Abstract: A gradient index lens system in which spherical aberration and coma are well corrected and which has an excellent imaging performance comprises a first gradient index lens and a second gradient index lens. The second gradient index lens has a gradient index different from that of the first gradient index lens and is either cemented to the first gradient index lens or disposed with a predetermined air space with respect to the first gradient index lens.

Abstract: A binocular ophthalmoscope, having an optical viewing system, a light source and headgear mountable on an examiner's head during use for supporting the optical viewing system in optical alignment with the examiner's eyes and the light source with the output thereof above the optical viewing system. The light source has a selector for selectively providing both full beam and slit beam illumination of a patient's eye, a first condensing lens for focusing light on the bull beam or slit beam aperture, a second condensing lens for refocusing the light passing through the aperture onto an aerial image of the retina, and a third lens for shortening the focal length of the beam emitted from the light outlet of the light source and which is mounting for pivotal movement into and out of the beam path.

Abstract: The multi-color traffic signal for railways comprises for each one of the three colors a projector unit consisting of a lamp, an optical unit and a chromatic filter. The projector units are connected to an irradiating output optics by means of an optical channel system consisting of a main rectilinear channel presenting at one end the irradiating output optics and at the other end a first projector unit in axial alignment with the main channel. A second and third projector units are housed in transverse channels at 90.degree. with respect to the main channel and open thereinto. A first dichroic mirror is arranged in the main channel with an angle of 45.degree. in correspondence with the outlet of the transverse channel of the second projector unit and a second dichroic mirror is arranged in the main channel with an angle of 45.degree. in correspondence with the outlet of the transverse channel of the third projector unit.

Abstract: This invention relates to a lens system which can convert a focal length by adding a converter lens. A rear converter lens having a positive refractive power is added between an image surface rearwardly of a standard or tele-lens system to obtain a wide angle lens. At this time, it is necessary to make the full length of the converter lens small and to prevent an increase in positive Petzval's sum of the converter lens and in negative distortion aberration. In this invention, in case of a wide angle lens, a rear converter lens is used which is composed of three to five lenses having an angle of view, 63.4.degree. and a magnification ratio, more than 1.4.

Abstract: The present invention relates to a support structure for a spectacles frame and a front intended to be adapted thereto. The support structure comprises a locking arm or shutter movable in rotation between an open position where it allows to penetrate the projecting element of the front in an interacting hollow housing and a locking position where it is folded back in order to block this projecting element. Application to the realization of spectacles frames having detachable fronts.

Abstract: This invention relates to a four-group-lens zoom lens which is small in size and has a high magnification changing rate of which zoom ratio is 4. The zoom lens comprises a magnification changing system in which a first group, a second group and a third group have positive, negative and positive refractive powers, respectively, and a fourth group in the form of a relay lens. It is advantageous to make the focal length of lenses in the first group small in order to miniaturize the magnification changing system. In addition, it is advantageous that the relay lens be made small in the focal length and made small in telephone ratio, in order to miniaturize the whole zoom lens.

Abstract: A zoom lens mounting capable of focusing beyond the usual range of object distances towards close ups in a particular region of the zooming range has a control member which changes its position depending upon the relative position of a focusing actuator to a zoom control cam member or vice versa, wherein the aforesaid focusing actuator and the aforesaid cam member are each provided with an area subject to constraint with the aforesaid control member and an area not subject to the constraint.

Abstract: A G force acceleration effects monitoring apparatus involving a pair of LED or other visual stimulus arrays, one randomly patterned by an electronic driving apparatus and one patterned by the manipulation of a G force test subject. The electronic driving apparatus preferably includes a sum of sines algorithm and the test subject manipulations are received preferably from a joystick controller. Mounting of the apparatus in a centrifuge gondola and also in off-line training stations and use of the invention by animals are also disclosed.

Abstract: The invention concerns a process and device for measuring the degree of ametropia of an eye.The rays of a luminous source passes through a focussing lens and a test lens in order to create an image on the retina. The rays issuing from the source or from the image pass through a black optical slit and are reflected by at least one reflecting surface defined in a revolving screen driven in rotation by a motor.Application to refractometric instruments for measuring the degree of ametropia of the eye.

Abstract: This eyeglasses temple comprises a leg portion and spring-loaded devices for enabling the leg opening to occur elastically beyond an overcenter position, and enabling the leg to be closed with a snap action. The spring-loaded devices comprises a leaf spring, pivotally inserted into a pocket formed in the eyeglasses leg and acting with its free end onto a head portion made rigid with the eyeglasses frame, and shaped to provide two stable opened-closed positions for the leg, resilient extra opened positions and an opening travel limit stop therefor.

Abstract: Apparatus for recording eye movement. A light source has its rays directed toward the eye of a subject and a glass dome secured to spectacle frames worn by the subject. The primary and secondary glints reflected off the glass dome and eye cornea, respectively, are transmitted via mirrors, lenses and a fiber optic image guide to a video camera tube. The position of the glints on an XY axis is electronically determined and the information is fed to a computer which compares the data from the two glints and compensates for the head movement which corresponds to movement of the primary glint.

Abstract: An eyeglass assembly includes first and second lens holding frames, each of which has a temple piece pivotally attached to and extending rearwardly from an edge portion of the frame. The first and second frames are releasably and pivotally connected to each other in an overlapping manner and the snap connector use to join the frames is disposed within recesses in the frames so that when the frames are connected they will be flush against each other and no portion of the connector will be visible.

Abstract: A dual screen filming apparatus has a fully reflective mirror positioned in the optical path of part of a projected image at an angle of 45.degree.. The mirror reflects the part of the projected image onto a first front projection screen set at 90.degree. to the path of the reflected image. The mirror also has a non-reflecting portion which lies in the path of the remainder of the projected image and is arranged to allow the light to pass therethrough without reflection onto a second front projection screen. The light reflected from the first and second screens is collected by a semi-reflective mirror, positioned intermediate the projector, and the fully reflective mirror and is directed into the lens of a camera to provide a composite image.

Abstract: Disclosed is a refractor of the type having a housing which has patient eye position for viewing along a sight axis extendible therethrough, a pair of superimposed cylinder lens assemblies, means for positioning a particular lens in front of the sight axis, axis control means for controlling the axis of each cylinder lens, a cross-cylinder assembly which is synchronously coupled with said cylinder lens assemblies. The improvement of such type of refractor comprises the positioning means including an internally threaded cylinder axis drive gear having a lock shaft, said gear located outside of the housing and having its lock shaft extending through an opening in the housing coincident with the common axis of both carriers, said shafted cylinder axis drive gear riding upon bearing means disposed between it and the housing. The housing opening for the lock shaft has a sleeve within the housing which circumscribes the opening. There is an annular space formed between the lock shaft and the sleeve.

Abstract: A behind stop lens has, in succession from the object side, a first lens which is a positive meniscus lens having its convex surface facing the object side, a second lens which is a biconcave negative lens, a third lens which is a biconvex positive lens, and a fourth lens which is a negative meniscus lens having its convex surface facing the image side, the third lens and the fourth lens being cemented together to form a positive cemented lens. The behind stop lens satisfies the following conditions: ##EQU1## where f represents the total focal length of the entire system, .SIGMA.d represents the distance from the vertex of the object side lens surface of the first lens to the vertex of the image side lens surface of the fourth lens, f.sub.2 represents the focal length of the second lens, r represents the radius of curvature of each lens surface, n and .nu. represent the refractive index and the Abbe number, respectively, of each lens, and the subscript numbers mean the order from the object side.

Abstract: A method and apparatus for measuring the intraoperative and immediate postoperative effects of radial keratotomy are provided. Essentially, the method includes the steps of measuring the preoperative corneal thickness and radial distance along multiple meridians, plotting the preoperative internal radius of curvature of the cornea, measuring the intraoperative or immediate postoperative radial distances along multiple meridians, plotting the intraoperative or immediate postoperative internal radius of curvature and predicting the resulting anterior radius of curvature of the cornea.

Abstract: Spectacle frame with a removable elastic securing band which attaches to the temples of the frame. Each of the two temples of the spectacle frame has a hole in the vicinity of the temple end on the ear side, of which at least one extends substantially in the longitudinal direction of the temple. The securing band, realized as an elastic cord, has at least at one end an end enlargment. The securing band is brought through the holes, where the enlarged end bears against the hole end of the hole of the first temple and the securing band is brought through the hole, extending essentially in the longitudinal direction of the temple, of the second temple in a self-locking manner.

Abstract: A microlens for use with an optical fiber or the like. It comprises a single lens having a diameter of about 0.5 mm. It provides an ideal combination of the length of the lens with the refractive index of its opposite surfaces for a minimum curvature of field.

Abstract: A specular microscope in which the image of a slit aperture of an illumination optical system is formed at an endothelial cell layer of an eye to be examined and including a light intercepting plate having a main aperture and additional apertures adjacent said main aperture so that an image of the endothelial cell layer is formed at said main aperture and a reflection light reflected by a corneal surface of the eye is transmitted through said additional apertures of said light intercepting plate.

Abstract: A lens system for optical recording type disks comprising a first and second lenses wherein the first lens is a positive lens and the second lens is a positive lens, the lens system being arranged that at least one of the exit surface of the first lens and respective surfaces of the second lens is formed as an aspherical surface, the lens system being small in size and light in weight and having a long working distance and favorably corrected aberrations.