Abstract: Laminae suitable for use in molds for forming retroreflective cube corner elements and methods for making such laminae are disclosed. A representative lamina includes a first row of cube corner elements disposed in a first orientation and a second row of optically opposing cube corner elements disposed. The working surface of a lamina is provided with a plurality of cube corner elements formed by the optical surfaces defined by three groove sets. Opposing first and second groove sets are formed in the working surface of a lamina. The first groove set forms a plurality of structures having first and second optical surfaces disposed in mutually perpendicular planes that intersect along a reference edge. The second groove set forms a corresponding plurality of structures on the opposite side of the lamina. A third groove is formed in the working surface of the lamina along an axis substantially perpendicular to the axes of the grooves of the first and second groove sets.

Abstract: An illumination device produces a desired illumination pattern by tailoring the configuration of individual light extraction structures. At least two of the light extraction structures have different configurations from one another. The illumination device includes a light guide having a light guide core and an optically smooth surface for propagating light through the core. A light emitting region extends along a portion of the core and includes a plurality of light extraction structures distributed along the optically smooth surface. The light extraction structures are configured so that light reflected therefrom is emitted from the light guide through the optically smooth surface.

Abstract: Simplified continuous processes are disclosed for converting standard woven or nonwoven fabric into reflectorized fabric in a continuous fashion and in bulk quantities. These processes are easily capable of achieving reflectivities of well over 100 cd/(lux·m2). In the processes, an extended length of fabric is provided such as by unwinding an input roll of fabric to be reflectorized, and the fabric is passed through a station that applies a coating of binder material to the fabric. The fabric then passes through a station where aluminum-coated beads are applied to the coating of binder material. An etching station removes exposed portions of the aluminum coating from the beads after the binder material is allowed to substantially solidify. End-use materials other than fabrics but suitable for enhancing personal conspicuity can be reflectorized in the same way.

Abstract: Laminae suitable for use in molds for forming retroreflective cube corner elements and methods for making such laminae are disclosed. A representative lamina includes a first row of cube corner elements disposed in a first orientation and a second row of optically opposing cube corner elements disposed. The working surface of a lamina is provided with a plurality of cube corner elements formed by the optical surfaces defined by three groove sets. Opposing first and second groove sets are formed in the working surface of a lamina. The first groove set forms a plurality of structures having first and second optical surfaces disposed in mutually perpendicular planes that intersect along a reference edge. The second groove set forms a corresponding plurality of structures on the opposite side of the lamina. A third groove is formed in the working surface of the lamina along an axis substantially perpendicular to the axes of the grooves of the first and second groove sets.

Abstract: A method of forming a stacked laminate mold.

Abstract: A method is disclosed for manufacturing a plurality of laminae for use in a mold suitable for use in forming retroreflective cube corner articles. Each lamina has opposing first and second major surfaces defining therebetween a first reference plane. Each lamina further includes a working surface connecting the first and second major surfaces. The working surface defines a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane.

Abstract: A cube corner article having a structured surface of geometric structures, each geometric structure having a plurality of faces at least some of which are arranged as a cube corner element, is made by providing a first substrate having a plurality of grooves therein, replicating the first substrate in a second substrate, and forming a second plurality of grooves in the second substrate. Geometric structures in the second substrate are formed in part by replication of the first plurality of grooves and in part by the information of the second plurality of grooves.

Abstract: Laminae suitable for use in molds for forming retroreflective cube corner elements and methods for making such laminae are disclosed. A representative lamina includes a first row of cube corner elements disposed in a first orientation and a second row of optically opposing cube corner elements disposed. The working surface of a lamina is provided with a plurality of cube corner elements formed by the optical surfaces defined by three groove sets. Opposing first and second groove sets are formed in the working surface of a lamina. The first groove set forms a plurality of structures having first and second optical surfaces disposed in mutually perpendicular planes that intersect along a reference edge. The second groove set forms a corresponding plurality of structures on the opposite side of the lamina. A third groove is formed in the working surface of the lamina along an axis substantially perpendicular to the axes of the grooves of the first and second groove sets.

Abstract: A method is disclosed for manufacturing a plurality of laminae for use in a mold suitable for use in forming retroreflective cube corner articles. Each lamina has opposing first and second major surfaces defining therebetween a first reference plane. Each lamina further includes a working surface connecting the first and second major surfaces. The working surface defines a second reference plane substantially parallel to the working surface and perpendicular to the first reference plane and a third reference plane perpendicular to the first reference plane and the second reference plane. The method includes orienting a plurality of laminae to have their respective first reference planes parallel to each other and disposed at a first angle relative to a fixed reference axis. At least two groove sets are formed in the working surface. Each groove set includes at least two parallel adjacent V-shaped grooves in the working surface of the laminae.

Abstract: A retroreflective cube corner article is manufactured by providing a substrate having a surface that includes cube corner elements formed therein, and removing at least a portion of one of the lateral faces on at least one of the cube corner elements, wherein the height of a peak on such cube corner element is reduced. Manufacture of the article can also include forming a replica of the surface of the substrate.

Abstract: Various combinations of retroreflective sheeting and multilayer polymeric reflective films are disclosed. The reflective film includes alternating layers of at least a first and second polymer, the alternating layers being configured to exhibit a high reflectance for light within a first spectral range and a low reflectance for light within a second spectral range. At least two of the alternating layers can have out-of-plane indices of refraction which differ by no more than 50% of the maximum in-plane refractive index difference. The polymeric layers can define optical repeating units arranged in a sequence to have a specific thickness profile designed to give sharpened spectral transitions. The retroreflective layer preferably exhibits retroreflectance in all planes of incidence, but alternately it can be retroreflective in at least one plane of incidence but not in at least one other plane of incidence.

Abstract: Cube corner articles are disclosed in which a substrate has a base surface and a structured surface opposite the base surface. The structured surface has a first and second zone of cube corner elements bordered by grooves, and one of these zones is raised relative to the other one. In one aspect, the raised zone has groove bottoms that are at least as high relative to the base surface as tops of cube corner elements in the other zone. In another aspect, tops of cube corner elements in the raised zone are higher than tops of cube corner elements in the other zone.

Abstract: Laminae suitable for use in a mold suitable for use in forming retroreflective sheeting and methods of making such laminae are disclosed. A representative lamina includes a single row of optically opposing cube corner elements disposed on its working surface. The working surface of a lamina is provided with a plurality of cube corner elements formed by the optical surfaces defined by three groove sets. Corresponding surfaces of opposing groove sets intersect substantially orthogonally along a reference edge to define first and second optical surfaces of the respective cube corner elements. The third optical surface of each respective cube corner element is defined by one surface of the third groove set.

Abstract: A reflective article has a structured surface which includes a first and second array of reflective elements. The first array includes elements which have at least a first, second, and third reflecting face arranged to retroreflect incident light in a retroreflected beam. The second array includes elements which have at least a fourth, fifth, and sixth reflecting face arranged to reflect incident light in a second beam at an observation angle greater than 2 degrees. In signing applications, the second beam can be light originating from a stationary light source, the second beam having a direction and beam width suitable for illuminating an observation zone of interest. The retroreflected beam can be light originating from a moving light source such as a vehicle headlamp. Sheeting comprising such an article can be used both where external lighting from a suitable stationary light source is available and where it is not available.

Abstract: Laminae suitable for use in a mold suitable for use in forming retroreflective sheeting and methods of making such laminae are disclosed. A representative lamina includes a single row of geometric structures disposed on the working surface. Each geometric structure includes three faces arranged as a cube corner element and at least one additional face. A set of parallel grooves is included, each groove having one of the three faces of one geometric structure and the at least one additional face of an adjacent geometric structure as groove side surfaces.

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 retroreflective applique (10) includes a supporting structure (12), a layer of optical lens elements (14), and a reflective material (16). The layer of optical lens elements (14) is partially embedded in the supporting structure (12), and the reflective material (16) is disposed on the embedded portion of the layer of optical lens elements (14). The supporting structure (12) may contain a binder layer (24) and a heat-activatable adhesive layer (26). The binder layer (24) includes a non-filamentary acrylic polymer layer. The use of such a supporting structure (12) eliminates the need for a release liner on the rear surface (20) of the heat-activatable adhesive layer (26), and it also enables a carrier web (28) to be separated from the polymeric supporting structure (12) before the applique (16) is permanently secured to a substrate. The separation step can be accomplished without causing substantial harm to the retroreflective performance of the applique (10).

Abstract: An imaging element is disposed on a front surface of a retroreflective sheeting to form an image-displaying sheeting. The imaging element includes a light-transmitting prismatic sheeting that has a surface provided with a plurality of parallel prisms. The imaging element also includes an adhesive layer that adheres the prismatic sheeting to the front surface of the retroreflective sheeting. At least a portion of the imaging element is shaped in the form of indicia. In some cases the prismatic sheeting itself is shaped in the form of indicia. In other cases the imaging element includes a light-transmitting colored layer disposed on the front surface of the retroreflective sheeting and shaped in the form of indicia. In the latter case, the prismatic sheeting can be shaped as before to match the indicia-shaped colored layer, or it can extend continuously across the entire retroreflective sheeting.

Abstract: A reflective article has a multilayer film covering a patterned retroreflective layer. In one embodiment the patterned retroreflective layer includes a separate indicia layer covering a retroreflective substrate. The indicia are substantially hidden under normal viewing conditions but easily detectable under retroreflective lighting conditions. Various types of retroreflective layers are disclosed. The article can also include microstructured relief patterns which produce holographic images under ambient lighting but which disappear under retroreflective conditions. The multilayer film includes alternating layers of at least a first and second polymer, and has a relatively high reflectivity for normally incident light within a first spectral range which is approximately coextensive with the visible spectrum, and a relatively low reflectance for normally incident light within a second spectral range.

Abstract: A master mold suitable for use in the manufacture of retroreflective sheeting is disclosed. The master mold comprises an array of cube corner elements formed by two intersecting groove sets. The cube comer elements comprise a tetragonal base, three tetragonal optical faces that mutually intersect at a point to define a cube corner apex, and two non-optical faces. Also disclosed is a method for making a master mold suitable in the manufacture of retroreflective sheeting is disclosed. A first groove set including a plurality of parallel grooves is formed in the working surface of a suitable substrate. Each groove in the first groove set forms a first optical surface and a second non-optical surface. Adjacent grooves in the first groove set are separated by a distance sufficient to define therebetween a structure defined by a first optical surface on one side, a top surface, and a first non-optical surface opposite the first optical surface.