Abstract: A retroreflective article 10 has a body portion 14 and a multitude of cube-corner 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: Luminous retroreflective sheetings have a transparent cover layer, an optical layer disposed beneath the cover layer, and a reflective layer. The optical layer includes a first polymer layer and a monolayer of beads at least partially embedded therein. The reflective layer is disposed proximate a focal plane of the monolayer of beads. The monolayer of beads includes transparent beads that, in combination with the reflective layer, retroreflect incident light. The monolayer also includes light-emitting beads that emit light under the influence of an applied voltage or ultraviolet (UV) radiation. Processes for making such sheetings are also disclosed.

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 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 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 reflective article has a structured surface which includes geometric structures each having at least three specularly reflecting faces which converge at an apex or other extremity. The article is marked with a plurality of spots located between the extremities, the spots having different reflectivity characteristics than the specularly reflecting faces. The geometric structures can comprise cube corner elements. The spots can be diffusely reflecting and distributed uniformly on the structured surface or distributed to define a particular pattern. The article can have a plurality of first active areas at a first illumination geometry, and the spots can be sized and positioned such that they avoid the first active areas. The article can have first inactive areas adjacent the first active areas, and each spot can cover a majority of one inactive area.

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: 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 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: 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 retroreflective sheeting includes a first array of cube corner element opposing pairs and a second array of cube corner element opposing pairs. The symmetry axes of the cube corner elements in the first and second arrays are tilted in a backward direction at an angle of about 12.degree. to about 30.degree. from an axis normal to a base surface. The second array of cube corner elements is oriented approximately perpendicular to the first array to yield a retroreflective article providing generally uniform total light return about a 360.degree. range of orientation angles and/or a minimum total light return of about 5% across such 360.degree. range. Also disclosed is a mold assembly suitable for use in forming the present retroreflective sheeting and a method of making a retroreflective article using the mold.

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: 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 light directing film including a first surface and a second structured surface. The structured surface includes a repeating pattern of prism zones including at least a first zone having a plurality of prism elements with peaks disposed at a first distance from a reference plane and a second zone having a plurality of prism elements with peaks disposed less than the first distance from a reference plane. The width of the first zone preferably measures less than about 300 microns.

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: A cube corner article and method of manufacturing the article from a series of unitary substrates. A plurality of pins are assembled to form a mold having an array of cube corner elements on a surface. Then, a replica of the cube corner element array is produced in a substrate suitable for forming retroreflective surfaces. Portions of the replica substrate material are removed. The removal of these portions forms at least one cavity bounded by side walls in the replica at a depth at least that of the cube cube corner elements. The replica is replicated to produce an additional directly machinable substrate suitable for forming retroreflective surfaces having at least one raised section having sidewalls at a height at least that of the cube corner elements. At least one raised section is directly machined to form an array of cube corner elements.

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: 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.