Abstract: An improved hollow retroreflector assembly with a hard mount assembly is provided, comprising a hollow retroreflector assembly adhered onto a mounting member. The hollow retroreflector has three plates having optically flat reflective surfaces disposed at right angles to each other and non-reflective surfaces opposite to the reflective surfaces of the plates. Each of the plates has first and second sides disposed at right angles to each other, the first side of each plate abutting and being adhered to the reflective surface of the plate adjacent to it. The mounting member has first and second receiving surfaces disposed at right angles to each other. The first receiving surface has adhered to it a portion of the first side of one of the plates, and the second receiving surface has adhered thereto a portion of the second side of the same plate. The mounting member also has a base member having a threaded bore extending therein for receipt of a correspondingly threaded member extending from a support.

Abstract: A miniature prism assembly which in its preferred embodiment utilizes a one inch prism, a stationary target, a yoke, and a housing bracket, all in an integrated unit which can be strung with a plumb line without removing the reflective prism housing from the yoke and which can be strung in the same manner irrespective of whether the prism is adjusted for a 0 or 30 millimeter offset and while the target remains with the yoke. Further, the present invention utilizes a stationary target easily mounted and having a center line that does not alter its position irrespective of the elevation of the prism. The novel yoke and target of the present invention permit the stringing of a plumb line while the target remains affixed to the yoke by utilizing unique bushings and dual purpose slots which permit plumb line stringing around the periphery of the yoke and simultaneously assist to retain the target.

Abstract: A road sign for clearly presenting an informational legend to a viewer in front of the sign under direct and back lighting conditions, comprising an aluminum background sheet (10) having a cutout (12) in the shape of the legend (11). A retroreflective portion (14) is sized and shaped such that when the retroreflective portion is placed into the cutout, a uniform gap is left between the portion and the cutout. A translucent sheet (13) is mounted behind the background sheet and the retroreflective portion such that a translucent border (15) is visible from in front of the sign. When the sign is illuminated by direct lighting such as a driver's own headlights, the retroreflective portion will reflect much of the light such that the legend will be clearly visible to the driver. When the sign is illuminated by strong back lighting such as a low sun or oncoming headlights, the translucent border of the legend will glow brightly such that the message will be clearly seen by the driver as an outline of the legend.

Abstract: A prism assembly and sighting target which are omni-directional in azimuth and which provide a plurality of prisms dispersed symmetrically around the radial wall of a cylinder for reflecting incident laser light from any direction over 360 degrees in azimuth. A uniquely shaped sighting target for use with the prism assembly of the invention provides a visible target pattern from any direction over 360 degrees in azimuth. A cylindrical housing portion of the invention provides receptacles for receiving six prisms spaced at 60 degree intervals so that irrespective of the angle of azimuth from which the laser light is incident, a sufficient amount of light energy is reflected back to the laser light instrument to permit distance measuring over a pre-selected minimum distance.

Abstract: A retroreflective article (30, 50) has opaque pigment particles (38, 58) dispersed in a retroreflective region (33, 53) of a front portion (35, 55) of a sheeting (32, 52) that includes a body portion (34, 54) and a multitude of cube-corner elements (36, 56). The opaque pigment particles (38, 58) scatter white, yellow, or light brown light to allow the retroreflective article to demonstrate improved lightness and, if colored fluorescent, improved fluorescence. The improvement in lightness and fluorescence makes the retroreflective articles more conspicuous to persons during the daytime.

Abstract: Methods and apparatuses are disclosed for setting the nodal point of a retroreflector such as a corner-cube prism. The apparatuses permit rotation of the retroreflector about a stationary first pivot axis and motion of the retroreflector along its optical axis relative to the first pivot axis, wherein the first pivot axis is perpendicular to the optical axis. Methods comprise using the retroreflector to produce a reflected image of a stationary reference object, and pivoting the retroreflector about the first pivot axis and moving the retroreflector along the optical axis to a position at which the reflected image remains stationary as the retroreflector is pivoted. Thus, the retroreflector is adjusted so as to produce a reflected beam that is exactly parallel to a corresponding incident beam even when the optical axis of the prism is not exactly parallel with the propagation vector of the incident beam.

Abstract: The marker has a pair of upwardly converging reflectant planar panels facing approximately in opposite directions. In its correct attitude on a support surface the panels slope at 2.degree.-6.degree. to the vertical if the marker is intended for assisting the landing of fixed wing aircraft and at 8.degree.-10.degree. to the vertical if the marker is intended for assisting the landing of helicopters. The reflectant panels are preferably retroreflectant.

Abstract: Reflective tape for pinstriping of automobiles or other vehicles. The tape has strips of retroreflective material sandwiched between a bottom release liner of polyethylene coated paper and a clear top release liner having an adhesive undersurface for retaining the tape composite intact with the strips parallel one another prior to and during application to a vehicle. The retroreflective material is highly visible at night for safety. The strips include pressure-sensitive adhesive. When the tape is applied to a vehicle, thin pinstripes of retroreflective material are seen. The material may be colored to contrast with the color of the vehicle paint, which is visible on either side of the tape and also through the open middle section between the pinstripes of retroreflective material. The strips are applied by peeling away the bottom liner as the top liner and strips are applied to a surface; thereafter, the top release liner is peeled away leaving only the two retroreflective material strips on the surface.

Abstract: A modulating device based on the principal of frustrated total internal reflection that functions over a wide range of angles and wave lengths. The modulator is comprised of two refractive elements that initially are in contact. The edges of the elements are forced apart by a piezo electric transducer and the elasticity of the second refracting element lifts the center of that element away from the first refracting element. The amount of reflection at the interface of the two refractive elements is a function of their spacing. This reflection is reduced to zero by the addition of a thin plastic layer on the surface of one of the refracting elements which allows total contact across the entire surface of the two refractive elements.

Abstract: An article for presenting dye/pigment images therein comprising a substantially transparent viewing region 20; photodeveloped, printed, deposited or diffused dyes and/or pigments 21 in the viewing region; and a substrate region 22 adjacent to the viewing region. The outer surface 23 of the viewing region is configured in a relief pattern comprising microscopic, smooth, sharp pyramids 31, cones 48, or ridges 29, to provide a series of at least 3 surface reflections of any light impinging thereon, before the light travels toward the viewer's eyes. The reflectivity at any one surface reflection is less than about 5% of normally incident light, so less than about 0.05% (and preferably not more than 0.02%) of such incident light is returned toward the viewer after 3 reflections, and less after 4. A viewer thus can see the dye/pigment images clearly from any direction and free from noticeable reflected light from the outer surface, and without loss of detail or contrast in dark areas.

Abstract: Cube-corner type retroreflective articles which retroreflect infrared light but do not substantially retroreflect visible light. The cube-corner elements comprise a polymeric matrix selected to be highly transmissive to infrared light but substantially opaque to visible light.

Abstract: A reflective liquid crystal display includes a retroreflector made of an array of full corner cube elements which have their optic axes tilted away from the normal to the plane of the display by an angle of between about 10.degree. and about 45.degree..

Abstract: The present invention provides an improved cube-corner retroreflective article that exhibits a wide range of retroreflective angularity in multiple viewing planes. The present invention provides cube-corner retroreflective elements having a decreased size, as measured by the height of the cube corner, thereby decreasing the amount of canting required to achieve a given angularity. Alternatively, angularity can be enhanced by leaving the degree of canting constant and decreasing the size of the cube corner.

Abstract: A reflectant surface of retro reflective material comprises a plurality of parallel convex outward ribs having a center-to-center spacing of between 3/8" and 1/16". The retro reflective surface preferably employs an arrangement of triads mutually perpendicular surfaces, which triads and surfaces are indistinguishable at normal minimum viewing distances.

Abstract: A scanning laser helmet mounted sight that determines helmet or sight position from externally mounted light sources and detectors. No electronics, including light sources and detectors, are on the helmet. Also, no electrical cables or mechanical linkage is connected to the helmet. The helmet has passive reflectors for reflecting a scanning light beam from a laser source. The return times and directions of the returning light beam relative to a return of a light beam from a reference point, processed by the off-helmet electronics, result in a position indication of the helmet.

Abstract: A hollow surveying retroreflector assembly is provided which is comprised of a hollow retroreflector received within and adhered to a receptacle. The retroreflector has three plates having optically flat reflecting faces disposed at right angles to each other. The receptacle has a conically configured interior for receiving the retroreflector and for maintaining the perpendicular alignment of the reflecting faces of the plates of the retroreflector. The receptacle having the retroreflector inside is then received within an outer casing to allow for mounting of the hollow surveying retroreflector assembly.

Abstract: Retroreflective elements, such as cube-corner elements or right triangular prisms containing cube-corners, are arranged on articles to define separation surfaces between the elements; in another embodiment, the elements are truncated cube-corners incorporating similar surfaces on the elements themselves. If the surfaces are transparent they will transmit light through the article, rendering it partially transparent and partially retroreflective. The surfaces may be flat or curved. Standard grooving techniques may be employed to construct the elements, using mold cutting tools having flattened or curved tips instead of V-shaped tips; alternatively, electroformed molds may be lapped to include the shape required to produce surfaces. The elements and surfaces may be embodied in sheeting materials or internally illuminated signs.

Abstract: The present invention provides improved, flexible retroreflective articles based upon an optically clear, aliphatic polyurethane polymer. The aliphatic polymer has a plurality of hard chain segments of the formula--C(O)N(H)--C.sub.6 H.sub.10 --N(H)C(O)--.

Abstract: A novel optical device, comprising, in one embodiment, a modified corner cube retroreflector. A conventional corner cube retroreflector may be modified so that a face plate comprises an enhanced reflectivity coating. The novel device functions such that at least five percent of the energy of a radiation beam incident to the device, may be reflected at the face plate in accordance with Snell's Law. It is disclosed that the novel device may be advantageously employed in a novel optical alignment assembly.

Abstract: A truncated pyramidal pylon, has retroreflectant side walls each sloping at 8.degree.-10.degree. to the vertical for helicopters and 3.degree.-6.degree. to the vertical for fixed wing aircraft. The pylon may be constructed as a permanently erected unit or as a collapsible arrangement from hingedly connected flat surfaces, with a surface corresponding to each side, foldable to provide the assembled pylon.

Abstract: An optical coordinate transfer assembly provides angular correlation between spatially separated objects. In a particular embodiment of the invention, roll, pitch and yaw of a second directional device 12 relative to a first directional device 11 can be measured (and correction and/or compensation therefor can be made) using an optical alignment sensor 20 mounted on the first directional device 11 and a rooftop-mirror/lens assembly 21 mounted on the second directional device 12. Light beams projected from the optical alignment sensor 20 are reflected by reflector devices 35 and 36 on the rooftop-mirror/lens assembly 21 to linear arrays 69, 70 and 78 of photodetectors, which generate electronic signals indicating angular discrepancies between the orientations of the first and second directional devices 11 and 12 in three degrees of freedom to sub-microradian accuracy over a wide range of measurements.

Abstract: A constant-deviation device is disclosed which comprises a first reflective element in the form of one or more roof prisms and one or more second reflective elements providing one or more reflections. The first and the second reflective elements are mutually adjustable by rotation about one or more axes thereby to set an angle between the incident and the exiting beam. In one or more planes the angle is substantially unaffected by changes in the direction of incidence of the incident beam.

Abstract: A retroreflective sheeting comprising a substantially transparent face member, an encapsulating member having a front and a back side, the front side of the encapsulating member being sealed by a network of interconnecting bonds to the face member, and retroreflective elements disposed between the face member and the encapsulating member in substantially a monolayer with an air-interface. The encapsulating member comprises a plasticizer-resistant barrier layer which prevents migration of plasticizer therethrough, thereby protecting the aforementioned elements of the sheeting therefrom.

Abstract: An optical input beam is transmitted through a non-linear medium capable of two-wave mixing gain by photorefractive, Brillouin, Raman, or other non-linear optical mechanism. A psuedo-conjugator retroreflects the input beam which has passed through the medium, back into the medium. The retroreflected beam acts as a seed, which lowers the threshold for producing a self-pumped conjugate reflected beam in the medium by stimulated scattering. The pseudo-conjugator may be a flat array of retroreflecting elements in the form of spheres or corner reflectors. A mosaic pattern of conjugating elements can be phase-locked to yield larger apertures and/or energy scaling, in a master-oscillator, power-amplifier (MOPA), or a four-wave mixer (FWM) configuration. The retroreflected beam can be modulated to temporally encode information onto the conjugate beam, and/or polarized to increase the system efficiency. The input and self-pumped conjugate reflected beams can be used as reference or pump beams in a FWM configuration.