Abstract: A viewfinder system capable of changing over the magnification includes an objective lens unit having at least two negative lens elements replaceable with each other for magnification change-over, and an eyepiece unit having a positive refractive power and constituting an inverted Galilean telescope type viewfinder with the objective lens unit. When the radius of curvature of that surface of one negative lens element for low magnification which is adjacent to the object side is rw.sub.1 and the radius of curvature of that surface of said one negative lens element which is adjacent to the eyepiece side is rw.sub.2 and the radius of curvature of that surface of the other negative lens element for high magnification which is adjacent to the object side is rT1 and the radius of curvature of that surface of said other negative lens element which is adjacent to the eyepiece side is rT2 and Q.sub.W and Q.sub.T are defined asQ.sub.W =(rw.sub.2 +rw.sub.1)/(rw.sub.2 -rw.sub.1)Q.sub.

Abstract: An optical projector (11) for a two-color head-up display wherein light of a first color from a first data source (15) passes through a first lens arrangement (23) into a first wedge-shaped body (27) wherein the light is, in turn, internally reflected at first and second angled faces (35 and 33) of the body and then exits the body at the first face (35) to pass via a second lens arrangement (25) to the system combiner (13) in a direction at an angle to that which light enters the body, and light of a second color from a second data source (37) passes through a third lens arrangement (41) into a second wedge-shaped body (43) wherein the light is reflected at one (49) of first and second angled faces (47, 49) of the second body and then exits the body at the other angled face (47), which is adjacent the second angled face of the first body, and then passes through the first body to the second lens arrangement, there being a dichroic coating at the interface of the two bodies to effect reflection of light of the

Abstract: A display source emits light. A first hologram receives the light from the display source and diffracts the received light. The light from the display source is applied to the first hologram at an incident angle A1 and moves from the first hologram at an outgoing angle B1. A second hologram receives the light from the first hologram and diffractively reflects the received light. The light diffractively reflected by the second hologram forms an image of the display source in viewer's field of view. The light from the first hologram is applied to the second hologram at an incident angle A2 and moves from the second hologram at an outgoing angle B2. The first and second holograms are nonparallel to remove a ghost image of the display source which would result from at least one of surface reflections at the first and second holograms. The first hologram has an angle .theta. relative to the second hologram. The angles A1, B1, A2, B2, and .theta.

Abstract: In the field of optics, collimators are adapted not only for testing, calating and measuring instruments, but for target projection and simulation. The technique is to use standard targets which are commonly available as target sets, such as three-bar and area targets. Such standard targets, although in wide use, are subject to certain disadvantages, particularly when the light source is not in the human visible range. Targets used with this radiation are subject to mechanical constraints. Since, like stencils, they are dependent upon cut-outs, images formed are subject to the same limitations as stencils. That is, bands or strips must support the cut-out image. By this invention, mechanical constraints of cut-outs in targets now employed are obviated, and many of the thermal limitations of such targets are alleviated.

Abstract: A light beam focusing system provides a diffraction limited spot across a wide flat field format by using a scanning surface arranged with a system of spherical mirrors to achieve dynamic field flattening. The scanning surface is pivoted about an axis of rotation to image the beam along a noncircular image line, and the spherical mirror system provides magnification of the image in a sense and amplitude to provide a substantially uniform focused scanning spot throughout the flat object field. The system compensates for higher order spherical aberrrations, is fully achromatic and can be used with high power beams.

Abstract: An optical system having a grating lens assembly including a first grating lens which diffracts rays of a beam incident thereupon so as to provide non-parallel diffraction rays and a second grating lens which converges the non-parallel diffraction rays at a predetermined point substantially without aberration.

Abstract: An optical system for a semiconductor laser beam comprises a semiconductor laser which generates light comprising both stimulated emission light and spontaneous emissions in accordance with the amount of electric current applied thereto, a convergent lens disposed in the light path of the beam emitted by the semiconductor laser, and an optical element disposed in the light path of the beam from the convergent lens which cuts more spontaneous emission than stimulated emission.

Abstract: An interference filter, also referred to as a notch filter, of the type which reflects a certain wavelength range while letting pass over wavelengths bands of a range is disclosed. The filter is designed for operation in the visual and infra-red regions of the electromagnetic spectrum and in the disclosure the uniform layer pairs of material are such that the optical thickness of each layer of the or each layer pair deposited on a plane light-transmitting substrate is a non quarter-wave unequal thickness with respect to its complementary layer. Each layer pair has an overall optical thickness adding up to in total a half-wave thickness.

Abstract: An abrasive jet blasting machine for a continuous abrasive jet blasting treatment of wire-shaped and rod-shaped workpieces includes a plurality of centrifugal wheel units arranged angularly offset relative to each other. To each centrifugal wheel unit are assigned two jet conducting and guiding plates which are adjustable relative to each other. All jet guiding plates are adjustable jointly either toward or away from the workpiece by means of an adjusting device which includes a swivelable lever. The adjusting device includes a sensing device which is directed toward the workpiece and is adjustable in the same sense as the jet guiding plates. The sensing device is in operative connection with an adjusting drive which acts on the lever of the adjusting device.

Abstract: A shift mirror or reflector (SP) which is noted by high azimuth velocity around a first axis (A1) and dependent upon that can be tilted around an axis rotating therewith. The rotary movement is transmitted from a motor (M) arranged at the side by means of a belt drive (RS) (Z1) or directly from a coaxial hollow shaft motor (M1) via a first shaft and a reflector-suspension to the reflector. The tilt movement arises from an up and down movement of a second shaft via tilt levers (K1, K2), with the second shaft being guided within the first shaft and rotating therewith. The second shaft (A2) is coupled via an axial bearing to the up and down movement of a spindle/nut arrangement, which is actuated by a separate drive (RS2) or another hollow shaft motor (M2). First shaft, second shaft, spindle, nut and also, if desired, the hollow shaft motors are arranged coaxial to each other.

Abstract: A zoom lens comprising a first and a second lens component that are related to each other for zooming. The first lens component consists of four lens elements and has a positive focal length f.sub.I satisfying the condition 0.35<f.sub.I /f.sub.M <0.85, where f.sub.M is the focal length of the system at unit magnification. The second lens component consists of a negative miniscus lens and possibly a positive lens and has a negative focal length f.sub.II satisfying the condition, 0.7<-f.sub.II /f.sub.M <3.0.

Abstract: A device is provided with at least one parallelogram-shaped suspension mechanism built up with arms arranged along parallel planes and deformation joints interconnecting the arms and a setting device both of which are fastened to a table provided with a through hole and suitable for clamping the optical element to be set. Advantage of the setting device according to the invention is represented by the unvarying setting of the angular position of an optical element with a setting and resetting accuracy identical with or better than the wavelength of the light. Construction of the setting device is simple since its production does not require special technology. The setting device is applicable to advantage for optical measurement requiring high setting and resetting accuracy and unvarying setting, mainly in the case of lasers.

Abstract: An optical device for focusing images on the retinas of the left and right eyes of a human user, containing left and right corrective lenses each having a light receiving surface and first and second lens segments of different focal lengths for focusing near and far objects respectively. The boundary between the first and second segments of each of the lenses extends in the same direction and parallel to the light receiving surface, and the lenses are supported and oriented with respect to the eyes of the user so that the boundary is substantially perpendicular to a line connecting the eyes of the user, and so that each first lens segment occupies a nasal position with respect to the user's eyes and each second lens segment occupies a temporal position with respect to the user's eyes.

Abstract: A display device with wide field and high optical efficiency is provided including an optical assembly having a spherical holographic mirror used on the axis and a semitransparent mirror. A generator of light images emits a radiation which strikes first of all the convex phase of the spherical mirror, passes through it, and is then reflected by the semitransparent mirror in the direction of the spherical mirror, which reflects it and finally sends it towards the observer. This optical collimation and combination assembly is included in a transparent medium formed by a glass plate with parallel faces and forming a stigmatic optical system at infinity, required for the correct reception of the radiation coming from the outside landscape.

Abstract: When a zoom lens system is focused by moving a lens other than the foremost lens group, the advancing amount of the focusing lens varies according to the variation in the focal length even whyen focusing on an object at the same object distance. When a zoom lens system is zoomed to a certain focal length, the object distance and advancing amount of the focusing lens has a relationship expressed by a function resembling a logarithmic function. The present invention enables one to focus a zoom lens system using only one movement amount curve by arranging to move the focusing lens along the movement amount curve, utilizing different portions of the movement amount curve according to the amount of zooming.

Abstract: The present invention provides a lens system for projecting to a screen a video image formed on a face plate of a cathode ray tube. The lens system comprises, from the screen side to the tube side: a first positive lens unit; a second positive lens unit; a third negative lens unit having a screen side surface convex to the screen side; a fourth lens unit of bi-convex lens; and a fifth negative lens unit having a screen side surface concave to the screen side, at least the fourth lens unit being made of glass material, wherein the lens system includes at least one aspheric surface and fulfills the following conditions: ##EQU1## wherein; f represents the focal length of the whole lens system; f.sub.1 represents the focal length of the first positive lens unit; f.sub.2 represents the focal length of the second positive lens unit; f.sub.3 represents the focal length of the third negative lens unit; and .nu..sub.3 represents the Abbe number of the third negative lens unit.

Abstract: A changeover type variable magnification optical system whose focal length is changed by locating an auxiliary lens on the image side of a master lens assembly. The system satisfies following inequalities of:0.2<f.sub.2 /f.sub.1 <0.71where f.sub.1 and f.sub.2 are the effective focal lengths of the master lens assembly and the auxiliary lens, respectively. The auxiliary lens is constructed include of at least one aspherical lens surface.

Abstract: A production initializer for a plurality of document scanners each comprising a fiber optic subassembly and a discrete sensor array is provided by moving a spinning light beam along an axis and positioning the linear entrance field of each of a plurality of subassemblies along radial axis. The beam spins at a rate fast compared to the rate at which the beam is advanced along the axis. A large number of subassemblies can be initialized simultaneously in this manner.

Abstract: A converter hologram providing radially symmetric exposure of coaxially located holograms from an off-axis source and displays utilizing the same.

Abstract: A lens of variable equivalent focal length where two lens groups located on either side of an aperture defining means move relative to the aperture defining means, and a lens group of positive power is positioned close to the aperture defining means. The aperture defining means and the associated positive power group may either be stationary or move with change in equivalent focal length.