom lens system in accordance with this invention is composed of a first fixed lens group, a first movable lens group, a second movable lens group and a second fixed lens group arranged in this order from front to rear, wherein a stop is are located at the center of the whole lens system and the first fixed lens group and the second fixed lens group consist of the same lens elements and located symmetrically with respect to the stop, and similarly the first movable lens group and the second movable lens group consist of the same lens elements and are located symmetrically with respect to the stop. The first movable lens and the second movable lens are asymmetrically moved with respect to the stop in accordance with the location of the whole lens system that is changed to vary the magnification, whereby the distortion and the focus shift caused by the field curvature fluctuation are eliminated throughout the variable range of magnification. Further, the zoom lens system in accordance with this invention is characterized in that the power of the lens groups and the lens elements is designed to make the whole lens system compact in size.

In a zoom lens system dividable into a zooming lens component which varies the magnification without moving the image plane and a relay lens component, at least a part of the relay lens component is made to have no power so that the axial movement thereof may not vary the focal length of the zoom lens system and is moved along the optical axis in association with the zooming lens component to compensate the fluctuation of aberration caused by the movement of the zooming lens component.

A projection lens system comprises a positive meniscus lens G1 (as numbered consecutively from front to rear) convex to the front, a biconcave lens G2, a biconvex lens G3, a positive meniscus lens G4 convex to the front, and a biconcave lens G5. The projection lens system is designed to be well matched with the halogen lamp of cold mirror type in which the distance to the secondary focus is short by using a negative lens at the rear end thereof, making the Petzval sum small, locating the entrance pupil as near to the aperture as possible and shortening the back focal distance. The image surface is made flat and spherical aberration and astigmatism are well corrected. The high order comatic flares are markedly reduced and an image of high sharpness and contrast can be obtained thereby. Further, the radii of curvature of all the surfaces in the lens system are made not smaller than 0.68f so that the lenses can be manufactured at a low cost.

Projection lens system for motion picture projector

In an optical system including an objective lens to form an image on a focusing plane and a relay lens system to carry the image to another focusing plane, an image rotating prism is inserted in the relay lens system and a field lens is provided between the objective lens and the relay lens. The pupil of the relay lens system is positioned at the center of the optical path of the prism by properly selecting the power of the field lens.

Growing community of inventors

Omiya, Japan

Yoshikazu Doi