Abstract: A zoom finder has first to third lens groups sequentially arranged from an object side to an eye pupil side and performs a zooming operation by fixing the first and third lens groups and moving the second lens group. The first lens group is constructed by a positive single lens. The second lens group is constructed by a negative single lens. The third lens group has a positive combinational focal length and is constructed by a negative single lens arranged on the object side and a positive single lens arranged on the eye pupil side. A frame system of the zoom finder is formed by an eye pupil side lens face of the negative single lens of the third lens group and the positive single lens of the third lens group. Radii R.sub.1 and R.sub.2 of curvature of lens faces of the first lens group on the object and eye pupil sides satisfy the following condition.0.8<R.sub.1 /.vertline.R.sub.2 .vertline.<1.2 (I)At least one lens face of the first lens group is constructed by an aspherical surface.

Abstract: The invention provides a four-unit type of zoom lens system which is of compact size albeit having a high zoom ratio, and comprises a first unit G1 of positive refracting power, a second unit G2 of positive refracting power, a third unit G3 of negative refracting power, and a fourth unit G4 of negative refracting power, wherein the spaces between the units vary during zooming, said zoom lens system being characterized in that all these units are moved toward the object side for zooming from the wide-angle to telephoto end.

Abstract: Enhanced performance of an uneven surface image transfer apparatus is provided by using a well-defined convergent field of illumination that is nominally focussed at the stop of an imaging lens. An integrated optical system exhibiting such enhanced performance includes an aspheric illuminating lens that directs radiant energy onto a presentation platen from which fingerprint or bar code images are transferred to an external image sensing device, such as a charged coupled device chip. An evanescent wave image is totally internally reflected (TIR) off of the platen along an optical path including a plurality of TIR surfaces to achieve a predetermined optical path length. One or more of the TIR surfaces may be curved to reduce or eliminate astigmatism and geometric distortion. An aspheric imaging lens having a split-axis aperture stop transfers the image rays to the image sensing device. The split axis aperture stop has its stop axes on opposite sides of the nominal focal point of the aspheric illuminating lens.

Abstract: A rear-focus zoom lens system with four lens group. A stationary first lens group of a positive refractive power; a second lens group of a negative refractive power that moves for zooming; a stationary third lens group of a positive refractive power; a fourth lens group of a positive refractive power that moves for zooming and focusing. The first through fourth lens groups are arranged in that order from the object side. This zoom lens system also satisfies the following conditional expression:3.7<f.sub.4 /fw<6wherein f.sub.4 is the focal length of the fourth lens group and fw is the focal length of the zoom lens system at the wide-angle end.

Abstract: A wide-conversion lens for attachment to a master lens system consists of a bi-negative first lens in a object side and a bi-positive second lens in a master lens side, and in the second lens its radii of curvature of both surfaces are selected the same.

Abstract: A microscope has an objective optical system coupled to an observation optical system with parallel optical axes. A stage, which holds a sample, rectilinearly moves in a direction toward and away from the observation optical axis, which is perpendicular to the plane of the stage. The objective optical system rectilinearly moves in a direction perpendicular to the movement of the stage. The microscope thus permits viewing of a large sample with a small stroke of the stage, whereby a compact and lightweight structure may be achieved.

Abstract: A daylighting system usable in either a skylight or a dormer includes a film having a plurality of negative Fresnel lenses.

Abstract: This invention concerns chromatic light separators, and is particularly intended to reduce their dimensions. A chromatic separator in accordance with the invention contains at least two selective wave length mirrors. According to one characteristic of the invention, the two selective mirrors are nested holographic mirrors. The invention is particularly suitable for three-color rear-projection type picture projectors using liquid crystal screens.

Abstract: A zoom lens system having in order from the object side, a first positive lens group, a second negative lens group and a third positive lens group. At least the second lens group and the third lens group are movable along an optical axis for changing magnification. This lens system further satisfies the following conditions:(a) 0<fw/f1<0.25(b) -0.9<fw/f2<-0.4(c) 0.3<fw/f3<0.8(d) 0.7<logz3/logz<1.0wherefw is the focal length of the overall system at the wide angle end,f1 is the focal length (i=1, 2, 3) of the i-th lens group,z is the change ratio (z=ft/fw) of magnification of the overall system,ft is the focal length of the overall system at the telescopic end,z3 is the change ratio (z3=m3t/m3w) of magnification of the third lens group,m3t is a lateral magnification of the third lens group at the wide angle end,m3w is a lateral magnification of the third lens group at the telescopic end.

Abstract: A photorefractive apparatus is exposed to a write beam or radiation for creating a system of interference fringes in the apparatus, as well as to a read beam or radiation which diffracts the system created and includes at least one elementary pattern (1) having an electrooptical material (6) with a high electrooptical coefficient with respect to the read radiation, which is transparent to the read radiation and which is surrounded by photoconductive materials (2, 4). The photoconductive materials are transparent to the read radiation and under the effect of the write radiation are able to respectively produce electrons and holes having a high mobility. Application to the optical processing of signals.

Abstract: A light microscope with lenses projecting the rear aperture of an objective lens at a location remote from the objective lens enhancing high power stereoscopic viewing and photographing with a binocular (two eyepiece) viewing system and when combined with an iris in close proximity to the projected image of the rear aperture of the objective lens, controls flare.

Abstract: A zoom lens comprising, from front to rear, a first lens unit of positive refractive power, a second lens unit of negative refractive power, a third lens unit of positive refractive power, a fourth lens unit of positive refractive power and a fifth lens unit of positive refractive power, the second lens unit being axially moved toward the image side to effect zooming from the wide-angle end to the telephoto end, while simultaneously moving the fourth lens unit to compensate for the shift of an image plane, and the fourth lens unit being axially moved to effect focusing, wherein the following condition is satisfied:0.4<f4/f5<1.2where f4 and f5 are the focal lengths of the fourth and fifth lens units, respectively.

Abstract: A novelty filter utilizes self-nulling and self-aligning of reflection and transmission phase conjugate beams. A photorefractive crystal is arranged so that the contributions to the phase conjugate are equal and opposite in the steady state to produce destructive interference when the input image is stationary, and thus no output image is displayed. If the image moves, then the gratings will rewrite and erase themselves, each with their own response times, total destructive interference will not occur, and transient enhancement and surpression of the phase conjugate output signal will indicate the direction of motion of the input image.

Abstract: A zoom lens of five group construction utilizing an inner focus system. The zoom lens includes a first lens group G1 having a positive refracting power, a second lens group G2 having a negative refracting power, a third lens group G3 having a negative refracting power, a fourth lens group G4 having a positive refracting power and a fifth lens group G5 having a negative refracting power, which are arranged in this order from an object side, and the distances among the respective lens groups are selectively varied to effect the desired zooming operation. During close-up photographing, the second lens group G2 is moved along an optical axis to effect the desired focusing.

Abstract: An objective lens system for a microscope comprises, sequentially from an object side, a first lens group having positive refracting power, a second lens group shiftable in an optical-axis direction and a third lens group. The first lens group has a cemented lens component composed of a plano-convex lens element with its plane surface toward the object side and a meniscus lens element with its concave surface toward the object side. The second lens group has a first sub-group having the positive refracting power and a second sub-group having negative refracting power. The second sub-group of the second lens group has a negative meniscus lens element with its concave surface toward an image side. The third lens group has a meniscus cemented lens component with its concave surface toward the image side.

Abstract: A narrow bandwidth bandpass filter having high transmission efficiency for the passband and excellent out-of-band attenuation employs a transmission holographic grating sandwiched between the oblique faces of a pair of right angle glass prisms. An incoming laser beam to be filtered is incident normal to one of the prism faces so as to intersect the holographic grating at about 45.degree.. The grating frequency is such as to diffract light of the transmission wavelength through substantially 90.degree. so that it exits the cube formed by the two prisms from the right angle face of the second prism. The out-of-band wavelengths of the incident beam are either transmitted unaffected through the grating or diffracted at a different angle than the light of the transmission wavelength.

Abstract: The present invention relates to a zoom lens system used for photo-taking in a 35 mm single lens reflex camera. The zoom lens system consists of, from the object side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power. Zooming from a wide-angle side to a telephoto side takes place by moving all of the first lens unit through the fourth lens unit to the object side. Focusing on an object at a short distance is performed by moving the second lens unit to the object side.

Abstract: An optical element uniformly distributes radiant energy on a target surface, such as for discharging an area of a photoreceptor in a xerographic printer, or for applying infrared energy to dry an ink-jet image. A cylinder lens collimates light beams from a light source and directs the collimated light beams to a preselected area on the target surface. First and second refractive portions, each attached to and extending parallel to the cylinder lens, totally internally reflect light beams from the light source and direct the light beams reflected therein to the target surface.

Abstract: The present invention is directed to an optical system which includes an image region having at least one light source which directs a beam of light along an optical axis and an object region which is adapted to receive the light from the light source. An optical delivery system is between the image region and object region. The optical delivery system receives the light from the image region and directs it to the object region. The optical delivery system is formed of a plurality of optical elements, such as lenses and volume holograms. The optical delivery system is designed to either receive a plurality of beams of light from a plurality of sources or different modes of a single light source and form a single spot of light in the image region having the combined power of all of the beams of light or modes of a single beam. The optical delivery system can also condense or expand the spacing between the beams of light from a plurality of light sources.

Abstract: A controllable liquid crystal polarizer has nematic liquid crystal and pleochroic dye in plural, parallel, elongate volumes in a sheet-like containment medium. Polarization effectiveness is variable as a function of electric field. A method of making the polarizer includes continuously forming a sheet-like film of a containment medium having a plurality of volumes of liquid crystal and pleochroic dye therein, and during curing of the film, stretching it to elongate the volumes.