Abstract: A retroreflector construction comprises a first transparent layer of a relatively high refractive index having on its rear surface one or more cube corner retroreflector elements; a second thin transparent layer of relatively low refractive index in substantially uninterrupted contact with the rear surface of the first layer; and a third metallic reflective layer in substantially uninterrupted contact with the rear surface of the second layer. The ratio of the indices of refraction of the two transparent layers is sufficient to allow TIR at their interface for at least some of the cube faces. The third, metallic layer assures face reflection when TIR fails. The construction provides greater retroreflectance than would be achieved with a single metallized transparent layer, and provides retroreflectance over a broader range of entrance angles and orientation angles than would be achieved with a single non-metallized (air-backed) transparent layer.

Abstract: Reflex pins for use in the manufacture of reflector assemblies or surfaces have three faces, the relative position of each face with respect to adjacent faces is 120 .degree.. According to the disclosure, selected cube faces of pins are cut to an angle that is adjusted from the convention angle of 120.degree. whereby light reflected from a product of such reflex pins is redirected or redistributed from one area of the zone of reflectivity to substantially increase the intensity of light to the location of a viewer or a recording device's light sensitive element at another area of the zone of reflectivity. A method of making such pins is also disclosed.

Abstract: A cube-corner retroreflective sheeting 60 includes an array of cube-corner elements 30 that are defined by three sets of intersecting parallel grooves 45, 46, 47. The cube-corner elements 30 are arranged in the array such that the sheeting 60 glitters when exposed to light. The glitter is in the form of many discreet points of light that tend to blink on and off when viewed by the naked eye. The array may be configured such that a dihedral angle .alpha. varies between adjacent cube faces 31 of adjacent cube-corner elements 30 in each groove in one of the groove sets 45, 46, or 47 and such that base planes are not parallel to each other when the sheeting 60 is laid flat. Preferably, the dihedral angle .alpha. between faces 31 of adjacent cube-corner elements 30 varies in essentially all of the grooves such that the cube-corner elements are randomly tilted throughout the array. The sheeting glitters very well under daytime viewing conditions and also to some extent under nighttime or retroreflective conditions.

Abstract: Retroreflective prisms are formed with windows thereon by removing a portion of the prism mold on one prism pair leaving the apex of the prism intact. In this manner smaller prisms are formed adjacent larger prisms. Optionally, the optical axis of the prisms may be tilted with respect to one another, preferably in a negative direction. The smaller prisms with windows provide increased brightness and optimize the retroreflection light.

Abstract: A retroreflective element that exhibits exceptional wet retroreflectivity, and a method of manufacturing the same. The retroreflective element includes an assembly having a multi-sided retroreflector and a clear thermoplastic. In one embodiment, the clear thermoplastic is at least partially thermally deformed to create a convex retroreflective dome for capturing high incident angle light rays. The retroreflective elements may be used in a pavement marking system, such as attached to pavement marking tape or deposited in pavement marking paint.

Abstract: A retroreflective structure is described in which an array of transparent prisms is formed on a release coating of a sheet. The facet side of the prisms is made reflective and the prisms are either released to form a plurality of individual retroreflective structures or the array is adhered to a supporting substrate and then released from the base sheet. In the latter case, the array can be applied to a pre-existing structure formed of compatible fabrics, such as tarpaulins.

Abstract: A cube corner article has a plurality of geometric structures formed by at least three intersecting groove sets. Each geometric structure has three faces arranged as a cube corner element. Some of the geometric structures also have a fourth face which is not a part of a cube corner element. At least one of the grooves in the three intersecting groove sets has a first and second side surface extending uniformly from a groove vertex, the first side surface forming one of the three faces and the second side surface forming the fourth face.

Abstract: The present invention provides improved cube corner retroreflective articles which exhibit a wide range of retroreflective entrance angularity in at least one plane, and preferably in two or more planes. An article in accordance with the present invention includes a structured surface having at least one array of cube corner elements formed by three intersecting sets of substantially parallel grooves. Each cube corner element includes a base triangle bonded by one groove from each of the three intersecting groove sets, the base triangle being scalene.

Abstract: A mold 79 that includes an array of cube-corner elements 80 that are arranged in the array such that a retroreflective cube-corner sheeting 60 that is formed thereon is capable of glittering when light is incident on the sheeting. The array may be defined by three sets of intersecting grooves 25, 26, 27 where each groove set includes two or more generally parallel grooves. At least one groove in at least one of the sets has faces 22 of adjacent cube-corner elements 30a, 30b arranged such that a dihedral angle .alpha. located between adjacent faces varies along the groove(s) in the set.

Abstract: The present invention provides cube corner retroreflective articles that have improved retroreflective performance in at least one plane, and preferably in two or more planes. A preferred article is a retroreflective sheeting that includes a structured surface having at least one array of cube corner elements oriented at a predetermined angle relative to the edge of the article. The angle is selected to align one broad plane of entrance angularity approximately parallel with the edge of the sheeting and another broad plane of entrance angularity approximately perpendicular to the edge of the sheeting. Individual cube corner elements on the structured surface are canted to yield an isosceles base triangle or a scalene base triangle. Additionally, the structured surface may include a plurality of cube corner element arrays arranged in a tiled fashion to yield greater than two planes of broad entrance angularity.

Abstract: A retroreflective structure is described in which an array of transparent prisms is formed on a release coating of a sheet. The facet side of the prisms is made reflective and the prisms are either released to form a plurality of individual retroreflective structures or the array is adhered to a supporting substrate and then released from the base sheet. In the latter case, the array can be applied to a pre-existing structure formed of compatible fabrics, such as tarpaulins.

Abstract: A flexible, durable, cube-cornered retroreflective article capable of accommodating the expansion and contraction of the underlying polymeric substrate where such article has a pillowed or curved microstructured member bonded in a regular pattern to a sealing member. The retroreflective article has normal and stressed states. In the normal state, the microstructured member is substantially parallel with the sealing member. In the stressed state, the microstructured member is either compressed or elongated and the sealing member is substantially flat. The retroreflective article may be attached to traffic control devices, such as polymeric barrels, cones, or tubes to direct and guide motorists through road construction areas.

Abstract: A device that will enhance the signature of a target by utilizing retrorective articles and can operate in an "active" or "passive" mode. The device consists of a sphere on which a number of corner cube reflectors are mounted. The sphere is then mounted on top of the target and, in the "active mode", is rotated around its vertical axis. The sphere is then illuminated by a laser and the reflected energy is received by an appropriate electro-optical sensor, such as an image intensifier or a FLIR. In the "passive" mode, the sphere is either rotated around its horizontal axis, or remains stationary, and the reflected ambient radiation is received by an appropriate sensor.

Abstract: A retroreflective article comprising an ultra-flexible structured retroreflective sheeting having a front surface and a back surface, the sheeting retroreflecting light entering through the front surface, wherein the sheeting comprises an overlay film, a two-dimensional array of substantially independent structured elements, the structured elements bonded to the overlay film, and a sealing film forming the back surface of the sheeting and bonded to the overlay film between the structured elements; a plurality of indentations in the sealing film; and a seal coat located on the sealing film, wherein the seal coat at least partially fills the indentations in the sealing film.

Abstract: The present invention provides a tiled cube corner retroreflective sheeting that exhibits improved retroreflective performance in at least one plane substantially parallel with an edge of the sheeting, and preferably in two or more planes. A tiled retroreflective sheeting includes a structured surface having a plurality of cube corner element arrays oriented at a predetermined angles relative to the edge of the sheeting. The angles are selected to align at least one broad plane of entrance angularity approximately parallel with the edge of the sheeting and preferably to align another broad plane of entrance angularity approximately perpendicular to the edge of the sheeting.

Abstract: Ultraviolet luminescent retroreflective sheeting includes a retroreflective portion containing retroreflective elements and an ultraviolet luminescent portion to facilitate nighttime viewing by persons not located at or near a source of light being retroreflected by the retroreflective portion. At least part of the ultraviolet luminescent portion is provided as the bonding lines for bonding the transparent cover sheet to the support sheet to form a series of sealed cells in which the retroreflective elements, which may be of the encapsulated lens-type or the encapsulated cube-corner-type, are disposed. The ultraviolet luminescenct portion includes fluorescent agent which emits light when irradiation by ultraviolet irradiation.

Abstract: The present invention provides a retroreflective sheeting including a structured film having an array of structured elements and a sealing film attached to the structured film by a plurality of rivet-like connections perforating the sealing film. Preferably, the rivet-like connections form flanges. The preferred sealing film is a thermoplastic polymer with a ductile yield of at least about 20%. The retroreflective sheetings according to the present invention can also include a seal coat located on the sealing film. In some embodiments, the seal coat can be prepared from a seal coat precursor comprising radiation curable components. The present invention also includes methods of manufacturing the various embodiments of the retroreflective sheetings.

Abstract: A marker comprises a metal sheet bent to curve about an axis and forming, in sector perpendicular to said axis a hairpin turn and where there are median extents on each side, approximating in the sheet planar panels, defining an angle of 0.degree.-30.degree. to each other and having on their convex side, a retroreflectant layer.

Abstract: A retroreflective article that exhibits high retroreflective efficiency in response to light incident on the sheeting at high angles of incidence is disclosed. A retroreflective article includes a body portion having a base surface and a structured surface opposite the base surface. The structured surface includes a plurality of retroreflective cube corner elements defined by two intersecting groove sets. Each cube corner element has three tetragonal optically reflective faces that intersect to define a cube corner apex and two tetragonal non-optical faces that intersect along an edge. The symmetry axes of the cube corner elements are substantially parallel.

Abstract: The present invention comprises lens-type retroreflective sheeting which is excellent in appearance and having constant thickness and desired retroreflective performance, wherein the transparent microspheres in the retroreflective layer are composed of transparent microspherical lenses (A) having a refractive index of 1.8 or more and transparent microspherical fillers (B) having a refractive index different by at least 5% from the refractive index of the lenses (A).

Abstract: A retroreflective article that comprises:(a) a retroreflective layer having first and second major surfaces, and(b) a cover layer juxtaposed against the first major surface, characterized in that:the cover layer comprises a surface layer, an optional intermediate layer, and a back layer, with the provisos that: (i) when the intermediate layer is present in the cover layer the intermediate layer contains a vinylidene fluoride base polymer as a primary component, and the surface layer and back layer each comprise a methyl methacrylate base polymer as a primary component; and (ii) when the intermediate layer is absent from the cover layer, the surface layer comprises a methyl methacrylate base polymer (A) and a vinylidene fluoride base polymer (F) in a weight ratio A:F of 55:45 to 95:5, and the back layer comprises a methyl methacrylate base polymer and a vinylidene fluoride base polymer with the vinylidene fluoride base polymer being the primary component.

Abstract: A cube corner retroreflective sheeting construction comprising alternating zones of cube corner element arrays disposed at approximately ninety degrees orientations to provide exactly two principal plane of improved retroreflective performance in response to light incident on the sheeting at high entrance angles is disclosed. According to one embodiment the sheeting includes a body layer which has an elastic modulus less than 7.times.10.sup.8 pascals and cube corner elements formed from a material which has an elastic modulus greater than 16.times.10.sup.8 pascals. According to a second embodiment the sheeting includes an overlay film having two major surfaces and comprising a first polymeric material and a plurality of arrays of substantially independent cube corner elements bonded to a major surface of the overlay film having a minimal, fractured land.

Abstract: A cube corner article and method of manufacturing the article from a series of directly machinable unitary substrates. The method of manufacture comprises the first step of providing an initial unitary directly machinable substrate of material suitable for forming retroreflective surfaces. Then a first cube corner element array zone is formed having a plurality of geometric structures including cube corner elements. The zone is created by directly machining at least two sets of parallel grooves in the substrate. A replica of the cube corner element array zone is formed as an additional unitary substrate suitable for forming retroreflective surfaces. Portions of the replica substrate material are removed. The removal of these portions forms at least two intersecting cavities bounded by side walls in the replica at a depth at least that of the cube corner elements formed by the groove sets.

Abstract: A method for manufacturing flexible cube corner retroreflective sheeting comprising the steps of:a) providing a tool having a molding surface;b) applying to the molding surface a volume of a flowable resin composition;c) contacting the resin composition with a first major surface of an overlay film;d) minimizing excess resin composition;e) curing the resin composition to form a sheeting comprising an array of cube corner elements bonded to the overlay film;f) removing the sheeting from the tool; andg) applying mechanical stress to the sheeting so as to cause a fractured separation of substantially each individual cube corner element from surrounding cube corner elements.

Abstract: Encapsulated retroreflective element comprising a retroreflective assembly made up of a transparent optical body and a reflective member and essentially completely encapsulated within a dense, substantially transparent oxide coating. Also a method for making such retroreflective elements and articles and compositions comprising such retroreflective elements.

Abstract: Retroreflective sheeting and articles are formed in which the size of the retroreflective and non-retroflective surfaces may be varied across an array of microprisms. This is accomplished by varying the location of the reflective coating applied to the microprism side facets, such that, some prism side facets are completely coated with reflective material while others are coated only at the apex area; and still others are coated with a non-reflective coatings, such as, a colored adhesive.

Abstract: An enhanced daytime and nighttime visibility marker for electrical lines is disclosed in two embodiments. Both embodiments are shaped to give visibility from all angles and to allow smooth covering with retroreflective tape. One embodiment includes a continuous burning interior light for maximum nighttime visibility.

Abstract: A fire-resistant retroreflective structure having an array of rigid retroreflective elements and a method for making the structure are disclosed. The retroreflective structure is formed of an array of rigid retroreflective elements having a first side and a second side. A transparent polymeric film is attached to the first side of the array of rigid retroreflective elements. A transparent fire-resistant outerlayer is attached to the transparent polymeric film. A flame-retardant layer is placed proximate to the second side of the array of rigid retroreflective elements. A fire-resistant polymer underlayer is attached to the flame-retardant layer. The fire resistant polymer underlayer can be bonded to the transparent polymeric film through the array of rigid retroreflective elements and the flame-retardant layer.

Abstract: A retroreflective structure having prism elements and a method for making the structure are disclosed. The retroreflective structure is formed of an extensible, elastomeric film and a rigid, non-extensible array of retroreflective prism elements. The array is bonded to the elastomeric film, thereby forming a retroreflective structure which can be significantly stretched without significantly diminishing the retroreflective properties of the structure.

Abstract: A retroreflective structure is described in which an array of free-standing retroreflective prisms is formed on a suitable substrate for application of the structure to pre-existing structure formed of compatible fabrics, such as tarpaulins.

Abstract: A display which when illuminated by a light source is adapted to present selectively to an observer colors and images that depend both on the angular position of the observer and on the angular position of the light source relative to the display. The display includes a substrate on which is coated an opaque base layer having a color image printed thereon. Coated over the base layer is an intermediate layer of transparent material having interference pigment particles dispersed therein which impart goniochromatic properties to this layer, the color seen by the observer depending on said angular positions. Overlying the intermediate layer is a retroreflectivity layer formed by transparent beads whereby light reflected from the base layer or from the intermediate layer, as seen by the observer, passes through the retroreflectivity layer to enhance the brilliance of the colors or images presented to the observer.

Abstract: An integrated retroreflective data communication display for visual and electromagnetic communication is described. The display may be configured as an integrated retroreflective electronic license plate, with printed visual information, similar to the information printed on traditional license plates, on retroreflective sheeting. An antenna network is integrated within the license plate for electromagnetic communication and may be connected to external electronic modules. The display may also be configured as an integrated retroreflective electronic road sign, also providing visual and electromagnetic information in a unitary structure.

Abstract: A method and apparatus is described for producing a signaling device which uses sunlight or moonlight to signal a target by retroreflecting light through a window provided on the light reflective material of a mirror. A specular light reflective material with an opening coincident with the first opening is provided on the light reflective side of the mirror to aid in alignment of the mirror with the target.

Abstract: A method of machining a substrate to produce a cube corner element optical array. The method includes steps of directly machining a plurality of groove sets into a directly machinable substrate to form an array having a plurality of geometric structures including cube corner elements, and machining at least two of the groove sets along the same path in the substrate but at different depths of groove to produce a geometric structure side surface having both an optical portion and a non-optical portion.

Abstract: A method and apparatus for forming retroreflective sheeting with improved daytime whiteness performance is described in which air spheres are encapsulated into the prism structure when the prism base body is laminated to the prisms in a mold.

Abstract: Retroreflective target for laser ranging embodying at least one hollow cube corner retroreflector constituted by three reflective surfaces which are substantially planar and perpendicular to each other and intersect at three edges which are substantially orthogonal and converge at an apex (S), the cube corner retroreflector being associated with a geometrical normal at the same angle to each of the edges, the target including a reference point (O) substantially on the normal on the opposite side to the reflective surfaces at a distance e..sqroot.

Abstract: A cube-corner retroreflector for laser telemetry corrects speed aberration .delta. and has three substantially orthogonal mirror surfaces defining three substantially orthogonal edges converging at an apex. Each edge is associated with the surface substantially orthogonal to it. The shape of each surface is at least approximately that of a portion of a cone whose axis is coincident with the associated edge. The generatrices of this portion of a cone have a non-null average generatrix slope relative to a plane perpendicular to the axis of the portion. The average .alpha..sub.0 of the average slopes of the surfaces at least approximately satisfies the equation:.alpha..sub.0 .about.0.2.delta./kwhere k is a predetermined parameter dependent on the number, the geometry and the refractive index or indices or the media constituting the interior volume of the retroreflector.

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 (Collectively at 2.degree.-10.degree. to the vertical). The reflectant panels are preferably retroreflectant. Preferably the opposed sloping panels converge when considered relative to intersecting horizontal planes (when the marker is properly levelled). This convergence may also be measured as the angle between vertical planes respectively perpendicular to the opposed panels. Such convergence in plan may preferably be 0.degree.-6.degree. for use with fixed wing aircraft but may be larger for fixed wing aircraft in certain conditions. Such convergence in plan is preferably 16.degree.-20.degree.

Abstract: A signal mirror includes an irradiation device for reflecting incident light by a same reflection function as a plane mirror and irradiating reflected light to an irradiation target; and an optical axis finding device including a sheet having at least a surface on an irradiation device side as a retroreflection face, for reflecting incident light incident on the sheet from the irradiation device side in an opposite direction to the irradiation target using retroreflection and reflection by the irradiation device, thereby ensuring finding of an optical axis of reflected light irradiated on the irradiation target by the irradiation device. The reflected light can be irradiated on the irradiation target by the irradiation device while the optical axis of the reflected light is found by the optical axis finding device.

Abstract: A retroreflective structure having prism elements and a method for making the structure are disclosed. The retroreflective structure is formed of an extensible, elastomeric film and a rigid, non-extensible array of retroreflective prism elements. The array is bonded to the elastomeric film, thereby forming a retroreflective structure which can be significantly stretched without significantly diminishing the retroreflective properties of the structure.

Abstract: A road sign for clearly presenting a customizable message to a driver under direct and back lighting conditions, comprising a background board with an array of mounting holes. Message elements and background elements are placed into the appropriate holes to form a mosaic message. Each mosaic message has a retroreflective portion surrounded by a translucent border. When the sign is illuminated by direct lighting, such as a driver's own headlights, the retroreflective portion will reflect much of the light so that the message 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 will glow brightly so that the message will be clearly seen by the driver as an outline of the message. The message elements can be rearranged to form a variety of different possible messages and graphical designs.

Abstract: A retroreflective article 10 has a body portion 14 and a multitude of cube-comer elements 12 that project from a rear side 20 of the body portion 14. The body portion 14 includes a body layer 18 that contains a light-transmissible polymeric material having an elastic modulus less than 7.times.10.sup.8 pascals. The cube-corner elements 12 contain a light transmissible polymeric material having an elastic modulus greater than 16.times.10.sup.8 pascals. A retroreflective article of this construction can be highly flexed while maintaining good retroreflective performance.

Abstract: An optical beam switch is disclosed for sequentially pointing a laser beam to a plurality of terrestrial target locations at predetermined depression angles and at angular positions relative to a reference direction. The switch includes a CW laser whose collimated output beam is directed into a rotating retroreflector. The moving beam reflected therefrom describes a continuous circular path across the upper surface of a beam deflection device. The beam deflection device comprises a plurality of beam refracting prisms. The index of refraction and angulation of each prism determines the depression angle and azimuthal angle of the deflected beam. The depression angle is held precisely constant as the incident beam describes its arcuate path across the upper surface of the prism. The retroreflector may comprise three mutually-perpendicular mirrors, joined at a vertex, for providing a reflected beam parallel to and displaced from the incident beam.

Abstract: The invention relates to a glass for at least one signalling lamp, in particular for a motor vehicle. The glass includes a plurality of non-catadioptric elements that have the appearance of catadioptric needles but without performing the same function. At least a portion of the non-catadioptric elements have conical ends on the inside face of the glass. This makes it much easier to make a mold for mass-producing such a glass.

Abstract: A backlighting system employs a retroreflecting polarizer, comprising optical thin films coated on a structured material, to divide an incident beam of light into polarized components. One component is transmitted through the polarizer and the other is rejected. Optionally, a reflector (for example, a diffuser with a reflective layer) may be used; or, an absorbing polarizer may be added; or, a birefringent material may be included in the system.

Abstract: A runway 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: A photoluminescent retroreflective sheeting for use in structures when a power outage occurs. Guidance systems are made from this sheeting to mark exits and escape routes as well as possible hazards and safety devices. The novel sheeting includes photoluminescent properties that glow in the dark as well as retroreflective properties that retroreflect light incident upon the same sheet such that only one sheet has to be used rather than individual sheets with separate properties.

Abstract: A surveyor's retro-reflective device, such as a corner cube prism, is striped along the reflective surfaces to provide an internal visual center target. The precise center of the prism is identified by the visual target which allows the prism to be used both for distance measuring purposes as well as visual alignment for the one step setting of surveying points or locations. The corner cube prism has the ridges of the intersecting reflective surfaces on the back of the prism striped or lined either with a stripe having equal thickness or tapered towards the center apex of the prism. The stripes are formed with a highly visible paint, ink, tape, or sheet material. This arrangement produces a highly visible visual center target. The prism target can be mounted in an enclosed case and the case can be rigidly mounted or tiltably mounted on a horizontal axis to tilt the prism in a vertical direction for use in mountainous terrain.

Abstract: Article comprising an ultraviolet screening screen layer and a color layer containing a defined daylight fluorescent dye dissolved in a defined polymeric matrix. The article exhibits durable fluorescence and resistance to degradation from exposure to sunlight. If desired, the article is retroreflective.

Abstract: An improved lateral transfer retroreflector assembly is provided, comprising a tubular member having a channel, a mirror member and a roof mirror mounted to a mounting member. The tubular member has first and second ends, the first end having mounted thereat the mirror member, and the second end forming a channel within which the roof mirror is mounted. The roof mirror is adhered to a mounting member along a junction formed in the roof mirror. The shape of the mounting member substantially conforms to the shape of the junction in the roof mirror thereby ensuring a secure, accurate mount. The channel has an upper and lower opening through which the roof mirror extends. The openings created and the manner in which the roof mirror is mounted within the channel ensure that the depth of the tubular member will be minimized.