Abstract: A zoom lens includes a first negative lens group, a second negative lens group, a third positive lens group, an aperture diaphragm, and a fourth positive lens group arranged in this order from an object side. When power varies from a wide angle end to a telephoto end, the first and second lens groups are moved to an image surface along an optical axis and then moved to the object side. The third and fourth lens groups are moved to only the object side along the optical axis. The first lens group includes at least one aspheric lens, and the aspheric lens has an aspheric shape in which a positive refractive power is increased toward the periphery of the lens when a paraxial refractive power is positive and a negative refractive power is decreased toward the periphery of the lens when the paraxial refractive power is negative.

Abstract: The variable-power optical system is provided and includes a first lens group having a negative refractive power, a stop, and a second lens group having a positive refractive power, in order from an object side. The first lens group includes a first sub lens group having three negative meniscus lenses and a second sub lens group having a biconcave lens and a positive lens, in order from the object side. The second lens group includes a first positive lens arranged closest to the object side and having at least one aspheric surface and a second positive lens arranged immediately after the image side of the first positive lens. When the absolute value of the focal length of the first lens group is |f1| and the focal length of the entire system at a wide angle end is fw, the Conditional expression: 1.9<|f1|/fw<3.6 is satisfied.

Abstract: A plurality of lens elements and spacer rings 30-38 for constituting a part of an optical system are inserted into a lens-barrel-like jig 40 in predetermined order. A reception portion 43 for receiving the lens element 38 which will be first inserted is formed in the jig 40. When inserted into the jig 40, the lens elements 30-38 are brought into abutment against one another in one way of the optical axis so that spaces among the lens elements 30, 32-34, 36 and 38 are positioned. After that, adhesive is applied to at least three circumferential places of the outer circumference of each abutment portion where the lens elements and spacer rings 30-38 abut against each other, through opening portions 41 provided in the outer circumference of the jig 40. Thus, the plurality of lens elements and spacer rings 30-38 are formed into an integrated structure.

Abstract: A lens assembly is provided and includes: a plurality of lenses; a lens frame having a hollow part which includes an opening on each of an object side and an image forming side of the lens assembly and into which the plurality of lenses are inserted with their optical axes aligned; and a first coating film provided on an image forming side surface of a first lens that is located nearest to the object side among the plurality of lenses inserted into the hollow part, the first coating film being more hydrophilic than that of a base body of the first lens.

Abstract: An imaging lens is provided and includes: in order from the object side, a first lens group including a biconcave lens; a second lens including two lenses whose convex surfaces are arranged opposite to each other and having a positive refractive power as a whole; a third lens group including a biconcave lens; and a fourth lens group including two lenses whose convex surfaces are arranged opposite to each other and having positive refractive power, as a whole, the imaging lens satisfying the specific condition.

Abstract: A first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having the negative refractive power, and a fourth lens group having the positive refractive power are included in order from an object side, and variation of magnification from a wide-angle end to a telephoto end is performed by monotonically moving the second lens group toward an image side and compensation of a fluctuation of an image surface resulting from the variation of magnification is performed by moving the third lens group. At least one positive lens having an optical material satisfying a conditional expressions is included in at least one of the first lens group G1 and the fourth lens group.

Abstract: Binoculars include first and second lens barrels. A bridge interconnects the lens barrels. First and second optical systems are accommodated in respectively the lens barrels. First and second focus lenses are included in respectively the first and second optical systems, for focus adjustment by moving in an optical axis direction. An operation barrel is secured to the bridge, and externally rotatable and movable in the optical axis direction between a focus adjusting position and a diopter adjusting position. A focus adjuster with gear teeth and screw threads moves the first and second focus lenses simultaneously in the optical axis direction when the operation barrel is rotated in the focus adjusting position. A diopter adjuster, including gear teeth, an intermediate rod and screw threads, moves the second focus lens in the optical axis direction when the operation barrel is rotated in the diopter adjusting position.

Abstract: Disclosed is an imaging lens having both high heat resistance that enables the imaging lens to be mounted on a printed circuit board by a reflow mounting method and a high optical performance. The imaging lens includes: a first positive lens group; a second negative lens group; a third positive lens group; and a fourth positive or negative lens group. Each of the first to fourth lens groups includes a parallel plane glass plate and a resin lens that has heat resistance and is arranged on the parallel plane glass plate so as to be integrated with the parallel plane glass plate.

Abstract: An imaging lens includes, in order from an object side, a first lens having a negative power and including a concave image-side surface, a second lens having a positive power, a stop, a third negative lens, which is a biconcave lens, a fourth lens having a positive power, and a fifth lens having a positive power and including a convex image-side surface. The imaging lens satisfies the following conditional expressions: 0.18<(D4+D5)/f<0.44, and 0.18<D1/f where f denotes a focal length of an entire lens system, D1 denotes a thickness of a center of the first lens, D4 denotes a distance from an image-side surface of the second lens to the stop on an optical axis, and D5 denotes a distance from the stop to an object-side surface of the third lens on the optical axis.

Abstract: An imaging lens includes in order from an object side: a first lens including a positive lens having a convex surface directed to the object side; a stop; a second lens including a positive lens having a convex surface directed to an image side; a third lens including a negative meniscus lens with a concave surface directed to the object side; and a fourth lens including, near an optical axis, a positive meniscus shape with a convex surface directed to the object side. An air space between the second lens and the third lens is smaller in a periphery than near the optical axis. And f1>f2>|f3| and 1.0<f/f2<1.5 are satisfied where f1, f2 and f3 are focal lengths of the first lens, the second lens, and the third lens, respectively and f is an focal length of the whole lens system.

Abstract: A variable power optical system is provided and includes: in order from the object side, a first lens group having a negative refractive power and including a negative lens group and a positive lens group; a stop; and a second lens group having a positive refractive power and includes a sub-lens group having a positive refractive power as a whole and arranged on the most object side, the sub-lens group including a first lens having a positive refractive power having at least one aspherical surface, a second lens having a negative refractive power, and a third lens having a positive refractive power. The second lens group is moved to the object side along an optical axis to perform a variable power operation from the wide angle end to the telephoto end with moving the first lens group to make a correction of an image plane position.

Abstract: An endoscope objective lens includes, in order from an object side, a negative first lens, a first cemented lens, an aperture diaphragm, a positive fourth lens and a second cemented lens. The negative first lens has a concave surface directed to an image side. The first cemented lens is formed by cementing a second lens and a third lens. One of the second and third lenses is positive and. The other is negative. The positive fourth lens includes a flat surface or a surface having a larger absolute value in radius of curvature, directed to the object side. The second cemented lens is formed by cementing a positive fifth lens and a negative sixth lens in order from the object side. The second cemented lens has a positive refractive power as a whole. The endoscope objective lens satisfies the following conditional expressions (1) and (2). f 2 × ? v 5 - v 6 ? ? R A ? × ( Bf + d 6 / n 6 ) > 10 ( 1 ) Bf / f > 2.

Abstract: A cleaning adapter unit for connecting a cleaning fluid supply device to different type endoscopes comprises adapter valve assemblies which correspond to the different endoscopes, respectively. Each adapter valve assembly comprises a valve sleeve detachably connectable to the cleaning fluid supply device and a valve body received in the valve sleeve for slide movement and forming a valve chamber leading to the passage in the valve sleeve. The valve sleeve has a passage and is provided with a first fitting at one end thereof which is formed so as to be hermetically received in a valve casing of one of the different endoscopes, and the valve body is provided with first and second passages formed separately therein and opens at opposite ends, respectively, and with a second fitting at one ends thereof opposite to the one end of the valve sleeve at which the first fitting is formed so as to be hermetically received in the valve casing of the other different endoscope.

Abstract: A position detection sensor is provided and includes: a scale including a self-emitting part that emits light to form a pattern on the scale; and a relative movable part provided in such a manner to be opposed to the scale and to be movable relative to the scale, the relative movable part including a light receiving part that detects the light emitted at a position in a portion of the scale where the pattern is formed, the position corresponding to a current position of an object to be measured. At least one of a traveling amount, traveling speed and absolute position of the object is detected based on a detection signal outputted from the light receiving part.

Abstract: An imaging lens includes, in order from an object side, a first lens group having a positive power, an aperture diaphragm, and a second lens group having a positive or negative power. The first lens group includes, in order from the object side, a first lens which is a biconcave lens, a second lens that has a positive power and includes a convex image-side surface, and a third lens that has a positive power and includes a convex object-side surface. The second lens group includes, in order from the object side, a fourth lens that has a negative power and includes a concave image-side surface, and a fifth lens which is a biconvex lens. Each of the first to fifth lenses is a single spherical glass lens.

Abstract: An endoscope apparatus comprises: an insertion section including a distal end; a power changing movable lens that makes observational magnification variable, the power changing movable lens being movably built in an objective optical system provided at the distal end; a linear transmission member that drives the power changing movable lens, the linear transmission member being disposed from a drive section provided at a position other than the insertion section to the distal end; a focus adjusting movable lens that achieves automatic focusing function, the focus adjusting movable lens being movably built in the objective optical system separately from the power changing movable lens; and an actuator that drives the focus adjusting movable lens, the actuator being arranged in the distal end.

Abstract: A balloon controller for an endoscope apparatus, which expands or shrinks a first balloon attached to an insertion portion of an endoscope by supplying fluid to the first balloon or drawing fluid from the first balloon, and which expands or shrinks a second balloon attached to an insertion assist implement for guiding the insertion portion when the insertion portion is inserted, by supplying fluid to the second balloon or drawing fluid from the second balloon, the balloon controller including a display device which displays an image expressing the states of expansion and shrinkage of the first balloon and the second balloon.

Abstract: A projection lens unit includes a magnifying optical system is provided. A second magnifying lens barrel has a shape of double circular cylinders, and a first magnifying lens barrel is fitted to an outer circular cylinder. Further, a second magnifying lens is in contact with and fixed to a step portion of inner circular cylinder. In a manufacturing step thereof, the second magnifying lens is inserted into the inner circular cylinder of the second magnifying lens barrel to be into contact with the step portion. A front end portion of the inner circular cylinder is plastically deformed by being heated and pressed to fix the second magnifying lens. An outer peripheral edge of the front end portion has a curved surface. The curved surface of the front end portion is made to be smaller in radius of curvature than the second magnifying lens.

Abstract: The present invention provides a lens controller which electrically controls a focus and a zoom of a taking lens, the lens controller comprising: an AF control device which automatically controls the focus of the taking lens so that a given subject imaged by the taking lens is in focus; and a view angle correction device which keeps an angle of view of the taking lens constant by moving the zoom of the taking lens to prevent a variation of the angle of view associated with a movement of the focus moved by the AF control device; wherein, when the focus is moved by the AF control device, the view angle correction device detects a current position of the focus by a position detecting device, obtains a position of the zoom for preventing the variation of the angle of view based on the detected current position of the focus, and moves the zoom to the obtained position.

Abstract: Taking lenses 11—4, 11—3, and 11—2 are housed in a lens frame 12. Then, the O-ring 13 is fitted into a groove 11—1a provided on the periphery of the taking lens 11—1, and the taking lens 11—1 is housed in the lens frame 12. Subsequently, an anterior surface 14b of a lens holder 14 in a screwing direction (directions of arrows P and P?) comes into contact with a wall surface 12b of the lens frame 12. Then, the lens holder 14 is gradually screwed into the lens frame 12. Thereby, a deformable portion 12c of the lens frame 12 on an O-ring 13 side of the wall surface 12b is deformed in such a direction (directions of arrows Q and Q?) as to press the O-ring 13.