Abstract: A large-aperture lens system with a lens having aspherical surfaces to be used to read out optical information and to be used in optical communication transmission systems or the like. The lens in the system has a large aperture despite its very small focal length, because it is manufactured using glass with both a high refractive index and a high Abbe number giving the lens excellent aberration characteristics. The system can be manufactured using ultra-precision press-molding technology.

Abstract: In an optical lens system for use in combination with a bar code sensor, first and second meniscus lenses are arranged back to back along an optical axis on object and image sides, respectively, and are identical in configuration and optical charcteristics with each other. Each meniscus lens has effective aspherical surfaces defined by predetermined formulae. On the assumption that the first and the second meniscus lenses have the same refractive index, the optical lens system satisfies the following formulae:0.25<(r1/r2)/(n/(n-1))<0.5.1.2<f1/f<1.8,0.3<D/f<0.6, and1.

Abstract: In an aspherical glass lens element which has an optical axis, a focal length f, a thickness along the optical axis, and first and second aspherical convex surfaces defined by first and second predetermined formulae represented as functions of first and second radii of curvature r.sub.1 and r.sub.2 at apexes of the first and the second aspherical convex surfaces and first and second conical coefficients k.sub.1 and k.sub.2, a first factor of f/D, a second factor of (r.sub.1 /r.sub.2)D, and a third factor of k.sub.1 /k.sub.2 fall within the following ranges:1.68<f/D<1.75,-0.18<(r.sub.1 /r.sub.2)D<-0.10, and-0.08<k.sub.1 /k.sub.2 <0.04,where an absolute value of the second coefficient k.sub.2 is smaller than 1000.

Abstract: In an aspherical glass lens element which has an optical axis, a focal length f, a thickness along the optical axis, and first and second aspherical convex surfaces defined by first and second predetermined formulae represented as functions of first and second radii r.sub.1 and r.sub.2 of curvature at apexes of the first and the second aspherical convex surfaces and first and second coefficients k.sub.1 and k.sub.2 of cones, f/D, r.sub.1 /r.sub.2, and k.sub.1 /k.sub.2 fall within the following ranges:2.0<f/D<4.0,-0.5<r.sub.1 /r.sub.2 <-0.1,-2<k.sub.1 <1, and-80<k.sub.2 <-10.A glass material of the aspherical glass lens element has a refractive index nd and an Abbe number .nu.d selected within the following ranges:1.45<nd<1.55 and75<.nu.d<90.

Abstract: In an aspherical lens element which has an optical axis, a focal length f, a thickness D along the optical axis, and first and second aspherical convex surfaces defined by first and second predetermined formulae represented as functions of first and second radii r.sub.1 and r.sub.2 of curvature at apexes of the first and the second aspherical convex surfaces and first and second coefficients k.sub.1 and k.sub.2 of cones, the aspherical lens element is formed by a low dispersion glass material which has a refractive index n and an Abbe number .nu. specified by:1.44<n<1.55,and75<.nu.<90.In addition, the aspherical lens element is defined by:1.5<(f/D)<1.9,-0.4<(r.sub.1 /r.sub.2)<-0.2,and10<k.sub.1 .multidot.k.sub.2 -1000E.sub.1 <30.

Abstract: A finite conjugation large-aperture lens with aspherical surfaces having aspherical first and second surfaces which meet the condition of the following formula (1) and satisfying the conditions of the following formulae (2) and (3):Z=[CiY.sup.2 /[1+ (1- (1 +Ki)Ci.sup.2 Y.sup.2).sup.1/2 ]]+EiY.sup.4 +FiY.sup.6 +GiY.sup.8 +HiY.sup.10 (1)2.0< (NAO/NAI)< 7.0 (2)1.2< r.sub.1 /[(n- 1)f]< 2.1 (3)where,z: distance between aspherical surface and a plane which is perpendicular to optical axis and which passes apexY: height from optical axisCi: curvature of apex of i-th aspherical surface (1/r.sub.i)Ki: conical constant of i-th surfaceEi to Hi: 4th to 10th order aspherical coefficients of i-th surfaceNAO: numerical aperture (NA) at object sideNAI: numerical aperture (NA) at image sidef: focal lengthd: thickness at lens centern: refractive index of glass.

Abstract: To test an aspheric lens, the lens is mounted on a base shaft having a central axis so that the center of a reference curvature radius of the lens agrees with a central axis of the base shaft. A stylus mounted on a rotary table is rotated about the lens such that its center of rotation lies on the central axis. The step of stylus is maintained in contact with the surface of the aspherical lens. As the stylus is rotated in contact with the lens, both the rotational and radial position of this stylus is monitored.

Abstract: Auto-focus binoculars in which only the center portion of the image viewed through the ocular lenses of the binoculars is used for focusing. Light admitting windows are formed adjacent right and left objective lenses of the binoculars. Light from the light admitting windows is reflected by fixed and movable reflex members through long focal length lenses onto a focus detecting module. The movable one of the reflex members is reciprocated by a motor until an output signal from the focus detecting module indicates that focusing has been achieved.

Abstract: An automatic focusing binocular is herein disclosed in which a light, signifying the inability of the automatic focusing system to operate due to the lack of available light contrast, is provided within the user's field of vision as he looks through the binocular. This is accomplished by the use of a focus detection module. When the reflected images from apertures proximate to the objective lens coincide in the module, a focusing signal is produced which terminates the motion of the eyepieces at a point corresponding to the distance of the object from the objective lens. When these coinciding images do not have sufficient light contrast for the module to produce the focus signal, a detection signal is produced which illuminates a warning light. A rod-shaped prism is disposed such that light from the light source condenses at the forward focal point of the eyepiece.

Abstract: A housing for binoculars including split upper and lower housing halves which entirely protects the main body of a binoculars including the left and right optical systems, the focusing mechanism and the eyepiece adjustment mechanism. Ocular and objective lens frames project outwardly from the main body of the upper and lower halves of the housing. The two halves of the housing are joined by rings placed over the objective and ocular frames. Only an eyepiece width adjustment knob and a focusing adjustment knob or switch project from the housing so that a tight seal is provided for all internal components.

Abstract: Binoculars including an automatically focussed optical system in which portions of the two incoming light beams are diverted to an automatic focussing module by two mirrors, one of which is fixed and the other movable. The movable mirror is adjusted until two images on an image screen coincide with one another. The position of the movable mirror is sensed and utilized in a servo control system for positioning the ocular lenses at a focussed position. The distance to the object being viewed is displayed by providing an indicator attached to the ocular lens positioning mechanism.

Abstract: Binoculars including an eye span adjustment mechanism and an automatic focussing feature. A pair of guide rails is disposed laterally in the binoculars housing. Drive rods threadedly engaged with the lens barrels are movable along the guide rails to move the lens barrels back and forth in response to rotation of a knob and adjustment rod. An automatic focussing is disposed between the lens barrel to move the ocular lens in response to an electronically produced focussing signal.

Abstract: Binoculars including an automatic focusing system with light entry windows on both sides of the binoculars provided outwardly of the objective lenses. Movable and fixed reflecting elements are disposed inwardly of the light entry windows both of which direct incoming light images onto a focusing detecting module. The movable reflector is oscillated back and forth scanning the image reflected thereby laterally with respect to the stationary image reflected by the fixed reflector. An output control signal is produced when the two images are in alignment with one another and the ocular lenses are moved in accordance with this signal to properly focus the binoculars.