Abstract: Dual axis retroreflective articles and methods of using them are disclosed. The retroreflective articles may combine dual axis retroreflection with three axis retroreflection to provide a steady glow due to the three axis retroreflective portions of the article and also provide intermittent or flashing retroreflection as the plane of retroreflection from the dual axis retroreflector passes through or near the light source. The retroreflective articles may also include dual axis retroreflective structures in combination with sparkling reflective structures, as well as dual axis retroreflective structures in combination with both three axis retroreflective structures and sparkling reflective structures. Methods of use include moving the dual axis retroreflective structures to obtain intermittent or flashing retroreflection.

Abstract: Retroreflective article that provides effective retroreflective brightness at very high entrance angles as well as low entrance angles.

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: 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 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: 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 retroreflective sheeting material comprising at least one retroreflective optical system (200, 300, 400) consisting of an entrance transmission optical element (201, 301) for receiving and focusing incident electromagnetic radiation from an irradiation source, and a reflective optical element (205, 405) for reflecting the incident electromagnetic radiation back toward the irradiation source; said reflective optical element being positioned in or near the effective focal point of the transmission optical element and the space between the optical elements optionally being constituted by a spacing material (202); wherein at least one of the optical elements (205, 301, 405) is a diffractive optical element, the reflective optical element (205, 405) for substantially all angles of incidence sends at least a part of the incident electromagnetic radiation back along the direction of the incoming chief ray (204), and the reflective optical element does not exclusively consist of a specular mirror type reflective op

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 method for making retroreflective sheeting comprising the steps of placing a light-transmittable protective film on glass beads in a support sheet which consists of a binder layer and a reinforcing layer, and which is provided with retroreflective glass beads embedded in the binder layer, and thermoforming parts of the support sheet under heating and pressure so as to partially bond the binder layer of the support sheet to the protective film, which is characterized in that the reinforcing layer of the support sheet consists of a crosslinkable resin having shearing stress S in the range of 6.times.10.sup.6 -1.2.times.10.sup.7 dyne/cm.sup.2 before the thermoforming. A retroreflective sheeting made by this method has a high uniformity of the joint portions of the support sheet and protective film. Even when this retroreflective sheeting is used outdoors for a long period of time, troubles including peeling-off of the protective film do not substantially occur.

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 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 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: 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 sheeting having a multiplicity of discrete, cube-corner elements cured in situ on a transparent, polymeric overlay film deformed into a three-dimensional structure so that base edges of a plurality of cube-corner elements are non-planar with respect to one another. The retroreflective article preferably has at least one target optical property. The present invention is also directed to a method of deforming the retroreflective sheeting to form a retroreflective article in which the base edges of a plurality of cube-corner elements are non-planar with respect to one another.

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: An imaging system for the generation of an apparent three-dimensional (3-D) image suspended in space for direct vieiwing includes a beamsplitter and a retroreflector. The optical property of reflecting light back along its original path enable the system to generate such an apparent 3-D image based on the perception of depth cues present in the original scene for viewing.

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: A fluorescent yellow article comprising polyolefin copolymer, perylene imide dye N,N'-bis(2,6-di-isopropylphenyl)-3,4:9,10-perylenebis(dicarboximide), and at least one yellow-green dye selected from the group consisting essentially of Lumogen F Yellow 083, CI Solvent Yellow 98, CI Solvent Yellow 160:1, Oraset Yellow 8GF, CI Solvent Green 4, CI Solvent Green 5, CI Pigment Yellow 101 and CI Solvent Yellow 131 wherein the resultant article has chromaticity coordinates (x,y) within the area defined by (0.425,0.480), (0.465,0.535), (0.557,0.440), and (0.500,0.410) in terms of the CIE 1931 Standard Colorimetric System and measured using 0/45 geometry and evaluated with CIE Standard Illuminant D65.

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 cube corner article which is a replica of a directly machined substrate comprises a plurality of single cube corner elements which are machined in the substrate. Each cube corner element is bounded by at least one groove from each of three sets of parallel grooves in the substrate so that the article comprises a plurality of different geometric structures.

Abstract: Retroreflective signage articles comprise a colorant layer directly thermally transferred to a top layer of a reretroreflective sheeting, the top layer devoid of priming treatments and extraneous print-receptive layers. Systems or kits are also described comprising a retroreflective base sheeting in combination with a thermal mass transfer donor element, the donor elements comprising a carrier and a colorant layer adhered thereto, the colorant layer of the signage articles and the donor elements comprising a binder and a colorant. Methods of producing the signage articles employing the systems or kits are also presented.

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: 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: Conformable cube corner retroreflective sheetings comprising a plurality of discrete cube corner segments which are conformably bonded together, each cube corner segment comprising a plastic body portion having a substantially planar front major surface and at least one minutes cube corner retroreflective element projecting rearwardly from the body portion and defining a cube corner point side of the cube corner segment. The peripheries of the cube corner segments can be defined by a plurality of separations extending from the cube corner point sides to the front major surfaces, the separations being disposed between adjacent cube corner segments. Adjacent cube corner segments are conformably bonded together in the sense that they are either: (1) separated by a gap of less than about 1 millimeter and bonded together through a conformable carrier layer; or (2) separated by a gap which is substantially filled with a conformable resin that bonds the side walls of adjacent cube corner segments together.

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: A retroreflective cube corner article which is a replica of a directly machined substrate in which a plurality of geometric structures including cube corner elements are machined in the substrate using only two sets of parallel grooves. At least two of the grooves in at least one of the groove sets are at a different groove depth.

Abstract: Spacers or wedges are disclosed for use in combination with mold elements such as lens and/or reflex reflector pins in a pin block or matrix assembly. Such assemblies are used in the manufacture of molds for producing, for example, front and/or rear light units for motor vehicles. The wedges or spacers are selectively located between rows or banks of reflex or optic pins to provide required orientation to selected groups of the pins so that the necessary reflectivity of the finished product is provided in the curved portion thereof.

Abstract: A method is disclosed for manufacturing a cube corner article comprising the steps of providing a machinable substrate material suitable for forming reflective surfaces, and creating a plurality of geometric structures including cube corner elements in the substrate. The step of creating the cube corner elements comprises directly machining at least three sets of parallel grooves in the substrate so that only one side of at least one groove in at least one groove set forms cube corner element optical surfaces.

Abstract: A method and apparatus for forming "seamless" retroreflective sheeting is described. At least two mold surfaces are used, each having alternate areas of arrays of prism recesses and spaces. In a first step, prisms are formed in one of the mold surfaces and applied to a base film or web. Next, prisms are formed on the second mold surface and applied to the spaced areas left in the first step.

Abstract: A method of manufacturing a cube corner article comprises machining first and second intersecting groove sets in a machinable substrate wherein the grooves in the first set are displaced by a distance d.sub.1 and the grooves in the second set are displaced by a distance d.sub.2. A third groove set comprising a plurality of parallel grooves displaced by a distance d.sub.3 is machined in the substrate, wherein d.sub.3 is different from d.sub.1 and d.sub.2. The machining steps result in a structured surface comprising an array of cube corner elements including at least two non-congruently shaped cube corner elements.

Abstract: A retroreflecting polarizer, comprising optical thin films coated on a structured material, divides an incident beam of light into polarized components, transmitting one component through the polarizer and reflecting the other back to the source.

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 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 method of increasing retroreflective brightness in a retroreflective sheet material. The retroreflective sheet material has a multitude of prism-like reflective elements imbedded in a transparent polymer plastic top film and glued by a grid of adhesive to a backing sheet. The method includes the step of heating the retroreflective sheet material until bubbles form in the transparent polymer plastic top film containing the prism-like reflective elements. The bubbles are confined by the grid. The bubbles serve as miniature magnifying lenses which increase retroreflective brightness and increase the exposure area thereby providing a wider observation angle.

Abstract: A scale comprising a regular arrangement of optically or magnetically different response characteristics such as light reflection and light diffusion portions or light reflection and absorption portions is attached to a moving object either directly or by way of an intermediate member. The scale can be attached to a motor or the like even after assembling with associated mechanical components, thereby enabling easy measurement of the mode of operation of the motor or similar movable objects. The light beam from the light emitting device is directed to the label media and the reflected light beam is received by a light receiving device to identify the individual object or product based on the label.