Abstract: A projection lens system of the type used in connection with cathode ray tubes, and more specifically a cathode ray tube projection system having an internal lens folding means, useful in projecting an image or series of images on a screen.

Abstract: A wide-angle zoom lens system comprising a front lens group consisting of a first negative meniscus lens component, a second negative lens component and a third positive lens component, and a rear lens group consisting of a fourth positive lens component, a fifth positive meniscus lens component, a sixth negative lens component and a seventh positive lens component. Said zoom lens system is so adapted as to perform the zooming operation by varying the airspace reserved between said front and rear lens groups.

Abstract: A tilting device for use in an anti-glare mirror including a prism mirror, a plate for holding the prism mirror, and a casing for accommodating the prism mirror and the plate in it. The tilting device includes a contact projection mounted on the plate, a spring for urging the plate and the prism mirror, a rotary member having a cam face formed on its one face, and a reversible motor for driving the rotary member such that the prism mirror is changed over to either one of a normal position and an anti-glare position.

Abstract: An objective refractometer which enables a doctor to visually conduct optical pointings by projecting onto the retina of a patient an image coming from at least one point light source. The image is projected along an image projection path and observed through an observation path. A stand supporting the refractometer has stationary objective lenses mounted thereon while a movable unit carries an eyepiece and other apparatus which augment the projection and observation paths. An electronic control means comprising a microprocessor is operatively associated with a linear displacement detector, which detects movement of said movable unit relative to the stand, and an angular displacement detector, which detects angular rotation of test patterns on the optical axes of said projection and/or observation paths, as well as apparatus for operator controlled transmission of information derived from the detectors.

Abstract: Telecentric projection lenses are disclosed which are precise in terms of their F number and which have a high resolving power and high contrast, namely well corrected spherical aberration, coma, curvature of field and distortion, and are intended for use at aperture efficiency of 100% and at magnification of about 1/10. The telecentric projection lens comprises a first lens group consisting of a positive single lens, a second lens group consisting of a negative single lens and a third lens group consisting of two positive lenses, arranged in this order as viewed from the object field side. The lens of the second group is a double concave lens and one of the positive lenses in the third group has a cemented surface whose center of curvature lies on the side of object field. The focal lengths f.sub.1, f.sub.2 and f.sub.3 of the first, second and third groups and the focal length f of the whole lens system satisfy the following conditions:1.69.ltoreq..vertline.f.sub.1 /f.sub.2 .vertline..ltoreq.2.55-0.33.

Abstract: In an eye periphery portion illuminating device in an ophthalmologic instrument having a chin supporting member and a forehead applying member for fixing a patient's face to the apparatus body, a downwardly open depression is formed in the forehead applying member and a light source is contained in the depression.

Abstract: A projection lens with a long working distance for projecting a magnified image of an object comprises, in the order from the image side, a diverging first lens group containing a positive lens element and a negative lens element, a diverging second lens group having a negative meniscus lens element with a convex surface thereof facing toward the image side, a converging third lens group containing a positive meniscus lens element whose concave surface faces toward the image side, a converging fourth lens group having a positive lens composed of mutually cemented negative lens element and positive lens element, and a converging fifth lens group. The projection lens of an elevated magnification has a working distance from twice to five times longer than the focal length and is bright with a limited number of lens components.

Abstract: The disclosed zoom lens includes a first lens group of positive power movable for focusing, a second lens group of negative power movable for varying the focal length of the system, a third lens group of positive power movable for image shift compensation, and a fourth lens group of positive power stationary during focusing and zooming. The fourth lens group consists of front and rear assemblies of which the front comprises, from front to rear, a singlet of positive power convex toward the front and a meniscus doublet of forward convexity with its cemented surface convex toward the front, and the rear comprises a single of positive power and a meniscus doublet of forward concavity, and is characterized by fulfilling the following requirements:0.65<F.sub.I,II /F.sub.R <0.71 (1)-0.45/F.sub.R <.phi.II<0.17/F.sub.R (2)0.14F.sub.R <r.sub.R4 <0.24F.sub.R (3)whereF.sub.R : the focal length of the fourth component;F.sub.I,II : the focal length of the front assembly;.phi..sub.

Abstract: An improved, compact optical system comprising a concave primary mirror and a convex secondary mirror. The primary mirror converges radiation to the secondary mirror. The secondary mirror comprises a lens having a first and a second surface. The second surface is coated with reflective material. The radiation received by the lens is refracted at the first surface, reflected back from the second surface, and then refracted once again by the first surface. The first and second surfaces have a shape for providing control of field curvature.

Abstract: A Galilean-type telescope system comprises three components arranged successively along the optical axis thereof. The first and the second components are single positive menisci, constituting the objective of the system and separated by an air space from the third component, which is a negative concentric meniscus forming an eyepiece of the system, all three components being concave towards the eye side of the system. The third component is a lens member cemented together from two lenses having their cemented surfaces of the same shape and equal refractive indices but different dispersion, the dispersion of the lens disposed closer to said eye side being substantially less than that of the following lens. The thickness of the air space between the second and third components complies with the relationship: ##EQU1## wherein: d.sub.x --thickness of the air space,f'.sub.1 --rear focal distance of the objective,.GAMMA.--magnification provided by the system,R.sub.

Abstract: A point focus radiation concentrator using two linear echelon surfaces crossed at approximately 90 degrees with the two linear echelon surfaces having a generally cylindrical shape with a radius of curvature approximately equal to the focal distance. The two echelon surfaces may be formed on separate sheets positioned in close proximity to each other or may be formed on opposite sides of a single sheet. The cross section of the curved concentrator surface may be circular or other aspherical shape, such as parabolic, ellipsoid and hyperbolic.

Abstract: In a liquid crystal imaging display comprising a liquid crystal layer formed over the top surface of a MOS integrated circuit, the reflectivity of the pixel control electrodes is enhanced by means of a polycrystalline silicon layer formed over the MOS integrated circuit and polished to have an optically smooth surface over which the pixel control electrodes and the liquid crystal may be placed. Contrast ratios on the order of 100 to 1 are achieved.