Abstract: Shutter 30 produces a pulsed emission from a beacon. Hot plate 40 radiates upward through openings 67. Shutter plate 52 slides to open and close the view of the hot plate. Outer optical plate 38 has divergent and adjoining reflector openings 67 so that a large area source is seen when the shutter is open. Means are also provided for urging the shutter into close engagement with the outer optical plate so that while in the open position the shutter plate is cooled so as not to become a radiator of energy when it is moved to the closed position.

Abstract: A compact zoom lens system is disclosed having a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a fourth lens group with negative refractive power, such that the second and third lens groups are moved for the purpose of zooming, and the first lens group is moved in order to compensate for the movement of image surface, the entire system having a large zoom ratio.

Abstract: In a camera-equipped ophthalmoscope, an aspherical objective lens is connected to one end of a cord wound about a cord-roll-up drum biased by a helical spring to rotate in a direction to take up the cord. The rotation of the cord-roll-up drum causes a lens-barrel contained therein to move in the direction of its optical axis, whereby the focus of the photographing lens is corrected depending upon the amount of the movement of the aspherical objective lens.

Abstract: A zoom lens is composed of, in the order from the object side, a focusing lens unit of a positive refractive power, a variation lens unit of a negative refractive power, a compensator lens unit of a negative refractive power, a front relay lens group of a positive refractive power and a rear relay lens group of a positive refractive power. The rear relay lens group is composed of, in the order from the object side, a negative lens component and a positive lens component. Optimum conditions are employed in the refractive power arrangement of the front and rear relay lens groups and of the negative and positive components of the rear relay lens group, and in the distance between the negative and positive components of the rear relay lens group.

Abstract: A telecentric rear converter mountable on the image side of an objective lens to enlarge the composite focal length of the rear converter and the objective lens more greatly than the focal length of the objective lens includes a first lens group of negative refractive power and a second lens group of positive refractive power disposed on the image side of the first lens group. The two lens groups are disposed so that the spacing between the principal points thereof is substantially equal to the difference between the respective absolute values of the focal lengths of the two lens groups. When the telecentric rear converter is mounted on the image side of the objective lens, the rearward focus of the first lens group is substantially coincident with the image point by the objective lens and converts the convergent light beam by the objective lens into a substantially parallel light beam, and the second lens group maintains its telecentricity while securing a predetermined back focal length.

Abstract: Disclosed is an area type beam splitter disposed in the light beam from an imaging optical system to split the light beam. This beam splitter has dot-like reflecting surfaces formed on a substrate. The dot-like reflecting surfaces are arranged at pseudo-random.

Abstract: In engraving of printing forms particularly of gravure cylinders, it has previously been possible to produce run-free color raster configurations for only two colors. The present invention discloses rastering methods for run-free color production of four color impressions and polychromatic impressions.

Abstract: An optical instrument which measures with great accuracy certain anatomical dimensions of an eye utilizing finite light beams which strike the eye from pre-determined angles and distances. The instrument measures, among other things, the critical sagittal depth of the eye where the finite light beams converge at a recognizable point. The measurements provide optimal fitting of a contact lens to the eye.

Abstract: Fluorescence of the anterior chamber of an eye is determined by projecting a ribbon of light from the side of the eye through the anterior chamber in a direction generally perpendicular to the optic axis of the eye. The ribbon of light is obtained by imaging the face (20) of a fiber optic bundle (18) and directing that image into the anterior chamber by a mirror (30) mounted adjacent to a contact lens (40). The contact lens (40) includes a flexible membrane (14) backed by a fluid. The pressure of the fluid can be varied by a syringe (44) to vary the curvature of the contact lens membrane (14). The fluorescence can be detected either directly by a photodiode (68) or through a fiber optic bundle (34) by a photomultiplier (76).

Abstract: A zoom lens system comprising a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having negative refractive power and a fourth lens group having positive refractive power, the zoom lens system being arranged to be zoomed by moving the second and third lens groups, at least one lens element in the fourth lens group being arranged as a plastic lens, the zoom lens system being thereby arranged to be small in size, light in weight and low in price and, at the same time, to have high performance.

Abstract: This invention consists of a geometrically patterned lens for primary uses in the field of image projection and refraction.

Abstract: Apparatus for displaying eyesight tests for patients comprising a viewing station a test support having a plurality of eyesight tests selectively visible from the viewing station along first and second optical paths, the first optical path being for near vision and devoid of optical focusing means and the second optical path being for far vision and having optical focusing means. The optical paths have a common section running from a selected test support panel. Each of the optical paths comprises a mirror for bending the viewing axis toward the viewing station, the mirror for the first optical path being rockably mounted or semireflecting for providing access to the second optical path.

Abstract: A novel vision tester and vision testing method is described which comprises a pair of translucent displays, each transilluminated by electroluminescent lighting panels, the images of the two patterns being superimposed to provide a combined image characterized by a pattern of variable contrast. Light sensors near each light panel provide a measure of the relative intensities of the two images, which provides a measure of the contrast of each combined image. Contrast may be directly read out by processing the signals from the light sensors. The tester may be battery powered for portability.

Abstract: A compact and light-weight lens system for optical recording type disks comprising only one lens element and arranged to have favorably corrected aberrations and a long working distance by forming both surfaces of the lens element as aspherical surfaces.

Abstract: A connecting device includes a cylindrical body to both ends of which are connected an endoscope and a television camera and from which a light guide provided with an eyepiece section at its one end for connecting a steal camera is extended. In the cylindrical body is provided a support in which first and second prisms having different light splitting ratios are movably provided to selectively face the other end of the light guide.

Abstract: Eyeglasses have a quick disconnect unit including temples insertable through apertures in the frame and detachably affixed thereto by a sleeve mounted on the portion of the temple extending beyond the frame. Earpieces could be detachably maintained to the stem part of the temple by a mated sleeve connection. A temple to frame hinge is provided by a flexible tubular material.

Abstract: An ultracompact telephoto eight-group ten-element or eight-group eleven-element lens comprises, in order from an object, a front four-group four-element lens group including a first positive lens having a surface of a smaller radius of curvature directed toward the object, a second positive lens having a surface of a smaller radius of curvature directed toward the object, a third double-concave lens, and a fourth positive-meniscus lens having a surface of a smaller radius of curvature directed toward the object, an intermediate three-group five-element lens group including a compound lens composed of a fifth negative lens and a sixth double-convex lens, a compound lens composed of a seventh negative lens and an eighth double-convex lens, and a ninth negative lens having a surface of a smaller radius of curvature directed toward the object, and a rear lens group including a single tenth positive lens or a positive compound lens composed of a tenth positive lens and an eleventh negative lens.

Abstract: An apparatus forming a wedge shaped mirror tunnel makes the intensity distribution across a light beam uniform. A light beam is directed along a predetermined path through a cylindrical lens to focus the beam to a line at a particular point P. A plane mirror is placed along the predetermined path near point P so that the beam is folded onto itself. A plurality of cascaded optical means of this type, each stage of which comprises a focusing lens and a reflective surface, is used to achieve the beam uniformity needed for the chosen application. In each of the cascaded stages, the reflective surface is positioned at the appropriate angle to fold the beam upon itself.

Abstract: A flat field lens system wherein the Petzval sum is corrected without requiring many spaced high powered elements or sharply bent elements. This is achieved by having the Petzval sum correction dominated by the index difference. In an embodiment suitable for use in endoscope transfer optics where medium or high aperture is required, the spherical aberration is best corrected by use of an aspheric surface on the low index material. Where high aperture is not required, as for example in a photographic wide angle objective, spherical aberration is kept low by using a relatively small aperture.

Abstract: A binocular ophthalmoscope of the type including an optical viewing system. The binocular ophthalmoscope includes a headgear adapted to be worn on the examiner's head for supporting the optical viewing system in optical alignment with the examiner's eyes and light source for illuminating a patient's eye which is slideably mounted on the headgear and movable in a lateral direction.